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Sanity Check

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whlla

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Jun 1, 2020
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Brand new to this and I've been staring at wire sizing charts for a couple days now bouncing around different ideas.
How does this look for starting layout?

untitled (1).png

Buddy had some 2/0 gauge wire laying around so figured I could use that for green wires in diagram. The charge controller however has max of 6 gauge for its terminals. Would it be alright to use 6 gauge on the red wires in diagram? Anything else out of place or wrong that I should correct? Not trying to burn the house down
 
I don't trust breakers over 200 amps.
I suggest you add an mrbf fuse of 250 amps at the battery positive and a disconnect switch between the fuse and the positive busbar.
The inverter positive wire should be fused at 250 amps.
Suggest a shunt between the battery negative terminal and the negative busbar.
A 100 amp hour lifepo4 battery can't supply enough current for that inverter.
 
smoothJoey said:
A 100 amp hour lifepo4 battery can't supply enough current for that inverter.
Click to expand...
I was just typing the same, plus no info on panel size or voltage. Not sure 2/0 wire size is good enough either.

OP do you really need a 2.2kW inverter ? or intend to ever run it at full capacity ?
 
Umpa said:
I was just typing the same, plus no info on panel size or voltage. Not sure 2/0 wire size is good enough either.

OP do you really need a 2.2kW inverter ? or intend to ever run it at full capacity ?
Click to expand...
2/0 awg is fine unless the wires are unexpectedly long but the high current fuses should be 275 amps.
 
Thank you guys for your help.

No intention of using full capacity, I only plan on using about 200-500 watts for now (fridge and lights) until I can afford another battery.
Yeah realizing inverter is large and thinking about returning and getting something in 1000-1500 range. Wanted to get an inverter I could continue to use as I increased load + batteries.

I had been using this table for sizing breakers, but if I should avoid breakers over 200A then will need to change to fuses.
Panels wise I was thinking of two of these in series (310w, 40.0V voc, 9.83A isc).

So 250/275 amp fuses on battery and inverter positive, remove the 250 amp breaker on battery and add disconnect switch, and consider downsizing inverter?
 
whlla said:
Thank you guys for your help.

No intention of using full capacity, I only plan on using about 200-500 watts for now (fridge and lights) until I can afford another battery.
Yeah realizing inverter is large and thinking about returning and getting something in 1000-1500 range. Wanted to get an inverter I could continue to use as I increased load + batteries.

I had been using this table for sizing breakers, but if I should avoid breakers over 200A then will need to change to fuses.
Panels wise I was thinking of two of these in series (310w, 40.0V voc, 9.83A isc).

So 250/275 amp fuses on battery and inverter positive, remove the 250 amp breaker on battery and add disconnect switch, and consider downsizing inverter?
Click to expand...

Yep.
If you are a bit careful I say keep the inverter.
Maybe put a 15 amp fuse on the ac side.
 
Now I might be wrong here, but the breaker rating was calculated at inverter full use.
If your only going to use 500W or there about's, then then the fuse/breaker can be much less on the low side. Understand though it will break/blow if you forget and connect a bigger load to the higher voltage inverter side.

You could stick a breaker on the high voltage side of the inverter in like a small CU. Then you can protect the low voltage side with a good quality 200A breaker, and then use it as a disconnect - whilst protecting against an overload situation like short in the inverter or cable.

Thats what I have done, I am well oversized with my inverter - but never intend to use it to the full capacity.
 
Heres how I calculate the wire and fuse for the inverter.
2200 ac watts / .85 conversion efficiency / 12 volts = 215.68627451 dc amps
215 dc amps * 1.25 fuse factor = 269.607843137 fusible amps.
 
On second though, maybe you should put a 125 amp mrbf fuse on the postitive terminal and swap for the 275 amp fuse when you add a 2nd battery.
 
smoothJoey said:
On second though, maybe you should put a 125 amp mrbf fuse on the postitive terminal and swap for the 275 amp fuse when you add a 2nd battery.
Click to expand...
Doesn't the fuse rely on the load ? So no mater how many batteries are connected - its only going to blow if the load is greater than the rated capacity of said fuse ?

I reckon a 100amp cheap Chinese breaker would do it for the 12v side after tails to protect the inverter, with a 150A fuse at the battery terminal to protect the tails against a short. And a 6 amp breaker post inverter would suffice against an overload. AC Voltage of 110 is an assumption here.

What do you think ? @smoothJoey
All input is good.
 
Umpa said:
Doesn't the fuse rely on the load ? So no mater how many batteries are connected - its only going to blow if the load is greater than the rated capacity of said fuse ?

I reckon a 100amp cheap Chinese breaker would do it for the 12v side after tails to protect the inverter, with a 150A fuse at the battery terminal to protect the tails against a short. And a 6 amp breaker post inverter would suffice against an overload. AC Voltage of 110 is an assumption here.

What do you think ? @smoothJoey
All input is good.
Click to expand...


I can't bring myself to endorse a cheap chinese breaker even if its backed by a proper fuse.
MRBF fuses are ~$10USD from waytech. Buy 2 and learn quickly :)

Eaton's Bussmann Series MRBF-125 Marine Rated Battery Fuse | Waytek

Eaton's Bussmann Series MRBF-125 Marine Rated Battery Fuse, rated at 125A for 58VDC systems with bolt-down design are available at Waytek today. Order today!
www.waytekwire.com www.waytekwire.com
 
smoothJoey said:
I can't bring myself to endorse a cheap chinese breaker even if its backed by a proper fuse.
MRBF fuses are ~$10USD from waytech. Buy 2 and learn quickly :)

Eaton's Bussmann Series MRBF-125 Marine Rated Battery Fuse | Waytek

Eaton's Bussmann Series MRBF-125 Marine Rated Battery Fuse, rated at 125A for 58VDC systems with bolt-down design are available at Waytek today. Order today!
www.waytekwire.com www.waytekwire.com
Click to expand...
Yeah - fair enough - no cheap Chinese shite, but the logic is sound ?
 
Man, thank you guys so much for your help. I am picking up some mbrf fuses and a good 100A breaker.
 
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