Backyard Aquaponics
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Disclaimer: If you burn your house down trying to replicate this don't blame me... There are plenty of websites covering this technique for you to research before attempting this project.

With the storms in Perth recently I had an urge to provide my system with a redundant power/pump backup, with Xmas around the corner the accountant didn't look approachable; nothing else to do apart from to head out to the shed and see what I could mash up.

I found this old UPS I bought about 7 years ago that pretty much failed to deliver any sort of back up power to my computer at the time, now if only I could make it last longer. Lucky for the interwebs.









Battery ~ $120
Terminals ~ $10
Box ~ $37

Will post performance details when I fly back... Wasn't really a good time for it when I put it together.

A lot of those small UPS don't have any form of current limiting on them. This means in a flat battery situation they can be overloaded by the battery pulling excessive charge current.
Just be careful it does not overheat in that situation.

Don't fully load it to its max capacity either. Again they are designed to run 5-10 mins at full load then shutdown before heat buildup becomes too much a problem.

Thanks for the info, I'm doing the same thing, just got the battery. Haven't hooked the two together yet. Just using it for an air pump.

Thanks for the input Privatteer, I will be testing for heat when I get back by running the system flat. When I initially tested it for 15 minutes there where no signs of heat build up using the finger test. I wouldn't have thought a pump drawing >80 watts would overload the system but I will post back with the results.

If you are worried about charge current you could very easily add a LM338 adjusted to 4+ amps for charging and bypass it for dicharging using a couple of diodes.
That would only increase cost by a couple of dollars.

However I find it surprising that the cheap ups's dont have any form of current limiters on the charge circuit...

80w should be fine since your not running it near max output.

I'm not sure why they don't have a current limiter for the charge circuit but have come across it a couple times now.

Nice one Belleye, great idea. How are those fish going?

I'm picking up an old UPS next week, ironically from an accountant
thanks for your post

Hey belleye, do you play modern warfare? Your avatar indicates you are into such things...

Cheers; 14/15 ATM not too bad for a system less than 6 weeks old.

Nice, It would be good to hear about your experience - maybe create a information source here for future UPS hackers.

Clocked about 500hrs on MW, but I think they lost it with MW2 and I haven't bought another COD game since. I hear MW3 has LAN suppport which would indicate they are starting to listen to the PC gamers again, I would try it if I had more time to play.

Test results for Sola UPS 305 250VA - pondmax 4500 - Century 12 volt car battery NS40Z 330 CCA

time(min) Volts (multimeter on battery)
2 - 12.6
25 - 12.6
50 - 12.6
111 - 12.5
134 - 12.5
155 - 12.4
220 - 12.3
237 - 12.3
330 - pump stopped.

I think the inverter side tripped out (the casing was warm), the battery still had plenty of charge and there was no noticeable heat during charging. Not sure how this stacks up against other systems, it might be time to get brave and hack a cooling fan into the system.

Add this Bedini designed Super charger to the charging output of your UPS to keep your batterys in tip top shape and able to run far longer than a normal charged battery.....

http://www.r-charge.com/RC_ALM-1.html

they have come down in price, and i think are now $55 vs the $75 listed on this old web page

I will be posting a DYI version of this circuit for the UPS for the Hako 80CFM and 40CFM air pumps on my AP system, once i get it all worked out and installed....

RS

pickup up a MGE pulsar evolution 800 UPS. The battery is obviously dead and it hasn't been turned on for 5 years according to the previous owner.

my question is: should it turn on even without a battery? because this doesn't even have a standby light on when I plug it in. so I'm not sure if this UPS only has a flat battery or some other issue

I tried hooking up my new marine battery to the used UPS this weekend and it immediately clicked and showed the overload light. Tried resetting the circuit breaker button but that didn't help so I think the UPS is hosed. I think it still works as a power strip though.

Mine also didn't show any lights on until I tried hooking up a battery to it. It did have a reset button on the power cord that I think I had to press so maybe that was why no lights showed before? I.e. so maybe make sure the fuses/circuit breakers, reset buttons have all been pushed?

okay, so last week I scored a ups from work, but it has the sockets that go into computers, not normal power sockets. how do I hook up the air pump to this?