Solar questions

[Shawn & Ash]

Nick,

How many 120 Circuits do you have? what breaker panel do you use?

[ermracing]

Originally Posted by Shawn & Ash

Im unsure on what breaker box i need to install for my solar setup.

Ill have 3 15 amp circuits but id like to have the capability to add at least one more. When i go to home depot i see models that are 200 bucks all the way down to like 40.

I have determined that ill need around a 75 amp breaker box but im not sure exactly what i'm looking for. Im sure an electrician could answer this but i figured id see if anyone had a link to one they have used on a similar system.

We used a sub panel box that had only 2 slots and then installed 2 double breakers for a total of 4 circuits. It's roughly 8" wide, 15" tall and 6" deep. I think we had to buy the bar for the neutral leads as well.

[JDOnTheGo]

Originally Posted by Shawn & Ash

Im unsure on what breaker box i need to install for my solar setup.

Use of "breaker box" and "solar" in the same sentence is a little odd - or at least confusing - to me anyway.

It is fairly typical to use a large ANL type fuse (and 'holder' - like this) OR a breaker (like this) between the panels and charge controller and another between the charger controller and battery.

Originally Posted by Shawn & Ash

Ill have 3 15 amp circuits but id like to have the capability to add at least one more. When i go to home depot i see models that are 200 bucks all the way down to like 40.

This really confuses me. You must be talking about your house AC (alternating current) system??

If AC electrical system... IMO, it is easiest to go to your favorite home improvement center and find a breaker box AND circuit breakers to match (there are many different styles) that "fits" (fits = the right physical size as well as the necessary number of circuits. There are many different styles and it might be easiest to get some guidance from one of the staffers (leaving out the "bus" part). That said, you do need to know if you are going with split-phase 240VAC (two 120VAC legs each with 50 amp potential) - generally referred to as 50 amp service in the RV world, or 30 amp service (one 120VAC leg with 30 amp potential).

[Shawn & Ash]

Maybe the correct terminology would be the “distribution box”? Whatever comes after the inverter not including ANL fuse.The box where my 15 amp breakers will be and distribute to my outlets. Definitely 120v. I’m guessing it would be just a smaller version of a residential model?

[BlackJohn]

"I have determined that ill need around a 75 amp breaker box but im not sure exactly what i'm looking for."


How did you establish this figure? Most houses wouldn't use that at any one time.


What type of appliances or whatever are you using? Bewlidering.


John

[dzl_]

Originally Posted by Shawn & Ash

Im unsure on what breaker box i need to install for my solar setup.

Ill have 3 15 amp circuits but id like to have the capability to add at least one more. When i go to home depot i see models that are 200 bucks all the way down to like 40.

I have determined that ill need around a 75 amp breaker box but I'm not sure exactly what I'm looking for. I'm sure an electrician could answer this but i figured id see if anyone had a link to one they have used on a similar system.

You are over-complicating things in your head by thinking about Solar and AC power in the same thought.



I am not an expert when it comes to AC power. But what I can tell you is that solar is just one of your charge sources, that feeds your batteries and DC system. Your AC wiring will be exactly the same with or without solar. And any advice that applies to motorhome AC wiring, should apply to your situation regardless of whether you have solar or not. There are probably resources online you could check out (either from the RV world or the Marine world).



Start with these short videos:

Intro to AC and DC panels on boats

Intro to the AC Panel

And this longer video on fusing and circuit breakers:

Intro to Fuses and Circuit breakers

Finally, this video is a good high level comprehensive overview of electrical system design (aimed at boats, but almost totally applicable to skoolies):

Marine Electrical System Design

If it were me, I think I would probably avoid the big box store, and buy from a specialty seller that has knowledge and expertise of either marine electrical, rv electrical, or off-grid residential electrical systems. Bay marine supply would be one option, but there are many others.

[kazetsukai]

Originally Posted by Shawn & Ash

My first question arises from the Mppt charge controller. I gather we will need a 125 amp controller to allow for some wiggle room. Is this accurate? What’s the suggested brand? (I’ve heard Xantrax)

Depends on your battery bank. 1200W of panels with a 12V bank means you'll need a charge controller with a rating of at least 100A. 1200W with a 24V battery bank: 50A. 48V: 25A.

800W and up, you start to see benefits from bumping your battery bank to 24V. There are also drawbacks, but you can convert down to 12V for appliances. 1200W is about as high as I'd ever go on a 12V bank.

As for brands, I love my Victron Energy 150V/100A.

Originally Posted by Shawn & Ash

Also the Inverter/Charger. I believe we will need a 3000 Running Watt 6000 Surge watt inverter with auto switch considering our desired hookups and our wish to use a 6k OR 9k BTU a/c, an RV Fridge, outlets, DC hookups etc. is that an accurate size? What are the suggested brands?

First, to put things into perspective: I have a 9k BTU mini split, which consumes anywhere from 300W to 800W heating my bus. I hope to put up 2400W-3600W in panels.

A traditional window unit a/c you're looking at probably 1200W-1500W draw, which will bleed you dry even in full sun. Remember, you won't be making 1200W most of the time, you'll likely peak at 800W-900W most days with your panels lying flat.

I have an 8000W split-phase inverter (240VAC + 120VAC via two hots and a neutral), although I wouldn't trust it with much more than about 4000W, or 2000W on each leg. That's enough to run any one appliance I want in any of my 20A outlets. 3000W single phase is _plenty_ unless you want to run table saws, angle grinders, and air compressors all simultaneously.

Originally Posted by Shawn & Ash

what breaker panel do you use?

Because I have a split phase inverter I just used a residential 8 posiition square-D panel. If your inverter is single phase, make sure whatever panel you get is also single phase.

[john61ct]

So many confusions going on here, impossible to sort out when the wrong questions are being asked.

Best to start a new thread, and build from one foundation at a time.

Forget shore power for now, input or output.

Start with the battery bank + solar input circuit(s), get that all nailed down.

Then alternator charging.

Then move to shore power charging.

Then a genset.

Then start looking at an inverter load, wiring out from there (first mention of AC distribution to loads).

Finally the trick part, shore power hookups.

Each of these could have a separate thread for clarity, just post links between them for background context.

Simple questions, one or two at a time.

[kazetsukai]

Originally Posted by john61ct

So many confusions going on here, impossible to sort out when the wrong questions are being asked.

Yeah, reading back I just saw this:

Originally Posted by BlackJohn

"I have determined that ill need around a 75 amp breaker box but im not sure exactly what i'm looking for."

How did you establish this figure? Most houses wouldn't use that at any one time.

Its just not possible that he'd need 75A. OP: This is why I don't like throwing around amperages (current) ratings, as it isn't telling the whole picture. I prefer wattage (power). If you plug a microwave oven into your inverter that uses 1100W, its drawing (1100W/110V=) 10A from the inverter. However the inverter, which has to provide 1100W of power to its appliances, has to get that much power from the batteries at a much lower voltage. For a 12V battery bank, the inverter has to draw (1100W/12V=) 91A. For a 24V battery bank, (1100W/24V=) 45.83A.


To need a 75A breaker box for AC electrical at 110V, you're hoping to support (75A * 110V=) 8250W power draws, or (8250W/12V=) 687A from the batteries (or 343A @24V). That's insane.

[Shawn & Ash]

Originally Posted by BlackJohn

"I have determined that ill need around a 75 amp breaker box but im not sure exactly what i'm looking for."


How did you establish this figure? Most houses wouldn't use that at any one time.


What type of appliances or whatever are you using? Bewlidering.


John

How did I come up with this...

Three 15 amp circuits. All go to either outlets on the left side of the bus or the right.

15x3= 45

I say 75 because I wanted to leave room in case I would wire in another circuit. Also I only saw 75 amp boxes available at Home Depot (there were 100 and 200 aswell but I wouldn’t need one that big I gathered) so I assumed that if I was to add another circuit this is roughly where I would fall.

Maybe I’m confused about how I’m adding this up but I thought it was simply adding up the breakers to get to my overall needed size.

All I’ll have 120v is the fridge and outlets for laptops, maybe some kitchen appliances but nothing that would blow a 15 amp breaker.

I’m not doing a great job of explaining. However these questions don’t seem as complicated to me as your making them out to be.

Maybe where I went wrong was I didn’t need three circuits. I could get away with two but I wanted to have the fridge on it’s own circuit.

[john61ct]

Well for a start, what you're currently talking about has nothing to do with solar.

Laptops, and other native-DC devices (clue: have batteries, 12V "car chargers" are available) should not be run off inverter power, just convert your DC to the right voltage.

If you're living mostly off grid, just put inverters in for those few appliances that need them, fewer the better for efficiency.

Then when you do get to shore power, only the bank charger needs to plug in.

[Shawn & Ash]

Originally Posted by john61ct

Well for a start, what you're currently talking about has nothing to do with solar.

Laptops, and other native-DC devices (clue: have batteries, 12V "car chargers" are available) should not be run off inverter power, just convert your DC to the right voltage.

If you're living mostly off grid, just put inverters in for those few appliances that need them, fewer the better for efficiency.

Then when you do get to shore power, only the bank charger needs to plug in.

Thanks, good tip. And yeah these questions are coming from all over the place. I’ll get organized and try stay on thread. Start new one appropriately.

[dzl_]

Originally Posted by Shawn & Ash

Thanks, good tip. And yeah these questions are coming from all over the place. I’ll get organized and try stay on thread. Start new one appropriately.

I highly recommend watching the video I posted earlier (or one like it), it should help you organize your thoughts and think through the whole system in a sort of systematic modular way. Devoting a bit of time to the fundamentals early pays off in the end.

[Shawn & Ash]

Originally Posted by dzl_

I highly recommend watching the video I posted earlier (or one like it), it should help you organize your thoughts and think through the whole system in a sort of systematic modular way. Devoting a bit of time to the fundamentals early pays off in the end.

I was able to watch all three. Definitely helped. This stuff has been my life for the past few months and I definitely am getting a basic understanding. Although it is brand new to me so it’s been a bumpy road. I appreciate your help!

[dzl_]

Originally Posted by Shawn & Ash

How did I come up with this...

Three 15 amp circuits. All go to either outlets on the left side of the bus or the right.

15x3= 45

Maybe I’m confused about how I’m adding this up but I thought it was simply adding up the breakers to get to my overall needed size.

Maybe where I went wrong was I didn’t need three circuits. I could get away with two but I wanted to have the fridge on it’s own circuit.

As I've mentioned a couple times, AC is not my strong suit. But it seems to me you are thinking about this in a reasonable way (deciding how many circuits you want and multiplying that number by 15 (for 15 amp circuits)), so long as your wiring is all sized to handle 15+ amps.

My first question arises from the Mppt charge controller. I gather we will need a 125 amp controller to allow for some wiggle room. Is this accurate? What’s the suggested brand? (I’ve heard Xantrax)

Here is a good article on MPPT & PV Array sizing from Victron. Wiggle room is not really necessary on the output side (which is what the 125a rating is), a safety margin on the input side is prudent though (pay attention to Voc and Isc). As for brand, I would second Kazetsukai's endorsement of Victron, epever is a popular budget option.

Also the Inverter/Charger. I believe we will need a 3000 Running Watt 6000 Surge watt inverter with auto switch considering our desired hookups and our wish to use a 6k OR 9k BTU a/c, an RV Fridge, outlets, DC hookups etc. is that an accurate size? What are the suggested brands?

Look into the Samlex Evo (Evo info megathread here) or the Victron Multiplus

[Doktari]

This free Wiring Unlimited ebook from Victron Energy on wiring offers fairly comprehensive information on wiring for vehicles:

https://www.victronenergy.com/upload...limited-EN.pdf

Victron also has another ebook called Energy Unlimited which explains more about a how all the components of a alternative energy system work together as a system:

https://www.victronenergy.com/upload...limited-EN.pdf

There are many helpful illustrations in these books and examples. If you are a book person these may help. If you are a video person as mentioned by previous poster there are numerous videos on Utube about wiring and electricity.