solar wire and connectors sizing.

[Cire Edhor]

12 v 400ah lithium house bank, 25 feet from 12 v parallel array of 3 310 watt REC panels into 60 amp HQST MPPT controller. What wire, connectors and fuses? I have another HQST 60A controller if needed. Is this a sound setup?

Any help is greatly appreciated. This is my first solar project.
Thanks.

 

[robbob2112]

What is the max current output of the battery? Is the 'lithium' LiPo or LFP/LiFePo4 chemistry?

 

[Cire Edhor]

LiFeoPo4, I am not looking to size wires to the Victron Inverter only from panels to charge controller and controller to battery bank.
Thx

 

[robbob2112]

LiFeoPo4, I am not looking to size wires to the Victron Inverter only from panels to charge controller and controller to battery bank.
Thx

more details needed to answer correctly. 300w panels typically have a Voc of 28v.... what are the specs of your panels?

are these them?


Assuming this is your MPPT

60A MPPT Solar Charge Controller with Li-Ion Battery Low Temp Protection, Parallel Charging, and Bluetooth

HQST 60 Amp MPPT solar regulator adopts high quality components with maximum conversion efficiency of 98%. Limited time sale, 5% off: WELCOMEHQ5

hqsolarpower.com

it has a 150v max voltage and your panels put out 119.4v in series. Voltage adds in series and current adds in parallel. So wire your panels in series and your current stays the same at 9.9a. For that you can use 14 awg wire.


If either of my assumptions about your equipment are wrong holler. If you have a smaller MPPT with a max voltage of 100v hooking your panels in series will fry it in moments.


Wires need to be sized for the highest current used at one time. If the inverter contains a charge controller fine. The highest use out of the battery is usually the inverter when supplying power. If the inverter doesn't contain a charge controller (which I assume is your case) then the wire to the MPPT needs to be sized according to the MPPT.

In this case your MPPT is 60 amps. Wire for 50 amps is 6 awg and you are a touch over it. This is standard THHN, but you really want to use welding wire because of the high strand count it won't have as much loss. The manual will probably say something about the type wire to use.

In THHN you would need to run 4awg for 80 amps. In welding wire with a temperature rating of 105c you can run 108 amps with 6awg. They don't make it in smaller.