Connecting two solar controllers to one set of batteries. Possible?

Old Forum Closed – Maintained as an Archive Old Forum Closed – Maintained as an Archive Ask for Help Connecting two solar controllers to one set of batteries. Possible?

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    I have a truck camper that has a factory installed 95 watt solar panel, hooked up through a 30 amp controller to my batteries.

    I recently bought a renogy 100 watt folding suitcase unit which incorporates a controller.  I chose that over an add-on rooftop panel so I could tilt and move it as needed to maximize output.

    It would be easy for me to run a cable from the portable suitcase unit with controller and hook up directly to my batteries.  Not so easy to go around the batteries and and the suitcase controller and splice into the down-leads from the existing panel.

    My question is… would it work to hook up the suitcase/controller directly to the battery and not disconnect the existing panel/controller system without damaging either controller?  I would think they would act independently , but not sure.

    I appreciate any thought on this.



    It shouldn’t hurt anything but may not be the most efficient for charging. Best if they are set up with the same charging profile voltages if that is possible.

    If they are different one controller may think the batteries are fully charged and go into float mode limiting its current output too soon by being tricked by say a higher voltage the other is putting out.

    But this may be your only option as mixing panels that are the same in parallel can create problems too.

    • This reply was modified 5 years, 8 months ago by Ray.
    Eddie & Aileen

    Again Ray, I tip my hat to you! That is what I was going to add to the post, but been to busy.

    Happy Trails…Pal!!!


    Thank you, Ray.  I did not think about the mixing panels issue.  I’m not sure if I can set up the same custom charging profile for both, but I’ll look into it.

    When I get down south in March, I’ll play around with it a bit to see if anything weird happens with two controllers working on one pair of batteries at the same time.  You’ll know it wasn’t a good idea if you see smoke rising over Death Valley.


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