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Solar while the RV is in Storage

dufferdj
Explorer
Explorer
Need some guidance for how to use solar while in storage. My solar panels are suppling a daily charge, topping off both my house and chassis batteries. Each night my class A has the charge drawn down due to minor drains . That means that my battery charge will rise and fall daily, if only a small amount. If I shut off the battery disconnects that would prevent this fluctuation. Should I leave my batteries "live" so that they will charge during the day and slightly discharge each night or do I flip the disconnect switches to keep the batteries from either increasing or decreasing their charge. Which method should extend the life span of new batteries, or does it really matter? Thanks for sharing your knowledge and opinions.
19 REPLIES 19

BUB1988
Explorer
Explorer
So while we had our RV in storage we kept it on solar to keep the batteries charged. We have 4 - 12 V batteries, 2 coach and 2 chassis. The solar panel was only 100W and we never had an issue. We live in Florida and it never was in storage for over 6 -8 weeks at time.

dufferdj
Explorer
Explorer
Thanks to all of you that replied and the many questions and suggestions that have been made. After reviewing your various questions I tried disconnecting the battery bank. Since the solar panels (400W) are wired directly through the Blue Sky Solar Boost 3000i they are keeping the batteries fully charged even though we had a cloudy day today. Since I have the battery bank disconnected ,the draw throughout the night should be minimal. So at this point I believe that this condition should be best for the life of these batteries and the new ones I will be installing soon. Thanks again.

All_I_could_aff
Explorer
Explorer
If we are talking about maintaining charge while in storage, a couple of cloudy days in a row wouldn’t be anything to worry about with small solar setup. It would be a problem boondocking!
1999 R-Vision Trail Light B17 hybrid
2006 Explorer Eddie Bauer
2002 Xterra rollin’ on 33’s
1993 Chevy Z24 Convertible
Lives in garage 71,000 miles

wolfe10
Explorer
Explorer
I certainly have no problem with shore power plugged in 24/7 with a smart charger or smart inverter charger, but many thousands of motorhomes use solar to maintain battery charge in storage with no ill effects.

If you have access to shore power where you store, excellent. If not, solar is a good "plan B".
Brett Wolfe
Ex: 2003 Alpine 38'FDDS
Ex: 1997 Safari 35'
Ex: 1993 Foretravel U240

Diesel RV Club:http://www.dieselrvclub.org/

CA_Traveler
Explorer III
Explorer III
wolfe10 wrote:
RLS7201 wrote:
I see no difference in leaving the solar connected or leaving your coach plugged in all the time. If both are smart charging systems, you're good to go.

Richard


I agree. Assuming solar of sufficient size, snow kept off it, smart controller, etc. Expect that you may have 3-4 cloudy days in a row when sizing the solar panels.
I disagree. Utility power maintains the float charge 24/7 including night unlike solar with constantly changing light.
2009 Holiday Rambler 42' Scepter with ISL 400 Cummins
750 Watts Solar Morningstar MPPT 60 Controller
2014 Grand Cherokee Overland

Bob

wolfe10
Explorer
Explorer
RLS7201 wrote:
I see no difference in leaving the solar connected or leaving your coach plugged in all the time. If both are smart charging systems, you're good to go.

Richard


I agree. Assuming solar of sufficient size, snow kept off it, smart controller, etc. Expect that you may have 3-4 cloudy days in a row when sizing the solar panels.
Brett Wolfe
Ex: 2003 Alpine 38'FDDS
Ex: 1997 Safari 35'
Ex: 1993 Foretravel U240

Diesel RV Club:http://www.dieselrvclub.org/

RLS7201
Explorer
Explorer
I see no difference in leaving the solar connected or leaving your coach plugged in all the time. If both are smart charging systems, you're good to go.

Richard
95 Bounder 32H F53 460
2013 CRV Toad
2 Segways in Toad
First brake job
1941 Hudson

time2roll
Explorer II
Explorer II
13.0 to 12.1 is a significant drop while connected. Either the battery is not full or they are shot. What is the programmed peak absorption/bulk voltage? How cold is it?

13.0 down to 12.65 while disconnected from the RV seems to be in good shape. Although the batteries could still be weak.

13.0 is a bit low for a float voltage in Winter. Is that the programmed voltage or is that late in the day with minimal solar power drifting down to sunset?

Does the controller support temperature compensation?

For now I would let the batteries set with the disconnect switch remaining in the disconnected (off) position. Need to figure out the programmed voltages before you get new batteries.

How many watts are the panels rated?

wolfe10
Explorer
Explorer
Again, either of two things could cause this:

Dead batteries-- where even a small draw will discharge them. The batteries are only "storing" a small amount of their design amp-hrs.

Higher amp draw what would take down even a good battery bank.

If you know the batteries are bad, replace and THEN evaluate.

Another option is to use an ammeter to determine draw.
Brett Wolfe
Ex: 2003 Alpine 38'FDDS
Ex: 1997 Safari 35'
Ex: 1993 Foretravel U240

Diesel RV Club:http://www.dieselrvclub.org/

dufferdj
Explorer
Explorer
Thanks to all for your replies thus far. I know that I need new batteries so I'm trying to figure out what to do so that the new ones will last as long as possible.
At the end of a sunny day after the sun is low in the sky, so that I'm not really getting any more solar gain, my Blue Sky 3000i Solar Boost controller shows 13.0 with the Float and Absorption lights lit up. The next morning before sunrise it was reading 12.1. Nothing was being used in the RV as it was in the storage lot --- no TV. no lights, no heat --- no nothing other than the random draws from the house electronics.
Last night, after a sunny day the controller showed a reading of 13.0 F/Ab. I turned the disconnect switches off on both the house and chassis battery banks. Checked them again this morning prior to sunrise and got a reading on the controller of 12.7/6.
This info seems to tell me that by disconnecting the battery banks, the voltage drops significantly less than when leaving them connected.
Once I install new batteries I'm sure these stats will change. But from what you can see, would I be better off just leaving the batteries connected to the solar panels 24/7, or disconnect the battery bank and just reconnect it one sunny day a week? Which way will extend the life of the new batteries or does it really make a difference ?

wolfe10
Explorer
Explorer
Yup, for a more considered answer, you will need to tell us how low the voltage goes.

So, what is float voltage at the end of a sunny day? How low in the morning after a couple of cloudy days?

Also, what controller do you have? Quite a range of quality/capabilities.
Brett Wolfe
Ex: 2003 Alpine 38'FDDS
Ex: 1997 Safari 35'
Ex: 1993 Foretravel U240

Diesel RV Club:http://www.dieselrvclub.org/

CA_Traveler
Explorer III
Explorer III
time2roll wrote:
Sounds fine to me unless the voltage on the battery is dropping significantly. Depending on conditions you could be a week+ with minimal to no solar.... will that be a concern?
Good suggestion, get a digital voltmeter that will read 2 digits and see what is going on. Like 12.68V.

Better get a AC/DC clamp on meter and check the battery drain. So much better than "minor" drain. Reasonable ones are about $80.
2009 Holiday Rambler 42' Scepter with ISL 400 Cummins
750 Watts Solar Morningstar MPPT 60 Controller
2014 Grand Cherokee Overland

Bob

WAFlowers
Explorer
Explorer
My PV system is direct connected to the batteries and has its own shutoff. Of course, I designed and installed the system myself so YMMV.
Bill and Willemina Flowers
George, Sammy and Teddy (the dogpack)
2008 Tiffin Phaeton 40QSH
2005 Keystone Monata 3400rl (5/21/11 to 9/9/17)
(Was in a 2000 Coachmen Catalina Sport 220RK)

time2roll
Explorer II
Explorer II
Sounds fine to me unless the voltage on the battery is dropping significantly. Depending on conditions you could be a week+ with minimal to no solar.... will that be a concern?