Help With Fuses and Breakers

[hepheastus]

I am having immense trouble finding what fuses and breakers I need.
It feels like there is a bit of knowledge gap and assumed knowledge in some of the resources I have been able to gather.

I have drawn the image below, the spots in yellow are my knowledge gaps and final hurdles before I can complete this system.


Main goal of this system is:
Having mostly reliable power for work from home during day-time hours.
Offsetting power consumption of network rack (500w always on power according to smart meter from electric company)

I had planned 10x 240w panels, 5 in series, 2 in parallel but recently I found it's operating voltage would have been too much (186) than it's allowed 145v (thanks to Will in that video where he had two arrays going to a Growatt, and in testing both, finding out one was too much and the other within spec).
So I had trimmed a panel down and did 3 in series 3 in parallel giving me 111v.

I also had planned on a running this with no battery but I have purchased the wrong model. In researching this I saw Will had mentioned in a thread about this specific model to just get any battery that will amount to 48volts.

I have also purchased this breaker for the battery (https://www.amazon.com/dp/B089TNNRS6) after searching what was recommended in the manual but when receiving the breaker and then watching a lot of videos I saw the symbol on it was AC and now I'm questioning my progress.
I have also purchased this breaker housing for the battery breaker (https://www.amazon.com/dp/B0C5WQ8JGR) so I would like something that could go into it but if recommended something else I am not too worried about returning it.

Components of my system so far -
Solar Panels - Trina 240W Solar Panel (x9) https://www.solarelectricsupply.com/trina-solar-tsm-240pa05-solar-panels
The Solar Inverter - Growatt SPF 3000TL LVM (48V version) https://en.growatt.com/products/spf-2000-5000tl-hvm（lvm）
Batteries - Timeusb 12V 50Ah LifePO4 (x4) https://www.timeusbpower.com/products/12v-50ah-pro-lifepo4-battery

Please, any help to get me past the finish line would be greatly appreciated.
I would love to get this nearly two year project in the rear view mirror.

 

[sunshine_eggo]

When figuring max voltage, you use Voc, not Vmp.
When figuring max current, you use Isc, not Imp ( it appears you've done this).

You list panel voltage at 29.7V, but you list 111V @ MPPT input.

Panels should have max fuse value on their label. One per 3S string. Given the panel size, 12A or 15A are probably fine.

You do not need breaker between combiner box and MPPT. If you want something for convenience, it needs to handle peak Voc on the record coldest day and the 26A x 1.25 min current.

Over-current protection between AiO and battery:

3000W/48V/.85 = 74A

Wire must handle this, and the fuse/breaker you use must be 1.25X higher than this.

Battery size matters. That inverter on and powering no loads will consume about 30% of your battery capacity.

Those batteries can only be charged at 50A, so 50A * 48V = 2400W max, so keep that in mind if you ever add PV.

Looks like they're also discharge limited too.

 

[robbob2112]

When figuring max voltage, you use Voc, not Vmp.
When figuring max current, you use Isc, not Imp ( it appears you've done this).

You list panel voltage at 29.7V, but you list 111V @ MPPT input.

Panels should have max fuse value on their label. One per 3S string. Given the panel size, 12A or 15A are probably fine.

You do not need breaker between combiner box and MPPT. If you want something for convenience, it needs to handle peak Voc on the record coldest day and the 26A x 1.25 min current.

Over-current protection between AiO and battery:

3000W/48V/.85 = 74A

Wire must handle this, and the fuse/breaker you use must be 1.25X higher than this.

Battery size matters. That inverter on and powering no loads will consume about 30% of your battery capacity.

Those batteries can only be charged at 50A, so 50A * 48V = 2400W max, so keep that in mind if you ever add PV.

Looks like they're also discharge limited too.

One more note on top of what eggo said - you will need an active balancer across the batteries to keep them from drifting apart voltage wise. It isn't expensive.

Always better to buy a battery at the correct voltage instead of stacking multiple batteries together. If you can change your order it would be worth the time to do so. If you were to get a 48v battery you would use an appropriate sized buck converter to run 12v loads.

 

[hepheastus]

Okay.
I'm researching and parting for what Eggo had recommended.
A 32A DC breaker for proximity to inverter convenience.
100A breaker on the positive side for the batteries and that I should also find a device for active balancing. I see them online and are pretty straight forward. That's a very good recommend that I have not seen mentioned anywhere.
I have in my cart a 2 gauge wire.

I'm assuming the 40A single pole breaker in my main panel for the AC in is correct as it has not been made mentioned.
I also do not really plan on expanding. But that's a great mention on the batteries charge max. If I do I'll probably have to get another inverter and put it in parallel, which would be fine as it would allow me to use all breaker spots in the load panel that I'm installing for the AC out. Right now I plan on just using 1,3,5 with 2,4,6 marked as dead.

If I am on the correct path, this will be a major relief and hopefully an end to this project.

 

[sunshine_eggo]

Okay.
I'm researching and parting for what Eggo had recommended.
A 32A DC breaker for proximity to inverter convenience.
100A breaker on the positive side for the batteries and that I should also find a device for active balancing. I see them online and are pretty straight forward. That's a very good recommend that I have not seen mentioned anywhere.

Example:

https://www.amazon.com/iSunergy-Battery-Equalizer-48V-Balancer/dp/B0BDF68PRJ

I have in my cart a 2 gauge wire.

Should do it.

I'm assuming the 40A single pole breaker in my main panel for the AC in is correct as it has not been made mentioned.

https://en.growatt.com/upload/file/SPF_3000TL_LVM_User_Manual_EN_202109.pdf

Page 9.

40A breaker
8awg wire.

I also do not really plan on expanding. But that's a great mention on the batteries charge max. If I do I'll probably have to get another inverter and put it in parallel, which would be fine as it would allow me to use all breaker spots in the load panel that I'm installing for the AC out. Right now I plan on just using 1,3,5 with 2,4,6 marked as dead.

That MPPT can handle close to 4000W, so unless you need more AC output, you don't need another AiO

 

[robbob2112]

Example:

https://www.amazon.com/iSunergy-Battery-Equalizer-48V-Balancer/dp/B0BDF68PRJ

Should do it.

https://en.growatt.com/upload/file/SPF_3000TL_LVM_User_Manual_EN_202109.pdf

Page 9.

40A breaker
8awg wire.



That MPPT can handle close to 4000W, so unless you need more AC output, you don't need another AiO

Make sure the wire you are ordering is pure copper welding or battery wire rated 105c, like windy nation. The flexibility is important and the higher temperature rating adds a better safety margin. This is for the wire between the batteries and to connect the batteries up to the inverter.

Between the inverter and your load panel use THHN.

 

[hepheastus]

Make sure the wire you are ordering is pure copper welding or battery wire rated 105c, like windy nation. The flexibility is important and the higher temperature rating adds a bettery safety margin. This is for the wire between the batteries and to connect the batteries up to the inverter.

Between the inverter and your load panel use THHN.

That's good advice.
I have used THHN before in overhead lighting wiring using exposed conduit so I am familiar with it.
It just so happens that the wiring I have purchased before (incorrect 8AWG for this exact purpose) and the one in the cart is from WindyNation.

 

[robbob2112]

That's good advice.
I have used THHN before in overhead lighting wiring using exposed conduit so I am familiar with it.
It just so happens that the wiring I have purchased before (incorrect 8AWG for this exact purpose) and the one in the cart is from WindyNation.

One last thought. The breaker you linked doesn't seem to be marked well for DC, most DC breakers are polarized. So make sure to hook it up with the correct polarity or it will probably smoke check in fairly short order. They didn't show all sides of the breaker so I couldn't see any markings other than a diode symbol on the front.

Over time reading here it seems to me that midnight solar breakers are a better choice when you need DC. @Hedges would have a lot to say on the subject.

 

[hepheastus]

One last thought. The breaker you linked doesn't seem to be marked well for DC, most DC breakers are polarized. So make sure to hook it up with the correct polarity or it will probably smoke check in fairly short order. They didn't show all sides of the breaker so I couldn't see any markings other than a diode symbol on the front.

Over time reading here it seems to me that midnight solar breakers are a better choice when you need DC. @Hedges would have a lot to say on the subject.

Okay, anything that's recommended for safe operation.
The breaker I had linked previously in the original post I had already abandoned as usable in this instance.
If this is the breaker you are intending (https://www.amazon.com/Midnite-Solar-Circuit-Breaker-MNEPV100/dp/B06XHW4R16), I can plan on its purchase.

 

[robbob2112]

Okay, anything that's recommended for safe operation.
The breaker I had linked previously in the original post I had already abandoned as usable in this instance.
If this is the breaker you are intending (https://www.amazon.com/Midnite-Solar-Circuit-Breaker-MNEPV100/dp/B06XHW4R16), I can plan on its purchase.

Good choice and clearly marked.