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12V DIY UPS for PicoPSU?

Posted: Sat Jun 28, 2008 11:44 pm
by kirbysdl
Since UPS use 12V sealed lead acid batteries, and PicoPSUs and similar PSUs take a 12V input, shouldn't there be a pretty easy way to rig up a DIY UPS system for a PicoPSU powered machine? Has anyone done this or even considered it?

A low powered system could probably run for hours on a small battery, thus changing the UPS from a power buffer to give you enough time to shut the system down into a long-lasting secondary power source to last through most outages.

We could mirror the design of online UPSes, and have a continuously-charging battery be directly hooked up to the PicoPSU.

Thanks!

Posted: Sun Jun 29, 2008 1:19 am
by Bluefront
I've considered the project before.....you'd of course need to tap into the 12v battery directly, bypassing the other circuitry in the UPS. Presumably the system would pickup the battery drain, and recharge normally.

I was all set to try this on my new/fancy UPS from BestBuy (house brand with a big lcd display). When I took it apart, I found the thing used two 12V batteries, wired in series......so the output was 24V. My PICO works off 12V only, and tapping into just one of the two batteries seemed a bad idea.

If you were using the PICO model that works off the variable input voltage....this might work with this model UPS. My other UPS does work off a single 12v battery. But it's too small to last for a long time. So I just use an old car battery to run the PICO, charged by a solar panel, and a back-up standard battery charger.

Good idea though....could be made to work. :)

Posted: Sun Jun 29, 2008 2:56 am
by IsaacKuo
I think his idea is to make a DIY UPS from base components, not to modify an existing UPS.

Posted: Sun Jun 29, 2008 3:43 pm
by kirbysdl
Yeah, sounds similar to what Bluefront did, but on a slightly smaller scale. Bluefront, how do you hook up the solar panel and charger to the battery? Has anyone else done something like this? Thanks!

Posted: Mon Jun 30, 2008 2:19 am
by Bluefront
My setup is nothing fancy.....a car battery in a plastic battery box, and a solar panel attached to my car port. Two wires routed into the house through the attic, and routed around to the battery location. The panel is hooked up and charging all the time when the sun is out. It's output is too low to over-charge the battery.

You can use a program like Speedfan to monitor the battery voltage, when you're using a battery/PICO combination. It's easy to tell when the battery charge is getting too low. If that happens, I just turn on the little AC battery charger attached to the side of the battery box.

Relatively simple system, that's working well so far. It mostly uses the Solar panel to recharge. Depending on the size of the auto battery you use, and the current draw of your system, this setup will run for 24 hours straight...or longer in total darkness, without any recharging taking place. Car batteries are cheap to use, compared to other solutions.