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diy solar

Quick question on battery wire size

Firetodd

New Member
Joined
Aug 24, 2020
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147
Location
Arvada, CO
In ordering wires and associated pieces of my solar set up for the RV, I see that my Overkill Solar 16S 48V BMS will have two 8 gauge wires output to a lug. The DC input of my LV6548 recommends 2/0 gauge wire.... How do i proceed?
 
How many amps does the LV6548 want? What is the largest load you will put on the inverter?

If your largest load (with surge and inverter inefficiency) is below what the Overkill can deliver- then get the 2/0 wire. Or get a bms that can deliver more amps. Or double up batteries and bms.
 
For 6500 watts, it would be 135 amps at 48 volts. Realistically though, I will probably be around 3500 watts max. Which would be under 100 amps. I will connect the BMS to the shunt. But my question is, do I then jump the wire size up to 2/0 from there?
 
Yes bump it up at the shunt.
You may want to look at the cable size/amps charts. 2/0 can handle 200 amps. If that size gives you problems- you could go smaller 1awg can handle 150 amps - but then you lose the surge of the inverter (which you already lost due to the bms).
 
Two 8 gauge wires is equivalent to a single 5 gauge wire. Not quite 2/0, but it's getting there. :)

I have three 8 gauge wires on my BMS, which is equivalent to 3 gauge. I stepped up to 2/0 after the shunt. The only cable calculators I look at are the ones that are for distance and voltage drop.
 
@HRTKD - On a separate issue, I will have a 48v battery..... but my RV has its own 12v deep cycle battery. Is there a DC to DC charger so I can charge the deep cycle battery without having my inverter on?
 
Haha thanks! I went to their site and missed it. I appreciate you answering all my silly questions!
 
How far away is the inverter from the battery? That has a great deal to do with how large the cables need to be. The wires on the BMS are very short, which is how they get by with undersizing them

Don
 
How far away is the inverter from the battery? That has a great deal to do with how large the cables need to be. The wires on the BMS are very short, which is how they get by with undersizing them

Don
They will be right next to each other.
 
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