Can you just add a panel?

[kenandterry]

My motorhome has a factory installed 100 watt roof mounted solar panel connected through a Zamp Controller unit. (See attached photo). It does charge both the engine compartment battery, and the two house batteries under the entrance steps.

For the past two years, including right now, this solar panel has kept all the batteries mentioned above, perfectly charged all winter long. The rig is parked completely out in the open with the house battery switch turned off. It constantly displays voltages nicely in the 13 volt range for the off season.

We don’t dry camp very often, however……..

Would it improve my charging to the batteries if I did nothing more than purchase another 100 watt standalone solar panel, (see photo) and connect it to the motorhome by plugging into the 12v socket located on the exterior sidewall?
Can it be this simple without causing any damage to the existing solar equipment or batteries? I’m considering this so that it would provide more charging capability OR offer at least 100 watt charging IF the factory roof panel were under tree cover.

Thanks

[W5CRE]

It would help and would not cause any issues with the existing system. Make sure the polarity is correct when you connect.

[SeaDog]

The stand alone solar connected to the batteries say with alligator clips would enhance the system provided it had its own charge controller like most suitcase systems do. JMHO

[NJBreeze]

The point of the controller is to control the voltage so that it doesn't climb above say 14V. Probably not a good idea to run the panel w/o a controller.

Seems much easier just to put them in parallel on the roof and into the charge controller after of course you look up the specs on that controller and see if it can handle both which likely it can. IF trees weren't causing a problem now then why do they in the future? I suppose a campground could have trees over the roof but not over where you put your panel but that seems to be just a hassle for a "maybe".

[kenandterry]

Originally Posted by NJBreeze

The point of the controller is to control the voltage so that it doesn't climb above say 14V. Probably not a good idea to run the panel w/o a controller.

IF trees weren't causing a problem now then why do they in the future? I suppose a campground could have trees over the roof but not over where you put your panel but that seems to be just a hassle for a "maybe".

The motorhome gets parked completely in the open for the winter storage….so no chance of solar panels hidden from sun by trees.
I am looking at more camping possibilities going forward, that we COULD have tree cover over the roof, but a standalone might have direct sun access as you stated.

[ppine]

Your controller is rated for 30 amps. You can add a panel as long as you run it through your controller.

[kenandterry]

Originally Posted by ppine

Your controller is rated for 30 amps. You can add a panel as long as you run it through your controller.

The unit I’m considering, is on sale has it’s own controller as shown in my post #1, so it’s independent of whether you tandem or use alone.

[NJKris]

Ken, I have same setup as yours, but with gopower instead of Zamp. I use Renogy solar suitcases (2), running through their own controller plugged into side. It will greatly increase your charging, and there are no conflicts between charging with 2 controllers, as discussed on other threads. Having the suitcases you can better aim directly out of sun, and hopefully get out of shade is very useful.

[distracto]

dammit, NJKris beat me to it!

Originally Posted by W5CRE

It would help and would not cause any issues with the existing system. Make sure the polarity is correct when you connect.

This is correct, and the only answer you really need. So long as the wiring of your "solar on the side" goes straight to the batteries and does not go first to the on board controller.

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Other fun DIY option would be to swap out those alligator clips with ring terminals and mount them to your battery, then use the supplied quick connect when you set up the panels. This would remove any doubt of the positive and negative SAE connectors being reversed on the camper, and give you a guaranteed straight shot from the Noma controller to the batteries.

I did that with my Noco charger quick connects when i ran 2 6v batteries on my old trailer's tongue, see pics below. (of course i forgot you have a motorhome which hides the batteries somewhere, so not sure how much easier this would be, but i dont feel like deleting all this now haha)

[NJKris]

Originally Posted by distracto

dammit, NJKris beat me to it!



This is correct, and the only answer you really need. So long as the wiring of your "solar on the side" goes straight to the batteries and does not go first to the on board controller.

------

Other fun DIY option would be to swap out those alligator clips with ring terminals and mount them to your battery, then use the supplied quick connect when you set up the panels. This would remove any doubt of the positive and negative SAE connectors being reversed on the camper, and give you a guaranteed straight shot from the Noma controller to the batteries.

I did that with my Noco charger quick connects when i ran 2 6v batteries on my old trailer's tongue, see pics below. (of course i forgot you have a motorhome which hides the batteries somewhere, so not sure how much easier this would be, but i dont feel like deleting all this now haha)
Attachment 270052

Attachment 270053

This is a good idea. Cuts out the extra several feet of small gauge wiring from wall inlet to batteries as well, less line voltage loss. I bought a big crimping tool and ring terminals for the LiFePO4 battery addition and might just run two leads off batteries with MC4 connectors, cut out the whole SAE deal.

[mnoland30]

If your extra panel is over about 20 watts, you absolutely need a charge controller to keep from boiling your batteries. From what I've read, they recommend a separate controller for a different brand of panel. The closer your controller is to the battery, the better. I cut the ends off of an old extension cord and put SAE connectors on it to be able to put my extra panel out in the sun, and facing the sun. It charges much faster than the flat panel on the roof. You need a fairly high voltage (over 14 volts) going into your charge controller to get maximum output from your panel, so don't make your extension cord too long. There are online charts that show voltage drop depending on amperage, wire gauge, and length of run.