Please QA final DC electrical plan

[corn18]

I have all the parts on the way to finish my DC power install. Before I put everything in, would you take a look and see if there is anything I should consider changing? Especially WRT wire size and breakers. All wire runs are really short (<18") except the runs from the solar panels.

Thanks a bunch!

[Bobby F]

It could be that I'm just misunderstanding your diagram, but regarding your shunt - are you running a connection from battery-negative to the shunt AND to chassis ground? Or does that ground connection hook up on the other side of the shunt from the battery? (It seems like you're bypassing your shunt.)

[corn18]

Originally Posted by Bobby F

It could be that I'm just misunderstanding your diagram, but regarding your shunt - are you running a connection from battery-negative to the shunt AND to chassis ground? Or does that ground connection hook up on the other side of the shunt from the battery? (It seems like you're bypassing your shunt.)

The way I drew it is WRONG! Oops. I cleaned it up to show the right way to hook it up (I hope). It gets very crowded when trying to use line weight to represent wire gauge.

[Bobby F]

Originally Posted by corn18

It gets very crowded when trying to use line weight to represent wire gauge.

Your diagram is a lot clearer than my attempt when I built mine!


One more question: How are you turning off your converter when not on shore power or generator? Unplug?

[corn18]

Originally Posted by Bobby F

Your diagram is a lot clearer than my attempt when I built mine!


One more question: How are you turning off your converter when not on shore power or generator? Unplug?

If not on shore/generator power, the converter will not get power. The 1200W inverter is dedicated to the residential fridge. The 2000W inverter goes to the sub-panel and it does not power the converter. I went with a sub panel for the large inverter to give me more control. I thought about auto switching the entire AC load panel, but that made my head explode. What I have on the sub panel is all I want and I have one spare breaker if I want to add anything else. The stuff NOT on the subpanel:

- Two air conditioners
- Electric fireplace
- Electric water heater
- Converter

Keep the comments coming! I am making changes as they are posted.

Closeup of sub panel:

[twinboat]

You have some circuit breaker far from the source of power ( bus bar ).

The breakers protect the wiring, so they need to be close to the bus bar ( power source ), not up in a front compartment.
That includes the battery side of the charge controller.

I see 2 100 amp breakers between the bus bar and converter. Your converter can't make over 60 amps, a 100 breaker will never trip. If the cable can handle 60 amps, no breaker needed. The batteries can produce lots of amps and melt wire if converter shorts,, breaker needed on that end.


The solar panels will never make enough power to trip the breaker. Although a switch or breaker is handy to turn off the solar.

[Bobby F]

Ah, I see what I was missing. There's another AC system powered by shore/genny that isn't shown here. Makes sense.

[corn18]

Originally Posted by twinboat

You have some circuit breaker far from the source of power ( bus bar ).

The breakers protect the wiring, so they need to be close to the bus bar ( power source ), not up in a front compartment.
That includes the battery side of the charge controller.

I see 2 100 amp breakers between the bus bar and converter. Your converter can't make over 60 amps, a 100 breaker will never trip. If the cable can handle 60 amps, no breaker needed. The batteries can produce lots of amps and melt wire if converter shorts,, breaker needed on that end.


The solar panels will never make enough power to trip the breaker. Although a switch or breaker is handy to turn off the solar.

The distance is actually quite small from the bus bar to the breaker. Just hard to draw everything to scale.

I am going to put two 100A breakers on the positive line to the converter/charger. One right at the converter and one right at the + bus. I never considered the current can flow both ways. The reason for the one next to the charger is to protect the wire in case the charger shorts.

I am going to add a switch between the panels and each charger.

Awesome sauce! Trying to keep up.

[Bobby F]

Also, just as an FYI: I have 400 watts of panels. On a very good sun day in the North states, I generate about 1.5kWh. I say this only so you can match this up with your fridge requirements.

[corn18]

Originally Posted by Bobby F

Also, just as an FYI: I have 400 watts of panels. On a very good sun day in the North states, I generate about 1.5kWh. I say this only so you can match this up with your fridge requirements.

The fridge is a hog. It pulls 50A for about a second when it kicks on and then 10A to run. Not sure how much I will use during a 24 hour period yet. So I am going to start with the 2x200 on the roof and a 2x100 suitcase that I can move around on the ground. I'll see how that goes. I have room for another 4x200W panels on the roof, so room to grow.

[corn18]

Any recommendations for a switch between the panels and charge controllers? Really don't think I need a giant battery cutoff type switch just for that low amperage.

[twinboat]

These are compact and come in all amp ratings.

[corn18]

Originally Posted by twinboat

These are compact and come in all amp ratings.Attachment 343089

I'm not keen on using a bimetal CB as a switch. They aren't the most reliable CB and flipping them on and off makes them less so.

[Bobby F]

Originally Posted by corn18

I'm not keen on using a bimetal CB as a switch. They aren't the most reliable CB and flipping them on and off makes them less so.

Oh oh. That's what I use. 30 amp. Seems to be a standard choice. But I don't think I've ever actually switched it off in two years, except at install.