A200 A300 A400 A500 A600 Gassing Charging Shipping HazMat MSDS1 HazMat MSDS2 Prevailer/Gel-Tech AGM types

  MG Battery is an independent Florida battery distributor supporting Sonnenschein Gelled 
Battery Technology since 1987.

The following is a small sampling of our technical mail.

  They range from Nuclear power stations, cruising yachts, passenger submarines and schoolchildren engaged in projects. No names or e'mail addresses will be posted but Specific items of general interest will be. The following bookmarks will link you to the relevant paragraphs dealing with.....
#ABYC Section 10.7.2.  #ABYC recommendation 10.7.3  #1nverter #types of gels batteries #Battery Capacity #Hydration  
RoHS(and WEEE)compliance pdf 
 #Sulphation  #safe to use on their side  # Permissable Pressure  #Non Sonnenschein gel products
  #Usable Battery Capacity
Case flexing 
  Most asked question?   Boating safety circular # 78  and  # 80

 Here is an excellent site for an Electrochemistry Dictionary. http://electrochem.cwru.edu/ed/dict.htm#c14 
and a special tip of the hat to William Darden 

Now please.. before you plaster poor old Bruce to the wall with e'mailed questions
 of great technical complexity,  read this... GelHandbookPart2.pdf


Correct wiring for a Series/Parallel battery bank or set.
 (ventilate batteries well, and Always leave air gaps between the batteries to assist in cooling them.) 


  Copy of 6vSets.gif (32451 bytes)

 Basic and very important formulas.

Current = Voltage/Resistance
Power = Current Squared X Resistance
Power = Voltage X Current
Power = Voltage Squared / Resistance
Voltage = Power/Current
Voltage = Current X Resistance
Resistance (ohms) = Voltage/Current
1 horsepower = 746 watts
1 horsepower = 42.4 BTU/min.

Horsepower times 746, divided by the voltage, will give you amperage.

Do the three 'Power' types above, or Three phase calculations baffle you?

If you have to ask, you_ should_not_ be_ doing_ it.
Call a trained Qualified Electrician. PLEASE! 

Wire size versus Distance and Current.(for 12v Circuits)

                                        Amps   |                   Distance In feet

  10' 15' 20' 25' 30' 40' 50'
5 18 16 14 12 12 10 10
10 14 12 10 10 10 8 6
15 12 10 10 8 8 6 6
20 10 10 8 6 6 6 4
25 10 8 6 6 6 4 4
30 10 8 6 6 4 4 2
40 8 6 6 4 4 2 2
50 6 6 4 4 2 2 1
60 6 4 4 2 2 1 0
70 6 4 2 2 1 0 2/0
80 6 4 2 2 1 0 3/0
90 4 2 2 1 0 2/0 3/0
100 4 2 2 1 0 2/0 3/0
120 4 2 1 0 2/0 3/0 4/0
140 2 2 0 2/0 2/0 4/0 4/0
160 2 1 0 2/0 3/0 4/0 4/0+4
180 2 1 2/0 3/0 3/0 4/0+10 4/0+2
200 2 0 2/0 3/0 4/0 4/0+4 4/0+0


 ref:-The batteries I have are A500 (A512/25 G5)..running a small shuttle....inside a -20'C freezer... 10 mo. old ...... however cycle count is about 300 cycles...Chargers have a two hour timer that must elapse before the charge ...The charger shuts off after only about
\ two hours..... 28.3v"<<<. 

 They are definitely not being fully recharged so please check your charging device.
If you use a good constant voltage charger -- then 28.8v Vmax with a current  Maximum of 10 Amps please (0.4A/Ah)  might be worth experimenting with.
When the amperage drops to less than  1 Amp then simply switch the charger  off for the capacity test below.  
( Preferably use a temperature controlled 3 step charger set for Gel battery type..)

 Ref; We're contemplating new batteries for our cruising sailboat/home, and almost everything we've read seems to indicate that AGM batteries
 are superior to other types.  But then we came to the comments and charts on 
http://www.sonnenschein.org/AGM's.htm.  We're planning to be in the tropics for the next year or two, so high temperatures are definitely an issue for us

         That is twice in three years we've been asked about that - so we will expand and qualify the website a mite.

 1/ High ambient heat may be of concern in the high temperature area of an engine room where radiated engine heat could be an issue  - but if the batteries are located elsewhere , in a ventilated bilge etc and you have good voltage regulated equipment -  then relax on the ambient Temperature of the tropics.

    We have many thousands of marine AGM battery systems working nicely in such environments.
Proper voltage regulation of charge devices and battery ventilation - which is necessary for cooling to avoid any heat buildup,  are key to battery performance and safety.


     What kind of degradation of total capacity can we expect? 

       None.  While Heat will generally shorten the life cycles (or longevity) of batteries, you will actually notice a slight Apparent-Capacity increase in warmer environments and a decrease in the Apparent- capacity in colder environments.
      This is related to internal resistance which decreases with (internal heat) temperature of any given battery unit.
See below for more detail.

What are 'minimum' and 'maximum voltage (cycle)'? 
 There are  two great charts at the bottom of the referenced page, but unfortunately we  have no idea what they indicate. 

 2/ Cycling is for daily usage with the battery being charged/discharged daily, or more frequently - while the lower voltage setting are to maintain full battery capacity in 'standby' work or very occasional use.

    Generally cruising Yachts are in the 'Cycling' voltage range.

     As shown, both voltage levels are also influenced by Temperature.
 Standard factory Charging  voltages are generally based on a temperature of 68-72F and most of the good marine
 voltage regulation devices use that as a base figure for their voltage settings.

      You must always follow the Battery Manufacturers specific advice and graphs,  though generally Lead Acid Battery Manufacturers  recommend a  +/- 0.1v change from their 'normal' recharging voltage for every +/- 10F increase/ decrease from that stated 68-72F. (It varies with the Battery Manufacturer and product type , so be sure to check.)

To explain the  charts you mention - As the Battery Temperature_Drops the voltage required to recharge, increases -
and as the Battery Temp_Rises, less voltage is required , (a factor of internal resistance of the battery.)

     If you have well regulated recharging devices, or you have a automatic Temp Comp regulation, fine  -  but as a practical day to day  matter given the  usual number of wiring flaws,  minor corrosion, loose connections and even the amount of ships load (discharge) variables while recharging on board the average cruising yacht,  we rarely advise a manual voltage change outside of a rough 50F to 86F range.
The second chart simply shows the decrease in available capacity as the Temperature drops.
 Graphed out it's approx; a 5% capacity drop per 10F fall in internal Temperature.

   Unless charging is already  automated as noted above, or the vessel is based in Alaska (or colder) for a good few months and then the Panama Canal, its barely worth the manual adjustment from the standard factory approved settings for a few percent of battery efficiency/capacity.  (If you are sense that we prefer automated Temp;Comp;Charge devices,to human adjustments, then  you are quite correct.)

 And what are 1XI20, 4XI20, and 20XI20?  

3/ The I.20 is the current or load (I) you can consistently withdraw for 20 hours from a given battery - to achieve
it's full withdrawable, or usable capacity rating at 68-72F.

 e.g  At 68- 72F a new, 200Ah fully charged battery unit will supply 10A for 20 hours before the voltage reaches unusable levels and need to be fully recharged
 Now the more current (amps) or (bigger load - I) you withdraw the less 'apparent' capacity a given battery has.
 For new fully charged batteries heres a rough rule of thumb Conversion from 20 hour rate to any given I. hr rate..
...for 'apparent' or 'usable' capacity at higher rates of discharge..

 200/1 = 200 A load ..or I1
 200/2 =100 A load ...or I2
 200/3 = 66.66 A load....I3 etc

 which graphs out roughly to an hourly rating for our 200Ah battery example..

 1- .57% of the 20 hour rated capacity. (114Ah usable capacity )
 2- .67%  (134Ah usable capacity)
 3- .74
 4- .77
 5- .82 (164Ah etc;)
 6- .84
 7- .86
 8- .87
 9- .89
 10- .91 (182Ah etc.)
 20 - 100% (200Ah etc.)

Our second question is about charging.  We have a mature
 Heart Link 200-R interface/regulator on a 100+ Amp alternator.  The
 regulator has settings for gel and liquid lead-acid batteries, but not for AGM.
 Can we simply use the liquid=battery settings for AGM batteries?

4/  Second question? Har  Har!  As to your Heart 200R settings? - H'mm. I simply don't know; Just check the manual and use whichever voltage setting (Gel/Wet) is closest to the Battery type voltage requirements that you install and to be really sure - just monitor the Voltage delivered AT THE BATTERY TERMINALS while recharging, and if suitable, then observe  the performance for a bit - but Please replace with a properly regulated unit if necessary.

Happy Holidays!
Bruce. The Helpful.


Ref:-"Define float voltage" I don't understand the two... <graph>...lines. Please educate me.
Float voltage (lower graph line) is a voltage generally set just below the batteries gassing voltage - which the charging device should switch to after a complete charge cycle to help maintain battery capacity at a full 100%. It is used mainly  in standby situations like UPS or backup applications and is normally between 2.2v and 2.3v per cell but depends on the temperature***   and the application.
On some battery technologies it is very necessary for capacity maintenance as losses from self discharge can be up to 13% per month .
 However as Sonnenschein Gel cells such as the A500 series you use have only very minor self discharge losses - float charging is rarely required for most applications.  A charger which totally switches off after recharge and has a low cut in voltage, is my preference.   
ref;- "No load voltage".
That is a voltage measurement of a new, rested battery, neither charged nor discharged,  taken after at least 6, but preferably after 18 hours of rest , to  give a very rough  indication of  capacity remaining.  (A google search for Peukerts Constant will give you all you can possibly handle on the theory.)
For a 24v bank at 68-72F*** a rested voltage reading of-
24.0 v or lower -100% Discharged.
24.4v - 25% capacity remaining
24.8v..- 50%
25.6v and higher -100% indicates fully charged.
ref:-What load test do you recommend? What currents and at what discharge?
To load test a fully charged A512/25G battery for available capacity;-@ 68F -72F*** 
Ideally apply a load TO A SINGLE 12v BATTERY of 2.2 Amps for 10 hours or until the voltage drops to 10.2v (1.7V PER CELL) 

For faster results, again only after a full charge at 14.4 Vmax, merely connect each battery separately**

to a 12 volt load  of  21 Amps (253 watts) or so and set a timer.
When new, each should handle that  load for 30 minutes without the voltage dropping below 10.2 volts.
Either  simple test will show what % usable capacity remains after all those cycles  -. 
** This verifies also that each 12v battery unit has the same capacity....  
*** Batteries lose approx  3-5% of their usable capacity per each 10F below 68F in case you're curious. 
I hope this is of assistance.
Regards, MG/ Lauderdale Battery - 14th May 2002

Case Flexing - Sonnenschein Batteries.

This flexing of the casing walls generally indicates normal functioning of the battery.

It is the process of internal recombination of the hydrogen and oxygen back into water 
which gives the very low gassing feature of the cells; This makes unnecessary, the
 "topping up" with water which conventional batteries require.

The process is achieved by the use of a pressure valve in each cell which completely seals
against contamination of the cells by external air etc.

The valves act as safety devices against high internal pressure development but allow a
max. working pressure of approximately 0.1 bar to develop within the cells, as internal
gasses recombine.

This slight pressure can cause a slight bulging of the certain battery casing walls.

Conversely, during deep discharge or when the battery is not in use, slight self discharge
and chemical reaction inside the cells can result in a negative pressure - since the valves
will not allow pressure to equalise from outside. This often results in a normal "sucking in"
 or contraction of the casing walls . 

Hi ,

> may be you have an answer to my question below. Most manufacturers recommend to charge their Gel or AGM batteries with  currents not to exceed C5 i.e. 20 Amps for a 100 Ah battery.

> However there have been investigations showing that high initial charge  currents will prolong the life of lead acid batteries.  Up till now I thought this is true for flooded as well as for VRLA type  of batteries (including Gel cells).

> When I tried to explain this fact in a German newsgroup I was critisised (sic) by an expert who said that this is not true for Gel batteries.... which says, that fast charging is the leading cause of GEl Cell failure,
> whereas ******* AGM batteries are not affected by fast charging.
> On the other hand a military handbook from Sonnenschein says that slow charge rate is no good for all batteries including their Gel  Cells. They recommend to use the maximum (allowable) charge voltage of
> 14,4 Volts in order to get high charge currents for maximum number of  charge/discharge cycles.

> Can you clarify this conflict?
> Thanks for your help!

Hello again, Hans.

That unit  you mention is a privately label AGM product and is independently 'promoted' 

Ref;>>>Most manufacturers recommend to charge their Gel or AGM batteries with
currents not to exceed C/5 i.e. 20 Amps for a 100 Ah battery, 
Ref; ...

Hans, I will offer no opinion on charging other manufacturers AGM/Gel product as I would muddy even
further their conflicting claims.

Dryfit Gels; Using a Constant Voltage device there is no current limit on the dryfit.gel. They are self-limiting on current. If using a Constant Current device there is a current limit for each dryfit type .The  charge rate depends on the Temp;, size of the battery bank and the dryfit series (Flat Plate or Tubular etc)
It is our experience that the combination of both charging techniques - with Temp Comp V. - that have the most beneficial recharge rates and empirically, maximum life cycles (CAVEAT; I  personally find it a stretch to equate high initial current charging techniques to 'product longevity'  when there so many, many more
Variables such as AC fluctuations to the charging device , AC Ripple, Vibration, Heat, Depth of Discharge, Sitting time of partial discharge, cabling, corrosion etc etc.to take into account... )

Ref:>>>>a military handbook from Sonnenschein  says that slow charge rate is no good for all batteries including their Gel  Cells. They recommend to use the maximum (allowable) charge voltage of 14,4 Volts in order to get high charge currents for maximum number of  charge/discharge cycles.<<<<

That is quite correct in our experience, at a temperature around 68F.

MG/Lauderdale Battery. 07/18/ 01.

 I was wondering if there is anything that can be done to restore  18 electric car. batteries
 listed below.  (Sonnenschein DF6-180 6V batteries.)  They are currently running down and give a much
 more limited range than original.  Is there some procedure that can be
 employed to rejuvenate them?  Also, If you have any spec's on the
 replacement batteries please let me know.



Hello again Rob,

           'Battery rejuvenation' is  a strong term. Lets just aim for capacity remaining vs designed capacity
So,  let's establish some  data on your DF6v180's .
Marked on the battery case top should be either - 4 (small) numbers OR 4 letters.
If there are numbers the first two are the production week; second set are the production year.
If letters ? then e'mail me and I'll  check them.
Now-That gives us the product age.
What is the banks nominal voltage design? 108v?
Is there any signs of physical damage to the batteries?
Are there any signs of cable corrosion?
Are the battery bank cables of consistent size, type and torqued alike ? 
Do the existing units still function?
For how long under what approx load?
What type of recharging device? Is it capable of -and set for - a max  of 2.35 to 2.4v per cell?
Does it have an automatic shutoff at a predetermined Voltage level?
Is it a constant voltage type? Three step regulated type?
How many amps is the charge device capable of ?
When completing a full recharge, after a discharge, what is the measured upper voltage limit on the charger?
Generally this can be measured when the charger output is less than 10%  of its current rating.
Has the charger been checked for AC ripple when in the charging mode?
Charger off.
Battery power to car off. (Main safety disconnect?) then
allow the batteries to rest overnight neither charging nor discharging.
With all rings, jewelry and watches removed of course and
Using a good - preferably Fluke 77 series or up - digital voltmeter
read and record the bank voltage at the primary Pos and Neg of the bank - then ditto for the 
 voltage of each battery at its own pos/neg posts. No need to disconnect any cables yet.
Then -- Send me that information.
MG/Lauderdale Battery 04/03/02

Sent: Friday, March 22, 2002 8:40 AM
Subject: batteries for subsea bouys

Whar are your recommandations for the application of rechargable batteries
used in susea bouys.

Our specific application requires ca 75Ah battery capacity at 12VDC.  Idelly
we would like a soultion where no ventilation is necessary when th ebouy is
recovered for recharging.


Hello Svein.

Our basic Caveat.... The production of Hydrogen gas is not
the sole reason for a chance of an explosion. There is a much greater need
for a spark. The greatest danger of generating a detonating spark, arises
from improperly secured battery terminal clamps, and from inflexible battery
cables which come loose from the battery and so cause an electric spark.
Batteries must be secured against motion,and the cables supported properly.
Use of solid bar connectors in any motive or mobile battery application is
prohibited. Well supported, good quality flexible cable or wire of suitable
size will help absorb any minor motion or vibration and remove strain from
the terminal connections where a spark is most likely to occur. NEVER use or
mount any spark producing device in the battery chamber or box.

So in summary,

Elimination of any spark producing devices within the chamber.
Securing all wire connections with 'Nylok' or anti-vibration locknuts.
Battery units must be securely attached from motion within the chamber.
Wire chafing opportunities must be engineered out of the design.

That done we use the following.
Any 12volt Sonnenschein Gel of adequate amperage will do
1/Suitably prepared for sealed use by pre-cycling the product as noted
2/ recharged at a controlled maximum voltage using a well regulated device.
3/Addition of catalytic stones within the chamber.

1/ Preparation.
Batteries generally are delivered 85% formed from the factory. They should
be cycled (discharged /charged) approx; 10 cycles which brings them to up to
100% capacity - prior to installation and use. Discharge using a 20Amp load
until 10.2 volts is reached -then recharge fully using a good constant
potential charger @ 2.4v/Cell (14.4v max @ ambient temp; of 68 F ). This
cyclic preparation minimises any gassing. See
http://sonnenschein.org/Gassing.htm. which notes that a

".. 30 V 130ah set..19 hours recharging at a constant charging voltage of
2.37 V/cell....... During the charging operation the following amounts of
gas escape from the complete battery assembly:
New battery assembly: 10 liters
After 10 charge-discharge cycles: 4 liters
After 150 charge-discharge cycles: 1 liters"

2/ When recharging while in use in a sealed chamber. Max voltage is 2.3v per
cell @ 68F. A recharging voltage variation of +/- 1/10v per cell - opposite
to temperature rise or fall - per 20F change in ambient temperature is
recommended .(eg. 48F = 2.4v/cel l ~ 28F = 2.5v/cell. ~ 88F and up =

3/ Within the Battery chamber and preferably at the highest point attach a
couple of Catalysing stones. (Approx $8 US each) Platinum ore based they
combine loosed or purged H and O gases back into water with a minor amount
of exothermic heat generated - linear to the gas volume.. These can be dried
in a small oven and reused if necessary.

I have forwarded a copy to the factory and the technical Dept is available
for further inquiry.
I hope this is of assistance.

MG/Lauderdale Battery

My name is Molly and I am doing a reprot (sic) on gell cell batteries. I was
wondering what you might be able to tell me. The price ranges, Washington
USA. And the main component if possible. If you could get this info. to me
soon that would be great.
Thank you

MG reply;  Hello Molly.

That's a fair sized project! Hope you like reading!

This pdf  is Part 2  and is very relevant.
For some bizarre reason your ISP ( aol ) blocks our response, so I will post it on this site.                           

The only Gelled Electrolyte Types we endorse or support are the patented, origonal Sonnenschein dryfit ,German types and those made under license by Deka (Gel Tech) in the USA.

These Sealed Valve Regulated Lead-Acid batteries are constructed of low gassing, Lead Calcium Grid plates whose design corresponds to a standard 'wet 
battery' and can be subjected to relatively high currents for starting purposes - but having special metals, acid chemistry,and highly specialised 'separators', they exhibit superior charge/discharge, deep cycling abilities.- (Metal content: Lead +calcium + tin.)
The Sonnenschein dryfit / Deka Gels use two acids, Sulfuric and Phosphoric, which never mix and elegantly work in opposition, hence the electrolyte remains conductive at all states of charge. This makes this battery technology very easy to recharge from any voltage level with minimum resistance - and of course removes the need for Ph checks of the acid electrolyte. (Electrolye; Thixotropic Gelled Sulphuric and +/- 2% Phosphoric for approx 35.8% of weight. ( dryfit series. )
This well engineered combination of metals and chemistry ensure also, a battery of very low internal resistance which allows the battery to be recharged very safely and efficiently.

These liquid acids are then 'gelled' with a silicic acid additive- and thus immobilised, allowing the battery to be used in any position even upside down on occasion. Tiny capilllary channels in the Gel, trap any freed gases (Hydrogen from the negative plate and Oxygen from the positive), recombining them back into water for the electrolyte-hence the battery needs no maintenance nor addition of water in its entire service life. A safety chacteristic of the Gel is that it will not leak even from  a cracked case and is rated safe for Air transport fully charged (A boon to travellers with electric wheelchairs,medical devices and worldwide warranty etc)

MG Battery Comments on Recommendation ABYC Section 10.7.2. ‘..provision shall be made to contain leaking and spillage of electrolyte….’ and ABYC
recommendation 10.7.3
‘fasteners isolated from acid catching trays..’
There is no free liquid electrolyte contained within the product. (Gelled ) It is rated non-dangerous goods and cannot flow from a
ruptured or cracked case upright OR inverted while at a temperature up to 55C.

This implies total Acid containment under ABYC, USCG and other rules including Nippon Kaijii Kyokai,Japan).
The product has passed all applicable tests for Non-Leakage FROM A CRACKED CASE tests including Vibration, Heat, Vacuum , Liquid Nitrogen freezing and shatter test. (Carnegie Mellon Institute, 1989 for IATA, IMDG (C8,Un # 2800) DGR (A67) and are considered non dangerous goods and marked non-spillable. However the positive posts MUST be covered by a non conductive rubber or plastic boot to avoid any danger of an accidental short cicuit.
CAVEAT. The above opinion applies SOLEY to the patented and tested Sonnenschein gelled Electrolyte process manufactured by Sonnenschein and those
manufactured under license By DEKA in the USA .The stated opinions in no manner implies endorsement or exemption from any safety measure, or
recommendation by any marine authority or advisory society, to ANY other gelled electrolyte battery product, whether manufactured or distributed by Keystone, Johnson-Controls, C&D, Dynasty ,Yuasa, Trojan or Exide. For the purposes of this discussion ALL Non-Sonnenschein gel products, are to be treated in ALL respects as wet or flooded products and full compliance with relevant advisories for wet batteries is strongly advised.

Each cell has a special one way sealing valve (Bunsen vent type) designed to safely vent, if necessary, at a predetermined pressure,(atmosphere + 2-3 PSI approx) and seals the battery under a slightly positive pressure to assist internal gas - recombination and stop the penetration of Oxygen from the air (which is poisonous to the plates).This internal recombining of gases is a marked safety feature as opposed to releasing the explosive gases into the surrounding enviroment.

Thus built and sealed, the dryfit product can withstand a wide pressure range.

Any Exothermic heat generated from the recombining of gases is absorbed and transferred by the Gel to the plastic Battery case.where it is dissapated to the air in a way similiar to the very good heat dissapation characteristics of wet or flooded batteries in this regard- and far superior to the AGM' (Absorbent Glass Mat)  products.  With very low Internal  Resistance by efficient design, heat from overcharging is minimised.(Battery heat is generally not_a_good_thing.)
Any battery 'self discharges' in storage and can lose 50% of their capacity in a few months and generally must be trickle charged  and occassionally 'equalised'(high voltage induced vigourous gassing) to replace these losses and to retard Plate Sulphation and acid stratification - however, gels have a unique shelf life of 18 months with only 13% self-discharge- NATO Field Storage Testing - making them a strategic battery of great value  where unattended use or storage is necessary (eg Tactical vehicles,Remote solar applications, Avalanche Sensors, Deep sea Buoys etc) so do not require trickle charging nor an 'equalising' charge.

So, the easily transportable, user friendly Sonnenschein dryfit/ Deka gel-techs are a very safe, sealed, zero maintenance, easily recharged, high performance deep cycling battery which cost about 1/3 more than a top quality deep cycle wet battery, but which last up to three time longer in cycling ability through advanced design.

I hope this is of assistance! Good luck with your research and please let us know how your report goes!


MG/ Lauderdale Battery. 02/05/01

> Dear Supplier
> I am a ROHS investigator here at ** Safety Products. [..] 
> Name of the device -
> Part number 2081-9279 BATTERY 110AH
> A212/110A
> 2081-9279 BATTERY 110AH
> A512/110A

> I would like to know 

> 1) Whether the device is ROHS compliant.
> 2) If the device is not ROHS compliant the equivalent ROHS compliant part
> number 3) Availability
> Kindly reply me with the above information.[..]  
> Best Regards:
> Nalin - B. Eng
> ROHS Investigator 


Attached please find the supporting document in .pdf format containing the following

>both WEEE and RoHS do not apply to Batteries (quotation
> from both Directives below). The relevant requirements for our Products
> are described in the Battery Directive (91/157/EEC) and the national
> adoption of the Battery Directive. In the attached pdf-file, you'll find a communication developed with
> Martin Sinz on this item.
> Please be aware of the following (there were some severe misunderstandings
> in Europe):

> * RoHS bans several brominated flame retardants,
> * Battery Directive does not consider flame retardants,
> * This does not mean that, we are allowed to use those flame
> retardants. In addition they are banned in general chemical legislation

> So our answer should be:
> * our products are not subject to WEEE / RoHS
> * our products are regulated by the Battery Directive * we comply to the requirements defined in the Battery
> Directive
> I hope this is of help.  

MG/Lauderdale Battery
954 525 5557 



Great web site, very helpful and entertaining! I have an application that I would like some advice on, if you don't mind?

I have a system that includes 4 portable sensors. These are to be 12 V battery operated and I am seeking some advice on the battery power source. I am leaning toward Gel Cells but there are some other considerations. The battery is to be enclosed in a robust shipping container together with electronics. The container is watertight so that it can stand outside in the rain while operating and protect the electronics inside from the elements. The container is foam filled to prevent the gear from rattling around inside and this includes the battery compartment. Charging the battery will only occur outside the case, on a bench back at the facility. Obviously, discharge will occur inside the case. Total current draw is about 2-3 amps and I am looking
to run the equipment for about 24 hours.

My main questions pertain to battery ventilation and heat. How much heat can be expected to be generated by the battery during discharge/operation. Also, I understand that Battery ventilation is mandatory but how much is enough? I can create some ventilation holes in the case that will be situated such that rain water will not easily  enter the case. Considering that the battery will be surrounded by foam do I need to create air access around all 6 sides of the battery? (top, bottom and 4 sides) or is ventilation of the top only sufficient? No forced air flow will be implemented so how big should the vent holes be? Are these primarily needed just for the gasses or also to allow signifcant heat to escape. These sensor units may need to be shipped around by air so Gel Cells sound like the only option. Please share your wisdom and advise. I will need a total of eight batteries and 4 chargers. Do your batteries come with the mandatory insulating terminal
covers to comply with the air transportation requirements? Thanks.

Jon B.20 Feb '01.

Hello Jon,

So long as the foam does not cover the vent valves,it should not be a problem. We have similiar applications where ventilation is either very little, or non-existant (Deep Ocean Bouys). For those applications we use a 'catalysing' stone- which is a platinum based ore,(don't grab your wallet like that! They're only $8 bucks!)which are very effective at recombining loosed Hydrogen and Oxygen in the 'box' and recombining them into a little water.(The stones get wet, but can be dried when the box is accessed for charging. When catalysing gases - Caveat. The stones gain a little heat of course!)

The key to managing battery heat /Gassing safety, is minimising the two type of heat generally associated with Lead acid batteries - 'Resistive', caused by charging and 'Exothermic Heat' caused by internal gas recombination- and the minor amount of gas that MAY!! be released.Good voltage per factory spec; control and minimises heat and certainly minimises gassing. http://sonnenschein.org/Gassing.htm  

However ,As you state the units product will be charged outside the box with air access,that should not even raise a problem. Drilling high on the box 1/8"(or so) ventilation holes and a couple low, for upward flow, and/or the insertion of a 'catalysing' stone in the box will minimise any gas. (Hydrogen is of course, pretty slippery stuff !)

Air travel is not a problem for these gels and post covers can be supplied. (Caveat. Always disconnect and insulate the positive battery post when in air-transit.) http://sonnenschein.org/Transport.htm  

Now 2-3A draw for 24 Hours.- 72Amp hours max (?)- You will need approx 100+ Ah + of Battery capacity to maintain usable voltage. Two DF125 - will do nicely. http://sonnenschein.org/Prevailer.htm   ref DF125
Cost each is $137.08( + freight.) Size and weight data are on the website.

See also http://sonnenschein.org/Really%20FAQ's.htm   Ref # usable battery capacity.

If you have any questions call me at 954 525 5557

MG/Lauderdale Battery 21st Feb 2001.

Neville K. wrote:

I use the A200 battery in my wheelchair and want to find out what are the recommended charge and float current for the A200 batteries and the float voltage please.. or any other information that will help in setting up the new charger..Yours Faithfully,Neville K.11/09/00

Hello Neville.
You have a good wide range to work with using a constant voltage charger.
For a 12v system the correct charging voltage is (2.35-2.4v/cell) 14.1v/14.4 @ 68F.
Float voltage is generally (2.2 to 2.3v/cell) 13.2 -13.8v. and merely double these figures for a 24v system.
http://sonnenschein.org/Charging.htm has more info.

Note . The batteries are self limiting on current if a constant voltage charger is used. 11/09/00

Are gel batteries like the dryfit A500 series safe to operate on their side?
My installation requires a low profile and some of these batteries would fit
in on their side, but not upright.
Gordon C.11/10/00

MG Reply. Hello Gordon.
Yes they are safe to use on their side.
All Sonnenschein dryfit series - including the A500 - are position independent.

Regards, MG/Lauderdale Battery 11/10/00

Does the A512/16.0SR contains any magnetic material ?(Steel ect)
Thanks Dieter 08/18/00

MG reply Hello.
The A512/16.0 has no magnetic components.The 6 mm connecting bolts and screws- however- may be magnetic! They should be stainless steel and therefore Non-Magnetic. This can be verified with a small magnet.

regards MG/Lauderdale Battery . 08/18/00

D. Ltd wrote:

Sirs Please forgive my intrusion onto your site, BUT I have a major problem with Sonnenschein SL115 Batteries, which were NOT supplied by yourselves, but purchased from a supplier here in England, and from whom, I am not sure I am being given sufficient information.. In the hope that you are still reading, I will attempt to outline my plight, in the hope you may have some words of wisdom, that could be of help?
*****We have connected 4 No. 12V 130 a/hr batteries in series to give a bank of 48V we then have 2 No. 48V banks connected in parallel to give a total capacity of 1040 a/hr @ 48V.
****We have problems that with a constant system current drain of 0.5A we keep getting 1 of the batteries from each bank failing , and dropping to below 9V
My questions are ( from a simple mechanical engineer ) 1, Do batteries, when used in a bank have to be matched. 2, Are batteries manufactured to a close enough tolerance ( internal resistance ) to be able to chose any 4 batteries and make a 48V bank ( same type, age make etc) 3, Any ideas why we should have these batteries fail?????? Hope you can help.... Any other info you require please contact me by return e-mail. Yours in hope..... Jim S.10/10/00

MG reply #1.Hello Jim,
I will be forwarding a copy to the Plant for a thorough follow up to assist you , but regarding your listed points how old are the product? Now;
***** Capacity would be 260Ah @ 48v if arranged in series/parallel as described.( Only the Voltage increases in series- not amperage.When you paralleled the sets, you increased the Amps.)

**** What is the drain and over what time period?
Next, your numbered points.
1/Yes. batteries in any set generally should be the same manufacturer, type, age, weight, state of charge,internal resistance and have the same resistance connectors and those connectors torqued alike.

2/ Generally. If bought as a group and discharged before recharging and all from the same production run, Yes.

3/ See **** above . The 'Time' info is critical to answer this question.

MG/Lauderdale Battery 10/10/00.

D. Ltd wrote:

Hi Al Many thanks for your quick response ( better than our British chums ) Sums never were my strong
point..... The current drain is a constant 0.5 amps Discharge giving a total 21.66 days capacity. There is also a 20 Amps discharge for 5 secs occasionally 3 - 4 times in a day then nothing but system drain for weeks. 260 Ahrs / 0.5A = 520 hrs = 21.66 days We started with 2 strings of 4 Sonnenschine SB12 / 130 in March 2000 ( supplied as a special order of 8 )The system is supposed to be charged by a 48V DC Wind Generator /Charge regulator. ( unfortunately no wind through the summer - just our luck ) The system was periodically charged using a 48V - 15 Amp charger run from a stand by 240V generator. After only a matter of 8 -10 weeks, 1 battery from each string went belly up, and were all replaced by the present 2 strings of 4 Sonnenschine SL115 ( 12V/130 Ahr ) (brand new - off the shelf )

Again after only a matter of 8 -10 weeks, 1 battery from each string also went belly up. Both times the duff batteries have dropped to below 9 volts, with the rest of the set at about 10.5 volts, and each time the duff batteries have been returned to the supplier, only to be replaced, and told the batteries were faulty???? We have been discharging / charging a string of 4 SL115's using a Trace SW3048E Inverter/Charger with a 2 Kw load and have noticed a marked difference in 1 of the set ( weakest link ) on the voltage after 1 1/2 hrs discharge, down to 43.2 volts, but this quickly recovers from 9.3 volts to about 11.0 volts. and the set recovers to 46.4 volts.It is also noted that for the first hour all 4 batteries drop at the same rate, then the weak
one drops quicker in the last 1/2 hr. Again I hope this info is of more assistance, as I am lost in a load of electrical mystique. And once again thank you for you time to help me with my problem. Jim S.11/11/00


thank you for the reply and the added information brings a couple of points to mind.

Our experience with the Sonnenschein Gels has me feeling there was nothing wrong with the batteries. The discharge and charge method you describe however implies that Battery Hydration was perhaps the cause of the origonal cell failures, or at worst a cell was polarised at very low voltage.

Now a little battery chemistry! It won't hurt I promise!.
We have noted some mis-understandings between Sulphation ( The formation of lead sulphate on the surface of a plate
caused by lengthy periods of leaving cells in a fully discharged condition. Correctly termed "Over-Sulphation", it is quite normal and 'generally' reversible.)
and Hydration a condition caused by partially discharging a battery and failing to recharge it in a timely manner When this happens, the lead in the cell goes into solution forming lead-hydrate, (generally on the separators) rendering the cell useless. It is usually irreversible. Low continuous load (current draw) and then only partial recharging, can aggravate this.

The key here might be that the 48 volt set was not 'formed' fully before use . As built - they are delivered at approx; 85% 'formed' capacity but quickly gain 100% capacity over ten cycles (discharge/charge) or so. Thus fully formed, and with a properly regulated and timely charging regimen established, the chances of hydration or other failure phenomena are statistically remote.We have similar systems in the field functioning quite normally after nine years.

For an application ( small draw - long duration ,) such as you describe however, we routinely complete the formation process in our shop for the user (Rapid deep cycles of the battery set or bank) prior to shipping - so the 'set' is ready for the real world upon arrival OR we supply instructions to the user advising them to do so. With proper and timely recharging thereafter the chances of failure are usually quite remote.Was such technical literature or applications given you by the supplier?
NOTE: To 'kill' a battery is remarkably easy; Merely partially discharge it and then leave it under-charged for a lengthy period.

>>>>D.Ltd wrote....260 Ahrs / 0.5A = 520 hrs = 21.66 days<<<<
Please be advised that the Usable Battery Capacity is approx; 50%- 60% of the 'fully formed' battery rating, with the occasional and permissable deeper discharge to 80% or so. When cell voltages are reached below these levels- cell polarisation may occur (positive plates take a negative charge etc )and you have a fairly warm 10 volt battery instead of a cool 12 volt. (They can produce more heat than light so to speak.)To obviate this,we generally add a low voltage cutout to the system and recharge them fully as soon as possible. Not to beat the drum, but the descriptive literature supplied with the product should prominently mention this ???
>D.Ltd wrote ...The system is supposed to be charged by a 48V DC Wind Generator / Charge regulator. ( unfortunately no wind through the summer - just our luck ) The system was periodically charged using a 48V - 15 Amp charger run from a stand by 240V generator. We have been discharging / charging a string of 4 SL115's using a Trace SW3048E Inverter/Charger with a 2 Kw load and have noticed a marked difference in 1 of the set ( weakest link ) on the voltage after 1 1/2 hrs discharge, down to 43.2 volts, but this quickly recovers from 9.3 volts to about 11.0 volts. and the
set recovers to 46.4 volts.It is also noted that for the first hour all 4 batteries drop at the same rate, then the weak one drops quicker in the last 1/2 hr.<<<<<

The entire battery set is new?? Does'nt the Trace unit have a built in low voltage disconnect?That battery requires immediate attention. I am curious if heat( as opposed to warmth) is detectable on any of the cells of the low voltage battery? (Heat is not_a_ good_ thing.)
I am quite sure the phenomena described can be avoided by 1/ Preparation of the set and 2/ your supplementary voltage regulated charging by your new solar panels and windpower charging system on a daily basis.
Caveat; We are a totally independent battery supply and applications company, so we have no bias towards Sonnenschein products. In our opinion  however, they are the single best deep cycle 'remote applications' product we have ever used. We feel it is most unfortunate that you have had this experience, but we are confident you will now engineer a satisfactory power system based (hopefully!) on the above comments or any further technical info we can supply you with.

Please let us know the outcome! (I have forwarded a copy to the Sonnenschein Export manager for info; )

MG/Lauderdale Battery 11/11/00.

Greg H wrote:

Three questions.
1. I recently ordered a Statpower Truecharge 20+ (20 amp three-stage battery charger). Will this charger be okay (voltage and otherwise) to use to charge Deka
Gel-Tek gel cell batteries? I assume it's suitable for all AGMs.

MG reply. Yes. Most Statpowers have a switch setting for AGM's or Gels.They of course have different voltage requirements as they are different technologies<<<<<<
2. What are your recommendations of Group 31 size batteries (gel cell? AGM?) and model numbers to be used in the following manner: Use two or more sealed batteries to power VCR/TV for continuous 8 hours in area away from AC power source. At other times power computer and printer. Also, limited use in powering powerful photographic strobe units (for short periods of time). Batteries will spend a lot of time in storage and ultimate lifespan with limited use is a prime consideration. The batteries will be charged before they discharge to 12.5 volts during storage.
MG reply.Both are very functional. AGM's have fractionally more power -but a Gel cell will have more usuable cycles (Life). Sonnenschein/Deka gel cells have the best 'shelf' storage life and will lose only 15% or so in eighteen months. Merely charge fully before storage.
3. The amp/hour capacity of a battery decreases as the rate of discharge increases due to internal resistance, temperature increase and other factors.

Correct.The higher the discharge rate the less apparent usable capacity for a given unit.

The question is: When using two batteries in parallel, is the amperage draw shared between the two batteries such that efficiency is improved with the result being that the capacity of two batteries used together is greater than twice that of one battery? For example, assume that a 105 A/H battery is being used and the capacity of a single battery is reduced to 80 A/H or so at a 20 amp discharge. Also assume the A/H capacity of this battery is about 90 A/H at a 10 amp draw. If two of these batteries are parallel-connected, does each battery pretty much see a 10 amp draw? Will the amp/hour capacity of the two batteries being used together be 180 A/H (90 A/H each battery) rather than 160 A/H (80 A/H each battery)?

>>>> Shared. Battery Capacity is a function of load/time. However As the load is 'shared' it lowers the apparent rate of discharge of each unit in parallel. Each battery will supply one-half of a given load -ergo, apparent capacity increase. <<<
I hope this has been of help.

MG/Lauderdale Battery 10/19/00

I'm the guy who sent an e-mail a short time ago with three questions. I forgot to clarify that I'll be using an Exeltech
XP1100 inverter (true sine wave inverter rated for 1100 watts) to power the VCR/TV, photographic strobes, etc. And the
photographic strobes, at full power and with modeling lights on, suck about 1080 watts each when recycling. The inverter
is rated to handle surges of 2200 watts.

MG reply. Hello Greg.
I am not familiar with that unit. Just check its efficiency (usually around 90-95%) and remember it takes
roughly 11.5A-13A (depending on efficiency) of DC to make 1A of AC.
If necessary measure the DC load with an amp clamp at the battery cables for true DC load.vs AC output.
Check the unit has a low voltage cutout (usually around 10.2 V on a 12v type inverter) to protect its circuitry.


I really appreciate your tremendously quick replies. I was thinking about getting some L. AGMs but you (and your web
page) convinced me that that the Sonnenschein or Deka gel cells are what I need. I'll spread the word about these great
batteries. Greg H. 10-19-00

William D. wrote:

Gentlemen, Ten years ago I purchased 10 8D gell  cell battaries (sic) from you and I am pleased to tell
you that they lasted the 10 years you said they would. These batteries did not have the Prevailer label on
them  and they were (I think)220Amp each. I would like to price 10 more of these same type batteries. I am in
Trinidad and will need to have the batteries shipped here. A  quote from you will be appreciated and suggestions
on shipping as I am sure you have more experience at that than I. Please respond to Bill D. email 07/21/00

MG reply. Hello Bill. Yes, we labeled a bunch 'dryfit Traction' and you had those. They are in stock and ready to ship.
Oh, they are the same price as 10 years ago! (Bruce.The Poor! says HI and mentions he's got a family to feed and enough with the ten years already!)07-21-00

Tom K. wrote:
I have a battery application question. It may sound strange, so bear with  me.   I want to play a movie at the beach. I will have a projector, a DVD player, and an amplifier and speakers. The movie will last 2    hours. Can I use a Deep Cycle/Marine battery to power the stuff I need? If so, where do I buy one (or multiple) and how much should I expect to pay? How do I recharge the  battery?

Thanks, Tom. 02/02/01

MG reply. Hello Tom,
Sure that is straightforward enough

An 12volt inverter/charger with a small battery bank will do
everything you need.

Size of both will depend on how many Amps the equipment draws  and amount of time of use.
Where are you located?

Regards, MG/Lauderdale Battery 02/01/01.

I'm in San Francisco. The projector is 5 amps (I assume when it says 100-120V; 5A; 50/60HZ the 5A
means 5 amps). The DVD is ??
Tom. 02/01/01

MG Reply. Hello Tom,
Pretty painless and the power equation won't hurt a bit I promise!
5 amps @ 110 volts = 550 watts Add 3 amps @ 110 volts for the DVD = 330 watts for an approx total of 880 watts load.

So- a 1000 watt Inverter should do you nicely. This comes with a built in 50 Amp battery charger and Heart makes a good, reliable unit.

Each AC amp derived from a 12v inverter takes approx +/- 12 DC Amps from a 12 volt battery. As we need 880 watts x two hours = 1760 watts for the duty cycle. 1760 watts / 12v = 147 Ah (+/-)of "usable" battery capacity.
(Caveat. The usable capacity of a 'standard' wet battery is usually 50% of its label 'rating'.- Top quality batteries about 75%) A nice choice would be a couple of quality ( Deka or Trojan) 6v Golf Cart batteries joined in series for approx 200 Ah.

Each battery weighs 66 lbs approx. If you can stretch the extra dollars get Gel cells. Save you all sorts of fuss with acid and gas, and very user friendly. You even can use them in your house if your CA power gets cut (again.)

(Enclosed name of a local Supplier.)
Regards and good luck,
Bruce . The Generous!  02/01/01


Dear Sir,
in our application we need to use a lot of Sonnenschein batteries
(A300series), that should be hosted in a vacuum chamber (pressure about
10 mBar). However, they will be charged in air.
My question is if it is possible for this kind of batteries to operate
in a vacuum environment, or some problems might occur (i.e. gas leaks,
degradation of the battery, contamination of the vacuum chamber, etc.).

Thanks in advance.
Best regards - 02-03-01
Vincenzo D- Istituto Nazionale di Fisica Nucleare

Hello Vicenzo,

Please note from the added addresses above that I have forwarded a copy of your request to the relevant Sonnenschein
departments for any updated material spefically for the A300 series, but here is the most current pressure data.

Permissable Pressure for dryfit series A200 - A500

Maximum pressure:4000 hPa (-equivalent to a water depth of approx 30m.)

Minimum Pressure 30hPa .(equivalent to a height of 30000m)

Max pressure increase and decrease: p/t=150mbars/s
(1000 hPa are equivalent to 1000mbar / 1m- 3.28ft)

Regards MG/Lauderdale Battery 02/03/01


(Most asked question? ...when will M&G ... write/talk/explain  about the Yacht "Avatar" battery related explosion???)

May-2002 - MG replies->>> Ok.  My opinion on the explosively fast gas event on the yacht Avatar? Frankly?  Without Circular #78, this was a non-event, albeit a hefty deductible on a yacht Insurance bill, as happily no one was reported injured.
In 1996 The USCG Boating Safety folks issued a worldwide safety advisory, stating it was based on a discussion at an ABYC Project Technical Committee/ DC Electric Systems meeting; and  released worldwide as Boating Safety Circular # 78  its opening headline  stated ".....danger of explosion if SVR (Sealed valve regulated) gel cell  Batteries improperly recharged..."
(You may link to this Please Do not copy without my written permission. Respect the copyright)
  answers or minor corrections to Readers comments have been dated and highlighted in yellow as received.

That was the first official word relating to a battery produced, spark ignited gas event (explosion) on the Yacht Avatar, Antigua.

The body of # 78 stressed temperature compensated recharging techniques -  advisable but far from compulsory -(05/23/02) apparently by the Battery manufacturer - and that's fair enough - but no caution to avoid containment of  any very ignitable gases, H and O....especially if despite world_class_charging devices and instrumentation, the gas is  caused by a simple loose cable.....

Oh yes. It is  containment of rapidly expanding gases that differentiates a simple rapid burn event from an explosive one - much as ignited compressed Gasoline vapours explode, as in an engine cylinder- while in the open air the same amount gives but a small flash... so ventilation/air dilution of some form, ambient or forced is compulsory.

   Then the 4th Paragraph - " Constant voltage chargers must never be used".. Woah now;  for gel types?? Since when?  Did someone  mis-hear the Power Supply known as a "Constavolt" and parse that as  "Constant voltage?"  Who knows. In fact Constant Voltage is the only preferred way to recharge any gelled type Battery. Yes "any" Gelled electrolyte type - for all Four separate Gelled types Batteries produced by various manufacturers back then, it is  continuous "Constant Current charging"  that is hazardous.
As is stated in earlier A. to previous Q , it is the well controlled combination of both constant Voltage and constant Current, used in 3 step charging - where safe and speedy charging benefits are achieved - and this was noted way back when in the Sonnenschein Military Applications manual <circa '85 - '86>. Such well built systems and proven 3 step regulation  were in use aboard. 

I sent a note to the various parties named above - that the charging advice in #78 was , to put it mildly, wrong. 

No one answered and there were no corrections. (Oh, well, just call me a true innocent.) At that point who cared?
By default, outside the builders etc, I did.  I'm the guy who helped introduce Gel cells into the USA marine Industry.

  I'd already given, and had accepted  my own technical opinion, of Gelled technoIogy type gas related events. Of   the 10 or 11 worldwide; Only seven of those had reliable observers over an eleven year period. (Yep, there simply aren't many given the astounding numbers of SVR gelled types in use worldwide.) In five of those cases probable cause was found to be charging related phenomena way outside normal battery voltage requirements; Containment of any vented gas this overcharge produced ( lack of ventilation) and a spark producing device (ignition of gas). Of statistical interest, that spark had a very high probability of being narrowed down to a loose or sparking current carrying conductor - a simple battery bank cable. 

     The other two reported events I was able to physically examine.  One/ when a crewmember of a local charter yacht in Fort Lauderdale,  knelt on a large aluminium battery box creating a spark and got a harmless but loud, ignited battery gas event. I drove over there with the original installer, switched on everything and measured that the charger had been  pouring in a nice un-rectified 28 volts AC volts !! (1min 16 secs to analyse and verify. Oh yes, that will electrolyse  water never mind conductive acid.) Incident Two./ involved unsecured, paralleled Batteries sliding around on a large smooth Fibreglass sole board (floor) of a large locker, at  high speed on an  offshore cruiser. No Battens. nor restraints. Both alternators at full output (34 seconds to analyse.)
  (Guess what the  cables did to the soft lead posts as the batteries rotated in free motion?)

     So lets call my interest in ignited battery gas events a Professional hobby, which is part of how I make my living. Everyone relevant was already aware of the ventilation issue but in my experience, even  Gas containment was pretty minor and sometimes possibly inevitable by application .  Submerged research bouys, mini subs and occupied diving devices worldwide are full of gelled types with no problems.   

 So I went looking for the key element. What had caused the SPARK ? That  satisfied, I  also deduced the gas cause.   
Knowing the surveyor, I called to discuss some details. I then called some members of the Project Technical Committee whom I knew; I called the USCG;  I called the Builder; I called the ABYC....and then the full delicacy of the ABYC's position sank in....ummph!....I called my Mom. <grin!>  The Surveyor's excellent report apart, little bricks walls were appearing pretty much everywhere. Given the possibility of lawsuits from such an event, I sympathised and remained discreet.

( 05/21/02 in answer to a blunt e'mail to me about  "Monday Morning Quarterbacking". Most of this was done and recorded and even faxed to the USCG by Dec '96 -  Isn't verifiable, recorded, factual documentation nice?)

Initially, in discussions with the various parties involved, just after the Chicago IMTEC  '96, I was requested (ahem,) not to get involved, and it was under control. (?) Well I wasn't exactly receiving anyone's wildly enthusiastic support, even to correct these minor but important errors so I simply let the matter rest. I hadn't sold the batteries or designed the systems so.......
 I collected all the reports and photographs, on the Avatar incident. Very handy they turned out, as what should have been a non-event technically, had become a fairly constant topic of discussion from my own customers and some interested others. There was simply so many wrong rumors going around; Why?  Oddly enough, to my reading,  the surveyors report on the incident clearly inferred the probable cause of the event though his report was apparently not discussed, or perhaps not available,  at said meeting. Photographs confirmed what I thought. However, if the powerful National Figures involved could play quiet, well so would I.....

        I now have to deliberately place emphasis on the phrase used above; "constant topic".

 For several years after, Major  publications articles quoted # 78; Web sites; Internet Chat groups; Certain folks in the Battery industry who didn't  know better seem determined to add silly rumors to the common wisdom... In Print ... Gleefully handing out printouts at the IMTEC and  Boat shows, helpfully inferring that  gel cells can explode on their AGM price sheets.-- As a public service no doubt;-- Show after show. For several years;  That would be the private Distributor and his ilk, of a Privately labeled AGM Battery. (which In a prior 'life' was named and labeled "Gel_Power" heh, heh.. in a weird, but deliciously ironic twist !)  Anyone with a real clue (all two of us) merely kept quiet and let the legal side of the event wind safely down. 
        For several years,  no one of any consequence in the Industry was even willing to comment publicly prior to any legal resolution. That  prudent and proper Battery Industry silence was perhaps taken, ahem, by the privately labeled AGM distributor as a sure sign of victory, who kept up the great silliness with the price sheets and battery gas output reports.  What's with the "great silliness" regarding "gas"  phrase?

     Its the high efficiency of  AGM's gas internal recombination that is also its most feared attribute in the Industry.

   By its nature the recombined gases makes lot of heat (exothermic) internally and is pretty_lousy at dissapating said heat. By its "starved electrolyte" design  there are no  conductive fluids or Gel to carry the heat to the battery case to cool it...
  . We also noted dryly that the said AGM's need for periodic Equalisation, (Yes,the need for acid equalising,)  just as a wet battery, was being perhaps, umm, understated.

 In Apr '98 I finally sent a private e'mail containing this basic same analysis to navcen.uscg.mil to be recorded forever in the public record. (A question has already arrived 05/21/02 "Why not an article in the.. popular press?"  

          What could be done? Tar and feather a beloved and respected Institution for timely and correctly warning the public?  Poor grammar?  A possible typo on charging advice?  An August marine advisory board for having an informal chat?  Distortion  of the well intentioned true intent of the Boating Safety Circular by a hungry saleman hustling for a buck??  The crew for a loose cable? Nah. Not my style. Easier to wait till truth got its boots on.

With regrets, I did decline to renew my companies membership in that otherwise admirable marine advisory body. I could totally empathise with their delicate position but this was simply an , umm, technical credibility issue. 
Circa '99, the  issues were finally becoming resolved. ? ( I simply do not know how,)  and the factory finally  became involved; So with a very sensible fellow from their upper management, we undertook a study of the facts I had quietly collected over the years regarding the incident.
      Interestingly we found others working quietly behind the scenes so with no controversy or fuss we gave our opinion which fitted all available known facts.

 A large virtually sealed battery box under a double bunk, containing a series/parallel bank of 8 Gelled 8d's.(Known)

All recharging equipment was verified by outside consultant Labs as within normal specifications. (Known)    indicating that-
 It wasn't the charging system.
 It wasn't the charge regimen.

 It wasn't lack of instruments. ( Lots, but some not connected properly anyway.)

Exploding Gel Batteries? Nope. That's what a certain irresponsible company selling private label AGM Batteries would like the world to infer or think though - that they exploded.  Nope. All the parts of the battery case tops were  inside the batteries - not blown around the box and cabin. That implies battery implosion from outside force or pressure. Not exploding batteries;

Did the batteries fail somehow? Nope. The gel batteries oddly enough were proven perfect - for amongst other neglected data - said reported loose cable was later reconnected by a crewmember and the batteries ran the entire ship perfectly for five more days after said event showing that all battery units were still electrically perfect.

 It wasn't the battery technology. So what generated the gas production?

 A mid-circuit loose jumper cable. (Known.)
 perhaps causing  Voltage Divergence (High Probability) 
 causing copious H & O gas from massively overloaded cells from said Voltage  Divergence, 
  (Similar to building a dam on a stream - A lot of potential energy on one side of an obstruction  In real terms Voltage can build to 18 volts on one 12v side of a series 24v set... Predictable and 100% Duplicable.) ***  during a very recent battery recharge. (H is a tiny, light very slippery gas even in a tight, but not sealed area - It gets out pretty quickly.) 
 A high DC current load from an electric deck-winch .(Known. Vessel was sailing,)
 generating a spark from a ..?..(Unknown).. possibly said loose cable? (High probability.)
 and Igniting contained gas  within the  battery box. (Known)**
  Earlier the ABYC had stated that the original meeting, on which # 78 was based, being  an 'informal discussion', should never have been recorded nor reported as it was NOT an "Official Technical Committee meeting" and washed their hands of it.  Having confirmed that, from a trusted independent observer at that meeting ( The esteemed N.C.) and as confirming is what I do folks,  I had respected their somewhat,  umm, delicate position. 

 I must admit my professional respect turned to genuine admiration for their impartial consistency  some years later, when they requested us not to attack a certain AGM type Battery while  we gave the Battery / DC Electric speech,, at the IBEX in Ft Lauderdale.( Yes, I'd renewed membership for the occasion.) That same ABYC official properly requested to both read and review our speeches and displays prior to our presentation. I was happy to see them keeping their Guard up - right until they mentioned that this reportedly was being done at the concern of a certain Battery Distributor? Huh?.  I was getting used to this - but enough already... Sadly ,that request was remarkably naive ( read as "really infuriating") on two levels;  We supply several AGM types worldwide, and  yes, we like  AGM technology - mainly for cold conditions and high Cranking demand Apps. Secondly? Public attack is not our style.

All of the above analysis?  We did not even mention it publicly. We value proper form. We declined also to enlighten anyone that if AGM's had been subject to this abuse, then a thermal meltdown and Fire would almost certainly have occurred. All the articles written and printed quoting #78 as an unimpeachable source?  Sadly Wrong. Sorry, but facts are such stubborn, unyielding things. (05/23/02)

       In fact all the serious work with anyone relevant to the issue at hand was already discreetly done and agreed, so we had nothing to add in the Public domain. To repeat - without the perhaps ambiguous meaning incited by , umm, a certain sales motivated (?) party #78 was a technical yawner. Again, sorry about that.(05/23/02).

       We gave a battery presentation, pure and simple. After the very sensible management fellow finished his very technical Battery presentation - I presented  Bruce. The   Wise. - which pretty gleefully defused any lingering tension. ( It's the  questions  from the very sophisticated IBEX audience afterwards that makes a presentation come alive. Truly fun and educational.) That over,  even the Coast guard attendees,  kindly applauded and smiled; The AGM distributor was quietly invited aside from the audience, by the very sensible management fellow and requested to refrain or face firm legal consequences. In private.
        The Coast Guard shook hands and we discussed how to perhaps clarify the intent of Circular # 78. The  ABYC  gentleman smiled and shook hands.Truth had finally got its boots on.

         USCG  Safety Circular # 80 was finally issued in clarification of  # 78, and we thank the USCG .

To assist in any future scenario's, involving other possibly complex, dynamic battery events,  we suggested and now have a representative of the Battery industry sitting on that very same Technical Committee and yes, I have continuously renewed annual ABYC membership ever since.  Most of the USCG fleet continue to use - or are changing to - gel cells on their noble fleet. That particular AGM battery? Its  lost most of its gained Marine market share, simply replaced in most of the market by a better, less expensive and, ahem, perhaps less controversial product,  fully factory labeled and technically supported by the manufacturer...and Bruce, who care about such matters...   

 (**The lesson ?  "leave ventilation holes high up, and routinely tighten your battery cables. Please ")
M&G Battery- May 2002.
(Still being edited at my leisure-You may link but please Do not copy without my written permission. Copyright)

  All the above is my own opinion of the events, and I reserve the right to change it 100% or whatever.
The facts, however will forever remain 100% constant.
 (PS. Eternal problem lately! I simply don't have the time to make this a short post!!).

***Building to scale a working Gassing Model for Gel types and associated Thermal runaway events in AGM high gas recombination  types has been removed - as children do use this site and we do not want any kiddies building this.  Kindly drop by Lauderdale Battery, in Fort Lauderdale at the next boat show or IBEX - if you have an interest. (Copyright. You may link to this page but do not copy please.)


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