Shelf life of Sealed lead acid batteries?

[Jason Arthurs]

I've recently been offered an APC SmartUPS 900 at a bargain price of £50 the unit is still sealed in the original packaging and is obviously unused. The seller cannot confirm how old the unit is (the SmartUPS 900 has been discontinued) and our best guess is that the date of manufacture could be as early as 2001.

Bearing in mind this unit has never been charged, what sort of condition are the batteries likely to be in. Sealed lead acid batteries are supposed to have a long working life, but does anyone have any idea what their shelf life would be?

Regards, Jason.

[Ian Stirling]

Unless you're very, very lucky, they are dead. I have a smartups 800, which currently has 2 car batteries obtained for a tenner from the scrapyard. Works well.

[Dave Liquorice]

If you don't want it tell me who is flogging it and I'll have it. B-)

Does that answer your question? Even if the batteries are shagged which I doubt they will be(*), a new set is only going to be around =A330...

(*) I'd check the dates on the batteries and measure the voltage. If all appears normal and they'll provide a bit of umph I'd apply a very gentle charge to start with then slowly bring the charge current up to the recommended level over a few hours.

[Yuki]

I'm still using one bought in 1995 in its third set of batteries, a hint about the age is if it has the old style logo (slanted APC text with a middle line)

Most probably they are shot, a stored UPS it's supposed to be charged every 3 to

6 months. The batteries are not too expensive, it's some years from the last change but I believe it uses four 6V, 10-12Ah (depends on brand) Lead-Acid sealed ones, OEM brands are Panasonic or Yuasa.

[Andrew Gabriel]

I bought a SmartUPS 900 in 1996. Sometime before 2000 (probably

1998 or 1999), I tried to buy another but that model no longer existed. So it will be older than 2001 certainly.

The APC ones have 1/4" tags, whereas the standard size tags on that size battery are one size smaller. If you close up the connectors with pliers to make them tighter and push them on past the shoulders on the tags, they seem to work OK on generic batteries. After a battery change and full charge, you must do a calibration run on the UPS or it will have the wrong idea of the capacity of the batteries. I never worked out how to update the battery change date stored in the UPS, although that didn't affect anything else.

The SmartUPS 900 did wear its batteries out rather quickly -- they normally drop to zero capacity in around 3 years of standby use, which was really rather poor (worse than any other UPS I used).

[Yuki]

Date change is done with some service software that I used to have.

Agree, my experience is 3 to 4 years per set in non air conditioned places (not zero capacity, they fail the autotest, annoying alarm) although the UPS in cold server rooms go over 6 years for a set of batteries.

[Andrew Gabriel]

Actually my experience of the short life was in an air conditioned server room, but we had another one on a different site which was in a non-aircon'ed office, and that had the same issue.

[Ian Stirling]

In some ways outside in an unheated shed is probably better for batteries, as long as it doesn't get too cold (under -10C), hot (+30C) or condense. The batteries last a bit longer in the cool.