Looking for the best way to keep my batteries charged when it may not be used for months at a time, like over the winter.2 6v batteries with a 12v load disconnect switch.160w solar using a 4 stage Bogart controller, the trailer sits uncovered in the sun.Converter/charger is a WFCO 45A.Also have a 1.5A Battery Companion (battery minder) available.Currently I've been leaving the trailer plugged in to city power with the batteries connected. I don't believe the solar does anything as long as it sees the WFCO's float voltage.Options1. Leave it the way it is2. Unplug city power, throw the battery disconnect and let the solar do it's thing when the sun is out. Which I suspect would be pretty much nothing if the 12v load is connected.3. Disconnect the batteries from the trailer and hookup the Battery Companion.

The solar is much better than the shore power.

I disconnect the master switch and let the solar (120W?) panel keep the batteriestopped up. The voltage varies between 12.6 and 12.8 all winter.

Since the WFCO series of converters is so well known to rarely if ever go into a rated 14.4 volt bulk charge I simply turned mine off and now charge / maintain my battery with a stand alone CTEK Charger that really does do 14.4 and is capable of properly maintaining the battery automatically, whether during the season when I'm using the camper or now during winter storage when I'm not. My 8 yr old Interstate G27 is still reading an unloaded 12.8 volts after last seeing this charger 3 weeks ago ... it's in better shape now than it has been for years when it was being abused by the WFCO.

Actually all three methods would work and are currently employed by forum members. Since you have a WFCO onboard, solar would be my choice since 160 watts should suffice for just keeping a pair of batteries topped off. Many do choose to remove batteries and place them on a battery tender type device, we store our rig in our sideyard plugged in and let our Iota IQ4 do it's job.

If there is enough sun for long enough in the day, the solar will get the batteries to a higher voltage than the WFCO has them floating, and follow the solar controller's charging profile.No idea why you never see that.You should be able to leave the WFCO on and the solar on with no confusion between them, so after the solar is over late in the day, the WFCO will keep them at 13.x overnight.

Keeping those batteries up to snuff during long term storage

11 Replies

Boon_Docker
Explorer III
Nov 17, 2016
kampinguru wrote:
I just charge the 2 12V AGM batteries and disconnect them from the trailer and leave them sitting over the winter. Batteries are 10 years old and still working fine when I boondock. Do the same with my truck batteries. Change em up and disconnect them from the truck and leave them in the truck. They have always started the truck fine in the spring without charging.

^^ That is exactly the same thing with I do every winter with my wet cells for the TT and the TV.
kampinguru
Explorer
Nov 17, 2016
I just charge the 2 12V AGM batteries and disconnect them from the trailer and leave them sitting over the winter. Batteries are 10 years old and still working fine when I boondock. Do the same with my truck batteries. Change em up and disconnect them from the truck and leave them in the truck. They have always started the truck fine in the spring without charging.
westend
Explorer
Nov 16, 2016
If you can tilt a panel, you don't have to worry about snow in the Winter. My single panel is snow free on the day following a snow event. At some point in the Winter, I may get on a ladder and remove snow around it as I'm clearing the rest of the roof.
time2roll
Nomad
Nov 16, 2016
+1 for just Bogart and the switch off to prevent discharge during any snow.
Temperature compensated right?
corvettekent
Explorer
Nov 16, 2016
I unplugged my converter years ago when I installed solar. Even in the clouds of western Washington my batteries stay charged with the solar.
DrewE
Explorer III
Nov 16, 2016
I'd vote #2 provided the battery disconnect does remove all or practically all of the loads. Some RVs have things like LP detectors powered up even with the disconnect open. If the non-disconnected parasitic loads are more on average than the solar can make up, you'd be heading for a dead battery.

As this is outdoor storage in a relatively cold climate, you could also just fully charge and completely disconnect and leave the batteries over the winter without trouble. They won't self-discharge down to worrisome levels over the winter (self-discharge is much slower in cold conditions than in warm ones). But, since you have the solar, there's no reason at all to do this since leaving the solar connected will largely or completely counteract any self-discharge.
BFL13
Explorer II
Nov 16, 2016
If there is enough sun for long enough in the day, the solar will get the batteries to a higher voltage than the WFCO has them floating, and follow the solar controller's charging profile.

No idea why you never see that.

You should be able to leave the WFCO on and the solar on with no confusion between them, so after the solar is over late in the day, the WFCO will keep them at 13.x overnight.
Sandia_Man
Explorer II
Nov 16, 2016
Actually all three methods would work and are currently employed by forum members. Since you have a WFCO onboard, solar would be my choice since 160 watts should suffice for just keeping a pair of batteries topped off. Many do choose to remove batteries and place them on a battery tender type device, we store our rig in our sideyard plugged in and let our Iota IQ4 do it's job.
SoundGuy
Explorer
Nov 16, 2016
Since the WFCO series of converters is so well known to rarely if ever go into a rated 14.4 volt bulk charge I simply turned mine off and now charge / maintain my battery with a stand alone CTEK Charger that really does do 14.4 and is capable of properly maintaining the battery automatically, whether during the season when I'm using the camper or now during winter storage when I'm not. My 8 yr old Interstate G27 is still reading an unloaded 12.8 volts after last seeing this charger 3 weeks ago ... it's in better shape now than it has been for years when it was being abused by the WFCO.
fitznj
Explorer
Nov 16, 2016
I disconnect the master switch and let the solar (120W?) panel keep the batteries
topped up. The voltage varies between 12.6 and 12.8 all winter.