Midnite Classic MPPT Controller & breakers

[kingofcary]

Hi Folks ... I have a Midnite Classic MPPT controller for my solar. It charges my 4 x 100AH LiFePo batteries with BMS, etc. This system is excellent and providing great service for me. I have attached 3 pics below. My question is with the breaker box. Any particular rationale and purpose for 2 breakers ... one 100a the other 30a. Thanks in advance ... Dennis

[gamayun]

I'm just setting up my 400 ah LFPs, too. My Midnite Solar charge controller is a KID that has a 30 amp fuse directly on the front for the battery output. Perhaps the 100 amp fuse is wired to something else? Can you trace it back? What size alternator do you have?

[gamayun]

Ah correction, I just noticed there are two fuses. One is a 30-amp "input" and the other is a 40-amp "battery" (output?). I'll add that to the list of questions that I have for my call to Midnight Solar today.

[kingofcary]

Gamayun ... thanks for responding. I hope to go to boat this week to trace, good luck with your install !! ... tx .. .Dennis

[noelex 77]

You will have to trace the wires, but I would assume that the 30 Amp breaker was wired between the panels and the controller and the 100 Amp breaker was between the controller and the batteries.

This suggests the solar panel voltage is probably about 3x the battery voltage and therefore the current will also be about three times higher in the wires between the controller and the batteries.

The 100A breaker is a two pole model, so presumably isolates both the positive and negative connection to the battery.

[kingofcary]

Thanks noelex 77 .... sounds very good. Your assumptions seem right.



I have 2 panels each one is as follows per the label on it.
Rated power = 285
Rated voltage = 32
Rated current = 9


Thanks again