Perhaps you’d like to build your own setup that includes Solar Panels, Batteries for storage, and an Invert for AC appliances. It’s good to understand how all the pieces wire together and where the power flows for choosing wire sizes and fuses. I have put together a diagram showing a simple method of wiring using the Charge Controller as the bus bar. When your amperage gets high enough you’d run an external bus bar to support larger wire. But this setup works up to the 40 amp range which the 10 gauge wire I’m using here supports. Keep in mind you should over-rate residential wiring. In my case if I have wire rated at 40 amps for my 12″ run and my inverter can pull 31 then 31 * 1.25 = 39 so I am within the 40A limit.

I am going to start at the battery as every charge controller I’ve seen requires the battery be connected before the Solar Panels. In this example we have a 48 Volt Lithium Ion battery, which by the way is only just a little more expensive than running new lead acid batteries. Check out one of the videos on this page to see an example of putting one together.

This battery has a BMS built in which provides our overcurrent protection known commonly as a fuse. We run the positive and negative wires from the battery straight to our charge controller where it should be clearly marked. This charge controller has two terminals for each polarity which is handy for our use case. No fuses are needed on this connection.

Wiring Diag.

Second step will be our Inverter. Our Inverter has fuses built in. It is certainly an option to run an external fuse so that if it blows it would be less trouble to replace, but for the sake of simplicity we will wire the Inverter straight to the remaining battery terminals of the Charge Controller. At this point the Charge controller should be on and you can go through the manual, or if you are using a Lithium Ion battery and the MrPowr charge controller check out the video on this page for a quick run-down, and make sure the settings are correct for the voltage and charge profile of your battery. This way when we connect the solar panels in the next step you know it’s ready to start charging with the power of the sun!

Time to free the electrons! Our final step is connecting some some Solar Panels to re-charge that battery you’re definitely not already running an air-conditioner off of. Yes I know it’s hot in that hunting cabin, may as well get the cool air blowing before you go outside to wire up the panels.

These panels are wired in series, each + of a panel is connected to the – of the next. Each end of the series will then have a + or a – that runs back to the charge controller. This should be clearly marked on the Charge Controller. This is another section where you will want a fuse or breaker in-line. Easiest is to get one of these nifty mc-4 connectors that has a fuse built in. You will need to determine what amperage of fuse you need though from the get-go to make sure you are protected and also don’t blow the fuse immediately after connecting. Since all of these panels are in series and a single panel is rated at 10 Amps max I chose a 15 Amp fuse since it was the next step up. The biggest consideration is you don’t want a fuse that has a higher rating than your wire can manage.

A massive part in staying safe is understanding what’s going on and not just plugging in where someone on the internet is telling you to. Here are some great resources on understanding the size of wire to use and what fuse size to use.


Renogy’s site for calculating wire sizes

Renogy’s site for calculating fuse ratings

Check out this video on how I repurposed the battery out of a BMW Electric Vehicle.

Video on setting up charge profile for Lithium Ion batteries.