Sizing a MPPT for RV system
I have three 370W solar panels that I plan to install on my travel trailer in parallel. Their specs are
Vmp – 38.15V
Imp – 9.7A
Voc – 47V
My battery set up will be two 180AH 12V LifePO4 batteries.
What is the size MPPT charge controller would I be needing?
I am confused on the calculation. I have read both ways to calculate.
1. Take total watts of solar array divided by battery voltage in my case 1110w / 12V = 92.5Amps so would need a min 100amp MPPT
2. Each panel produces 9.7A so in parallel a total of 29.1A so only need a 30A MPPT
Which is correct?
Also since this is on a travel trailer is there anything I need to do differently when installing the batteries to compensate for the way they charge from the truck alternator when the 7-pin connector is hooked up? I do know that the 7-pin connector hot lead is only live when the truck is running so there is no chance of the TT batteries draining the truck batter, but I am not sure if the alternator which is 80amps can handle the TT battery bank with no ill effects.
Thanks all for your time.