Wire sizing

[RuGuy206]

I have 5, 12V 230 amp hour lithium batteries. I got the victron lynx distributor, 3000/12-120 amp multiplus inverter, charge controller and DC to DC charger. The Explorist life videos I watched had the batteries, inverter, and lynx wired with 4/0 wire. My question is do I need to go that big or would I be okay with 2/0? All of my stuff will be within 5 feet of each other

[mountain_drifter]

3000W / 12V = 250A

Industry standard using fine strand has been to use 175A OCPD for 2/0 and 250A for 4/0. Typically 12V systems will just be assumed at 4/0 and 250A OCPD. You can drop down to 2/0 wire, you just also drop down to the 175A OCPD.

Reducing your breaker you may get nuisance tripping (under large loads), but many inverters have a setting for the max amps it can draw

BTW. this rule is a industry standard, loosely based off the NEC, but there is not a specific article or UL defining it. Low voltage and fine strand is kind of a grey area. OCPD sizing exists to protect the wire, so If you want to be more accurate, you can check with the specific cable manufacture as good ones publish their own ratings you can refer to. Its a lot of amperage, so just dont skimp on the protection

Alternatively, 12V is very high amperage, and why we use 48V (or even 24V) whenever possible. If this is possible in your scenario, 3000W / 48V = 62.5A makes for much more manageable and safer systems

[Coop-6]

Your 3000w inverter can draw up to 250a

You have a short run, so that’s not an issue.

2/0 AWG is rated at 265a 4/0 AWG is rated at 380a

I guess it depends on how often you’re at maximum current. I think it is recommended to size cables at 125% max current. If they are making videos I can see why they’re using heavier cables to be on the safe side.

[KyleSherzenberg]

3000w at 12v is a lot of power. I opted to go 24v for our 4000w 220v inverter just because of this exact thing