First Solar System for my in progress Promaster. I'd love some feedback!

[ForestTheBoy]

Hey all, I'm starting a buildout and just started to look into wiring/fuses the day before last. It's just as complicated as I feared, but I think I've gotten somewhere with my blueprint.

I've already bought the batteries, BMS, panels, inverter/charger, and MPPT; so I'm building the system around those. I'd love any and all feedback! The last thing I want is for my system to get as fried as my brain has been for the past two days researching fuses and gauges.

https://imgur.com/a/2DZtFfH

 

[John Frum]

Its a little unusual to have a 250 amp fuse for the battery and a 300 amp for the inverter/charger but I don't think it will be a problem as both fuses are large enough and not too large for the wires and the loads.

 

[John Frum]

I like that high capacity fuse block.
Link please.

 

[John Frum]

You are pushing the limits of 10 awg wire between the solar charge controller and the high capacity fuse block.
Make sure its pure coppper with inuslation rated to 105 celcius.
8 awg would be better.

 

[ForestTheBoy]

Would you recommend I step down the inverter fuse to 250? I've only got it rated that high because it has a surge of up to 4000w. I don't foresee ever using that much in my system.

The DC fuse block is a cheap one from amazon. The positive/negative busbar system is the Victron Mega Fuse Holder that I'm going to modify to add a negative busbar.

 

[ForestTheBoy]

You are pushing the limits of 10 awg wire between the solar charge controller and the high capacity fuse block.
Make sure its pure coppper with inuslation rated to 105 celcius.
8 awg would be better.

Just between the MPPT and Busbars? The panels to the MPPT could still be 10awg?
Also the distance between my panels and charge controller is going to be less than 10 feet.

 

[John Frum]

Just between the MPPT and Busbars?

Yes

The panels to the MPPT could still be 10awg?

That should be fine depending on the length of the run and the voltage of the panels.

 

[John Frum]

Would you recommend I step down the inverter fuse to 250? I've only got it rated that high because it has a surge of up to 4000w. I don't foresee ever using that much in my system.

The DC fuse block is a cheap one from amazon. The positive/negative busbar system is the Victron Mega Fuse Holder that I'm going to modify to add a negative busbar.

Can you please provide a link to the inverter/charger.
I have trouble believing a 1500 watt inverter can surge to 4000 watts for any meaningful amount of time even if its low frequency.
Also both fuses are in the high current path so unless the trip curves are quite different the 250 amp fuse should blow first.
Also the 300 amp fuse is only protecting the inverter/charger wire.
The 250 amp fuse is protecting the main wire which includes the inverter/charger and the dc fuse block.

 

[ForestTheBoy]

I went with the cheap Sigineer brand for the inverter/charger. There's not much I want to run off it, so I wasn't too concerned. I mostly wanted the charging feature for emergency cloudy days.

 

[John Frum]

I went with the cheap Sigineer brand for the inverter/charger. There's not much I want to run off it, so I wasn't too concerned. I mostly wanted the charging feature for emergency cloudy days.

Those are good inverters and good value.

 

[John Frum]

Why not put the pv panels in series, are you concerned with shading?

 

[John Frum]

Thats a lot of power to pull off 280ah@12 volts.
What BMS did you spec?

 

[ForestTheBoy]

Why not put the pv panels in series, are you concerned with shading?

Yeah, I'm gonna be on the east coast most of the time, so not as much direct sun exposure as the west lol.
What are the benefits of series over parallel though? I haven't really heard any yet.

 

[John Frum]

If that unit can do 4500 watts for 20 seconds it can likely do 3000 watts long enough to blow your fuse.
300 amps is the limit for mrbf fuses and that high amp fuseblock is probably also limited to 300 amps.

 

[ForestTheBoy]

Thats a lot of power to pull off 280ah@12 volts.
What BMS did you spec?

I went with the Overkill Solar bms. I heard great things, and the note he left in the packaging makes me 100% happy with the purchase. I haven't used it yet and wouldn't hesitate to buy from him again.
It's only 120a, does that mean I'll only ever max out at 120a draw?

 

[John Frum]

Yeah, I'm gonna be on the east coast most of the time, so not as much direct sun exposure as the west lol.
What are the benefits of series over parallel though? I haven't really heard any yet.

Panels is series double the voltage which helps with voltage drop on the wire.

 

[ForestTheBoy]

If that unit can do 4500 watts for 20 seconds it can likely do 3000 watts long enough to blow your fuse.

The only appliances I'll use with the inverter are a pressure cooker occasionally, battery chargers for my sound gear, and MAYBE a pc if the sun is shining bright.
I don't think I'll ever push the system past it's 1500w, but I guess I should stick with the 300a fuse?

 

[John Frum]

I went with the Overkill Solar bms. I heard great things, and the note he left in the packaging makes me 100% happy with the purchase. I haven't used it yet and wouldn't hesitate to buy from him again.
It's only 120a, does that mean I'll only ever max out at 120a draw?

Its grossly undersized for the system.
You want a bms of at least 300 amps.
Probably double that if its commodity grade and fet based.

 

[John Frum]

The only appliances I'll use with the inverter are a pressure cooker occasionally, battery chargers for my sound gear, and MAYBE a pc if the sun is shining bright.
I don't think I'll ever push the system past it's 1500w, but I guess I should stick with the 300a fuse?

You should have 300 amps fuses in both positions.
Its a shame to build a system that is hamstrung by design.

 

[ForestTheBoy]

You should have 300 amps fuses in both positions.
Its a shame to build a system that is hamstrung by design.

So besides the BMS, what else would you say is bottlenecking my system?
Also, if you have reccomendations for BMSs I'm all ears.