Off-Grid Battery Backup Garage - Part II, Batteries

Building one's own solar power system will require a lot of time input and lots of setbacks. There are many small details that will never come to mind until they are reached. While we hope to assist as much as possible, a lot of it comes down to individuals being brave enough to start and know they will overcome all the little challenges as they come.

All the things that we will describe were not build without any problems. Things were put in backwards, wires were cut too short, some components couldn't fit the way we wanted them to, are crooked, and most things we couldn't afford so we had to improvise and build ourselves.

And on we go!

How we connected the batteries to the system.

We connected wires to the batteries buy using solder (butane torch necessary) and these battery lugs.



To do that we heated up the lugs with the torch, then melted a bunch of solder inside the little cavity and while still hot and molten, pushed in the stripped wire.





Two long wires that go from the batteries to the bus bar (will be explained) and one short wire connects both batteries in series to increase the voltage from 12V each to 24V combined. They are 3 AWG wire rated for 75 Amps, purchased from the Home Depot. A third ground wire is connected to a pipe which connects to an 8 ft copper rod we beat almost all the way into the ground with a hammer.



The exposed copper wire is the ground wire.



And here it is connected to the pipe.



Here you can see the positive and negative battery wires coming out the back of the box we built for them. The metal box is standard electrical connector box.





On the other side, we have another box with wires going to the bus bars which allows other things to connect to the batteries.



In order to connect the two sets of wires together, we had to get some heavy duty power connectors. We eventually found these Tyco Series 120 power connectors. They are rated for 75 Amps, and can be connected together kind of like Legos.

We got two red and two black housings from Mouser. We also needed four pins that connect to the wires and are locked inside the housings.



Using the same solder process we connected the pins to the wires and locked the pins inside the housings. You can see the connection below.



From that box on the wall, it goes through the pipe, up to our modified breaker box. We had one and purchased another AC breaker box from Home Depot, removed everything inside and added our own components, including hinges and a self-lock to allow for easy access.




Bus bars are just metal bars with holes in them, where you can lock in wires and then they are all connected. We purchased them from Affordable Solar. Our breakers are also purchased from Affordable Solar



For an overall picture of the system, the diagram below shows how they are all interconnected. Opening it in a new window would be necessary.