# [EVDL] Reference material for flooded lead acid batteries



## EVDL List (Jul 27, 2007)

Hello Steve,

Just type in your search engine: Lead Acid Battery

There are several sites that give good info.

A good one is http://www.batteryuniversity.com

I am using Trojan batteries, so I normally go to The Trojan Battery Company 
site which has more detail info than any other company sites I ran into.

I am going to use U.S. Battery, but there site is not at specific as I like, 
so you have to e-mail the tech for much of the data.

Yes, email us as much as you want.

I been running a EV for 34 years now, and have learn not to do by the faults 
and errors which may not be listed in any articles that I can find. As for 
example:

Do not add water to a new set of batteries, first charge them to 1.277 
specific gravity to at resting voltage of 2.123 volts per cell and then 
record the electrolyte level. In my first set of batteries, my electrolyte 
level was 1/2 below the fill neck, so that where I made adjustment to my 
watering spout by adding a length of hose.

Adding any water to the bottom of the fill neck will dilute the electrolyte.

Another is to not have the batteries set in a metal battery box, unless you 
have it totally insulated so the battery fumes do not coat any ground 
surfaces to the box and frame. My first battery box was made out of 
aluminum which was epoxy coated, but this surface corroded.

When you order a new set a batteries, make sure all the manufacturing dates 
are the same and at least not more than 2 to 3 weeks old. All my batteries 
I order, I specific the maximum age of 3 weeks, and the voltage to be in 
with 2.10 to 2.12 volts of each other.

The ampere of the battery shall at least be in with 5% of each other. I 
give a little more difference on a new set of batteries, because it takes 
about 50 to 100 charge and discharge cycles to close this difference. The 
surface of the pasted grids open up more while this cycling, which gives 
more surface area, thus more ampere.

I normally do this ampere check once a week until the warranty period is up, 
and if I find that any one battery is more than 19% difference, then I have 
if exchange. I normally specific this to be done if the ampere percentage 
is this much.

I use a battery analyzer, that just records voltage and ampere. You can get 
these units from E-Bay. You do not need a large shop one, that can record 
resistance, temperature, State of Charge, specific gravity by use of a pair 
of probes that can not only read the voltage or each cell, but the specific 
gravity of the electrolyte.

Doing all these techniques, my battery life has always been between 8 and 10 
years.

Roland




----- Original Message ----- 
From: "Steve Skarda" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Tuesday, September 15, 2009 8:56 AM
Subject: [EVDL] Reference material for flooded lead acid batteries


> Is there any good book or other reference material that folks could
> recommend to help someone that doesn't have a degree in chemistry 
> understand
> fundamental battery behavior?
>
> I have been driving my car for 4 months now and have built my own BMS
> system. I have quickly realized that continuing to be an EV driver 
> really
> requires us to be extremely knowledgeable on how our batteries function,
> each and every one of them. Everything I know about flooded lead acid
> batteries I have learned from Lee Hart and the people on this list. That 
> is
> an impressive amount of knowledge. However, it seems like I still have 
> day
> to day questions that I would be better able to answer on my own if I had
> better fundamental knowledge of batteries versus just what to do and not 
> do.
> Are there any good resources out there? I hate to email this list every
> time my batteries do something I don't quite understand when a searching
> archives doesn't provide an answer.
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## EVDL List (Jul 27, 2007)

Thanks Roland. That is a great summary of a few key points. I think I am
going to take this information along with key nuggets from the EVDL library
and some EVDL posts and try to write something up. It would be helpful to
start accumulating all of this stuff in one place. I have a hard time
really through someone else's experience and being able to automatically
recognize how that is applying to my situation in every case.
Since you offered, here are my most recent questions that have motivated me
to get a better fundamental understanding of what is going on inside the
batteries. I have been reading through the archive but don't feel like I
fully understand.

I have run my batteries into the known damage area 3-4 times. A few times,
I didn't get a full charge the night before but didn't realize it until half
way to work. Similarly, my charger tripped at work (my own fault) which
made it hard to get home. The choice is always wait and charge, get a tow
truck, or sacrifice batteries. Sometimes you have to get where you are
going so that only leaves the last option. I don't currently have a state
of charge meter but I do have a microprocessor and programmable display so I
need to write up some code. I was going to start with a amp-hour counter
and build from there.

I have 3-4 6V flooded lead acid batteries that I have difficulty staying
within 0.03V of the rest of the 120V pack. I typically pick the lowest one
each night and throw a Soneil charger on it but after a few cycles they just
end up low again. I presume I damaged them at some point. Last night while
knowingly sacrificing my pack, a few of these same batteries would drop as
low as 4 volts while keeping the majority of the batteries above 5.25V. I
checked specific gravity on one of them. It had a completely dead cell.
Can you have reversed cells on flooded lead acid? It seems like most of the
posts I could find regarding reversed cells were for AGMs. Once you kill a
cell like that, what are my chances of bringing it back to being useful?
Should I throw in the towel on that battery now? I can put them on a
charger and get them back up above 6 volts but they are clearly weaker.

They are under warranty. These are Sam's Club Energizer Golf Cart
batteries. While it might not be ethical since it was clearly my fault,
what does it take to qualify for warranty claim? Is it worth my time to
pull them out? I realize that you don't want a mismatched pack but if my
pack is only 3-4 months old, most of my batteries still look healthy, I
assume my best course of action is to replace the stinkers. Can you say a
little more about your battery analyzer? Those handhelds on Ebay
(searching battery analyzer) look like they range from $200-$2000. Am I
thinking about the right tester? Could I get the same function by loading
my batteries to a constant 100 amps (by driving and watching amps closely)
and writing down the voltage on each battery?

When charging, should voltage deviation between batteries concern me? Once
a charge is complete and the batteries rest, even the stinkers will end up
within 0.1 volts of the average. When charging however, I can see a range
of a full volt (1.0 volts) between highest battery and lowest battery. I
don't get that kind of difference discharging.

The Trojan website lists a fully charged 6V battery to be 6.37V. I am
currently charging my batteries to 2.55V/cell (144V) until the charging
current drops to 4 amps. After they rest, there are still batteries well
above that 6.37V. It is not unusual for all 20 of my batteries to be 129
volts when I first turn on the car. Maybe, my batteries really haven't
rested long enough? What causes a battery voltage to be that high? Am I
damaging them with overvoltage.

I thought I was going to be so much smarter about my battery pack than
others. After a few months of thinking I was being diligent, I feel like
the same newbies on here doing dumb stuff to their packs. I need to start a
data log so I can make some more useful observations.


>
>
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## EVDL List (Jul 27, 2007)

Hello Steve,

Replies inserted:


----- Original Message ----- 
From: "Steve Skarda" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Tuesday, September 15, 2009 12:15 PM
Subject: Re: [EVDL] Reference material for flooded lead acid batteries


> Thanks Roland. That is a great summary of a few key points. I think I am
> going to take this information along with key nuggets from the EVDL 
> library
> and some EVDL posts and try to write something up. It would be helpful to
> start accumulating all of this stuff in one place. I have a hard time
> really through someone else's experience and being able to automatically
> recognize how that is applying to my situation in every case.
> Since you offered, here are my most recent questions that have motivated 
> me
> to get a better fundamental understanding of what is going on inside the
> batteries. I have been reading through the archive but don't feel like I
> fully understand.
>
> I have run my batteries into the known damage area 3-4 times. A few 
> times,
> I didn't get a full charge the night before but didn't realize it until 
> half
> way to work. Similarly, my charger tripped at work (my own fault) which
> made it hard to get home. The choice is always wait and charge, get a tow
> truck, or sacrifice batteries. Sometimes you have to get where you are
> going so that only leaves the last option. I don't currently have a state
> of charge meter but I do have a microprocessor and programmable display so 
> I
> need to write up some code. I was going to start with a amp-hour counter
> and build from there.

You need some time of Ampere-Hour meter of A State of Charge meter. For a 
long time, before I had a Ampere-Meter, I had a large GE volt meter that was 
red line from 5.66 to 5.0 volts or for my pack of 180 volts is 165 to 170 
volts. I never had the resting voltage (no load voltage go below 180.3 
volts or 6.01 volts which is about 50% State of Charge.

I would only allow the sag voltage to go to 5.0 volts for a short time while 
acceleration.
>
> I have 3-4 6V flooded lead acid batteries that I have difficulty staying
> within 0.03V of the rest of the 120V pack. I typically pick the lowest 
> one
> each night and throw a Soneil charger on it but after a few cycles they 
> just
> end up low again. I presume I damaged them at some point. Last night 
> while
> knowingly sacrificing my pack, a few of these same batteries would drop as
> low as 4 volts while keeping the majority of the batteries above 5.25V. I
> checked specific gravity on one of them. It had a completely dead cell.
> Can you have reversed cells on flooded lead acid? It seems like most of 
> the
> posts I could find regarding reversed cells were for AGMs. Once you kill 
> a
> cell like that, what are my chances of bringing it back to being useful?
> Should I throw in the towel on that battery now? I can put them on a
> charger and get them back up above 6 volts but they are clearly weaker.
>
> They are under warranty. These are Sam's Club Energizer Golf Cart
> batteries. While it might not be ethical since it was clearly my fault,
> what does it take to qualify for warranty claim? Is it worth my time to
> pull them out? I realize that you don't want a mismatched pack but if my
> pack is only 3-4 months old, most of my batteries still look healthy, I
> assume my best course of action is to replace the stinker?

A battery that is only that old, may be ok. When I have to replace a 
battery, I try to fine a battery that has the closes manufacture date that's 
been setting at the dealer. If not, then I will put it on a load test set 
at the same average ampere that it takes to drive the EV.

The last time I had to replace a battery, that was only one month older than 
the pack, I calculated the daily ampere for amount of time, and number of 
charging cycles, and apply that to the new battery. Normally it was 75 amps 
for 1 minute which is the amount of time it only takes be to drive per day.

I notice that at Sam's Club, they only do Cranking Amp test, so if you take 
your battery to them, it will show on there battery checker as REPLACE 
BATTERY.

It is possible to bring that reversed battery back to normal, is by taking 
it out and charge it starting at C/10 (ampere hour rating/10) which may 
take some time to do. Others have use a very low charge rating for up to 
two weeks to bring it back, so you do not boil out the water and overheat 
the battery.




Can you say a
> little more about your battery analyzer? Those handhelds on Ebay
> (searching battery analyzer) look like they range from $200-$2000. Am I
> thinking about the right tester? Could I get the same function by 
> loading
> my batteries to a constant 100 amps (by driving and watching amps closely)
> and writing down the voltage on each battery?

The standard load tester for a deep cycle battery are normally 75 amp. You 
would have to leave it connected to the battery for the Reserved Minutes 
rated at 75 amps. If the battery has a Reserved Minutes (RM) rated of 100 
minutes for 75 amps, then you would to load test it for 100 minutes at 75 
amps. It is best not to go over 50 minutes at 75 amps and if the resting 
voltage is at 6.01 for a 6 volt battery, then you are at 50% SOC.

The battery analyzer I have only does a voltage check and ampere check. It 
will check the maximum ampere of the battery, where the standard cranking 
amp load may only check a lower amount for a length of time. This unit does 
it by conductance.

The analyzer I am using is a Midtronics MDX-640 Battery Conductance for 6 
and 12 volts up to 2000 ampere rating. Has options to send data to a printer 
and store data.

When I received my last pack of batteries, I use a shop analyzer which the 
battery shop has, and I not only mach the voltage of the batteries, but the 
ampere. Out of a pallet of 40 batteries there was one battery that was 200 
amps lower then the rest.

Normally the lowest battery ampere is the result of the amount of surface 
area that is expose to the electrolyte. The surface area of all the battery 
plates are not the same, there is always more atoms in some then another.

Charging and discharging a new battery will open up more area of the plate 
surfaces which increases the ampere and ampere-hour.

If you have two batteries exactly at the same voltage, but the area of 
plates in one battery is one-half of the other battery, meaning less surface 
area, then the voltage may be the same, but will always be a voltage 
different when discharge.

My Trojan batteries if not discharge below 50% SOC could have up to 5 
percent voltage difference between batteries which is consider acceptable 
for this type of battery, but I will not accept any battery with a voltage 
difference of 0.01 when new.




>
> When charging, should voltage deviation between batteries concern me? 
> Once
> a charge is complete and the batteries rest, even the stinkers will end up
> within 0.1 volts of the average. When charging however, I can see a range
> of a full volt (1.0 volts) between highest battery and lowest battery. I
> don't get that kind of difference discharging.
>
> The Trojan website lists a fully charged 6V battery to be 6.37V. I am
> currently charging my batteries to 2.55V/cell (144V) until the charging
> current drops to 4 amps. After they rest, there are still batteries well
> above that 6.37V. It is not unusual for all 20 of my batteries to be 129
> volts when I first turn on the car. Maybe, my batteries really haven't
> rested long enough? What causes a battery voltage to be that high? Am I
> damaging them with overvoltage.

This over voltage is only the surface charge after the batteries are charge. 
Remember the charging voltage may be between 7.2 to 7.8 during charging. My 
batteries even after 24 hours float down to about 6.44 to 6.42 for my 
batteries. Put a little load on them in your EV for about 10 seconds at 75 
amps and this should come down to the 6.33 to 6.36 volt range.
>
> I thought I was going to be so much smarter about my battery pack than
> others. After a few months of thinking I was being diligent, I feel like
> the same newbies on here doing dumb stuff to their packs. I need to start 
> a
> data log so I can make some more useful observations.
>
>
> >
> >
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## EVDL List (Jul 27, 2007)

It's really useful to have a dummy load you can use to load down your entire 
battery pack in the garage. Something in the area of 75-100 amps will 
usually let you locate the stinkers with an ordinary voltmeter. 

I don't know where you'd find a dummy load suited to a road EV's battery; 
most I've seen advertised were meant for golf cars at 36 or 48 volts. But 
various homebrewing methods have been used, depending on the voltage of the 
battery. Some examples :

Cheap household space heaters with their fans powered by the mains; each one 
draws about 12 amps at 120 volts, so 6 of them will make a 72 amp load at 
120v.

Electric water heater elements (immersed in water of course). A typical 240 
volt element uses 3000-4500 watts (12.5 - 18.75 amps at 240v).

Barrels of salt water with electrodes; dip the electrodes in further to 
increase current (use only outdoors; this produces poisonous chlorine gas!).

My dummy load is a couple of resistance heaters from derelict heat pumps, 
inserted into the side of an old, large metal rural mailbox. The door is 
long gone, and I cut a hole in the other end for the fan from a discarded 
range hood. I connect the load to the battery to be tested, plug the fan 
in, and apply 12 volts to the contactor. It warms up the garage nicely in 
the wintertime. ;-)

Like mine, most or all of these will need a properly rated contactor. If 
you use multiple units such as space heaters or water heater elements, you 
may be able to use a single switch on each unit, and that may be cheaper 
than a large contactor for the whole batch. Be sure your switches or 
contactor are DC rated at the proper voltage and current.

If you connect your load in place of a DC motor and add a series inductor, 
you can probably use your EV's contactor to turn it on and off, and maybe 
even use the DC controller to set the load current. In most cases though a 
controller isn't necessary. Just design the load for the current you want 
by Ohm's law, I = E/R or current = voltage / resistance.

David Roden - Akron, Ohio, USA
EVDL Administrator

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## EVDL List (Jul 27, 2007)

I used a rather crude set up on my badd-eries in the Jetta. I was looking 
for a "soft" one, ya know when you run about 100-150 amps and see a @#$%^ 
10-15 volt drop?I have a buncha BIG ass resisters, maybe old motor starting 
ones? And a 100 amp meter strung into this hookup, A nicrome strip resister 
coil. Hooked up to 30 volts worth of batteries take jumper cables, NOT those 
worthless Wal*Mart crap#10 size, but REAL ones I made with #6 wire or are 
they #4? Ballsy cable, though. Clamp one side to the batteries to be tested 
and clamp onto the desired amps, oh, about 70-100, DON"T connect directly to 
the battery!! Have yur jumpers hooked to the CAR'S battery and adjust at the 
resister end!!NO sparks around yur batteries! But on the gravel driveway, 
8-10 feet AWAY from the car, have at it! I clamped about halfway into the 
strip nichrome job, Yeah, things were getting hot as I added to Global 
Warming, on such a nice summer day!Letting things smoke along, deployed my 
trusty Harbor Fright 3 bux voltimeter across EACH badd-ery. Didn't take long 
top see the #$%^ drop!One was down to 3 volts pretty quick! Wasn't rocket 
science here! USUALLY, when I was driving my commute I'd beat the shit out 
of the battery coming home, pulling 200 amps 70-75 on the freeway, to heat 
'em up. IF I had a bum one I usually had a smokin' Trojan Teakettle on 
arrival home!Show them NO mercy! I HATE Lead acids, anyhow! The bum ones 
will be EASY to find! But not having to do 50 miles a day I'm going for more 
static testing.So, IF ya got several feet of cable and a buncha resisters, 
Tony Ascrizzi useta use steel banding from shipping crates, cheep, works 
fine as you won't have to load batteries long to find a bum one!Streatch the 
stuff out on yur driveway as they get HOT!Doing this INSIDE is nice on a 
cold day, on yur concrete garage floor. But NOTHING that you can set FIRE 
to? Safety first and DON'T create ANY sparks around your 
Badd-eries!!!!Remember the Hindinberg effect in quick time!?THAT finished 
off lighter than air air travel!

Have fun!

Bob
----- Original Message ----- 
From: "EVDL Administrator" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Tuesday, September 15, 2009 11:24 PM
Subject: Re: [EVDL] Reference material for flooded lead acid batteries


> It's really useful to have a dummy load you can use to load down your 
> entire
> battery pack in the garage. Something in the area of 75-100 amps will
> usually let you locate the stinkers with an ordinary voltmeter.
>
> I don't know where you'd find a dummy load suited to a road EV's battery;
> most I've seen advertised were meant for golf cars at 36 or 48 volts. But
> various homebrewing methods have been used, depending on the voltage of 
> the
> battery. Some examples :
>
> Cheap household space heaters with their fans powered by the mains; each 
> one
> draws about 12 amps at 120 volts, so 6 of them will make a 72 amp load at
> 120v.
>
> Electric water heater elements (immersed in water of course). A typical 
> 240
> volt element uses 3000-4500 watts (12.5 - 18.75 amps at 240v).
>
> Barrels of salt water with electrodes; dip the electrodes in further to
> increase current (use only outdoors; this produces poisonous chlorine 
> gas!).
>
> My dummy load is a couple of resistance heaters from derelict heat pumps,
> inserted into the side of an old, large metal rural mailbox. The door is
> long gone, and I cut a hole in the other end for the fan from a discarded
> range hood. I connect the load to the battery to be tested, plug the fan
> in, and apply 12 volts to the contactor. It warms up the garage nicely in
> the wintertime. ;-)
>
> Like mine, most or all of these will need a properly rated contactor. If
> you use multiple units such as space heaters or water heater elements, you
> may be able to use a single switch on each unit, and that may be cheaper
> than a large contactor for the whole batch. Be sure your switches or
> contactor are DC rated at the proper voltage and current.
>
> If you connect your load in place of a DC motor and add a series inductor,
> you can probably use your EV's contactor to turn it on and off, and maybe
> even use the DC controller to set the load current. In most cases though 
> a
> controller isn't necessary. Just design the load for the current you want
> by Ohm's law, I = E/R or current = voltage / resistance.
>
> David Roden - Akron, Ohio, USA
> EVDL Administrator
>
> = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
> EVDL Information: http://www.evdl.org/help/
> = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
> Note: mail sent to "evpost" an "etpost" addresses will not
> reach me. To send a private message, please obtain my
> email address from the webpage http://www.evdl.org/help/ .
> = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
>
>
> _______________________________________________
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> Usage guidelines: http://evdl.org/help/index.html#conv
> Archives: http://evdl.org/archive/
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> 

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## EVDL List (Jul 27, 2007)

Looking for something else I saw these links that may be useful:

http://toolmonger.com/2008/10/24/carbon-pile-load-tester/
http://www.globar.com/ec/bulk-ceramic-resistors/disk-washer-resistors.html
http://www.globar.com/ec/bulk-ceramic-resistors/water-cooled-resistors.html

Victor




> EVDL Administrator wrote:
> > It's really useful to have a dummy load you can use to load down your entire
> > battery pack in the garage. Something in the area of 75-100 amps will
> > usually let you locate the stinkers with an ordinary voltmeter.
> ...


----------



## EVDL List (Jul 27, 2007)

If a person has a BMS system monitoring all the batteries, could you just
take a snapshot of voltage while driving at 100 amps at the end of a trip?
What kind of voltage difference do you see where you start to have a
concern? Roland provided an amp reading but I assume the technique that you
are referring to where you load up the battery looks at voltage at a
constant discharge.
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## EVDL List (Jul 27, 2007)

Another permanant solution, though its about 100$ in parts and quite a few
hours at the soldering bench, is an array of voltmeters.

Like so:
http://www.evconvert.com/article/led-bargraph-battery-monitor-part-2

I photo-documented my build here:
*http://picasaweb.google.ca/nicolas.drouin/EVLEDBargraph#5308051189801943362
*<http://picasaweb.google.ca/lh/photo/ObVotvj8_3dbq-ho3gGFxg?feat=directlink>

And reworked the schematic here:
http://docs.google.com/Doc?docid=0AU1hUv2dAJlCZGhtenpuaDhfNmc3OTV0NTgy&hl=en


With this kind of meter, you can see the side-by-side voltage drop of each
battery in your pack. If you have a poorly performing battery, you will see
it drop in voltage significantly more than the others.

In my case, I have two chargers each doing half the pack, some days I only
have access to one plug, so I see which half of the pack is less charged and
I make sure to drive according to accomodate the lowest battery. In extreme
mixed battery cases (look up the 'Forknswift') it is a very useful meter for
driving to accomodate the lowest battery in the pack!

In fact, I don't have a watt-hour-meter. With this setup, I can see the
voltage sag under load and have developed a 'feel' for when the pack is
nearing the end of its range. Coupled with an amp-meter for the batteries
(or motor) and a voltmeter for the pack; that's all I use for
instrumentation.

Cheers,


-Nick Drouin
Montreal, QC
www.evalbum.com/1890










> Steve Skarda <[email protected]> wrote:
> 
> > If a person has a BMS system monitoring all the batteries, could you just
> > take a snapshot of voltage while driving at 100 amps at the end of a trip?
> ...


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## EVDL List (Jul 27, 2007)

> EVDL Administrator wrote:
> 
> > Barrels of salt water with electrodes; dip the electrodes in further
> > to
> ...


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## EVDL List (Jul 27, 2007)

> EVDL Administrator wrote:
> > > Barrels of salt water with electrodes...
> 
> Roger Heuckeroth wrote:
> ...


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## EVDL List (Jul 27, 2007)

> On 16 Sep 2009 at 8:57, Nicolas Drouin wrote:
> 
> > Another permanant solution, though its about 100$ in parts and quite a few
> > hours at the soldering bench, is an array of voltmeters.
> ...


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## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> 
> > EVDL Administrator wrote:
> >>> Barrels of salt water with electrodes...
> ...


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## EVDL List (Jul 27, 2007)

----- Original Message ----- 
From: "EVDL Administrator" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Wednesday, September 16, 2009 10:24 AM
Subject: Re: [EVDL] Reference material for flooded lead acid batteries




> > On 16 Sep 2009 at 8:57, Nicolas Drouin wrote:
> >
> >> Another permanant solution, though its about 100$ in parts and quite a
> >> few
> ...


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## EVDL List (Jul 27, 2007)

> EVDL Administrator wrote:
> > Many years ago, I made a monitoring panel for my Comuta-Car, and
> > spent quite a bit less than that. I used 8 analog edgewise panel
> > meters, one per battery...
> ...


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## EVDL List (Jul 27, 2007)

> Roger Heuckeroth wrote:
> > Why create these toxic compounds needlessly, and take risks that are
> > unnecessary when there are safer ways to do it?
> >
> ...


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## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> 
> >
> > For a simple dummy load, I prefer Rich Rudman's "calibrated
> ...


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## EVDL List (Jul 27, 2007)

> John O'Connor wrote:
> > Assuming you are able to isolate the surface of the water and
> > connections, what would be considered a max voltage for the wire and
> > coat hanger(s) technique?
> ...


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## EVDL List (Jul 27, 2007)

Thanks,

But I was wondering how many batteries I can string together before 
it becomes an electrocution waitning to happen or some other such 
problem.

For example can I use coat hangers to test my entire 144 v pack?




> Lee Hart wrote:
> 
> > John O'Connor wrote:
> >> Assuming you are able to isolate the surface of the water and
> ...


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## EVDL List (Jul 27, 2007)

Hello John,

If you test the entire pack, you would have to read the voltage of every 
battery to see which one drops off.

Here is what I did when I built my first load tester that can either test 2 
volt cells or 6 to 12 volt batteries.

Go to a welding supply company and get some of the stainless steel 36 inch 
welding rods that are about a 1000 F. rating. The ones I have are about 1/8 
inch in diameter by 18 inch long for 75 amp for a 6 volt battery. Use a 36 
inch length for 75 amp for a 12 volt battery.

To double the ampere, just double the rods for 150 amp or double again for 
300 amps which will be eight 1/8 rods. Could use a larger diameter rod for 
higher ampere.

With these stainless high temperature rods, you do not need any water to 
keep from burning up.

Get two of those No. 6 set screw terminal lugs and set screw the lugs on the 
end of the wire. Fast the lugs to piece of wood or insulator board that you 
can get from a motor shop.

I pick up one of those old type starter solenoid, a 12 volt and 12 volt amp 
meter and a shunt for that meter.

Use a momentary toggle switch which is use to turn on the solenoid.

Now first take one rod and test it to see what ampere it will pull on one 6 
or 12 volt battery. After I determine the length and how many rods I need, 
then I assembly the whole unit into a metal box. Attach a carrying handle, 
drill a series of 1/2 inch holes in the back at the bottom and top for 
venting the heat.

I use a insulator board to mount the terminal lugs and insulator bushings to 
install brass studs through the box for attach a set of jumper cable to.

With this rig, I can test 90 battery cells or 30 6 volt batteries right 
after the next without any cooling down of the SS rods at any ampere up to 
600 amps.

Roland




----- Original Message ----- 
From: "John O'Connor" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Friday, September 18, 2009 7:45 PM
Subject: Re: [EVDL] Reference material for flooded lead acid batteries


> Thanks,
>
> But I was wondering how many batteries I can string together before
> it becomes an electrocution waitning to happen or some other such
> problem.
>
> For example can I use coat hangers to test my entire 144 v pack?
>
>
>


> Lee Hart wrote:
> >
> > > John O'Connor wrote:
> > >> Assuming you are able to isolate the surface of the water and
> ...


----------



## EVDL List (Jul 27, 2007)

> John O'Connor wrote:
> > But I was wondering how many batteries I can string together before
> > it becomes an electrocution waitning to happen or some other such
> > problem.
> ...


----------



## EVDL List (Jul 27, 2007)

----- Original Message ----- 
From: "Lee Hart" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Saturday, September 19, 2009 12:17 AM
Subject: Re: [EVDL] Reference material for flooded lead acid batteries




> > John O'Connor wrote:
> >> But I was wondering how many batteries I can string together before
> >> it becomes an electrocution waitning to happen or some other such
> >> problem.
> ...


----------



## EVDL List (Jul 27, 2007)

Thanks,
That makes sense. I was going to just turn on the heater I have 
installed but wanted to a bit higher load.
I will look for a cheapo heater to get the extra load



> Lee Hart <[email protected]> wrote:
> 
> >
> > For example, get an inexpensive 120vac ceramic heater. Take it apart.
> ...


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