How to newb: Growatt 24v 3000w system

[skoobus]

Hi all, I have been trying for about a week now to start figuring things out but my head is spinning and I just don't think I can pull this off alone. I'm watching videos and seeing what other people did but everything seems to be so conflicting, and when I try to get a feel for the mechanics of things everything just goes over my head. It's especially difficult considering how dangerous this could be if I get things wrong. You guys that actually understand this stuff really have my respect.

So far I've figured out my solar array (with much help from this community) and found the wires I'll need, but not much else.

I have 6 250 watt panels going in to my MPPT in 3s2p configuration. The math of that, at least, I understand. 112v and 18amps. It fits my Growatt 24v 3000w AIO just right.

As for my battery bank I have 6 of the ECI power 100ah batteries going in to a 24v configuration, I get how to wire it but as for wire size I'm clueless. I think that 1/0 wire will definitely work, but at its price point could I go smaller safely?

From what I understand, the bank wire should be the same size going in to the inverter.. right?

My final worry (so far) is about all of the fuses and cut-off switches.. If anyone can broadly explain where and why I need them or point me in the right direction that would help tremendously. Like I said all of this stuff just goes over my head. If I had a general overview of things maybe I could figure this out on my own.

I'm sorry to be a complete newb on literally everything, but I'm floundering here. Any help is appreciated.

 

[HARG Hunter]

I believe 2/0 wire is sufficient for the batteries.
Cable to the inverter from the batteries does not need to be that heavy. 6 or 8 AWG should be fine.

I struggle with fuse stuff. My current setup has a fuse between the batteries and inverter.

Anyone else have input on this?

 

[WYtreasure]

I wonder if the OP is still around.

Yep this stuff is pretty mind boggling.
Here's my nickles worth.

Fuse/Circuit breaker Sizing and placement.

I am starting this thread to discuss Fuse/Circuit Breaker Sizing and placement. Edit: Updated the rule of thumb based on feedback in a later post from @JoeHam My rule of thumb is the protection Device should be the lower of 1) The capacity of the power source or 2) 1.25 x the expected current...

diysolarforum.com

 

[Rednecktek]

Hi all, I have been trying for about a week now to start figuring things out but my head is spinning and I just don't think I can pull this off alone. I'm watching videos and seeing what other people did but everything seems to be so conflicting, and when I try to get a feel for the mechanics of things everything just goes over my head. It's especially difficult considering how dangerous this could be if I get things wrong. You guys that actually understand this stuff really have my respect.

So far I've figured out my solar array (with much help from this community) and found the wires I'll need, but not much else.

I have 6 250 watt panels going in to my MPPT in 3s2p configuration. The math of that, at least, I understand. 112v and 18amps. It fits my Growatt 24v 3000w AIO just right.

As for my battery bank I have 6 of the ECI power 100ah batteries going in to a 24v configuration, I get how to wire it but as for wire size I'm clueless. I think that 1/0 wire will definitely work, but at its price point could I go smaller safely?

If your runs are just a couple feet, stick with the 1/0. Worst case scenario you have 2 of your battery banks fail/out/being serviced the 1/0 will still allow you full power to the inverter. If you're running more than about 10ft/3m then you might as well kick up to the 2/0.

Are you wiring your banks diagonally or going to bus bars? Bus bars is the optimum way to go for a couple reasons. 1: All your cable lengths can be made the same, 2: you can remove a bank for service without having to disconnect the whole system, and 3: once you get all the battery banks, SCC's, inverters, bucks, fuse blocks, etc all together, the bus bar makes life SSOOO much easier for getting all those wires to talk to each other.

From what I understand, the bank wire should be the same size going in to the inverter.. right?

Yes, since you already have a handful of 1/0 from wiring up the battery banks, stick with the 1/0 that will supply the amperage.

My final worry (so far) is about all of the fuses and cut-off switches.. If anyone can broadly explain where and why I need them or point me in the right direction that would help tremendously. Like I said all of this stuff just goes over my head. If I had a general overview of things maybe I could figure this out on my own.

Fuses protect the wire, cut-off switches are tools for isolating things. Breakers can be both at the same time. With your system you'll want 150a fuses at each battery bank, a 150a breaker between the battery bank and the inverter and 10AWG and a 30a breaker between the panels and SCC so you can disconnect and service the panels. Think about anything you might want to work on, a disconnect or breaker lets you kill power to service something without having to break out the screwdriver/socket/pipe wrench. Using a breaker that is DC rated to your voltage gives you protection for your wires AND a handy way to service.

I'm sorry to be a complete newb on literally everything, but I'm floundering here. Any help is appreciated.

We were all n00bs once, no worries.