solar options
Last summer I had a 240 watt kit(from Solar Blvd.) Installed on our MH. It has two 120 watt panels feeding a 20 amp charge controller. I recently had the two stock 12 volt marine house batteries rep...
Forum Discussion
First you need to figure the size of controller in amps needed for how many watts of panel. this is for PWM but you can go a bit more with some MPPTs where it clips the amps safely if you go over, where the PWMs let the amps through.
You need 20% margin in controller amps over the panel rating for amps using Isc not Imp. So your two 120s should have Isc of 7.6a each and your rated amps is now 15.2 so 20% of that is another 3a so you need a controller rated for at least 18.2a so your 20a controller is correct.
Working backwards, what can a 30a controller handle? the 30 is six parts and the panel five so the array can be 25a Isc or using 120w panels at 7.6a each that's three 120w panels.
So if you plan to double your solar you will want a 40a controller (or two 20s)
To choose which set-up is best depends a lot on whether you can do your own work I suppose. I agree two 20s and stay PWM is a good choice. Last summer I ran two arrays on my bank with each array having a 20. Total amps to the battery is the same with two 20s in parallel as using one big 40.
However cost of controllers does not just double with amps, so one 40 can cost way more than two 20s. "Depends" on sales etc of course.
You need 20% margin in controller amps over the panel rating for amps using Isc not Imp. So your two 120s should have Isc of 7.6a each and your rated amps is now 15.2 so 20% of that is another 3a so you need a controller rated for at least 18.2a so your 20a controller is correct.
Working backwards, what can a 30a controller handle? the 30 is six parts and the panel five so the array can be 25a Isc or using 120w panels at 7.6a each that's three 120w panels.
So if you plan to double your solar you will want a 40a controller (or two 20s)
To choose which set-up is best depends a lot on whether you can do your own work I suppose. I agree two 20s and stay PWM is a good choice. Last summer I ran two arrays on my bank with each array having a 20. Total amps to the battery is the same with two 20s in parallel as using one big 40.
However cost of controllers does not just double with amps, so one 40 can cost way more than two 20s. "Depends" on sales etc of course.
