Can I Join 2 Portable Solar Panels Together To Charge Batteries?

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Brian B. –


I want to know if i can join two portable solar panels together with an Anderson plug adaptor and then directly into my two 100ah batteries which are parallel in the front boot.

One is 100W and the other is 150W. I have also a 130W mounted on the roof of my caravan.


You can join multiple portable solar panels (including the 130W fixed panel on the roof, if you choose to) with Anderson plug adaptors as you suggest.

But if you’re going to connect them directly to the batteries, then you’ll need a regulator between the solar panels and the batteries.

Plenty of suppliers have portable regulators. Here’s a couple of examples:

There are plenty of other stand-alone solar regulators available from other suppliers as well.

The regulator ensures the voltage into the batteries is correct (so the batteries aren’t damaged) and that the batteries do not get over-charged.

How to figure out which solar regulator you need:

  1. Maximum Rated Voltage

    Take a look at the panels and check the maximum rated voltage. Take the lowest maximum rated voltage. Say it’s 18.0 volts.

  2. Calculate Maximum Current

    Power (W) = Volts (V) x Amps (A)
    Rearrange this equation to get maximum current:
    Maximum Current, Amps = Power/Volts

    In this example, Maximum Current (for the 2 portable solar panels) = (100 + 150)/18 = 13.9 amps.

    So a 20 amp regulator will suit this application.

    If you add the fixed solar panel as well, then Maximum Current = (100 + 150 + 130)/18 = 21.1 amps.

    You could still use a 20 amp regulator or go up to a 30 amp unit.

Also take a look at this article about How To Connect Two Solar Panels To One Battery. It goes into a lot more detail on the subject.

Hope this helps.



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Comments for: Can I Join 2 Portable Solar Panels Together?

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2 thoughts on “Can I Join 2 Portable Solar Panels Together To Charge Batteries?”

  1. It will help to fit isolation diodes to (amperage capacity to suit plus a factor for safety) each panel output to prevent any variation between panels effecting your final input to the batteries. Not good to run lead acid batteries in parallel as one less capable cell or string can drop the rate of charge to the other battery.


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