Battery Advice re Storage and Charging

[legolas]

Need advice from those who store thier MH over the winter and what you do about the batteries. I will be storing my MH at a place near my home. I begin storing in October and start camping in May. Assuming that I cannot put a battery minder on the batteries while in storage what options if any do I have. I could of course pick up the MH and bring it home for a couple of days and put the battery minder on it. Are there any other viable options. What do you do.

[Almot]

DrewE wrote:

The rate of self-discharge varies a lot based on the temperature of the battery. In very hot weather, it will be well over 30% in six months. In subzero weather, it's a lot less than that amount.

October through May isn't going to be hot.

As Time2 suggested, 100W solar with controller would've solved the problem of self-discharge (in any weather).

[red31]

specific gravity of the battery liquid, as the battery discharges the sg goes down and as it recharges it goes up.

one can measure the sg of a wet battery to help determine how fully charged it may be, often adjusted for temperature to base temp.

[legolas]

Jim@HiTek wrote:
After they've been serviced...water, cleaning the posts, fully charged, etc., just disconnect the grounds. They'll hold the charge for months, losing only a few tens of a volt.

The over winter period isn't a concern for batteries that have a good SG reading, which means the acid is nice and strong. Won't freeze. If a battery does freeze, it was on it's way out anyway.

I never bothered to check SG when I over wintered the RV in Fairbanks, Alaska and never had a problem. I've also left the RV parked for months at a time in the desert in the summer without a problem.

And all I did was disconnect the grounds.

ot familiar with the term SG

[legolas]

IB853347201 wrote:
I'd go with what Jim@HiTek said! Good advice.

I am not familiar with the term SG.

[DrewE]

Almot wrote:

Old led acid battery - completely disconnected from all loads - can discharge 30% in 6 months, if left without maintenance charge. Should still survive.

The rate of self-discharge varies a lot based on the temperature of the battery. In very hot weather, it will be well over 30% in six months. In subzero weather, it's a lot less than that amount. The general rule of thumb (which is reasonably accurate) is that there's a doubling or halving of the rate of self-discharge for every 10 degree Celsius change in storage temperature.

[time2roll]

Fully 100% charge the battery and disconnect is fine.
100 watt solar panel and controller connected direct to the battery would not hurt either.

[Almot]

Not sure why you can't put a battery minder on it, but there are battery minders that don't need 110V. It comes with a small 2W-20W solar panel and cables with clips to connect to the battery. Not really a minder, just a low-power DC supply. Sold everywhere. I would get the smallest, 1.5-2.5W, since it has no controller and won't know when to stop - so in theory there is a risk of overcharging, but with 2W panel I've never heard about this happening.

Old led acid battery - completely disconnected from all loads - can discharge 30% in 6 months, if left without maintenance charge. Should still survive.

[IB853347201]

I'd go with what Jim@HiTek said! Good advice.

[Jim]

After they've been serviced...water, cleaning the posts, fully charged, etc., just disconnect the grounds. They'll hold the charge for months, losing only a few tens of a volt.

The over winter period isn't a concern for batteries that have a good SG reading, which means the acid is nice and strong. Won't freeze. If a battery does freeze, it was on it's way out anyway.

I never bothered to check SG when I over wintered the RV in Fairbanks, Alaska and never had a problem. I've also left the RV parked for months at a time in the desert in the summer without a problem.

And all I did was disconnect the grounds.

[RoyF]

I like to start and run the generators (two Hondas) at least once a month. I let them run for about an hour, and that keeps the batteries at full charge.

[wildtoad]

If stored outside simple solution might be to make sure the battery disconnect switches are “open” to prevent battery drain. Then since you should run the generator from time to time anyway, close the switches and run then gen under load for about an hour which should recharge the batteries. Since being disconnected any battery drain would be minimal.

I don’t have this problem as I live in the south and park my mh less than 20 feet from my house under a carport....