Multiple UPS's off one battery?

[RedLance]

Hey all, this isn't really RE related, but I know alot of you know about batteries and chargers, so I'm asking here.

I'd like to hook several UPS's to one large battery bank, but I'm concerned that problems will arise, since each UPS has it's own charger.  Will this cause any problems, like will the chargers shut each other off, or anything?  I thought I might install a diode, to prevent all but one charger from charging the battery.  I also need to find out if I can adjust the float voltage on that one charger, since I will be using flooded cells, and the UPS's are expecting gell cells.

Anyhow, I'd appreciate any thoughts on this.

Thanks!

BRian

[hiker]

mind if i jump in with my own ?...

any reason why i can"t hook a 12v auto batt to my 250 watt ups..

seems to work fine..charges the batt. right up...works great with the power cord unpluged--has a switch to turn the sound alarm off....

--it had a small worn out lead acid battery in it---

[RedLance]

Nope, I don't mind.

The only thing about your situation, is weather or not the UPS charger will over/under charge your car battery.  Gell cells like a different charge voltage, so you may be abusing your car battery.  Weather that matters to you or not, is up to you.

[scottsAI]

Hello RedLance,

I have 3 UPS connected to one large flooded battery pack. APC 3000w, 1997 area.

My UPS state it's ok to replace the battery while the UPS is on or off..

No problems to report. I assume the UPS loads are independent.

Forget the diodes and stuff. The UPS charges the battery based on voltage, diode will mess it up in many ways. Do not add.

When the highest voltage is reached they all stop charging. The three help speed charging, otherwise it would take days.

I have an external charger I use to do the final charge, I do this once per quarter. I keep the battery on line while I do this. Have not had any problems. Other than remembering when to run the finishing charge.

Possible suggestion, test the flooded battery with one UPS, Add the charger off. Discharge the Battery some, watch the UPS charge it. after it's charged turn on the finishing charger. See what happens:-) If nothing other than it gets charged further then add the other UPS to the line.

Have fun,

Scott.

[richhagen]

Hiker, I have a camera system in a warehouse with a computer to record 12V batteries.  I rigged the UPS to connect to a deep cycle 12V 115 amp hour battery.  It worked fine to a point.  I also ran the cameras off of the 12V from the battery.  At some point the current drawn by the cameras caused the UPS to indicate that the battery was no good.  The charger couldn't keep up with the battery draw for charging and powering the cameras.  I remedied this by adding an auxilliary 12V charger I had that put out a steady 2 amps.  The UPS charger was also still feeding power as well.  That has been in place for several years, and works fine with one exception.  It steadily overcharged the battery, and I didn't keep a good eye on it so the electrolyte level was diminished and now, even refilled, the capacity of the battery is greatly reduced.  I don't know if any of this helps you, but this has been my experience with a similar project.  Rich Hagen

[hiker]

thanks rich....

seen a couple of ups at a local thrift store --a lot of times they throw things out they don"t understand--thats where i step in :] [i also learned to keep my mouth shut]

i even passed up some big ups when i didnt know what they really were :{

live and learn..........................

[nothing to lose]

Some things may depend on the batteries and the UPSs used,

I have also used a couple UPSs on one battery bank. In my case at the time I had one UPS on grid power and it was charging the batteries, others were running on the batteries but not connected to the grid. I also had a wind genny connected to the battery bank for RE charging at the same time.

 It worked well for me but I had to watch it to prevent over charging with the wind system and not to discharge too far with loads on the Battery ran UPSs.

[richhagen]

Here, a lot of people and businesses seem to throw them out when the batteries fail.  Rich