another battery charging question

hermit · April 2008

bought 16 new wet cell NAPA 215AH 115 mins at 75 amps 6 volt deep cycle golf cart batteries (same as deka gc15 wet cell) man march/08 battery temp 65 F. this is my first time charging 6 volt deep cycle batteries.

- i am charging 1 battery with a motomaster auto multi-amp battery charger. battery manufacturer says to charge and do an equilization before putting into service. battery initially had 6.27 volts.

- charged battery on 2 amp 6 volt setting for 2 hrs and amp meter is reading 2.6 amps and 6.9 volts. amps not tapering off. no electrolyte bubbling.

- set charger on 20 amp charge, amp meter reads 13 amps at 7.8 volts. electrolyte started bubbling immediatly. did this for 10 mins. amps did not taper off.

- went back to 2 amp charge setting and after another 2 hrs the battery is still taking 2.6 amps at 6.9 volts and not tapering off.

- this is a charger that will will digitally read full when the charger figures the battery is full. it works like it should on 12 volt batteries.

- question, is the battery in absorbtion or do these deep cycle batteries like a 2.6 amp float at this voltage or is my battery charger not intelligent enough to charge deep cycle batteries. i do not have a specific gravity reader yet.(tomorrow) is there something i am missing in my thought process. please add any info as i have 16 of these yet to charge before i put into service and do not want to start out by damaging the batteries. thanks.

westbranch · April 2008

Re: another battery charging question

Hermit , what are the recommendations from the manufacturer for charging? volts & amps, time for EQ, SG, etc?
FWIW A fully charged '12 v ' battery would be at ~13.2 v so I would guess a 6 v should really be ~ 6.6 V ? your manufacturer will be able to tell you.

Cheers
Eric

mike95490 · April 2008

Re: another battery charging question

Deep cycle batteries have a higher "full charge" voltage than regular automotive batteries, and need a charger designed for them. I've got no idea if your charger can be configured for Deep cycle batteries.

If your battery is still taking 2.6 amps, it's likely still in the final stages of charging, which go much slower then the initial stages. A 215AH battery will take about 40 hours to charge from 50%, at 2.6 amps. If the current drops, and no bubbling, you have reached the limit of the charger. If you've charged past 50 hours, either the battery was very low, or something else is wrong.

You need to determine what the proper voltage is, and if you can't get a proper charge, check the specific gravity of the cells. Were they filled with water or acid ? Do you have a good voltmeter to measure voltages with ?

Lots of things could be wrong, just not enough data to determine what is wrong.

Is this the charger you are using :
Motomaster Nautilus Intelligent Battery Charger or
Motomaster Automatic 10/2A Battery Charger or
what ??

System2 · April 2008

Re: another battery charging question

Yeah, I agree, 2 amps for 2 hours is really nothing, same for 13 amps for 10 minutes. It just tickles the battery. Tickle (from the batteries point of view) as in this is funny, what's he doing?
Most people not seriously experienced with the in's and out's of lead acid batteries usually vastly underestimate the power required to properly recharge them.
This post is not a put down at all, we all have to start somewhere, and you're doing the right thing by coming here to ask questions. Without the help of this form, I'd still be out stumbling around in the dark, learning everything the hard way.
Best of luck with your project.
Wayne

RCinFLA · April 2008

Re: another battery charging question

If you are confident your voltmeter is accurate then battery is about 20% discharged (80% state of charge). You have to have a voltmeter with about 0.1% accuracy to be sure.

2 amps for 2 hours is nothing. 7.8 vdc with 20 amp charge indicates battery is not 20% discharged. This voltage would be considered equalization voltage and should not be left for more then an hour.

Safest approach is to just let it go on 2 amp charger with a limit of 6.75 v float level for several days.

hermit · April 2008

Re: another battery charging question

i finally skipped using my canadian tire battery charger. i was using this charger because it is automatic and tapers off charge and tells me how many amps the battery is taking. i hooked up 2 seperate sets of 8 batteries in 12v configurations (2 in series, 4 sets parallel) and now have my 2 iota dls 75 charging the batteries. the iota`s with iq4`s took about 12hrs before they dropped into float mode.
1 of the 16 batteries i bought had warped plates on the center cell but had good voltage, the dealer ordered in a new one for me.
the voltages ranged from 6.21v to 6.29v before i charged them.
the dealer cannot find the details on charge/maint on these batteries, so i am using general specs for now.
i started keeping a log of cell voltages and depth of discharge to see if i can get a 7 year life span on these batteries.

icarus · April 2008

Re: another battery charging question

Get yourself a good temp compensating 3 stage charger. I don't know what you are using for a power source for charging, but especially if you are using a generator, I would recomend a Xantrex True charge 20 or 40.

Would also suggest that you get a good hydrometer as well. Volt meter readings to determine battery condition are very inaccurate. If you are looking for long battery life, consider the discharge amount very carefully. Avoid deep discharges, (I never let mine get below 80% s.o.c) and avoid partial recharges. Try to get them to 100% every three days at a minimum.

I would also invest in a good monitering system such as the Bogart Tri-metric meter. It gives you all kinds of useful information.

Good luck

Icarus

System2 · August 2008

Re: another battery charging question

Sorry to bring this post back after so long, but I have a question.

Is it better to charge 6-volt batteries as 6 volt singly or is it better to put them in series @12 volts and charge them together?

thanks.

mike95490 · August 2008

Re: another battery charging question

Tim F. wrote: »

Sorry to bring this post back after so long, but I have a question.

Is it better to charge 6-volt batteries as 6 volt singly or is it better to put them in series @12 volts and charge them together?

thanks.

It depends on if you have a 6 V or 12 V charger.

If your 6V batteries are all in good shape, series them to use a 12V system. If you have some "dogs" and you don't want to boil your good batteries trying to equalize the weak ones, get a 6V charger for them.

BB. · August 2008

Re: another battery charging question

As Mike said, charging batteries in series based battery bank will work very well--but only if the batteries are of matched size/capacity/age/brand/etc... If the batteries are not pretty much identical (with the same initial level of charge)--one battery will get overcharged and the other will not get enough charge (say two different batteries that are not always used together as a 12 volt series connected pair--or if one battery is failing and the other is still good).

-Bill

System2 · August 2008

Re: another battery charging question

I have a similar question. I have an 8d battery that will be used during the evening for lighting and a fan. Can I recharge with my truck via jumper cables during the day. What type of problems should I anticipate or precautions should I take. thanks

mike95490 · August 2008

Re: another battery charging question

refugioco wrote: »

I have a similar question. I have an 8d battery that will be used during the evening for lighting and a fan. Can I recharge with my truck via jumper cables during the day. What type of problems should I anticipate or precautions should I take. thanks

It will work POORLY, for a while, then fail

1) Deep cycle batteries will not get fully charged from a vehicle alternator

2) the high current surge <sparks> when your low battery is connected to the jumper cables, will be un-regulated, and likely way beyond the charge rating from the battery's manufacturer.

another battery charging question

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