UPS failures due to heat?

[hockeyoligist2]

I have had five UPS, less than a year old, die in the last two weeks. Two separate motor control buildings. The AC's in both buildings were down for two months due to sewer gas causing leaks in the coils.

The temps have been above normal for May/June here, mid to upper 90's. Inside the metal MCC buildings the temps were 100 + degrees, the thermometer in the buildings max out at 99 degrees, so I'm not sure of actual temps.

Could the heat have caused the failures?

 

[petersonra]

Cheaper UPS's are prone to failure anyway.

Heat just exacerbates that.

I pretty much avoid UPS's unless there is no way around them.

 

[hockeyoligist2]

No way to avoid them, PLC controls, switch gear involved.

 

[ControlFreak]

What brand UPSs? Size? Battery type, right?

 

[Electric-Light]

Every 20F rise cuts battery life in half above about 75F and obviously, battery area is going to be hotter than ambient.

If battery is meant to last 3 years at 75F, less than a year at 115F is not unreasonable.

APC plug-in type runs float voltage high for maximum runtime, at the expense of battery life. They claim 3-5 years, but with hardly any outage, I'm lucky to get about 3 in an air conditioned office before they fail completely.

 

[petersonra]

No way to avoid them, PLC controls, switch gear involved.

Do you really need a UPS on the whole system? Sola makes some pretty decent smaller DC units that can keep a PLC alive for a while.

Stay away from the office grade units completely.

Only backup the power for the stuff that really needs it.

Redundant DC UPSs are better than AC UPS's if you can make it work.

If nothing else, its almost always better to run wires from a place that is cooler than to put the UPS out someplace where it is hot.

If nothing else, replace the batteries every year.

 

[petersonra]

One other suggestion.

See if you can get a UPS that has a remote battery box. If so, ventilate the heck out of the battery box.