Badger110 Posted March 11, 2020 Share Posted March 11, 2020 Having a nosy around i saw that some folk have been using the innards of UPS ( uninterupted power supplies ) for pc's and servers as a 12v to 240v inverter in their vehicles. The UPS's apparently use PSW inverters inside them Can anyone who has a notion or idea of whether this is a good practice as PSW inverters are bloody expensive and UPS's aren't ( 2nd hand market ) Ta Quote Link to comment Share on other sites More sharing options...
zardos Posted March 11, 2020 Share Posted March 11, 2020 (edited) Yes, you can use a UPS as a pure sign wave inverter, we used one on a coach motor home we had, it worked brilliantly. We picked up a UPS that was for sale because the battery was dead for £16 (inc p&p) With a few little mods it worked as what is usually called a "Shore power" device. The mods was to take it apart and find the the on battery power warning buzzer and clip the connecting leg (you could also de-solder it or for some you might be able to configure it off with software) We also extended the battery leads to an anderson connector to allow easy connection to a much larger than normal battery bank (about 300Amp Hours of capacity) We also connected up the mains input to waterproof caravan style external connector to allow powering from mains and battery charging. We kept it in the original case just with a hole for external battery leads. The downside of using an old UPS is that as the power output of the devices goes up so does the voltage of the batteries. Our UPS was about 700w output but needed 24v power supply, which was fine for the coach, higher output models used 36v or 48v and lower output models used 12v. So you need to carefully research what batteries are need. Edited March 11, 2020 by zardos 1 Quote Link to comment Share on other sites More sharing options...
Badger110 Posted March 11, 2020 Author Share Posted March 11, 2020 Brilliant, thanks Zardos. I'll keep looking at what is out there and figure out whether it's worth running a single 12v or a 24v set up. Quote Link to comment Share on other sites More sharing options...
zardos Posted March 11, 2020 Share Posted March 11, 2020 Luckily for us the coach was all 24v so we could also use the engine alternator to run/charge it via a VSR Quote Link to comment Share on other sites More sharing options...
Badger110 Posted March 11, 2020 Author Share Posted March 11, 2020 Just as using it for powering 240v, i could run 2 batteries as 24v if the right system came along. Not sure how i'd charge it unless it was through solar set up for 24v, which isn't a bad thing. Would i need to then split the pair of batteries running 24v for normal 12v operation... Quote Link to comment Share on other sites More sharing options...
zardos Posted March 11, 2020 Share Posted March 11, 2020 You could charge it when mains is not available to charge it with a second 24v Alternator. Gigglepin to a dropper box where you could change a single alternator to 24v and drop it to 24v for things that needed it. I also thought they had a battery switch over system that would allow 2 batteries to be charged in parallel at 12v each and then switched to be in series to power a 24v item (a 24v winch in this case). The other simpler option is to just run a lower output ups (most 825VA/450w) which tend to use a single 12v battery and thus can be charge/run from a normal vehicle setup. If you want more power capabilities for more devises then run multiple 12V units 1 Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted March 11, 2020 Share Posted March 11, 2020 1 hour ago, zardos said: also thought they had a battery switch over system that would allow 2 batteries to be charged in parallel at 12v each and then switched to be in series to power a 24v item (a 24v winch in this case). That was goodwinch. Quote Link to comment Share on other sites More sharing options...
elbekko Posted March 12, 2020 Share Posted March 12, 2020 Ohh, this is interesting. I bought a carp inverter last year that couldn't even handle a laptop charger, this sounds like an interesting path. Off to look at old UPSes 1 Quote Link to comment Share on other sites More sharing options...
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