Check my Breaker/Fuse plan

[culty]

I need to order breakers/fuses for my current (and evolving) solar build. Hoping for final sign-off or correction so I can sleep well knowing it's all well-protected.

PV: My understanding is that I don't need fuses in-between panels when wired in series or 2 (or fewer) in parallel. That leaves a main fuse between panels and MPPT/AIO. Breakers just after those, between fuse and MPPT/AIO.

PV:
PV WIRE: 10awg solar wire for all connections.

PANELS:
ISC: 10.31a
VOC: 49.03v
Panel configuration 1 (Growatt): 2p2s, Each string <15ft to t-connector & combiner box, ~15ft into RV/Growatt
156% ISC for 2p2s configuration: 32.17a
Panel configuration 2 (Renogy Rover): Single Panel, <10ft to combiner box, ~15ft into RV/Renogy Rover
156% ISC: 16.08a

FUSES:
No fuses needed according to Solar Array OCP doc shared on this forum

Breakers:
CHTAIXI DZ47Z-63 2-pole breaker (Overkill on amperage, but same price as lower amperage breakers; using for both strings)

BATTERY:
CURRENT BATTERY CONFIGURATION: 8-24v20ah batteries in 8p configuration (160ah) — (cell design is Headway 38120S (nominal 3.2v10ah) 2p8s configuration with custom BMS)

WIRE: 1/0 gauge, <5ft pos, <5ft neg (is this high enough gauge for my use? My inverter (Growatt) is currently only able to draw 3000w/6000w peak, so I think I'm ok here with the run length).

FUSES: 200a class t fuse (busman, littelfuse, blue sea?) immediately off of the positive busbar.

BREAKERS/BATTERY DISCONNECT: Not sure what to do here. Breakers seem iffy, and fuses are said to be the heavy lifter in the event of a battery overload. I'm inclined to use a simple rotary disconnect like this Blue Sea 6006 m-Series battery disconnect for occasional manual shutoff just after the fuses. If there's a better known approach to breakers/disconnects, please educate me.

I am currently cap testing all Headway cells (many were lightly used and are testing above rated specs), and will likely build a few larger batteries out of the best cells. This will no doubt affect my wire/fuse requirements, so if you have guidance on protection for this near-future battery design, I'd be really grateful. Specifically, I am unsure whether I need to wire for max load potential (Growatt), or for total battery capacity. Here's that rough configuration plan:

FUTURE BATTERY CONFIGURATION: Raw Headway 38120S (nominal 3.2v10ah) cells in ~16p8s configuration, custom BMS/active balancer on each battery, in 2p or 3p configuration (~160ah per battery * 3 = nominal 24v480ah)

 

[DIYrich]

BATTERY:


WIRE: 1/0 gauge, <5ft pos, <5ft neg (is this high enough gauge for my use? My inverter (Growatt) is currently only able to draw 3000w/6000w peak, so I think I'm ok here with the run length).

6000W at 24V is 250 amps. 1/0 wire is rated for 245 amps chassis, 150 in conduit. You need 312 amp wire (250x1.25 safety factor), or 3/0 wire for chassis (open air).

If the "peak" is truly "short" lived (less than a few seconds), then 1/0 wire is fine for 125 amps continuous. I would use a 200 amp Class T fuse for the 1/0 wire. It can ride out the 245 amps for a short period.

BREAKERS/BATTERY DISCONNECT: Not sure what to do here. Breakers seem iffy, and fuses are said to be the heavy lifter in the event of a battery overload. I'm inclined to use a simple rotary disconnect like this Blue Sea 6006 m-Series battery disconnect for occasional manual shutoff just after the fuses. If there's a better known approach to breakers/disconnects, please educate me.

Blue Sea is a reputable brand, and the switch is rated for 48v, 300a continuous, well above the max of your 24v system. Minimize using the switch when under load (disconnect the battery when not being charged or discharged).

 

[culty]

6000W at 24V is 250 amps. 1/0 wire is rated for 245 amps chassis, 150 in conduit. You need 312 amp wire (250x1.25 safety factor), or 3/0 wire for chassis (open air).

If the "peak" is truly "short" lived (less than a few seconds), then 1/0 wire is fine for 125 amps continuous. I would use a 200 amp Class T fuse for the 1/0 wire. It can ride out the 245 amps for a short period.



Blue Sea is a reputable brand, and the switch is rated for 48v, 300a continuous, well above the max of your 24v system. Minimize using the switch when under load (disconnect the battery when not being charged or discharged).

Thanks @DIYrich! Are those overrated 2-pole breakers ok for solar? Or do I need to have them both over my max current *and* under some upper-end value?

 

[DIYrich]

Thanks @DIYrich! Are those overrated 2-pole breakers ok for solar? Or do I need to have them both over my max current *and* under some upper-end value?

I don't know about breaker quality. The CHTAIXI DZ47Z-63 has the right rating (1000v).