Solar panels to charge battery

[rfsod48]

Is it possible to charge the house batteries with solar panels when mh is not being used for a few months? I'm not able to keep mh at my home and storage location doesn't have electricity. As always advice is appreciated.

[Vulcan_Rider]

westend wrote:

I swear solar does a better job of charging and floating batteries than I can, manually. SG measurements are always spot on. Besides, I hate lugging batteries around.

Almost nobody recommends that you try to "float" your batteries manually.

The solar does such a good job because of the controller......which is similar to the electronics in a fully automatic plug-in battery tender. The only real difference is the source of the power.

[westend]

Paul Clancy wrote:
If concerned about winter in Michigan your solar will be covered in snow. I'd take the batteries out. Store at home on a battery tender.

Not for long if the module is tilted. I live in Central MN where we get 48"snowfall on average. Typical 6" drop of snow is melted by the following day and runs off. I did remove some snow from directly under the module's lower edge, once. That was a period of lots of wet snow that froze on the roof before melting.

I swear solar does a better job of charging and floating batteries than I can, manually. SG measurements are always spot on. Besides, I hate lugging batteries around.

[Vulcan_Rider]

Canadian Rainbirds wrote:
Running the engine once a month does more harm than good unless the rig is driven for at least 30 minutes.

Sorry can't agree with that.

The engine gets QUITE hot enough from running for 30 minutes to boil off any moisture that accumulates in the crankcase or exhaust......and the transmission is mostly sealed, doesn't accumulate moisture and doesn't need to be heated periodically.

You do have to run it long enough to get the engine parts hot but no need to actually go down the road to do that.

P.S. Just noticed that you are in Canada. If it is REAL cold when it's time for a monthly exercise and inspection.....I might just skip it or slip the schedule a bit. There is no good reason to be starting things up at -20 F just for exercise.

[Vulcan_Rider]

rfsod48 wrote:
If I run gen and motor once a month will that charge both chassis and house batteries? When not running I would use a battery disconnect for house batteries.

That's exactly what I do when mine is "down".

I run the engine first for 20 minutes or so, shut it off and run the gen for a half hour using the A/C as a load.
The truck charges at a higher rate than the gen does.

IF the batteries are near to fully charged to start with AND they are fairly healthy, that should be fine.

You do need to check the trailer voltage while things are running though to be sure that the charging really is occuring like it should. A little voltage monitor that plugs into a 12 V power socket is real handy for that.

Visiting once a month also gives you a chance to check for water leaks, check the water level in the batteries, check for insect and critter infiltration and to move the tires a few inches to help prevent flat spots. Oh, and air it out too if the weather is nice enough.

[Canadian_Rainbi]

Running the engine once a month does more harm than good unless the rig is driven for at least 30 minutes. This allows everything including transmission to fully warm up and also drives out all the moisture.

Running the gen to charge batteries is fine since it will be under load while charging though not very efficient as it needs to run a very long time in order to get the batteries FULLY charged. Solar works very well in this application.

[Paul_Clancy]

If concerned about winter in Michigan your solar will be covered in snow. I'd take the batteries out. Store at home on a battery tender.

[MrWizard]

batteries self discharge, even with nothing connected
some expensive batteries as little as 1% per month
some cheap flooded cells discharge 1% per day
disconnect switches are cheap.
ME i would get the solar and the switch
let the solar maintain disconnected batteries, is the best situation

[TucsonJim]

rfsod48 wrote:
If I run gen and motor once a month will that charge both chassis and house batteries? When not running I would use a battery disconnect for house batteries. Or would solar panels still be advised? I am concerned about winter.

You'll be fine. No sense spending the money when it's really not needed.

[rfsod48]

If I run gen and motor once a month will that charge both chassis and house batteries? When not running I would use a battery disconnect for house batteries. Or would solar panels still be advised? I am concerned about winter.

[Golden_HVAC]

I would recommend a 140 watt panel from this place. THey had them on sale for $229 recently.

SunElec.com Look for a panel with a frame. Look for a '12 volt nominal' that will actually put out about 19 - 21 volts 'open circuit' voltage. Then a cheap $30 20 amp PWM controller will complete the package.

Add some 2" aluminum brackets (Home Depot) and #10 grey direct burial wire (I think they sell 25' long packages of the wire). Run the wire down the refrigerator vent to a location for the controller, then a short wire to the battery, you are done.

Fred.

[gypsmjim]

Same situation...

Had battery problems,so installed a battery switch. Better, but still an issue.

Installed a Renogy RV Solar "System" (one 100 watt panel, controller, etc.) and my batteries are now at 100% all the time.

When we boondock, even in the cold with the furnace running all the time, the batteries are at 100% by about 10 AM. If its a cludy day , it might take till noon!

[Vulcan_Rider]

TucsonJim wrote:
Yep, they'll keep it charged. But a battery disconnect switch is much less money.

You need both actually.

Depending on the specific situation, it might be easier to remove the batteries and put them on a tender at home.

And yes it's been discussed in earlier threads a LOT already. Please look.

Either way, you should visit the RV at least once a month to inspect for unexpected water leakage, rodent infiltration, etc......and check the charge on the batteries if you go the solar route.

[time2roll]

100 watts should do it while in storage with everything off.
Need a controller also.

[TucsonJim]

Yep, they'll keep it charged. But a battery disconnect switch is much less money.

Jim