Storage of Deep cycle batteries

[OptsyEagle]

Is it hard on a deep cycle battery to be stored at outdoor temperatures in the winter ( below 0 degrees F) or would it perhaps be good for it by reducing discharge.

I would appreciate your thoughts on this.

 

[drewpster]

Re: Storage of Deep cycle batteries

I would be concerned with freezing damage. At very least I would store them in a place that stayed above freezing temps. Freezing can ruin the batteries.

Its also a good idea to keep them on a maintenance charger while they are being stored for long periods.

 

[Boatist]

Re: Storage of Deep cycle batteries

The cold slows the self discharge rate.
Still should charge at least every 2 months is winter.
Also if it is fully charge it will not freez until way below 32 degrees F.
My car battery did not freez and started the car fine at -30 in Montana,
but I had a Outlet that turned on a block heater and battery charger 1 hour before my normal drive.
Still for me I like to keep them above 32 Degrees inside.

 

[OptsyEagle]

Re: Storage of Deep cycle batteries

Thanks guys.

Drewpster, when you say you keep them on a maintenance charge, what would that be? My charger has a 10A or 2A, either manual or automatic. I think the automatic reduces the charge as it gets fully charged but I'm not completely sure. Would one of those settings work as a maintenance charge? My battery is a 70Ah, 12Volt deep cycle.

 

[wileecoyote985]

Re: Storage of Deep cycle batteries

Below is a list of approximate freeze points for battery electrolyte at various states of charge (or discharge).

As you can see, a fully charged lead acid battery has an approximate freeze point of -77 degrees Fahrenheit.

A fully discharged battery has an approximate freeze point of +20 degrees Fahrenheit.

Hope this helps

Gary

Electrolyte Freeze Points
at Various States-of-Charge
for a Wet Lead-Acid Battery Table



Approximate
State-of-Charge
(SoC)
Approximate
Depth-of-Discharge
(DoD)
Approximate Electrolyte Freeze Point

100%
0%
-77°F
(-67°C)

75%
25%
-35°F
(-37°C)

50%
50%
-10°F
(-23°C)

25%
75%
5°F
(-15°C)

0%
(DISCHARGED)
100%
(DISCHARGED)
20°F
(-6.7°C)

BTW. Conventional wisdom is that as long as the charge is maintained, the lower the storage temperature (within reason) the better.

 

[drewpster]

Re: Storage of Deep cycle batteries

In the early days I what is called a trickle charger. It consisted of a small unit that plugged into the wall with two wires that clamped onto the battery and maintained a constant low voltage charge to the battery. This kept the battery "hot" for use after extended storage periods. Trickle chargers worked in so far as they kept a battery charged, but they were not very good for the longevity of the battery. Nowadays I use "smart" chargers. I have one on board the boat an another I use while the batteries are on the bench. The one on the boat is very expensive and is intended to keep the batteries at an optimum state of charge based on each battery's state. It keeps me from buying batteries as often and is fully automatic. It works based on temp and state of charge and is also designed specifically to monitor and maintain the batteries for storage. It also allows me to keep the batteries and charger in the engine compartment without as much risk of blowing up my boat.

The charger I use on the bench is also a "smart" one and is considerably less expensive. It is made by Shumacher. It has different settings for different types of batteries, it has a storage mode and is automatic. The thing to look for when buying one is whether or not it is specifically designed for your battery type and is used to store batteries. Lower priced units may not have that feature.

The main difference between the two charges is that the on board charger is a bit "smarter" because it compensates for temperature, is designed for multiple battery banks and is ignition protected for use in engine spaces. The Shumacher is meant to charge one battery at a time and is not ignition protected.

Try to use a charger meant for your battery type (deep cycle, gel cell ect.). Get one that has a storage mode and is automatic. The Shumacher has worked well for me.

 

[OptsyEagle]

Re: Storage of Deep cycle batteries

Thanks for the info everyone. Really appreciated.

 

[Saskatoon2005]

Re: Storage of Deep cycle batteries

I live in Canada, and charge my batteries fully before winter (the one for my boat) and then I leave it all winter long. There is no loss of power and no damage done to the battery. I have done this for a couple years now with no problems...

 

[OptsyEagle]

Re: Storage of Deep cycle batteries

Is it left in outdoor temperatures?

 

[Saskatoon2005]

Re: Storage of Deep cycle batteries

Yes it is left in outdoor temperatures...up to minus 30 degree Celcius