6 Volt Batteries running down in Storage

[inlineskater]

In October I bought a new MH in IA. I drove it home and stored it because we are not going south from Minnesota this year. I have been up twice to bring things to it and get things from it. I store it in a garage 2 hours from my home. I have found the coach batteries (4 - 6 volt) to be dead when I get there after a couple of weeks with the battery cutoff switch turned off.

I spoke to McKee RV where I bought it and they said it is just the cold weather. Dennis said that they turn off at a certain voltage and you have to shock them to get them to recharge. In my other motor homes with 12 volt coach batteries I would shut off the battery switch and when I came back they would usually have at least 11 volts after being stored all winter.

Are 6 volt batteries different?

I left it plugged in this time and that should keep them up.

[A32Deuce]

Unless the cut off is on the batterys them self and do disconnect them, the factory ones usually have some draw from the batterys for CO/propane, radios to keep time, control panels sometimes etc. Best to have plugged in or disconnect that you disconnect the bats.

[carl.swoyer]

First thing that comes to mind is battery water level, then corrosion on the post.
Second would be, are you turning off the battery disconnect?
If the disconnect is on other things will draw off the batteries.

[inlineskater]

Originally Posted by carl.swoyer

First thing that comes to mind is battery water level, then corrosion on the post.
Second would be, are you turning off the battery disconnect?
If the disconnect is on other things will draw off the batteries.

There is no corrosion, and I checked the water, did turn off the red battery disconnect, that is why I am confused. I think this left over 19 was sitting on their lot for awhile. I wonder if some of the cells in the batteries are bad now.

[Mark_K5LXP]

Originally Posted by inlineskater

I spoke to McKee RV where I bought it and they said it is just the cold weather. Dennis said that they turn off at a certain voltage and you have to shock them to get them to recharge.

Batteries never "shut off". Cold weather will not cause batteries to go dead, in fact at lower temperatures the chemical activity is reduced and self discharge slows down preserving charge.

6V batteries aren't different. The issue you're having is parasitic or unswitched loads that aren't removed with your disconnect switch. The typical remedy is to add a switch or lift a cable for storage. Leaving it plugged in to shore power works too, but that has it's own perils so it depends on what your circumstances are which way you want to go.

Sometimes if a battery is run totally flat and kept there a long time, it does take a "boost" to wake it up so it starts accepting charge current. Some "smart" chargers won't turn on until they see some minimum voltage present on the battery, so having a "dumb" charger to get it started can be an advantage. This may take anywhere from minutes to days depending on how far down they are.

Mark B.
Albuquerque, NM

[theoldwizard]

All batteries self discharge when in storage, but dead in a couple of weeks is NOT typical. My guess is one battery is pulling all of them down. The only way to find out, is to fully charge the batteries and before storing them disconnect them from each other. Last use a hydrometer to measure the specific gravity of each cell in each battery. Record this.
Next trip to the storage location, check the specific gravity of all cells and compare to your previous results.

[Arch Hoagland]

There are battery shutoffs and battery shutoffs. They vary.

This is a guaranteed battery shutoff:
https://www.amazon.com/WirthCo-20128.../dp/B000CQFWLY

[inlineskater]

I called Forest River warranty dept, and they want me to take it to a service center to have the batteries tested.

[Old Scout]

….all good input...only sure way to disconnect batteries in storage is to disconnect positive cable at battery post.....even new batteries can have bad cells--if abused [eg, totally discharged] on the sales lot, they may be ruined....12.1 volts is about 50% charged, so 11 volts would be very low--its not a linear measure....likely these bats are not being fully charged to begin with--a fully charged battery, at rest for 3 hours, would be 12.6 or 12.7......

[Sbrownstein]

I used to rely on the salesman's switch and convinced myself that it was OK. Well, it really isn't for long term storage. My parasitic drain is around 400 ma. Not much but that means that every 24 hours I lose 9.6 AH. But that means 67 AH per week and I only have 240 usable AH in my house bank, so I am at 50% in 4 weeks or so.

Put in one of these https://www.amazon.com/Zoostliss-Bat...motive&sr=1-11 and 6 weeks later I am still at 12.7 v or 100%.

[Ted Lambert]

Originally Posted by Mark_K5LXP

Batteries never "shut off". Cold weather will not cause batteries to go dead, in fact at lower temperatures the chemical activity is reduced and self discharge slows down preserving charge.

6V batteries aren't different. The issue you're having is parasitic or unswitched loads that aren't removed with your disconnect switch. The typical remedy is to add a switch or lift a cable for storage. Leaving it plugged in to shore power works too, but that has it's own perils so it depends on what your circumstances are which way you want to go.

Sometimes if a battery is run totally flat and kept there a long time, it does take a "boost" to wake it up so it starts accepting charge current. Some "smart" chargers won't turn on until they see some minimum voltage present on the battery, so having a "dumb" charger to get it started can be an advantage. This may take anywhere from minutes to days depending on how far down they are.

Mark B.
Albuquerque, NM

I agree with you Mark.
I have never removed a battery because of cold weather. As long as it is charged before storage even minus 40 will not harm.
It amazes me how many people remove a battery to store over the winter in a nice cozy warm basement, does no good and actually harms them.
All I do is disconnect positive lead.