Solar panel wiring

[Effie]

You can charge the same 12v battery setup with multiple charge controllers, each with its own solar panel(s). I’m doing just that because just like you I had a smaller controller for my portable panel before installing a larger system on the roof. You did state that your panels are identical, so if one of your controllers can handle both panels it will make for a simpler setup.

[alanmalk]

I suspect the batteries wouldn't care since they can absorb far more than the total of 200 Watts coming from the panels, until nearly full. The chargers possibly could be confused, however - my standard answer for multiple anything electronic - would be to diode isolate each controller, and adjust to controller output to compensate for the typical 0.7 voltage loss.


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Alan

[Perry Butler]

Originally Posted by HABBERDABBER

Can I attach each 100W panel (identical units) separately and directly to my batteries, via & through the 2 different charge controllers?

Do the tandem lead acid batteries really care if they're receiving possibly slightly different charge voltages from 2 sources? I wouldn't.

There are many here with solar on the roof connected to the battery with one controller and portable solar connected to the battery with another controller. It's done all the time.

We have an ETI installed 170 watt GoPower panel on the roof going into the GoPower controller.

After my winter frustrations with the Renogy portable system, I sent their controller (bus bar too small to handle 10g wire) and wires back and kept the Renogy portable solar panel. Having verified what I just stated with Northern Arizona Wind & Sun (mostly a residential solar installer) we purchased a Victron Smartsolar 100/20 for the portable. NAW&S agreed when using two dissimilar solar panels the preferred method is to have two controllers, rather than trying to balance two panels.

Now the Victron controller handles the portable and the GoPower handles the rooftop, both hooked to the battery.

In your case you have two identical panels, you could either hook them together or go with two controllers. Rather than spend time trying to hook both our dissimilar panels together, and spend money there, we decided on the simplicity and redundancy of two systems connected to the battery.

Enjoy,

Perry