Newbie with a container needing advice

[TimmehTim]

You can't put 5 of those panels in parallel using the 5-way MC4 connector. MC4 connectors are usually rated to 30A at the most. Your 5 panels in parallel will be 45A.

The 5 to 1 connectors I have are related for 60a and the SCCs are rated for 80a.... if my math is correct, the 5 panels will create a 46.2v and 45a, so this shouldn't be a problem unless my math is a problem. Is this not right??
Why am I doing things the way I'm doing them...??? Because I don't know what the hell I'm doing. I'm certainly glad to have people like you to help make sure I survive this.

 

[rmaddy]

The SCC rating of 80A is its output for battery charge current. That's irrelevant to the input amperage from the panels.

But if the 5-way connector can handle 60A then it should work. But you still need to fuse each panel.

 

[TimmehTim]

The SCC rating of 80A is its output for battery charge current. That's irrelevant to the input amperage from the panels.

I'm super confused.

It says:
Max Power Current: 80a
Load Output Current: 40a
Max PV Input Power 2000w@24v
Max PV Input Voc 96V@24v

Will this not work?

 

[rmaddy]

I've never seen the term "load output current" for an SCC so I'm not sure what that means.

I'm assuming the 80A rating is the max battery charge current which at 24V means up to about 2000W of panels.

 

[Bluedog225]

I like your nice linear layout and list. Easy to digest.

 

[TimmehTim]

Could the "Load Output Current" be the current provided by the Load terminals? That's probably it.

Ok. So how do I find out for sure if this SCC can handle 46.2v and 45a from the solar panel array?

 

[rmaddy]

Look at the max PV input voltage for the SCC. It's 96V for a 24V system. Your panels are less than half that so you are well below the limit. There's no mention of a max PV input current so you should be fine with the 45A.

 

[TimmehTim]

Lol. Ok. I misunderstood something along the line. I thought you were doing some calculations that I wasn't following. Somehow I thought you were saying that the 80a rating was too low so I wad totally disregarding the 96v

 

[rmaddy]

The 96V limit is the one you must not exceed. You over panel with more wattage just fine. You can have higher input amperage. But never exceed the max PV input voltage. Bad. In some cases it's the "let out the magic smoke" bad.

Look back at post #26. for 5P you only need a 60A SCC, not 80A. 60A x 24V = 1440W. 5 x 315W panels is 1575W. Since your 5 panels will rarely give the full 1575W of power and the SCC will actually be more like 60A x 26+V then you get a really close match. No need to spend the extra money on two 80A controllers when two 60A controllers will meet your needs. If you plan to add more panels then that's a different story.

 

[LithiumCanuck]

What a great analysis Rmaddy!

I absolutely second that !

 

[TimmehTim]

Updated Diagram with Parts List
(Wiring list to come)

 

[rmaddy]

The shunt does not belong between the inverter and the bus bar. The shunt belongs between the battery and the negative bus bar.

The two wires from the bus bars to the batteries must not be to the same series pair. Connect one bus bar to the upper battery pair and the other bus bar to the lower battery pair.

Why is #8 labeled a battery disconnect switch? It appears to be an inverter disconnect switch. #7 is the only battery disconnect.

You have a 5000W inverter on a 24V system. 5000W / 20V LVD / 85% efficiency is up to 300A being pulled from the batteries. That requires 4/0AWG wire and a 375A fuse (between the battery and battery disconnect switch). Your bus bars and shunt must be larger than that. You do not want the shunt or bus bars to be weaker than the biggest fuse in the system.

Therefore you need beefier bus bars. 250A is too low. You need at least 400A bus bars. Same with the shunt. 300A is too low. 400A or more is required.

You need fuses between each SCC and the bus bars. For a 60A controller you need a 75A fuse.

 

[TimmehTim]

The shunt does not belong between the inverter and the bus bar. The shunt belongs between the battery and the negative bus bar.

I'll modify that.

The two wires from the bus bars to the batteries must not be to the same series pair. Connect one bus bar to the upper battery pair and the other bus bar to the lower battery pair.

Can I fix this by switching the bridges

Why is #8 labeled a battery disconnect switch? It appears to be an inverter disconnect switch. #7 is the only battery disconnect.

Isn't it the same though? I was thinking that by adding another DC disconnect between the positive bus bar and the inverter, I can shut off power to the inverter when I need to service it.

You have a 5000W inverter on a 24V system. 5000W / 20V LVD / 85% efficiency is up to 300A being pulled from the batteries. That requires 4/0AWG wire and a 375A fuse (between the battery and battery disconnect switch). Your bus bars and shunt must be larger than that. You do not want the shunt or bus bars to be weaker than the biggest fuse in the system.

So from the positive bus bar, electricity from the 4/0 wire to the battery would be met with the DC disconnect switch followed by the 375A fuse before hitting the battery? Is 375A what I need? I'm not finding it to be as readily available as a 350A or 400A. Could I use one of those?

Therefore you need beefier bus bars. 250A is too low. You need at least 400A bus bars. Same with the shunt. 300A is too low. 400A or more is required.

I'll upgrade it to 400A bus bars

You need fuses between each SCC and the bus bars. For a 60A controller you need a 75A fuse.

Will a 75A ANL fuse work here?

 

[TimmehTim]

Here is a rough of the schematics for the wires, fuses, breakers, and disconnects/isolators. Exactly how fast will this catch on fire the way I have it wired? How would I wire it differently to prevent a thermal event from occurring?

 

[rmaddy]

Can I fix this by switching the bridges

The easiest is to simply take the battery wire connected to the negative bus bar and move it from the upper-right battery to the lower-right battery.

So from the positive bus bar, electricity from the 4/0 wire to the battery would be met with the DC disconnect switch followed by the 375A fuse before hitting the battery? Is 375A what I need? I'm not finding it to be as readily available as a 350A or 400A. Could I use one of those?

battery positive -> main fuse -> main DC disconnect switch -> positive bus bar

Yeah, 375A is an odd size. Since you are planning on 400A bus bars you should go with the 350A fuse. If you ever try to use the full 5kW from the inverter it will be a little tight but not too bad. If you go with a 400A fuse then you must go with a 500A shunt and 500A bus bars.

Will a 75A ANL fuse work here?

I used a Bussman brand 285 series breaker for my SCC. Blue Sea also has a version of this breaker. It can also act as a disconnect if ever needed. If you use a fuse then a MEGA fuse is probably just fine. If you can't find a 75A then 80A will be fine (especially with your 4AWG wire.

Here is a rough of the schematics for the wires, fuses, breakers, and disconnects/isolators.

How long will the wires be from the 5-way PV connectors to the SCC?

What is the voltage rating of the breaker you will be using for the PV disconnect? Make sure it is rated for at least 50V or more and for DC.

The wire from the AC-out of the inverter to the AC breaker box is currently labeled as 4/0AWG. It should be the same 6/4 that you have out from the AC breaker box.

Your wiring change for the batteries looks correct but it is just weird. It seems clearer to keep series pairs side by side instead of crossed. Simply change the battery wire from the negative bus bar from the top-right battery to the bottom-right battery. But in the end both approaches work the same. If you ever add a 3rd series pair then your current "criss-cross" approach falls down.

 

[TimmehTim]

The easiest is to simply take the battery wire connected to the negative bus bar and move it from the upper-right battery to the lower-right battery.

I just did the crisscross for the diagram. I'll have them side by side in real life.

battery positive -> main fuse -> main DC disconnect switch -> positive bus bar

Perfect. Looks like I got it right on the diagram.

Yeah, 375A is an odd size. Since you are planning on 400A bus bars you should go with the 350A fuse. If you ever try to use the full 5kW from the inverter it will be a little tight but not too bad. If you go with a 400A fuse then you must go with a 500A shunt and 500A bus bars.

Ok. Already upgraded to the 500A shunt.

I used a Bussman brand 285 series breaker for my SCC. Blue Sea also has a version of this breaker. It can also act as a disconnect if ever needed. If you use a fuse then a MEGA fuse is probably just fine. If you can't find a 75A then 80A will be fine (especially with your 4AWG wire.

Thank you, I'll change those out

How long will the wires be from the 5-way PV connectors to the SCC?

Maybe 20 feet...

What is the voltage rating of the breaker you will be using for the PV disconnect? Make sure it is rated for at least 50V or more and for DC.

They will be 1000v 63A DC

Correct me if I'm wrong, but I connect one of these breakers on each of the PV arrays just before the SCCs. Using one port for the positive wire and the second port for the negative wires.

The wire from the AC-out of the inverter to the AC breaker box is currently labeled as 4/0AWG. It should be the same 6/4 that you have out from the AC breaker box.

Ok. I'll modify that.

Your wiring change for the batteries looks correct but it is just weird. It seems clearer to keep series pairs side by side instead of crossed. Simply change the battery wire from the negative bus bar from the top-right battery to the bottom-right battery. But in the end both approaches work the same. If you ever add a 3rd series pair then your current "criss-cross" approach falls down.

I really appreciate all your guidance. Thank you!!

 

[rmaddy]

Correct me if I'm wrong, but I connect one of these breakers on each of the PV arrays just before the SCCs. Using one port for the positive wire and the second port for the negative wires.

That is correct. And remember that anytime you ever connect or disconnect battery power to/from the SCC, the PV disconnect breaker must be off. The only time the PV disconnect breaker should ever be switched from off to on is when the SCC currently has battery power.

 

[TimmehTim]

That is correct. And remember that anytime you ever connect or disconnect battery power to/from the SCC, the PV disconnect breaker must be off. The only time the PV disconnect breaker should ever be switched from off to on is when the SCC currently has battery power.

Ok. With that said, if the fuse on the positive terminal between the battery and the disconnect switch blows the SCC will essentially be disconnected to the battery bank, leaving SCC's connected to the Inverter. Is this ok?

 

[rmaddy]

Ok. With that said, if the fuse on the positive terminal between the battery and the disconnect switch blows the SCC will essentially be disconnected to the battery bank, leaving SCC's connected to the Inverter. Is this ok?

If an SCC loses battery power while still connected to PV it is not an issue. But I would disconnect PV before restoring battery power. Once battery power is restored, reconnect PV.

 

[TimmehTim]

Just waiting on one more combiner box and my batteries... Does anyone see anything immediately wrong with this setup?