Has anybody ever heard of any 12 volt type solar panels not being able to wire them in series? Not physically of course but technically? I have 4 Coleman 100 watt panels and nowhere on the box or on the enclosed manual does it say to only wire in parallel or not to wire in series! Talked with a Coleman customer support rep, tech I think, and was told they can ONLY be wired in parallel?? I have been all over the Internet and cannot find anywhere, where there is some explicit instructions on any panel that I have seen to only wire them in parallel.Now I am not looking for pros and cons over series vs. Parallel I am aware of all that. Just whether there are panels made that must be wired in parallel only? __________________

I am aware of all that...and that Coleman sells their name to anyone for anything. Therefore finding out anything about a “Coleman” panel manufacturered by the lowest bidder that week will be near impossible. Similar to the Garmin 660.

Panel needs bypass diodes to wire in series. Otherwise shade issues could burn out the panel.Call the tech back and see if it has a bypass diode. Or open the terminal box and see if they exist. Post a picture.

It's not the panels, it's the controller.The issue is the PWM controller for 12v panels can only handle a low Voc like maybe 46 volts. Each panel has a Voc of 22v, so two in series is 44 (at 25C and higher when it is cold out.)If you are using an MPPT controller, it will have a Voc limit more like 100, so your four 22s in series is 88 and could be done.I have three 100s and have used them in parallel and in series. Got same amps to battery either way. I got the Isc value of 6.2 amps per panel in full high sun, so I was getting 18.6 amps with my PWM controller, panels in parallel. With four you could get 25 amps, so be sure to have at least a 30 amp controller (needs margin for times when panels get more than rated amps) whether you have a PWM or MPPT controller.

It’s not the diodes I’m concerned about, most all have diodes to prevent back feeding the panels from the battery! My question was about whether anyone was aware of solar panels that could ONLY be wired in parallel.My knowledge about solar panels is that they could from all manufacturers and types I.e. 36 cell 72 cell be wired series, parallel or series/parallel.This is also not about charge controllers pwm or mppt.

I said the panels can be used in series no problem. I do it with those Coleman 100w jobs Can Tire gets from Sunforce.The advice you got not to put them in series is about the controller, not the panels as such.There are mixing limits to doing either unless the panels "match" closely enough in their volt/amp specs for which way they are put together, but you have four the same, so no worries.

Solar panel wiring | Good Sam Community

13 Replies

BFL13
Explorer II
May 04, 2018
It's not the panels, it's the controller.

The issue is the PWM controller for 12v panels can only handle a low Voc like maybe 46 volts. Each panel has a Voc of 22v, so two in series is 44 (at 25C and higher when it is cold out.)

If you are using an MPPT controller, it will have a Voc limit more like 100, so your four 22s in series is 88 and could be done.

I have three 100s and have used them in parallel and in series. Got same amps to battery either way. I got the Isc value of 6.2 amps per panel in full high sun, so I was getting 18.6 amps with my PWM controller, panels in parallel.

With four you could get 25 amps, so be sure to have at least a 30 amp controller (needs margin for times when panels get more than rated amps) whether you have a PWM or MPPT controller.
time2roll
Nomad
May 04, 2018
Panel needs bypass diodes to wire in series. Otherwise shade issues could burn out the panel.

Call the tech back and see if it has a bypass diode. Or open the terminal box and see if they exist. Post a picture.
Lwiddis
Explorer II
May 04, 2018
I am aware of all that...and that Coleman sells their name to anyone for anything. Therefore finding out anything about a “Coleman” panel manufacturered by the lowest bidder that week will be near impossible. Similar to the Garmin 660.

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Solar panel wiring

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