Smart-UPS SUA2200 too high float voltage damaging batteries

[Anonymous user]

I have an old Smart UPS SUA2200XL. ES963316251 Manufacture Date 10/8/1996. I know it is an old unit, but it works great still.

But, after 8years of the same batteries, they died. They all got swollen and when I replaced the batteries, I was advised to check the float voltage for possible overcharging issues once the batteries reach full charge. With the new installed batteries, I recalibrated the UPS by letting the power cycle to discharge, recharged then ran the battery run-time calibration.

Now, I look at the battery status and it indicates the battery voltage is 56.15 VDC, and verified this with a DMM at the terminals. I've read a few posts and from what I read, the float voltage should be in the range of 54.5- 54.8 volts.

Isnt this too high and could this be a cause of premature failure of batteries? Has anyone succesfully reduced the float voltage? I have heard there is a capacity that generally fails causing this?

What is interesting is that in the course of debugging an earlier problem with the battery showing discharge state, (which I solved), I measured battery voltage after first installing new batteries, and that time, and it was 51 - 51.4v, which is a low float voltage. I then pulled the batteries to check the connections, and to make sure the terminals were solid, and re-installed, and ran all the calibrations, and then the unit was working, but the voltage increased to 56v. Which implies this is not a hardware problem, as I know these units can have faulty capacitors over time that cause this, and suggests some sort of calibration will fix the problem.

Michael

I attached a word file with my UPS Stats

Agent version 9.0.0.613.

Message was edited by: hatzakis

[Anonymous user]

I have an old Smart UPS SUA2200XL. ES963316251 Manufacture Date 10/8/1996. I know it is an old unit, but it works great still.

But, after 8years of the same batteries, they died. They all got swollen and when I replaced the batteries, I was advised to check the float voltage for possible overcharging issues once the batteries reach full charge. With the new installed batteries, I recalibrated the UPS by letting the power cycle to discharge, recharged then ran the battery run-time calibration.

Now, I look at the battery status and it indicates the battery voltage is 56.15 VDC, and verified this with a DMM at the terminals. I've read a few posts and from what I read, the float voltage should be in the range of 54.5- 54.8 volts.

Isnt this too high and could this be a cause of premature failure of batteries? Has anyone succesfully reduced the float voltage? I have heard there is a capacity that generally fails causing this?

What is interesting is that in the course of debugging an earlier problem with the battery showing discharge state, (which I solved), I measured battery voltage after first installing new batteries, and that time, and it was 51 - 51.4v, which is a low float voltage. I then pulled the batteries to check the connections, and to make sure the terminals were solid, and re-installed, and ran all the calibrations, and then the unit was working, but the voltage increased to 56v. Which implies this is not a hardware problem, as I know these units can have faulty capacitors over time that cause this, and suggests some sort of calibration will fix the problem.

Michael

I attached a word file with my UPS Stats

Agent version 9.0.0.613.

Message was edited by: hatzakis

[BillP]

yeah i posted too on the other thread..the unit is older and we have made several adjustments since then to the hardware platforms. i am not sure what specifics you'd need to adjust upon opening the unit but we cannot advise you to do that. if you got 8 years out of the batteries, that is a lot more from the typical 3-5 year lifetime though and maybe there isn't an issue here..

[Anonymous user]

No, is has not gone down since I posted. I did a calibration and although the load was only at 20%, I read that one should not do more than one per year as the deep discharge is not good for the DLA batteries.

So, the question is, with too high a float voltage, and the type of failure., ie, most batteries being open (electrically) and swollen, makes me think this problem may have been going on for some time, ie., too high float, increased temperature causing them to swell. I don't have the money to upgrade just yet, I want to trade up to the new SU2200, but I have concerns that this design problem may not have been solved as I have seen many others online that report the same problem, some going as far as using a terminal interface to try to change the battery voltage gain.

How would I reduce the float voltage? Is there a way to recalibrate in another way besides what I did? Ie., I know this is probably proprietary, but I know there are commands one can use to program the UPS in ways the Powerchute cannot. Is there a program that can be run to do this?

Michael

[BillP]

http://forums.apc.com/spaces/11/netbotz-hardware-software/forums/general/1186/modem-with-rackbotz-40...

you posted on this one

[Anonymous user · Accepted solution]

Yes, of course I did. Please see my comments over there as well... thank you..! Michael