Newbie need advice on 12v setup for our houseboat

[Dirtracer27x]

Ok so this is my first time putting together a solar setup. We have a house boat we will be installing on. We will be converting our norcold absorption fridge to a 12v compressors that will draw 11.6 amps. ounce cool probably less as it will kick on and off. Other usages will be less with just basic battery chargers for cell phones and my cpap machine, water pumps etc. I am not sure on what wire size I should use and my best way to run the panels In series or Paralell. Here is what I have so far

1. 2 x qcell 315 watt panels
2. 2 x qcell 335 watt panels
3. Epever 100 amp solar controller
4. renogy 2000 inverter charger
5. 2 x chins 300ah lifepo4 =600 ah
6. 10 awg wire
7. 4 panel solar combiner and breakers/ disconnects
8. also have a make sky blue 60amp solar controller if needed

can anyone lead me in the right direction. I also thought about only running 3 panels.

 

[time2roll]

Three panels is best in parallel since only pairs match. Actually all parallel is fine or the matching pairs in series is probably best.

What is the battery voltage?

 

[Rednecktek]

Need to see the specs sheet on the 335w panels to see how much difference there is and how well the 4 panels will match up. Initial gut reaction would be 2s2p ( so no combiner box needed) with 1 of each panel on each string to balance out the nerfing.

10awg wire would be the way to go.

 

[Dirtracer27x]

here is the 335 spec and this will be a 12 volt system

 

[Rednecktek]

Yup, those are pretty close. The amperage is off enough that you could easily do 2s2p with a pair of 315's and the other pair of 335's.

Get a couple Y branch adapters, wire into your MPPT and you're solid.

Now you just need to pick out the fuses, breakers, wire sizes, etc.

 

[Dirtracer27x]

I have 10awg solar wire, will be about a 30ft run. What size breakers should i get.
and will this set up charge my battery bank

 

[Rednecktek]

Well the panels to SCC would be 25a (20a × 120%)

SCC to batteries would be 120a (100a × 120%)

Battery to inverter would be 2000w × 1.15 (85% efficiency) efficiency × 120% = 2760w ÷ 12v = 230a, probably a 225a or 250a because 230 is an odd size.

Battery to DC fuse block would be Full DC Load × 120%. Gotta do the math for that one yourself. ?

Does that help?

 

[Dirtracer27x]

It does, ty so much. I was on the fence with the Epever hopefully It works ok. Does my setup seam like it will be putting a heavy load on the controller. I don’t want to burn down my houseboat lol

 

[Dirtracer27x]

And 10awg still good to go or should I get 8awg

 

[Rednecktek]

It does, ty so much. I was on the fence with the Epever hopefully It works ok. Does my setup seam like it will be putting a heavy load on the controller. I don’t want to burn down my houseboat lol

You're running it right at the limit of what it can do. How are you looking at mounting the panels? Flat? Port/stbd? Fore/aft? If all 4 panels get direct sun at the same time that'll max out the SCC but you should be fine. If you're doing a port/stbd setup then each set will be working while the other string isn't working as hard so not an issue.

 

[Rednecktek]

And 10awg still good to go or should I get 8awg

10awg is good for 30a, you'll max out at 20ish amps and most connectors are specced to take 10awg, but getting 8awg into the heads can be difficult.

 

[Dirtracer27x]

Mounted on the top of a awning so full sun on both

 

[Rednecktek]

Mounted on the top of a awning so full sun on both

You should be fine. Even at straight on noon you're still under the 1600ish watts of the SCC.

 

[Dirtracer27x]

What type fuses and breakers should I get

 

[Dirtracer27x]

I see some on Amazon I was going to by but not sure if I want the reset type or fuses

 

[Dirtracer27x]

also if i was to just go with 2 of the qcell 315 watt instead of 4 would it be best to run those two in parallel or series? and would it create enough amp hours to charge my bank? i anticipate about 225-275 ah consumed per day with my current load demands

another scenario I am thinking is running 2 315 watt and 1 325 watt for a toal of three panels, what would my config be for that. sorry for all the questions lol

 

[AmyG]

What type fuses and breakers should I get

This resource was a huge help to me when I was deciding on fuses/breakers for my system:

DC Fuses and breakers

 

[Rednecktek]

For the places where you need the disconnect function more than the protection (panels to SCC, SCC to battery) then a good BlueSea breaker is a good option.

From the battery to everything else perfect world would be a Class-T fuse, but those are hard to find.

For the individual 12v loads just regular blade fuses are fine.

If you go with 2 panels, go series. If you go with 3 panels you'll need a 2nd SCC involved for the odd panel. 2 panels might keep you broken even but a couple days of cloudy weather will seriously consume what you have in the bank and make it very hard to catch up.

If given the option though, the original plan of 2s2p would be simplest and get you the most power.

When doing the math, it helps to convert everything into watts and watt-hours. Forget about amps for anything other than calculating fuses and wires.

 

[Dirtracer27x]

4 panels it is makes sense. thanks so much