Breaker help

[spaniel]

I'm thinking through an off-grid system and could use some guidance on DC breakers.

I'm thinking of going with an 800W 24V kit: New 800 Watt 24 Volt Solar Premium Kit | Renogy Solar

Four 100Ah gel 12V batteries, wired in series/parallel for 24V.

My main question is I'm also looking at a panel which would simplfy the whole setup, including tying into the inverter, and it has a DIN rail to hold breakers for the DC side of the system and I'd rather go with breakers than the two fuses that come with the Renogy kit. One is an in-line fuse (rated current 20A, rated voltage 1000V) and the other is an ANL fuse set, rated 40A, voltage rating 72A. I'm looking for recommendations for specific examples of appropriate breakers. I'm not as familiar with DC components and wanted to double-check to make sure I'm looking at this correctly. Thanks in advance.

[bob-n]

Midnite Solar sells many different DC circuit breakers:

http://midnitesolar.com/products.php?menuItem=products&productCat_ID=16&productCatName=Breakers

In general, people here have found that prices are lower if you buy individual components rather than a complete kit. Solar panels seem to be selling at under $0.50 per watt, so 800 watts of panels should cost you less than $400. It may come out that in your specific case, the kit is better value, but it's worth investigating.

This system will have high current, so use large wire. It is often worthwhile to buy larger diameter wire than required to reduce the voltage drop (power lost in the wire). Some people go for <2% power lost in wire, but I strive for <1%.

[Mike90250]

I would not mix DC voltages & breakers into a panel with AC voltage & breakers.

Midnight has good DC rated DIN rail breakers, and AC breakers too, along with many boxes to put them in.

[spaniel]

I would not mix DC voltages & breakers into a panel with AC voltage & breakers.

Midnight has good DC rated DIN rail breakers, and AC breakers too, along with many boxes to put them in.

The Magnum box in question is designed for this. I am NOT designing this myself.

[spaniel]

Midnite Solar sells many different DC circuit breakers:
http://midnitesolar.com/products.php...tName=Breakers

In general, people here have found that prices are lower if you buy individual components rather than a complete kit. Solar panels seem to be selling at under $0.50 per watt, so 800 watts of panels should cost you less than $400. It may come out that in your specific case, the kit is better value, but it's worth investigating.

This system will have high current, so use large wire. It is often worthwhile to buy larger diameter wire than required to reduce the voltage drop (power lost in the wire). Some people go for <2% power lost in wire, but I strive for <1%.

Feedback appreciated. Part of the value of the kit to me is I don't have to design the system myself, sizing and compatibility is already determined.

Case in point the original question regarding replacing the fuse listed at 20A, 1000V with a breaker. A DC breaker at 1000V is a rare bird. Thus I am questioning if I am missing what is needed in this situation. I've wired plenty of AC but I am new to DC so I'm asking lots of questions before I do anything. The 40A MPPT controller has a max input solar voltage of 100V. So the 1000V on the fuse seems the wrong number to be looking at.

[chrisski]

I'm thinking through an off-grid system and could use some guidance on DC breakers.

I'm thinking of going with an 800W 24V kit: New 800 Watt 24 Volt Solar Premium Kit | Renogy Solar

Four 100Ah gel 12V batteries, wired in series/parallel for 24V.

Once you start doing your research, you can see that there is a whole lot left out of that Renogy kit that adds up quickly. One is the optional inverter, so that can add a bit to the price. A place to put the battery, proper wiring, so many things left out. I could write quite a bit. Once you find out what you need, you’ll realize the extra stuff that goes in it.

I don’t know the specifics of the rover with a 40 amp ANL fuse, but I would expect a fuse to be higher than the output of the 40 amp controller. Perhaps ANL is a slower burn fuse, but I doing it. I think the ANL fuse blows within minutes at the rated amps and very quickly at multiples of it. THere’s a chart here towards the bottom that explains this: http://www.bcae1.com/fuses.htm

I have two boxes for my midnight solar DC circuit breakers. The best is Midnight’s MNPV6 combiner box that will hold six circuit breakers and combine the six different strings of panels. I have another combiner box I made out of Gangbox connectors and CIcrcuit breakers on. DIN rails, and that was half price of midnights, but not near the quality.

There’s a big difference between the way AC circuit breakers and DC circuit breakers are made, and choosing the wrong one could be fire damage. Also, PV tends to have much more volts, like the 150 volts the midnight breakers are rated for compared to some other circuit breakers that have lower volts like 36 volts DC.

On my RV, I have a similarly powered system at 12 volts. That will run my lights and TV all I want. I can treat myself to a few K-Cups a day. Also, I can run the propane heater blower motor. I’ll have enough power to do this for two days in cold weather. When I don’t turn the heat on and still run the lights and TV, I could last a couple of weeks with just the lights, TV, and phone charger.

[spaniel]

Once you start doing your research, you can see that there is a whole lot left out of that Renogy kit that adds up quickly. One is the optional inverter, so that can add a bit to the price. A place to put the battery, proper wiring, so many things left out. I could write quite a bit. Once you find out what you need, you’ll realize the extra stuff that goes in it.

I don’t know the specifics of the rover with a 40 amp ANL fuse, but I would expect a fuse to be higher than the output of the 40 amp controller. Perhaps ANL is a slower burn fuse, but I doing it. I think the ANL fuse blows within minutes at the rated amps and very quickly at multiples of it. THere’s a chart here towards the bottom that explains this: http://www.bcae1.com/fuses.htm

I have two boxes for my midnight solar DC circuit breakers. The best is Midnight’s MNPV6 combiner box that will hold six circuit breakers and combine the six different strings of panels. I have another combiner box I made out of Gangbox connectors and CIcrcuit breakers on. DIN rails, and that was half price of midnights, but not near the quality.

There’s a big difference between the way AC circuit breakers and DC circuit breakers are made, and choosing the wrong one could be fire damage. Also, PV tends to have much more volts, like the 150 volts the midnight breakers are rated for compared to some other circuit breakers that have lower volts like 36 volts DC.

On my RV, I have a similarly powered system at 12 volts. That will run my lights and TV all I want. I can treat myself to a few K-Cups a day. Also, I can run the propane heater blower motor. I’ll have enough power to do this for two days in cold weather. When I don’t turn the heat on and still run the lights and TV, I could last a couple of weeks with just the lights, TV, and phone charger.

The kit doesn't "leave out" things, they never claim it to be a soup to nuts complete system. I've got the system fully figured out with one exception, and asked a very specific question about breakers vs fuses. I've gotten my answers from another source.