First off-grid solar design. Am I missing anything?

[ddanley]

Initially, I will start with one string of panels.... Add another later...

Here is my design. Any feedback is greatly appreciated!

 

[rmaddy]

1. A 250A fuse is stronger than 2AWG wire. That's very bad. The fuse should always fail before the wire it's supposed to be protecting.
2. 2AWG wire is too small. You want 1AWG. You have a 3000W inverter at 24V. 3000W / 24V / 0.85 efficiency factor = 150A. For a 150A you want 1AWG. Then for the fuse you want one between the 150A load and the 250A max fuse size for 1AWG. I would suggest a 200A fuse.
3. Assuming your resistor is for an inverter precharge, I'm not sure why you have a 30A fuse on there. Just wire the resistor and a momentary push button switch.

 

[ddanley]

1. A 250A fuse is stronger than 2AWG wire. That's very bad. The fuse should always fail before the wire it's supposed to be protecting.
2. 2AWG wire is too small. You want 1AWG. You have a 3000W inverter at 24V. 3000W / 24V / 0.85 efficiency factor = 150A. For a 150A you want 1AWG. Then for the fuse you want one between the 150A load and the 250A max fuse size for 1AWG. I would suggest a 200A fuse.
3. Assuming your resistor is for an inverter precharge, I'm not sure why you have a 30A fuse on there. Just wire the resistor and a momentary push button switch.

Appreciate the feedback. Yes , the resistor is for the precharge.

The 250 was the max surge I wanted before popping a fuse. If I did pull 250 for a second or two, would that damage the wire?

It doesn't seem 1awg is very popular... (At least on amazon) ... I suspect it would be safer to go with 1/0.... Right?

 

[rmaddy]

1/0AWG wire is definitely safer than 2 or 1AWG since it can handle more amps. Plus it will have even less of a voltage drop.

I'm not 100% sure about the safety of wire handling a brief surge but 1/0AWG can be fused up to 300A. So even though you wouldn't want to use 1/0AWG for continuous 250A loads, it should be fine for a 250A surge lasting no more than a couple of seconds.

And don't forget that a surge that high will only happen if you try to pull a 6000W startup load through the inverter. This might happen if you have a really big air conditioner.

 

[ddanley]

About how long does a fuse take to blow? Is it pretty instantaneous when the amperage is reached, or is there a delay?

Thanks

 

[Ampster]

About how long does a fuse take to blow? Is it pretty instantaneous when the amperage is reached, or is there a delay?

It depends on the fuse. Some are rated as slow blow. Look at your fuse specs.

 

[RV10flyer]

I use 4/0, 300A Class T Fuse/Fuse Blocks or a 250 A DC Double Pole Breaker for my 24V 3,000 and 4,000 Watt inverters. Spend the money, stay cool, stay safe.

Or if derating to 2500 Watts, I’d use a 200A Class T with 2/0.

On the battery, I’d do one 8S configuration with a Daly 24V 250 or 300A and Bluetooth Accessory.

Also add a solar disconnect switch. Also a Midnite Solar Surge Protection Device on the solar input if not in hybrid inverter.