Another Stupid Question

[Phantom]

I have set up epever 60 watt cc (mppt) , 6 100w rich solar panels 3s2p , 140 foot run from panels to cc 10 awg. Charge controller , batteries and inverter on same busbar. aims 4000w split phase inverter , 4 sok 12v 100 amp batteries 2s2p , 24 volt system. using 2 awg from batteries to bus bar Positive side goes to 250 amp fuse then bus bar , 6 awg from cc to bus bar , 4 awg from inverter to busbar . I have a 20 amp breaker between panels and cc. the inverter out goes to panel box (totally separate from grid). Now for the stupid question , do I need more breakers or cut off switches between the batteries and bus bar ? or any other place in the system?
its working perfectly running my well pump 24/7 and sometimes my fridge on sunny days.

 

[sunshine_eggo]

I have set up epever 60 watt cc (mppt)

60A?

, 6 100w rich solar panels 3s2p , 140 foot run from panels to cc 10 awg. Charge controller , batteries and inverter on same busbar. aims 4000w split phase inverter , 4 sok 12v 100 amp batteries 2s2p , 24 volt system.

ok

using 2 awg from batteries to bus bar Positive side goes to 250 amp fuse then bus bar ,

Depending on rating, 2awg may only be good for 100A.

6 awg from cc to bus bar ,

Marginal for 60A, but probably fine.

4 awg from inverter to busbar .

Horribly inadequate. 4000W/24V/0.85 = 196A.

I have a 20 amp breaker between panels and cc.

600W / 34V = 17A - 20A is on the line but probably fine.

the inverter out goes to panel box (totally separate from grid). Now for the stupid question , do I need more breakers or cut off switches between the batteries and bus bar ? or any other place in the system?

You need overcurrent protection (OCP) for every wire. For PV to MPPT, you only need OCP if you are 3P or more. At 2P or single string, the panels themselves are the "fuses."

 

[Browneye]

Yeah, for a 4kW inverter, 4awg is way too small. The installation manual will give you connect wire sizing requirements. I'm not going to guess cuz I work with 12V only.

I would want one of those BlueSea master cut off switches to take the battery bank offline for servicing/maintenance.
Your batteries presumably have a master fuse, but it's common to have a master ClassT fuse between the batteries and your bus - same deal, to isolate the batteries in the case of a direct short.

And the SCC should be fused or breakered to the bus as well, something to accommodate that 60A charging current, so a 75A switching breaker would also provide a cut off for servicing/maintenance, without shutting down the batteries and your load.
Looks like you have a switching breaker for your PV inputs - good for cutting solar power to the SCC. It needs to be DC rated, and sufficient amps to prevent nuisance tripping. Since it's just a switch it can be of higher amperage rating. Cutting both feed legs is a good idea, actually a NEC requirement now.

 

[Phantom]

60A?



ok



Depending on rating, 2awg may only be good for 100A.



Marginal for 60A, but probably fine.



Horribly inadequate. 4000W/24V/0.85 = 196A.



600W / 34V = 17A - 20A is on the line but probably fine.



You need overcurrent protection (OCP) for every wire. For PV to MPPT, you only need OCP if you are 3P or more. At 2P or single string, the panels themselves are the "fuses."

yes its a 60 amp not watt , OCP for every wire ? that would be 10+ OCP , is that right ?
for the 6 awg wire for the scc , it is the biggest I can put on their.

Yeah, for a 4kW inverter, 4awg is way too small. The installation manual will give you connect wire sizing requirements. I'm not going to guess cuz I work with 12V only.

I would want one of those BlueSea master cut off switches to take the battery bank offline for servicing/maintenance.
Your batteries presumably have a master fuse, but it's common to have a master ClassT fuse between the batteries and your bus - same deal, to isolate the batteries in the case of a direct short.

And the SCC should be fused or breakered to the bus as well, something to accommodate that 60A charging current, so a 75A switching breaker would also provide a cut off for servicing/maintenance, without shutting down the batteries and your load.
Looks like you have a switching breaker for your PV inputs - good for cutting solar power to the SCC. It needs to be DC rated, and sufficient amps to prevent nuisance tripping. Since it's just a switch it can be of higher amperage rating. Cutting both feed legs is a good idea, actually a NEC requirement now.

I typed the wrong number ... didnt see it until I posted it . its 2 (two) awg NOT 4 for the inverter to the bus bar , one foot long.

 

[Supervstech]

yes its a 60 amp not watt , OCP for every wire ? that would be 10+ OCP , is that right ?
for the 6 awg wire for the scc , it is the biggest I can put on their.





I typed the wrong number ... didnt see it until I posted it . its 2 (two) awg NOT 4 for the inverter to the bus bar , one foot long.

Still far too small.
196A needs 4/0 cables... if you ever plan on drawing full capacity, to say nothing of the surge.

 

[sunshine_eggo]

yes its a 60 amp not watt , OCP for every wire ? that would be 10+ OCP , is that right ?

Sorry, I should have said circuit. OCP goes on only the (+)

for the 6 awg wire for the scc , it is the biggest I can put on their.

It's on the line, but it's fine.

I typed the wrong number ... didnt see it until I posted it . its 2 (two) awg NOT 4 for the inverter to the bus bar , one foot long.

Still very marginal depending on rating unless you KNOW you'll never pull more than about 2400W.

 

[Browneye]

4kW inverter @24V nominal is still around 200A at full load. Here's the BlueSea wire chart - at 200A it's 2/0 awg. 2awg is good to 120A. High-current installations like that they'll usually over-wire with 4/0 as mentioned, to control heating and voltage drop. Size your fuse to 125% of your rated current.

Your battery capacity might power such a load for an hour or so. That's a LOT of juice. Since we don't know what your well pump draws, nor the refer, it's hard to say.

Perhaps the inverter was sized based in availability rather than design load.

 

[Phantom]

4kW inverter @24V nominal is still around 200A at full load. Here's the BlueSea wire chart - at 200A it's 2/0 awg. 2awg is good to 120A. High-current installations like that they'll usually over-wire with 4/0 as mentioned, to control heating and voltage drop. Size your fuse to 125% of your rated current.

Your battery capacity might power such a load for an hour or so. That's a LOT of juice. Since we don't know what your well pump draws, nor the refer, it's hard to say.

Perhaps the inverter was sized based in availability rather than design load.

The only reason I got a 4kw inverter was that was the lowest of what they offered in split phase 24 volts.
I use it for when power goes out ( not that often ) but decided to use it all the time for my well pump 1.5 hp
and sometimes if its sunny out I run my fridge during the day. so 20 amp for well pump 5 to 10 amp fridge.
Plus in my electrical panel dedicated to solar I have a 60 amp breaker 2 pole.
I would NEVER max out the inverter. well, never is a strong word
I checked what the Inverter says to use, it says 1 awg wire.

 

[Browneye]

There ya go...1/0 isn't too bad to work with either. The larger the wire the more difficult to work with - install lugs, connect in place, etc.

 

[Supervstech]

There ya go...1/0 isn't too bad to work with either. The larger the wire the more difficult to work with - install lugs, connect in place, etc.

He said 1awg, not 1/0

 

[Browneye]

He said 1awg, I said 1/0, you said 4/0.
It’s a high power inverter. 4awg is too light.