We have a solar panel on the roof of our travel trailer that keeps our two 6 volt batteries charged when we're boondocking. This winter we're leaving the trailer in an RV park in the mountains at 6900 ft. elevation, and, as this is 180 miles from where we live, I can't add dist. water when the batteries need it.The batteries will be un-attended for 7 months and temps will go down to zero or below.I've been told to just dis-connect the neg. connection and not worry about the batteries, or should I leave them connected with the solar charger running as usual or should I take them with us and hook a trickle charger to them?Sorry to be so long winded about all this, but I'm really confused about which way to do this.Thanks for any suggestions, BB

I would take the batteries home and care for them. Mainly because your solar will probley be covered in snow often. Let's see what others say?

If your charger is a smart mode charger it probably will never heat the batteries up enough to boil fluids out. I lost one battery due to the fluids being boiled out and then changed over to smart mode charging. I still check my batteries every couple of weeks but never see them low on fluids any more.I probably would just just remove the batteries in your case since you are not around to check on them for that long of a time frame...A fully charged battery will not freeze but being disconnected for that long of time the charge would probably start dropping off on you unless you had some sort of solar trickle charge feeding them.Batteries are too expensive to just abandon for that long of time without hands on maintenance of some sort.Roy Ken

I would leave them on solar. No water should be needed for at least six months.

Hi,I would fill them with water and leave them on the solar charger. What charge controller do you have?

Winter solar battery charging when you can't add water?

19 Replies

time2roll
Nomad
Sep 14, 2014
Secure them well in the truck bed.
3_tons
Explorer III
Sep 14, 2014
Removing the batteries and then replacing only once in seven months thus having no morning after sickness ($$)...Sorry, what was the silly question??
pianotuna
Nomad III
Sep 14, 2014
Hi,

The colder the better so long as they are fully charged. Mine winter nicely and we do get to -40. I do have solar.
Buckshot_Bill
Explorer
Sep 14, 2014
Thanks for all your different replies.
The rig in question will be in the White mountains of Eastern Arizona at 6900 ft. elevation- Show Low, Az. area- for those of you familiar with that "neck of the woods" (in an RV park and not out in the boonies,) so it'll be SOMEWHAT more secure, but I'm leaning toward the "put them in the back of the truck and take "em home" side too.
I'm mostly concerned about not being able to add H2O if they need it, and the variables about different loads, the cold killing them,etc.
Much obliged,I sure appreciate everyone's help.
Bill
JeepCB
Explorer
Sep 13, 2014
Take them home. Better safe that sorry. You might want to take propane tanks too! Man if both were gone..................just sayin'
Good luck!
mena661
Explorer
Sep 13, 2014
smkettner wrote:
I would leave them on solar. No water should be needed for at least six months.
X2
RJsfishin
Explorer
Sep 13, 2014
What make you think the batts will still be there when you get back ?
Too many risks, take them w/ you while you can.
MEXICOWANDERER
Explorer
Sep 13, 2014
Diapered Horse Trots Up...

A lot depends on what the charge controller is capable of or more importantly what it isn't capable of.

Myself I like BFL's answer.

Spring arrives. You drive all the way up there -ooooooops ---- happens. The panel got covered with three feet of snow. Oops, something, a load turned on when it shouldn't have. Oops, the controller got a sudden case of PMS.

You find all this out not in your driveway but way the hell and gone back in the sticks. Where does it leave you. Up el creeko is where.

I like to weigh decisions like this using the "Risk Benefit" ratio. IMHO the teeter-totter with the take-them-home side is jammed to the ground.
landyacht318
Explorer
Sep 13, 2014
If the solar controller has adjustable setpoints, lower ABSorptionVoltage to lower 14's and duration should be no more than 30 minutes.

lower float to manufacturer recommendations for expected temperatures.

Disconnect all loads on battery.

If batteries self discharge to 'zero' in winter, with all loads disconnected, then they are done for anyway and it does not matter what you do.
time2roll
Nomad
Sep 13, 2014
Cold battery also has a much slower self discharge. Yes disconnect all loads if snow can linger for a few days or more.