12V to 230V Inverter from UPS junk

PS - I get my UPS's from the local tip. Every time the battery dies people thrown them away and buy new.

If you local tip is supervised then park your car between the supervisors office and the electronic junk basket. I alsoways have loadsa electronic junk on the trailer so I can stay there for a while while if the guy is wandering around insted of watching the telly.

/H

Interesting request.
At the moment this computer is running from a junk UPS that is powered by 4x 100A/H batteries. These in trurn are charged from a solar panel and a 350W wind turbine.

In the rest of the house I have a UPS on the bedside clock/radio and 100A/H plus solar panel runnint the TV in the bedroom. In there I have a SPU (UPS running backwards). When the UPS warns of a low battery then an SMPSU charger comes for 6 hours.

I have a 1.4KW UPS in the basement I am thinking about using to run the oil-fired boiler and circulation pump, but for that I am missing just the two batteries and the time to do it. Spring is almost here, so I will be fully occupied with the garden and pool.

To use a UPS as an inverter:
- Remove the silly little 7.1A/H battery (make a hand lamp put of it)
- Locate the little peeper (black thing with a hole in it)
- Grab it with plyers and yank off the cover (complete with diaphragm)
- Take a car jumper cable pair and cut one aligator clip off each cable.
- Connect these to the battery power connectors of the UPS
- Connect the alligator clips to your wife's car battery

I used crimped cable connectors to make sure I have a good 30A connection, and lead the cables through two holes in the case.

Now you have a silent UPS, which needs no additional modifications to use it as an inverter. Just connect it to your car battery and switch it ON. If you plug power into the UPS then it will also trickle-charge the battery.

WARNING - A little 550W UPS can burn and stink REALLY BAD if you overload it. Use car fuses in EVERY battery you connect to the UPS. You need 8A for every 100W between the battery and the UPS.

BR Harry

Hi EugenM,
you are right, an UPS generally consists of a battery, charger, voltage monitor, some relays and an inverter. The most common cause of failure is the battery. If the inverter is OK, it can be reused.
I am afraid it is hard to give universal rules, though. The DC (battery) voltage may differ from 12V and details of solution may be different at different marks and types. Try to get the schematics of the UPS you have and proceed accordingly.

BR from Ivan

Hi Harry,

As we all have (or have had) an UPS that is not working anymore, it would be useful to use that junk to create an inverter (UPS it's an inverter after all).
Can you make an educational video about "how to use your junk UPS to transform in smth. useful - 12V 2 220V inverter" ?

Best regard and keep up the good work!

PS: I'm doing my research about how to make my solar panel buying (from eBay) only the cells, everything else should be made from junk parts (to keep the project cost as low as possible).

Eugen