Want to add capacity to a UPS

[ndemge]

Getting along on my Whole House Electronic UPS project... Circuit ran to each room of the house that goes to a central cabinet in the basement. Each outlet is Grey to distinguish it from the others.

I have 8 90AH batteries, And a Minuteman 2200r UPS that runs on 48v. It is made with 12ah internal batteries. (UPS like this can be had for $50 on ebay without batteries)

I know that the charger in this thing is NOT up to the task of keeping a 180ah bank charged.

Do you think it would hurt the UPS to add a secondary charger to keep the batteries charged? This way, after a power outage, the bigger rectifier can kick in and help the ups. (and I could run the rectifier off a small generator while the ups inverts to clean the power)

 

[ZmOz]

Re: Want to add capacity to a UPS

Geez...your power must go out a lot. I keep building generators but I never get a chance to use them, I don't think my power has ever gone out in at least 6 years. Why isn't it up to charging 180ah? It should work...slowly of course. I'm guessing it's at least 2 amps and that should charge them in 4 days.

Otherwise, I think you might have a problem with 2 chargers trying to charge the same bank, unless they're both "dumb" chargers. Is there a way you can disable the stock UPS charger?

 

[rwise]

Re: Want to add capacity to a UPS

I had a best ferups 1000 amp hr, all one had to do to extend run time was add external batteries! Never used it so I got rid of it, thing was half the size of my desk. You should not have a problem with charging the batteries, unless you have power failures very often not giving enuf time to charge between failures. It'll just take longer to top off. Or like Z said maybe you can dissable the internal charger, may be as simple as pulling a fuse, may be a PITA.

 

[12Footer]

Re: Want to add capacity to a UPS

To my way of thnking, a centralised UPS would not be the way to go. A UPS in each room desired would be almost the same expense, and theentire system operation would be independant of other rooms -- the one UPS fails, but the others do not. On the other hand, a centralised UPS fails, the entire house is down as a result.
So my approach would be to buy one of those 50buk units for each outlet, and tie them to a centralised BATTERY BANK, independantly charged by an adequate charger. And there should be no problems with isolating that charger from the UPS... Simply disconect all the UPS' returns from their internal charging circuits. The most difficult part of that plan is FINDING that point to disconnect. But it is there. You'll need comprehjensve schematic to find it, but once found, simplly cut it loose.

 

[ndemge]

Re: Want to add capacity to a UPS

As to a central point of failure..... Not worried about it. I'm not supplying anything critical.

I found a forum for the ups and the tech replied that It was ok to add a 2nd charger to the mix. They did say there was a heat issue, not from trying to charge it, but if it's inverting for a very long time, it will overheat. They are designed to be able to work at full load until the batteries are dead, at that time it should either have power restored, or shut down. Extending the battery allows it to work longer and get hotter. So extra cooling is required- also, not a problem.