Rotten eggs smell from a Smart-UPS 700

[Anonymous user]

I have an admittedly pretty old Smart-UPS (SU700INET, 220v, manufactured in 2001, firmware 50.11.I). The batteries are relatively new, one is 1-yr old, the second one 2-yr old (~27v according to powerchute) but they are ok for my modest needs. I tried to completely discharge them today and while at it I noticed an obvious sulfur smell coming from the unit while it was on battery. It went away immediately after the unit stopped. The UPS was not particularly warm, and neither are the batteries. I removed them and they seem ok... Neither smells, neither is hot to the touch (barely warm, in fact), neither has signs of leakage. There's no smell from inside the case.

What should I do? The unit has served me fine and seems in good condition judging by what powerchute reports. Can I be sure it is just the batteries? Is there something else in there that could smell like this?

Message was edited by: landsome

Message was edited by: landsome

[Techie_apc]

Hi Liviu,

As far as I know, the battery is the only part that can produce sulfur smell. Do you have the third party batteries installed in the UPS? Is the UPS still producing sulfur smell? Is the UPS operating normally?

[Anonymous user]

yup, they're installed in the ups. i'll leave them charging for 24h. no smell so far. i'll "do the discharge" one more time and see what happens.

could it be because they're produced by different manufacturers (exact same ratings, though...)? could it be because one was brand new when i installed it 1 year ago, while the other had been used a few weeks (in a back-ups) and then stored for 10-12 months before installation 1 year ago?

and since we're at it, is it advisable to use two batteries by different manufacturers in the same unit?

Thanks!

[voidstar_apc]

In my experience, the batteries can be one source of the sulfur smell however other electronic components like capacitors also give off this odor when they burn up. I'll be frank here: electronics are designed to work with the magic smoke still on the inside. If you're sure the smell came from the UPS and you can't isolate it to the batteries, then I wouldn't trust the UPS any further.

Last week in my office, I smelled sulfur. I was sure one of my electronics had just expired, but which one? I hunted with my nose but couldn't pin it down. Turns out, it was a blown capacitor somewhere else in the building. The smell got into the ventilation system.

[Anonymous user · Accepted solution]

The problem isn't just different manufacturers. It's the slightly different capacities (i.e. If they had been the same manufacturer but different use histories, I'd still be worried).

The problem with mismatched batteries is that the current needed to charge the larger capacity battery OVERcharges the lower capacity battery... In time the 'smaller' battery will die an early death. That's the basic reason why so many battery-powered devices says not to mix old and new batteries, or different types of batteries (not exactly the same problem, but close enough).

Message was edited by: darkonc