Should solar panels and system go directly to batteries?

[GPafundi]

We have a 2016 Airstream International 27FB that we added solar to when we purchased it. We added additional panels for a total of 300W and change to 2 6volt deep cycle batteries. The system was installed by the local Airstream dealership.

While the trailer was in storage, I would check battery levels and they would drop to 11.25 v. While the system seemed to be working fine, I pulled the batteries for the winter and put them on a battery tender. The batteries were significantly depleted, much more so than I expected.

The question I have is whether the solar should be connected directly to the batteries or not. I believe the intention of the installer was to allow charging when the trailer was in storage and switched to disconnected. My concern is that we store in a covered outdoor space, coupled with overcast fall/ winter days, the solar panels might actually be draining the batteries.

Does anyone have any experience with this? I really expected a 300W system to be able to keep a basic charge. I do turn off and disconnect everything when stored, and I can't find any excessive drain on the system except for the smoke detectors. I understand that a covered space dramatically lessens the charging voltage, but I didn't think we would still be draining the batteries so dramatically since we have solar.

We are new to RV'ing as a whole so please forgive me if my expectations are higher than they should be... and I love the forum so thanks ahead of time!

[SCOTTinNJ]

How covered is covered? No sun = no charge.

[lsbrodsky]

The propane detector, always connected, has a small load but enough to flatten your batteries in storage. Solar won't help you if you have covered storage; panels are not very efficient and indirect light will do nothing.
Larry

[thiel]

Yes, anything that's connected to the batteries that is not charging them is draining them.

[SSquared]

I also have a trailer with multiple panels (435 watts) on the roof, and keep it in covered storage. The panels don't work in my storage location, which has an open front facing due south. Only one time have I seen the solar controller producing current when the trailer is parked--and that was only 0.1 amps.

When I am storing the trailer for more than a couple of weeks, I make sure the batteries are charged when I put it away, then I disconnect all the loads (including removing the fuse to the propane detector).

[Jim Foster]

There should be a digital readout on the solar controller. That will show if and how much your solar system is charging your batteries when parked in storage.
Yes, the output from the solar regulator should be connected directly to the batteries. Disconnecting batteries from the regulator with the panels connected can damage some regulators.


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[lewster]

[QUOTE=Jim Foster;1882358]There should be a digital readout on the solar controller. That will show if and how much your solar system is charging your batteries when parked in storage.
Yes, the output from the solar regulator should be connected directly to the batteries. Disconnecting batteries from the regulator with the panels connected can damage some regulators.

Jim,

I don't know which solar controllers you have experience with, but NONE of the units that I have used in over 150 solar installations from Blue Sky energy, Morningstar and Victron Energy have NO PROBLEM being disconnected from the batteries they would normanlly be charging.

Thesis one of the many reasons that I install a disconnect switch for the solar array going into the controller and a marine circuit breaker between the controller and the battery bank.

[GPafundi]

Thanks everyone for the input. Now I need to figure out what to do if I disconnect the batteries. Should I leave an open circuit or will that damage the solar controller?

Again, I appreciate the input.

[alano]

Like Lew said above, there's no issue in having an open circuit for your solar controller. Simply disconnect the negative terminal for each battery you have to isolate the batteries during storage.