Will this set-up work?

[withaview2]

Hi!

I would greatly appriciate some feedback on this set-up. Should something be changed? Perhaps the DC>DC converter on battery instead?

 

[sunshine_eggo]

6awg PV wire is way overkill unless it's a very long run. Most PV wire is 8-14awg with 10awg being the most common for the larger panels (60-72 cell 250W+).

60A to MPPT should be 1.25X wire rating. If it's 60A, and you're putting out 60A, it will blow. If wire rated for 60A, fuse @ 75A.

1/0 from MPPT to battery is complete overkill unless you have long wires.

Why does battery isolator only isolate from MPPT and not loads? Should isolate everything.

3000W/24V/.85 = 147A

Depending on temperature rating, 1/0 may only be good for 125A.

300A fuse should be 1.25X wire rating, and wire should be good for 147A or more.

6awg to 24V @25A fuse is overkill unless you have long wires.

Need fuse between DC-DC and fuse block.

DC-DC may be more sensible off the battery unless you want to use the MPPT load ports for DC-DC cut-off, i.e., most MPPT load ports allow you to specify a minimum voltage at which the MPPT will cut power to the load ports to protect the battery. Ensure the load ports are rated for the needed current.

 

[withaview2]

6awg PV wire is way overkill unless it's a very long run. Most PV wire is 8-14awg with 10awg being the most common for the larger panels (60-72 cell 250W+).

Not long run at all but I have some 6awg PV wire I thought I use that

60A to MPPT should be 1.25X wire rating. If it's 60A, and you're putting out 60A, it will blow. If wire rated for 60A, fuse @ 75A.
1/0 from MPPT to battery is complete overkill unless you have long wires.

Ok. 6awg wire and 75A fuse?

Why does battery isolator only isolate from MPPT and not loads? Should isolate everything.

Good question. 1 near positive terminal on inverter and 1 before DC>DC converter?

3000W/24V/.85 = 147A

But if inverter draw max 6000W is not 300A fuse necessary?

Depending on temperature rating, 1/0 may only be good for 125A.

I have no cables yet, but if that's the case, better to go with 2/0awg?

300A fuse should be 1.25X wire rating, and wire should be good for 147A or more.

1/0awg @150A rating should be 200A fuse then?

6awg to 24V @25A fuse is overkill unless you have long wires.
Need fuse between DC-DC and fuse block.

Ok.

DC-DC may be more sensible off the battery unless you want to use the MPPT load ports for DC-DC cut-off, i.e., most MPPT load ports allow you to specify a minimum voltage at which the MPPT will cut power to the load ports to protect the battery. Ensure the load ports are rated for the needed current.

That was my idea. I will have to check MPPT manual. Thanks for clarification.

I'm a beginner to this so big thanks for helping out.

 

[sunshine_eggo]

Not long run at all but I have some 6awg PV wire I thought I use that

Ok. 6awg wire and 75A fuse?

You can always use bigger wire. Just fuse/breaker accordingly.

Good question. 1 near positive terminal on inverter and 1 before DC>DC converter?

Better to have a set of bus bars. The isolated would be between the battery and (+) bus bar with MPPT and Inverter attached to bus bar.

But if inverter draw max 6000W is not 300A fuse necessary?

You do not size for surge. You size for max continuous. Furthermore, if you were sizing for surge, 1/0 is not sufficient.

I have no cables yet, but if that's the case, better to go with 2/0awg?

Just make sure wire is rated for the needed current.

1/0awg @150A rating should be 200A fuse then?

150A * 1.25 = 187.5A, so 200A may be your only practical option.

That was my idea. I will have to check MPPT manual. Thanks for clarification.

Perfectly acceptable and a good approach provided the load ports can sustain the needed Amps. Many have lower current ratings compared to the MPPT output.

I'm a beginner to this so big thanks for helping out.

10-4 good buddy.

Lastly, assuming this is a DIY 8S 280Ah, ensure your BMS can handle the needed current. Also, I'm assuming you plan to use the BMS as a battery monitor for % charge and current. This is generally okay, but I would confirm the current measurement with a separate DC clamp ammeter before I trust it.

Will's site recommends a few good battery monitors if you want something that doesn't need a phone/tablet as well.

 

[hamaha]

Hi!

I would greatly appriciate some feedback on this set-up. Should something be changed? Perhaps the DC>DC converter on battery instead?
View attachment 130983

Other novice here.. can you provide a link to where you mocked up that diagram? Thanks

 

[solar_trees]

What software did you use to make that drawing?

 

[withaview2]

Other novice here.. can you provide a link to where you mocked up that diagram? Thanks

What software did you use to make that drawing?

Made with Adobe Photoshop.

 

[withaview2]

You can always use bigger wire. Just fuse/breaker accordingly.

Could you say as a general rule, bigger wire, bigger fuse/breaker?

Better to have a set of bus bars. The isolated would be between the battery and (+) bus bar with MPPT and Inverter attached to bus bar.

I was wondering what those busbars was used for.

You do not size for surge. You size for max continuous. Furthermore, if you were sizing for surge, 1/0 is not sufficient.

Ah, ok!

10-4 good buddy.

Lastly, assuming this is a DIY 8S 280Ah, ensure your BMS can handle the needed current. Also, I'm assuming you plan to use the BMS as a battery monitor for % charge and current. This is generally okay, but I would confirm the current measurement with a separate DC clamp ammeter before I trust it.

Will's site recommends a few good battery monitors if you want something that doesn't need a phone/tablet as well.

By meassuring on the positive battery wire?

Thanks for the tips

I'm going to update the schematic asap, hopefull it will be more accurate than the one above.

 

[sunshine_eggo]

Could you say as a general rule, bigger wire, bigger fuse/breaker?

yes. Specifically, fuses/breakers rated for 1.25X wire.

I was wondering what those busbars was used for.

Very handy.

By meassuring on the positive battery wire?

Yes.