How to make a Solar Generator from a Battery Backup

As promised, this is going to be a detailed thread on making a solar generator from several different types of backups. It will be very detailed, indepth, and will walk you through step by step. You may be able to skip some of the info and later come back to reference some of the material, but it will all be here. This thread will be an on-going project, I can't do it all in one day or even two weeks but once you understand the basics there are just some small nuances as we go through from small retail backups into large rackmounted backups.

Off we go...............

The first victim.

Buy APC BACK-UPS 1200VA 120V RETAIL - Technical Specifications and Information | APC

A retail version of the APC 1200 BX.

You first need to make sure the backup works. When I received this backup it had the battery light on. I threw some different batteries in and it powered up fine. You will find that newer versions may not even power on if the batteries are dead. It will simply do nothing. Often I can put enough life into a battery by simply connecting it to my charger for a night. When the batteries are low most backups won't even try to charge them.

Once I have a good backup (believe it or not most are good just bad batteries) I look up the specs which I provided a link for above.

When you are taking a backup apart do not cut any wires or discard and pieces until you are sure you don't need them. Most parts are reused. I especially always use the battery connection.

I removed the front cover and pulled the batteries.



The batteries just simply unplug and pull out leaving a large empty space and the battery connector. You can see that half of the backup is really just space to hold the batteries and get an idea of how small the electronics really are.

After disconnecting the batteries, I was left with this plug.



You will notice the plug has 3 wires. Red, Black, and a third wire. There are only 2 terminals on a battery. This is because the batteries are wired in Series +-+-



Because the batteries are wired positive to negative this doubles the amount of voltage. This backup is using 24v.

The simplest and cleanest way to connect the batteries is to use the plug that came with the backup. The wires just slide through the plastic cover.



This leaves me with the plug containing a black and red wire, as well as the jumper.

Time to give it a test...


Powers on..


Unplugged...


Unplugged running my grinder...

Now the batteries need to be disconnected, the backup unplugged, and carefully disassembled. As stated before, we are not cutting wires, hammering on stuff, ect.. We are going to reuse a variety of parts.

When taking a backup apart (remember no hammers), the best advice I can give is what I tell my wife. Take out all the screws and eventually it will fall apart....

On the front there are 2 screws.


Then the front just lifts off.

On the back there are 6 screws.
Two on the top.

Two in the middle

Two on the bottom


The back then just lifts off.

There are 2 side screws.

One at the top.



One at the bottom.



And, it opens right up.

What we are left with is a piece of light ABS plastic with a board and transformer mounted to it, a plug for the battery, a main power switch with lcd lights, and a back panel with power outlets and a fan.

There are very few wires. Each wire is connected with a blade terminal. Each wire is clearly marked on the board.

The board is held on the plastic with 1 screw.



Our main concern is getting rid of the bulk of the backup and remounting the "guts" of the UPS with different larger batteries in a different case.

Each battery backup is a little different. Rack mounted backups are mounted to steel (often the case) and need to be remounted (we will cover that later). Because this backup is cleanly, firmly, ALREADY mounted on light weight plastic I am going to leave it alone and use the bottom of the case as a mount. It would make no sense to pull the board.

While the original enclosure was way too small for my larger batteries, my larger batteries still fit in the footprint of the old batteries, giving me a nice place to mount my batteries.

The only things we have left to do is figure out what to do with the plugs/fan AKA the back panel.



And what to do with the front power button.

Then get it mounted.