Choosing The Right Size DC Cables for Battery to Inverter?
ligwyd Registered Users Posts: 98 ✭✭
I am in the process of hooking up my Battery Bank to my Inverter and just want to ensure I have adequate cable size.
My Schneider XW+ comes with a 250 Amp breaker. I also have a Midnite Solar DC Disconnect on my battery box also with a 250 Amp Breaker.
I will be using some equip from Blue Sea to connect and fuse (200 Amp per string) my three strings of batteries (not the best I know- but its what I got - in the future I will be doing ONE STRING ).
I have not verified exactly but will ASAP. For now I think my required DC cable length from Inverter to Battery Bank Bus Bars is around 20' or 6 Meters one way. A little long I know.......
[ update - approx. 17 feet max cable length - a little better than I thought ]
All Battery Inter-connect Cables and Cables running to positive and negative Bus Bars are 4/0 as well.
1. Do I need to calculate one way or round trip for my cable length?
2. Does my Length measurement start from the actuall battery terminal or the 3 string Bus Bars?
3. Do my Battery Cables need to accommodate 250 amp?
(I wouldn't think so since I believe my whole battery bank will only accept around 55 Amps from the Inverter/Charger and this is when it is equalizing and I don't anticipate putting heavy loads in the battery bank either so I thnk the Amps drawn from the Battery Bank will be even less)
Inverter does 6800 watts continuous
8500 watts for 30 min
11000 watts for 5 min
12000 watts for 1 min
=12000 Amps / 48 Volts
= 250 Amp Breaker
Some calculators say I need cable 3 sizes up from 4/0 and some say my voltage drop is under 1% with 4/0 cable?
I'm scratching my head a bit? As usual I know it is simple but not so simple until you fully understand it
Looking forward to hearing back from all who can offer some clarity on this!
Thank you in advance