astounded how fast batteries discharge in storage

Hart_family · 01-13-2019, 11:47 PM

We disconnected our two deep-cycle RV batteries from our trailer at the season's end. We store them in our garage and have worked to keep them fully charged using a smart trickle charger. Because I have two batteries but only one charger, I switch them out ever 1-2 weeks once they are fully charged.

I am finding that my batteries are going from 100% charged to near 0 in about 8 days time. Is this a normal depletion time when disconnected?

Here in Utah, our high temperatures have been in the 30's and our lows are often in the 20's. But these are in our garage, which is slightly warmer (but not a ton). The batteries are Interstate SRM-24 with 690 cranking amps (550 CCA), 81 amp-hours, and a reserve capacity of 140 at 24 amps.

Beachbourbon · 01-14-2019, 12:06 AM

I don’t think this is normal. I keep a group 24 in the garage with out charging and then charge it before I use it. It has never been at zero, and is usually only slightly discharged and takes less than 60 seconds to hit a full charge on the battery charger.

After you take them out of the RV do you charge them in the garage before trickle charging? My battery usually needs a charge after I remove it due to running the jack and slide out. Otherwise, It sounds like you have batteries that are past their useful life and need to be replaced.

Hart_family · 01-14-2019, 12:15 AM

Thanks. The batteries were fully charged on the RV before disconnecting them. Also, the batteries are brand new.

dsol · 01-14-2019, 03:48 AM

Cold weather is hard on batteries but your situation is terrible. I wonder if your batteries are damaged. Are they sealed? Have you checked the water level if not? Maybe they have been overcharged and you boiled out some water? They can’t be more than about 2 years old right? I don’t get it.

I would also check that trickle charger and see if it is actually cutting off when the batteries are full. Some do not and they will overcharge too.

Hart_family · 01-14-2019, 03:58 AM

The batteries were purchased brand new 6 months ago, so that is what I mean by "brand new".

Not sure what sealed means, but there are two panels on the top of each battery, each with three round water ports. I have carefully checked the water levels over the few months I have owned them and only had to add about 1/4-inch of distilled water one time.

Not sure how they would ever have been overcharged. The charger is new also and is a smart/intelligent charger with a microprocesser. It is a Noco Genius G3500 (3.5 Amp) smart charger (https://no.co/g3500). "Guaranteed" to not overcharge batteries and to be left connected indefinitely.

Beachbourbon · 01-14-2019, 04:00 AM

Quote:

Originally Posted by Hart_family

Thanks. The batteries were fully charged on the RV before disconnecting them. Also, the batteries are brand new.

Do you have the screws that came with the battery on the terminals when stored or on the plastic holder?

Hart_family · 01-14-2019, 04:08 AM

Quote:

Originally Posted by Beachbourbon

Do you have the screws that came with the battery on the terminals when stored or on the plastic holder?

Not sure what you meant...sorry. Here is a photo of the charging battery...

Beachbourbon · 01-14-2019, 04:11 AM

Quote:

Originally Posted by Hart_family

Not sure what you meant...sorry. Here is a photo of the charging battery...

Take the wing nuts off the posts! This is what I was talking about. You are discharging your battery by leaving the wing nuts on IMO.

Hart_family · 01-14-2019, 04:16 AM

Quote:

Originally Posted by Beachbourbon

Take the wing nuts off the posts! This is what I was talking about. You are discharging your battery by leaving the wing nuts on IMO.

Okay. I didn't think that wingnuts would be discharging electricity since they are not connected to anything or completing a circuit, but I am happy to try that and see what results I get. Thanks.

Beachbourbon · 01-14-2019, 04:22 AM

O.k, please let us know if this helps.

When we buy these batteries, they typically come with nuts that are attached to a red plastic post cover. The nuts are not touching or on the positive and negative screw posts of the battery. There is a reason for this.

Thom · 01-14-2019, 10:23 AM

Quote:

Originally Posted by Beachbourbon

O.k, please let us know if this helps.

When we buy these batteries, they typically come with nuts that are attached to a red plastic post cover. The nuts are not touching or on the positive and negative screw posts of the battery. There is a reason for this.

And what is that reason? Never heard this before but always willing to learn something new.

When you set the batteries in your garage, are you setting them on a piece of wood to insulate them from concrete or work bench?
That is one rapid discharge for static batteries!

chily3 · 01-14-2019, 04:34 PM

Might want to take them back, still under warranty and have them check out the charge level etc.

ArmyVeteran · 01-14-2019, 07:20 PM

Not a EE but know a lil about lectric

How does a wing nut attached to the lead alloy post of a battery any different than a battery with no wing nuts or for that matter 20 feet of cable that goes no where?? There is no path for current flow?

Just saying...............

Having said that. Under the conditions described by OP. There is definitely a problem. Not normal for a battery under temperatures that are not that extreme.

ArmyVeteran · 01-14-2019, 09:12 PM

Batteries on Concrete.
Yep, heard that one my entire life.
And I followed it. Even as recent as last year when I replaced the batteries on our golf cart. MY ACHING BACK ughh.

Here is the poop and not necessarily the scoop haha

https://northeastbattery.com/do-ceme...car-batteries/

1l243 · 01-15-2019, 01:07 AM

That is not normal. I don't agree with the wingnut attached theory. Actually have never heard of such a thing.

When you say your batteries are going from 100% to 0% what does that mean in actual voltage. Do you test it with a voltage tester and get a reading?

I run four 12 volt deep cycle batteries on my trailer. I have a battery disconnect switch which cuts all connection to the trailer but all the cables are still connected to the terminals. I fully charge the batteries before storing the trailer for the winter. Fully charged the batteries read about 12.9 volts (100%). The trailer has been stored for over 3 months now and the batteries read 12.6 volts (85%). There is a level of discharge but some of this is because I turn on the batteries run a few led lights for a few minutes once or so a week to check on the the trailer. Very little discharge so to speak.

I would make sure your charger is working properly. If it is, I would return the batteries for new ones since they are under warranty.

Once batteries become totally discharged it takes a toll.. You may not be able to ever get them to charge 100% again
My set

dsol · 01-15-2019, 02:44 AM

I agree that it sounds like the batteries themselves are likely the culprit. You are doing everything correctly unless your smart charger is screwing up but that is very unlikely.

Agree with the suggestions you should try and take them back.

and by sealed batteries I mean you cannot remove the caps and check the water. You do not have sealed batteries.

One other idea is you can use a battery water tester or hydrometer to test the water. That will tell you the condition of the battery. They cost like $10. Pretty cheap to try and see the condition of the cells. Basically it tells by the water what shape your battery is in.

Something like this:
OTC 4619 Professional Battery Hydrometer https://www.amazon.com/dp/B0050SFVHO..._PyvpCb8XD9698

sundancer 87 · 01-15-2019, 06:12 AM

I've said it once so I'll say it again. Any battery that has a CCA MCAA listing is not a deep cycle battery, regardless of the sticker.
All you have is possibly a heavy duty automotive starting battery.

Local150 · 01-15-2019, 07:46 PM

Quote:

Originally Posted by Hart_family

Okay. I didn't think that wingnuts would be discharging electricity since they are not connected to anything or completing a circuit, but I am happy to try that and see what results I get. Thanks.

The wingnuts have absolutely nothing to do with it. Do you have them sitting directly on a concrete floor ?

franktafl · 01-16-2019, 03:11 PM

Quote:

Originally Posted by dsol

I agree that it sounds like the batteries themselves are likely the culprit. You are doing everything correctly unless your smart charger is screwing up but that is very unlikely.

Agree with the suggestions you should try and take them back.

and by sealed batteries I mean you cannot remove the caps and check the water. You do not have sealed batteries.

One other idea is you can use a battery water tester or hydrometer to test the water. That will tell you the condition of the battery. They cost like $10. Pretty cheap to try and see the condition of the cells. Basically it tells by the water what shape your battery is in.

Something like this:
OTC 4619 Professional Battery Hydrometer https://www.amazon.com/dp/B0050SFVHO..._PyvpCb8XD9698

This will also let you know if you have a bad cell or a cell that is going bad.

rich2481 · 01-19-2019, 10:00 PM

How smart is your trickle charger and where are you storing your batteries? floors are a no no,, wood under them is best, Concrete seems to leach them, not sure why and I am a EE, some Smart chargers put a small load on a battery once it is charged then once it reaches a certain level it turns back on to charge. I dont know if this is the case. But I would suspect your charger.

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