12V going to 24V (15,360W). Brand Recommendations? DC Breaker from SArray to SCC, SCC to Battery Bank(BB) & TFuse from BB to Inverter - pic attached.

[Echo]

Hi, need advice on a 24v System please:

My Solar array will be 1755 Watts - (with panel expansion later on)/ Total - VOC 71.1 / VMP 59.4 / IMP 29.55 in Series/Parallel (shading issues) & about a 25ft run to SCC using 4 AWG.
Solar Charge Controller (SCC) is 80 Amps /200 Volts.
Inverter is 4000W 24V.
Battery Bank(BB) - (4) 12V 300 AH Batteries in Series/Parallel (with battery balancers)- 24V 600AH Bank.

I will have (3) 15 Amp Solar fuses at each positive string and a 500V/40A DC Breaker between Solar array and SCC (4AWG) and a 500V/100A DC Breaker from SCC to Battery Bank with 4 AWG. Can anyone recommend a good brand of DC breakers? I was looking at CHTAIXI brand on Amazon but noticed they may burn up and trying to stay away from China made.

Also, on a Fuse between Batteries and Inverter, do I add a 400 AMP Class-T fuse at each positive battery terminal (4) 400AMP fuses) or 1 fuse at the main Battery Bank positive cable to the Inverter and can someone recommend a good brand as well?


I will use 2/0 and 600A busbars to connect the batteries together and 3/0 from the battery bank to Inverter - not pictured.


All in all, I probably will never exceed more than 20-30 Amps at once but looking to use good breakers and fuses.

Thanks!

 

[chrisski]

and a 500V/100A DC Breaker from SCC to Battery Bank with 4 AWG

The 100 amp breaker is right sized for the 80 amp constant output. The voltage for the breaker does not need to be 500 volts for a breaker that will see in the low 30s tops. Big difference in price. If you use 4 AWG, check the ampacity of the wire. To handle 80 amps constant, I'd expect at least 75C insulation. To avoid getting the wire too hot, I'd wire it with as thick wire as the SCC could take.

Can anyone recommend a good brand of DC breakers?

I like the Midnite Solar Breakers. I use them for my builds and for my house, the installer used these.

Inverter is 4000W 24V.

If you're going to get a 4000 watt inverter for long term wattage 3000 watts and above, IMO, this needs to be 48 volts. If you are getting this to reach those voltages a couple minutes each at five or six times a day, then you may be OK.

 

[Echo]

Thanks for the advice on Midnight Solar

I'll look into it for the Solar side - funny thing, Amazon, as of recent, seems to only recommend brands that are mostly Chinese Junk and it would not display Midnight Solar, Blue Sea, etc. Good that I asked here and read up on what others were currently using.

On the 100 Amp, I was thinking the same thing, so I found a Blue Sea 100AMP/48V breaker. Has a good rep and noticed a few mentions here on the Forum and found some Blue Sea MRBF fuses for each battery as well.

The 4 AWG is THHN, 95 AMPs, 90C, has held up great and 4 AWG was the max the SCC would take.

On the inverter, I just recently bought it (24v), though not setup yet. It was really a cost issue and hopefully easier to convert 12V to 24V, though I did drop $$ on an 4000W LFP inverter, but it does have a surge rating of 12000W for up to 20 seconds, while my 3500W inverter only has a 7K surge time of less than 10ms.

I hope the new inverter does well

 

[chrisski]

The 4 AWG is THHN, 95 AMPs, 90C, has held up great and 4 AWG was the max the SCC would take.

Please check what your solar charger needs. Victron recommends many stranded wire which is not the THHN I get from Home Depot, and other SCCs recommend other things.

 

[Echo]

Good call. I knew it was not from a Big Box store but was hard to read. Its fine strand copper "THHW", bought a few years back. NEC chart says 85A@75C or 95A@90C.

Also looked up Epever and they only list Max PV and Battery wire size at 25mm2/4AWG for my 80A model, but not a specific type noted.