Hello! I am setting up a solar panel system on my property but I would like to get some feedback on my system. I have 4-100 watt panels=400 watts. From the solar panel to the charge controller (20 amp charge controller-that I still have to buy) is 10 gauge wire that is buried in a conduit. The panels will be on a mount facing south. From the charge controller to the batteries I"m unsure what gauge of wire I need. I have 2-12 volt marine deep cycle batteries wired in parallel. The wire that is connecting them is an 8 gauge. From the batteries to the 1000 inverter is also an eight gauge wire. From the inverter to the breaker box is the wire that came with the inverter. (I'm not sure of the size). I have a grounding rod with is connected to the breaker box.
1. What size of wire do I need from the charge controller to the batteries?
2. Is an 8 gauge ok to use even though i have a 10 gauge from panels to charge controller?
3. The pictures below show how my breaker box is set up with a jumper wire from one side of breakers to the other side. (one side is lights-other side is outlets). Any other suggestions to get the positive wire from the inverter to both sides of the breaker box?
4. Do you see anything wrong with my system.
5. What type of charge controller do I need? (is 20 AMP ok)
I'm only using solar for lights and charging things and the igniter on tankless water heater and clock on stove.
I plan on adding more solar panels as time and money comes.
The wires are fine for your current setup. The smaller the wire gauge the more amps it can carry in the future.
14 gauge = 15A, 12 gauge = 20A, 10 gauge = 30A, 8 gauge = 40A, 6 gauge = 55A
1000W = 24V x 40A, (8 gauge wire)
20A means 480W of panel aka 24V x 20A (10 gauge or even 12 gauge)
400W is already installed.
Your charge controller couldn't handle 600W aka 6 panels, so there is no room for growth.
I also wouldn't recommend installing 5 panels for 500W but you might be able to get away with it for a while (500W vs 480W)
How much AH does your batteries have?
Lets assume it is 20AH+ each for 24V x 20A = 480W
You would have to run your battery at 2C (twice it capacity) to get 1000W. In reality you want to run your battery at quarter capacity (0.25C). But its okay it will still work, at some point you want to get 24V and 160AH.
I would recommend getting a 50A charge controller
Iterations are fine, we don't have to be perfect
Location: Massachusetts, Zone:6/7, AHS:4, Rainfall:48in even Soil:SandyLoam pH6 Flat
You never want to discharge your 480Wh battery more than 50%, but even at a 80% discharge you can only get 380Wh out of it.
LED light = 10W/each, amount = 10, avg runtime each = 2hrs = 10x10x2=200Wh
Thankless Water Heater = 2W, runtime = 16hrs of no sun 32Wh
Clock = ??, lets go with 50Wh per day
Charging phones/etc = 50Wh per day
I agree. I would buy a bigger than 20 amp charge controller if I was planning to add more solar panels later. And go with a 24 volt system if you plan to grow the system a little. Go with a 48 volt system if you plan on growing it a lot.
If the 12 volt batteries are wired in parallel as you stated in your OP then you have a 12 volt system not a 24 volt system. If so that inverter will draw 80 amps give or take from the batteries through those small 8 guage wires. Also those DC wires are rather long between the inverter and the batteries. Even if your loads are currently very small it really is best to install correct size DC wire for the inverter. I think 4 guage would be more appropriate. And not so long. Raising the batteries off the ground on a tall platform would shorten the wires.
I would suggest a thicker wire from batteries to the inverter. Technically is should be 4 or 2 gauge... at least a multi strand 6 gauge to reduce losses through the wire. Where abouts are you? If you get cloudy periods of the year I would suggest you get an mppt charger so that you can run 2 strings of 2 panels each and get some charging on those cloudy days. As voiced above get more charger then you need right now. An mppt charger will also let you change the array without having to rewire to the batteries...
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