Im using weld cable from temco industrial 205amps. Should I get a bigger breaker? I got the breaker size from the suggestion in the owners manual on the inverter. Apologies for low level understanding.
For my build with a 3000 watt inverter, I used 4/0 wire. I sed TEMCO welding wire.
I do recommend that, but there are a couple of gotchas. Some inverter studs may not be able to take a 4/0 Stud and it has to be routed to the batteries. The 4/0 makes it easier to upgrade to a bigger inverter later.
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Not all breakers are created equal, so for your breaker, it needs to have a high enough AIC so that when it trips, the arc doesn't go across the breaker and continue to flow. I don't know what this is, but I do know that MRBF fuses for 24 volts are likely good, and Class-T for up to 48 volts is as good as it gets.
So, I put a 350 amp on off switch and a Class T- on my system.
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If the manual says 160 amps go with that.
Just realize that if you are running this at a high load it may trip the breaker. The inverter is a 3000 VA/3000 watt inverter. I won't pretend to understand VA very much but its related to the power factor, so a 3000 VA inverter is likely less than that continuous wattage. I think the Multiplus by Victron is rated at 3000 VA, but the max continuous output is 2200 watts, so if the same thing holds up for your inverter, than you will unlikely see the full 3000 watts for a sustained period of time.
Further in the Renogy manual or spec sheet, you should see a max sustained amperage.
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To choose a breaker size my formula is
Overcurrent Protection = Inverter Rated Wattage / Low Voltage Inverter Cutoff / Inverter Efficiency *1.25 Inverter Safety Factor.
220 amps = 3000 watts / 20 volts / 85% * 1.25
If you change that to 24 volts you get:
183 amps 3000/24 amps=3000 watts / 24 volts / 85% * 1.25
The inverter will likely be pulling 26 volts. so:
169 amps 3000/24 amps=3000 watts / 24 volts / 85% * 1.25
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The 1.25 safety factor is by NEC, if the wire ampacity must be 1.25 greater than than the max sustained amperage.
I know a lot of people use welding wire and they take the max amperage of welding wire to be the same as ampacity, but if you look on TEMCO's website, they say that the rating for that wire is for welding purposes and not for running that amount of current for long periods of time. Ultimately, the chart I showed you is an older chart for NEC, but the a good wire spec sheet will tell you what the amperage the wire is rated for and whether how that is, for example in air or grouped in conduit. The type of insulation will determine the amapcity of a wire the same size.
