Solar on a Pop Up Truck Camper ? or 2
I'm buying a new NorthStar 850SC pop up truck camper. The dealer is installing a 170w panel on top, a 30a controller with 2 AGM batteries. Says he's done a lot of this install which is supposed to b...
Forum Discussion
Your suitcase set would likely have its own controller, which you can have go to the battery separately from the roof set's controller. Or you can perhaps arrange to have the two arrays go to the one controller.
The size of controller in amps rating is more important for a PWM controller, which heats up of you "over-panel" so more amps go to the controller than it is rated for. The heat will fry the controller.
So the rule with PWM controllers is to have its amps rating be about 25% more than the "expected amps". How many amps is that? Use the Isc rating of the panel with PWM (not the lower Imp rating which only applies with MPPT controllers)
A 170w panel could be a 12v or a 24v panel. If it is a 24v panel, you can't just add your 12v suitcase set to it, so that means having the two controllers in parallel onto the battery bank. No problem when the two controllers have similar high output voltage set points --14.6v say. They will add their amps.
So the 30 amp controller with the 170w panel (even if it is an MPPT controller and the panel is a 12v)-- Isc if that is a 12v panel will be about 11.8 amps. Isc for a 100w panel is about 6.3 amps. So your expected amps with both on that one controller would be about 18.1 amps. So the 30 amper can handle that easily.
And to repeat, if it is an MPPT controller on a 24v panel, you can't add the 100w 12v panel anyway.
Another thing is with MPPT controllers, they have an amps cut -off so even if the array supplies more amps, the controller won't fry because it limits the amps to its rating.
The size of controller in amps rating is more important for a PWM controller, which heats up of you "over-panel" so more amps go to the controller than it is rated for. The heat will fry the controller.
So the rule with PWM controllers is to have its amps rating be about 25% more than the "expected amps". How many amps is that? Use the Isc rating of the panel with PWM (not the lower Imp rating which only applies with MPPT controllers)
A 170w panel could be a 12v or a 24v panel. If it is a 24v panel, you can't just add your 12v suitcase set to it, so that means having the two controllers in parallel onto the battery bank. No problem when the two controllers have similar high output voltage set points --14.6v say. They will add their amps.
So the 30 amp controller with the 170w panel (even if it is an MPPT controller and the panel is a 12v)-- Isc if that is a 12v panel will be about 11.8 amps. Isc for a 100w panel is about 6.3 amps. So your expected amps with both on that one controller would be about 18.1 amps. So the 30 amper can handle that easily.
And to repeat, if it is an MPPT controller on a 24v panel, you can't add the 100w 12v panel anyway.
Another thing is with MPPT controllers, they have an amps cut -off so even if the array supplies more amps, the controller won't fry because it limits the amps to its rating.
