I just bought a brand new Exide deep cycle battery and it will not charge above 75% on my battery/trickle charger. I did leave the battery hooked up for a couple of days after I returned which did drain it. I'm not sure if it drained it completely. I just can't believe that this could happen after one use. If anybody has any expertise in this area I would appreciate the advice. Thanks

Post battery model (and specs) and charger model and specs and where you are getting that 75% from. Are they Wets so you can take an hydrometer reading? If so what SGs?

Why are you charging a battery with a trickle charger? And what criteria are you using to determine it's only being charged to 75%?

Like others have said, where is that 75% figure coming from? Are you checking the voltage or the specific gravity?

You need to charge the battery with a good battery charger. Trickle chargers are for maintaining the charge, not achieving full charge.

Sorry, the battery is Exide deep cycle stow away 500 amps, 140 min reserve, 80 amp hrs part #24mdcst. The charger is a Schumacher SE 70ma manual/automatic 12v/24v. The directions for the charger stated that in automatic mode for deep cycle batteries it would charge the battery and once it reached its charge it would automatically switch to a maintenance/trickle charge. The charger has a regulator on it that indicated 75%. It would not go above 75% despite being on the charger for 2 or 3 days. I used the battery once and probably did drain it because I forgot about it still being hooked up. I just trying to figure out if I ruined it already because it won't charge to 100%. Thanks for the help.

Battery Question | Good Sam Community

MEXICOWANDERER
Explorer
Jun 25, 2013
A hundred cycles is a substantial percentage of a flooded L/A battery's life. For critical applications we used to "burn in" new batteries. 14.8 volts constant until the cell started to bubble at more than one bubble per second. This rendered more than 95% CCA and reserve capability.

Please keep in mind, the power company usually feeds even a small battery manufacturer with 750 kw capability. Electricity is expensive. So manufacturers green and condition new batteries with as few kWh as possible.

"Cycling" a new battery is a better PR term than "For best results slow charge the battery several hours". Plaid suits, fluorescent ties, and Italian loafers write the hype.
JamesJudasPries
Explorer
Jun 25, 2013
MEXICOWANDERER wrote:
"I would first assume"

Assume nothing unless you have money to burn.

Come on Mex, you're telling me that the first thing you would think of wouldn't be the slow 70mA charge is the reason the battery wont reach past the 75% indicator in a short time?
HiTech
Explorer
Jun 25, 2013
They don't get full capacity until they are cycled, but they reach full state of charge, just a bit sooner.

Jim
ryhed
Explorer
Jun 25, 2013
Aren't brand new batteries not supposed to achieve a full charge until a determined amount of charge cycles? I know golf cart batteries are that way. It takes around 100 recharges to reach max charge.
MVH1
Explorer
Jun 25, 2013
You guys are great! It sounds like I am using the wrong charger type of charger and that my battery might be ok. I will look into using the other charger and I appreciate all the advice. Thanks!
MEXICOWANDERER
Explorer
Jun 25, 2013
MEXICOWANDERER wrote:
"I would first assume"

Assume nothing unless you have money to burn. Did genuine battery shops disappear off the face of the earth when I wasn't looking?

Mark the wires according to the terminals. Remove the battery and take it to a rootin' tootin' battery shop and they will charge it, hydrometer test it and load test it. If the battery needs to be equalized they will do that too.

Batteries need to vacation fully charged. Trying to charge with a trickle charger would be like fighting a kitchen fire with a squirt gun. A discharged battery DOES NOT HAVE THE LUXURY OF WEEKS to recharge. Hard sulfation will form between start and finish and you will have doomed the battery.

If a trickle charger is all you have apart from the pseudo charger in the rig, you need some way to fully charge the battery. Easily. Fully. No guesswork. Many on this forum have a primary charger to raise voltage to a reasonable level then a mechanical charger to take over when the smart charger goes stupid in order to finish the job.
MEXICOWANDERER
Explorer
Jun 25, 2013
"I would first assume"

Assume nothing unless you have money to burn. Did genuine battery shops disappear off the face of the earth when I wasn't looking?

Mark the wires according to the terminals. Remove the battery and take it to a rootin' tootin' battery shop and they will charge it, hydrometer test it and load test it. If the battery needs to be equalized they will do that too.

Batteries need to vacation fully charged. Trying to charge with a trickle charger would be like fighting a kitchen fire with a squirt gun. A discharged battery DOES NOT HAVE THE LUXURY OF WEEKS to recharge. Hard sulfation will form between start and finish and you will gave doomed he battery.

If a trickle charger is all you have apart from the pseudo charger in the rig, you need some way to fully charge the battery. Easily. Fully. No guesswork. Many on this forum have a primary charger to raise voltage to a reasonable level then a mechanical charger to take over when the smart charger goes stupid in order to finish the job.
BFL13
Explorer II
Jun 25, 2013
rtmcavoy wrote:
BFL13 wrote:
Ignore the bogus 75% reading on the charger and just take SG with an hydrometer to get the truth. Or else let the battery sit for a couple days disconnected (no wires at all) and then take the voltage.

There are voltage vs SOC charts (of course they are all different, so check here before believing any one such chart)

I am trying to get educated what is SG with hydrometer?

http://www.engineersedge.com/battery/specific_gravity_battery.htm
JamesJudasPries
Explorer
Jun 24, 2013
Hi,

measuring SG means measuring specific gravity (also called relative density) of the battery electrolyte. This can only be done on a flooded wet cell battery, ie one that has vent caps. Basically, what happens is you take off the vent caps and use a hydrometer to measure the strength of acid/ state of charge in each cell (all 6) of the battery. The hydrometer draws some of the acid into its tube and you can see how much charge the battery has by looking at the floats on the hydrometer scale.

But really, I wouldn't bother with this quite yet. I would first assume that the charge rate on the charger you speak of is way too slow. I agree with the others on this forum. If you are sure your charger is 70 milliamps, ya it will take days maybe weeks to charge. You are better off with at least a 1.25a battery tender or something else with more current output.
MVH1
Explorer
Jun 24, 2013
BFL13 wrote:
Ignore the bogus 75% reading on the charger and just take SG with an hydrometer to get the truth. Or else let the battery sit for a couple days disconnected (no wires at all) and then take the voltage.

There are voltage vs SOC charts (of course they are all different, so check here before believing any one such chart)

I am trying to get educated what is SG with hydrometer?

Forum Discussion

Battery Question

About Technical Issues

Related Content

Battery Question??

Battery question

Battery Question

Battery Question

Battery/ charging question