Critique please

[Meeko]

Hello, just finished our electric, (solar cables not hooked up to charge controller yet) , looking for someone to take a look. Ty

 

[MisterSandals]

Is this a couple MRBF fuses? If so, what amp rating?
The fuse from DC-DC charger should be on the source/charger end as it is to protect the wire.

 

[Meeko]

The one closest to battery terminal is 200 the other is 60 going to charge controller.

 

[Meeko]

Is this a couple MRBF fuses? If so, what amp rating?
The fuse from DC-DC charger should be on the source/charger end as it is to protect the wire.

View attachment 134230

The one closest to battery terminal is 200 the other is 60 going to charge controller.

 

[MisterSandals]

closest to battery terminal is 200

2000W inverter / 10V cutoff / .85 efficiency = 235A max draw

If you stress that inverter or get near its likely cutoff voltage you may blow the fuse. If suspect your wiring is rated for 200A so the fuse, which protects the wiring, would be the right size.

other is 60 going to charge controller.

I would say coming from the controller which means the fuse only protects that wire if close to the charge controller.

 

[Meeko]

2000W inverter / 10V cutoff / .85 efficiency = 235A max draw

If you stress that inverter or get near its likely cutoff voltage you may blow the fuse. If suspect your wiring is rated for 200A so the fuse, which protects the wiring, would be the right size.


I would say coming from the controller which means the fuse only protects that wire if close to the charge controller.

I see the mistake on the 60 amp to the controller, it should be placed closer to the controller then to battery. I will fix that. Inverter will only be running a small water heater. 2/0 cable was used. Thank you, I'm learning.

 

[Bud Martin]

Did you tighten all the nuts? You may want to check them all again.
For example:

 

[DPC]

1/2 gypsum between combustable surfaces and electrical equipment mounted

Just in case things ever develop a fault and overheat is a good fire safety measure

Or alternatively a steel or aluminum sheet bonded to ground of course as a fire break would be fine

 

[chrisski]

The one closest to battery terminal is 200 the other is 60 going to charge controller.

EDIT: Looks fine. I now see the MBRF fuse located on the battery.


Am I looking at it wrong? Is the charge controller to battery unprotected but the positive busbar to the DC fusebox has the 60 amp fuse?

 

[Meeko]

Did you tighten all the nuts? You may want to check them all again.
For example:
View attachment 134266

Yes, I know, just setting this up, it's been a slow build because of the weather here in Maine.(no garage) and wasn't sure about leaving then electronics out in the cold, so I've been taking them in after figuring out the placement. Good eye. Ty

 

[Meeko]

1/2 gypsum between combustable surfaces and electrical equipment mounted

Just in case things ever develop a fault and overheat is a good fire safety measure

Or alternatively a steel or aluminum sheet bonded to ground of course as a fire break would be fine

Good idea, I will add.

 

[HRTKD]

I would connect the solar charge controller to the common bus bar, not the battery. A circuit breaker between the solar charge controller and the common bus bar is recommended. Should you ever need to work on the solar charge controller or PV while the rest of the system stays powered up, you'll want that circuit breaker.

 

[Meeko]

OK, I see what you're saying, why not direct to the battery?

 

[Meeko]

OK, I see what you're saying, why not direct to the battery?

I'm not using a common positive buss bar, it's a MBRF fuse holder, and can't exceed 300 Amps, I have 280 on it now, that why it's hooked to the battery, but yes I need a breaker.

 

[HRTKD]

You have a common positive bus bar. It's right there between your switch and the inverter. You conveniently have an open stud to put the solar charge controller cable on.

Power from the solar charge controller will be used by your inverter. It's splitting hairs but when the solar charge controller is producing power, it has to go through the cable to the battery, then to the switch, then to the common bus bar, then to the inverter. If you attach the solar charge controller cable to the common bus bar you skip much of that. Loads will pull power from the bus bar, with the battery making up any difference.

To split hairs even further, and reveal how OCD I am, put the battery cable on one of the inner studs of the negative common bus bar and the inverter cable on the other inner stud of the same bus bar. Less resistance through the bus bar for power to flow from the battery to the inverter.

What you have isn't wrong. It will work, as long as you have the fuses at the right ends of the cable and the fuses are sized right.

If you need to work on the batteries, the way you have it, if the sun is out then a charge is still going to the battery even if you turn off the main switch. If you put the solar charge controller cable on the common bus bar then zero power is going to the batteries and you're free to disconnect the battery cables without any sparks.

 

[Meeko]

That's a MRBF block, stud has no power untill a fuse is dropped in. All ready have a 200 amp fuse to inverter, and the other is a 80 amp to fuse block, the other stud is empty, because it can not exceed 300 Amps, I'm using 280 of this amps

 

[HRTKD]

I'm not talking about the MRBF block at all. But since you brought it up, in my opinion, you should be using a Class T fuse immediately downstream of the battery, not an MRBF.

 

[John Frum]

From left to right...

Do those batteries have a smart BMS?
If not you probably want to add a shunt.
Your inverter alone can pull ~240 amps from those batteries and they are only rated for 200 continous amps aggregate.
Add the dc fuse block loads to that number and its too high for the batteries.

Rotate the battery pack 180 degrees
That way the battery terminals line up with the inverter terminals
An MRBF fuse has sufficient breaking capacity for an 12 volt lfp battery bank so you don't need a class-t fuse.
You should upgrade the battery fuse to 300amps though.

Move the mppt.positive.out circuit to the busbar.
Move the positive fused busbar to the back left corner of the surface.
Move the negative busbar to the from left corner of the surface

kirchosffs law basically says that current in = current out.

Kirchhoff's circuit laws - Wikipedia

en.wikipedia.org

So moving the dc2dc charger to the fused positive busbar does not impact the aggregate current for the busbar.

The amp ratings for the busbar is in continuous amps
The busbar is rated for 300 amps continuous
300 amps continuous / .8 fuse headroom = 375 fuse_block amps

Each fused branch position is rated for 240 amps continuous
240 amps continuous / .8 fuse headroom = 300 fuse amps

2000 ac watts / .85 conversion factor / 10 volts low cutoff = 235.294117647 continuous inverter amps

300 busbar amps - 235.294117647 inverter amps = 64.705882353 continuous fuse_block amps

You can fuse the fuse block feeder circuit as high as 75 amps with 6 awg wire
You should fuse the inverter circuit at 250 amps with 2/0 wire
You can fuse the dc2dc charger as high 60 amps with 6 awg wire.
You can fuse the wire from the starter_battery as high as 80 amps with 6 awg wire.
Put the fuse at the starter battery end of the wire.

Move the disconnect switch to the fuse_block feeder circuit.
You can disconnect the alternator by turning off the engine.
You can disconnect the pv panels with the double pole disconnect on the wall to the left of the dc2dc charger
You can disconnect the inverter using its on/off switch
You don't need a disconnect switch for the batteries because every other circuit has a means of administrative disconnect.

I would like to congratulate you on the selection of the blue sea 5196, its very well suited to the application.
Hope the negative busbar is similarly rated and similar quality.

 

[John Frum]

To summarize the above.
Lets say your inverter and dc_fuse block can pull 300 amps.
Up to 50 amps could come from the dc2dc_charger and the balance will come from the battery.
If nothing comes from the dc2dc_charger then all current must come from the battery.
300 amps out means 300 amps in.

 

[Meeko]

You have a common positive bus bar. It's right there between your switch and the inverter. You conveniently have an open stud to put the solar charge controller cable on.

Power from the solar charge controller will be used by your inverter. It's splitting hairs but when the solar charge controller is producing power, it has to go through the cable to the battery, then to the switch, then to the common bus bar, then to the inverter. If you attach the solar charge controller cable to the common bus bar you skip much of that. Loads will pull power from the bus bar, with the battery making up any difference.

To split hairs even further, and reveal how OCD I am, put the battery cable on one of the inner studs of the negative common bus bar and the inverter cable on the other inner stud of the same bus bar. Less resistance through the bus bar for power to flow from the battery to the inverter.

What you have isn't wrong. It will work, as long as you have the fuses at the right ends of the cable and the fuses are sized right.

If you need to work on the batteries, the way you have it, if the sun is out then a charge is still going to the battery even if you turn off the main switch. If you put the solar charge controller cable on the common bus bar then zero power is going to the batteries and you're free to disconnect the battery cables without any sparks.

Thank you lots to go over