RV Solar and storage upgrades

[Stitzebr1]

I’m going from 200 watt PV to 400 watt PV in 2S2P configuration and from PWM to MPPT and from flooded to LiFePO4. Tried to cover all the bases putting a second auto transfer switch and DC-DC charger to protect the alternator while fusing every positive wire.
It’s a very short Motorhome @ 22’ otherwise I would have added more PV 3000 watt inverter larger MPPT but this will give no more nights without a furnace because my flooded were over 3 years old.

 

[jpcjtrtj]

I like your set up and the idea of 2P2S for the solar panels to keep the amps below 30 for 400 watts; I was thinking 4P and trying to figure out it 33 amps was too high for my 100/30 Victron SCC, but with your set up, you stay below 20 and double the voltage which the MPPT can bring back down the right way. I went with a 150 amp T Fuse from my 280 AH battery and a 40 amp breaker from the solar charger. (I don't know if the 120 Amp Breaker has the enough AIC for a 560 AH battery pack)

Hopefully someone smarter than me will chime in, but i'm not sure you need a battery isolator and a DC-DC charger in the same line. I thought the DC-DC charger was there to solve the problems of the Lithium/Lead/Alternator combination. For my set up, I ran the "on-off" for the charger from the running lights and capped the charging wire. So, the charger is only on when i have the running lights on; and the emergency breaks are powered by the battery. Alternatively, if I am driving at night and I don't want the charger on, I can just disconnect the charger connection between the truck and the trailer. Adding the isolator seems like a belt and suspenders. But it is entirely possible (maybe even likely), I don't know what I'm talking about.

 

[Stitzebr1]

I like your set up and the idea of 2P2S for the solar panels to keep the amps below 30 for 400 watts; I was thinking 4P and trying to figure out it 33 amps was too high for my 100/30 Victron SCC, but with your set up, you stay below 20 and double the voltage which the MPPT can bring back down the right way. I went with a 150 amp T Fuse from my 280 AH battery and a 40 amp breaker from the solar charger. (I don't know if the 120 Amp Breaker has the enough AIC for a 560 AH battery pack)

Hopefully someone smarter than me will chime in, but i'm not sure you need a battery isolator and a DC-DC charger in the same line. I thought the DC-DC charger was there to solve the problems of the Lithium/Lead/Alternator combination. For my set up, I ran the "on-off" for the charger from the running lights and capped the charging wire. So, the charger is only on when i have the running lights on; and the emergency breaks are powered by the battery. Alternatively, if I am driving at night and I don't want the charger on, I can just disconnect the charger connection between the truck and the trailer. Adding the isolator seems like a belt and suspenders. But it is entirely possible (maybe even likely), I don't know what I'm talking about.

Thanks for your input, the batter isolator came from the manufacturer and is in a very difficult place to get to. So I left it and not beat up my knuckles.

 

[jpcjtrtj]

That's a great reason (after spending all weekend cutting my hands to pieces)!!!!!