8 Comments

I have a “suitcase” style solar panel that includes a charge controller so installing one between the Zamo connector (on the RV) and the battery would be redundant and inefficient in my case. Mike or someone else might want to comment on weather having two solar charge controllers in series would cause any real problems. Another thing to watch out for is to make sure the solar charge controller is set for the proper battery chemistry (e.g., Flooded lead acid, lithium, etc.) and that the internal converter and the solar charge controller are both set to the same battery chemistry. I don’t doubt what Mike says about it being ok to run the solar panel and shore power at the same time but I have not tried it. I only have a briefcase solar panel and don’t have solar panels on my roof. I assume that roof top systems have their charge controller hard wired in so they are “on” all of the time (when the sun is out. If you add an external solar panel (because you are parked in the shade), you could end up with two charge controllers in parallel if the external panel has its own charge controller. Mike or someone else who has this setup might want to comment on how this works out in the real world.

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Two charge controllers in parallel is fine. (Each controlling a different bank of solar panels, charging the same battery bank. This is a common arrangement on sail boats). Two charge controllers in series will not work. The first one will lower the output voltage too low to allow the second controller to turn on. Zero output.

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Are charge controllers dependent on the size of one’s panels? That is, does it matter the model or size of the controller if I have a 100 amp or 200 amp panel(s)… or more?

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Yes, you need a solar controller rated for the max amperage you can expect from your solar panels.

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Some (but not all) solar panels designed to be used as portable panels “suitcase panels” or “foldable panel” will already have a charge controller built in to the panel. Also, some RVs that come as “solar ready” ports will come with charge controllers already installed. It won’t work if you have two charge controllers, one after the other. Also, check that the polarity of the port is the same as the polarity of the panel. There isn’t a standard polarity between different brands. It is best to check with a volt meter before plugging in the first time.

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An article on a solar charge controller would be great.

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I've had solar for a long time now (20-something years). When I went to lithium batteries I had some questions. One was, would I have to get an upgraded controller to replace the standard one that came with the trailer? It's not geared for lithium charging. My solar controller is a Morningstar TS-MPPT 60, and Morningstar tech support helped me reprogram the controller so it would properly charge my new lithium batteries. After talking to tech support at Progressive Dynamics, they said if the solar can top the batteries off there would be no need to replace the original controller that came with the trailer. The two controllers would work in concert. The Morningstar controller would do the 14.4 charge that lithium batteries need. I'm almost two years into this new situation and so far, no problems.

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Can a solar charge controller be used with older battery charger to control desulpher high charge from damaging Li battery?

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