APC SmartUPS smoked with new batteries

[Brian]

My SmartUPS 700 gave me a warning about a week ago that I needed to
replace batteries. Sounds good, they were
two years old. Well, while I was waiting for the 2 12v 7.2Ah in series
to come in, my UPS suddenly turned off and would not turn back on. I
was away from the computer at the time, so I have no idea how long the
UPS was in this state. Depression of the on button would cause the UPS
to emit a dying whine from the small alarm speaker.

At this point, i figured it was because of the dead batteries, and
needed good ones to power up. Removal of the batteries revealed
battery 1 appeared fine and registerd 12.54vdc. Battery 2, however,
has a overheated, bulging cell and registered 10.36vdc. Voltage
readings of the two batteries in circuit while UPS plugged in (but
still cant turn on) showed 7vdc?!? Batt 1, in circuit, read 12v, but
batt 2 read -4v? wtf?

Problem solved. Replaced batteries with UPS unplugged and got a
surprise arc. Status LED's on front came on for a second, and heard
relays click on and off. Plugged UPS in thinking all was well, and
heard speaker beep, then some crackling sounds and finally the dreaded
smoke. I immediately unplugged UPS from live power and battery power.
Smoke appears to have originated from some square caps near the
regulator ICs. Any ideas on why the new batteries coudl cause this?
they were direct from APC.

 

[Jerry G.]

I have seen users change their own batteries and put them in reverse
polarity. This blows the main board every time!

This type of procedure makes for the repairs to be very expensive. APC does
not sell the parts, or service manuals to non-APC servicers. You will have
to send back the UPS for an estimate. In the end, you will most likely find
that it may be cheaper to buy a new one! I have no idea if they will take
back the batteries. Usually, batteries are a non returnable item.

--

Greetings,

Jerry Greenberg GLG Technologies GLG
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My SmartUPS 700 gave me a warning about a week ago that I needed to
replace batteries. Sounds good, they were
two years old. Well, while I was waiting for the 2 12v 7.2Ah in series
to come in, my UPS suddenly turned off and would not turn back on. I
was away from the computer at the time, so I have no idea how long the
UPS was in this state. Depression of the on button would cause the UPS
to emit a dying whine from the small alarm speaker.

At this point, i figured it was because of the dead batteries, and
needed good ones to power up. Removal of the batteries revealed
battery 1 appeared fine and registerd 12.54vdc. Battery 2, however,
has a overheated, bulging cell and registered 10.36vdc. Voltage
readings of the two batteries in circuit while UPS plugged in (but
still cant turn on) showed 7vdc?!? Batt 1, in circuit, read 12v, but
batt 2 read -4v? wtf?

Problem solved. Replaced batteries with UPS unplugged and got a
surprise arc. Status LED's on front came on for a second, and heard
relays click on and off. Plugged UPS in thinking all was well, and
heard speaker beep, then some crackling sounds and finally the dreaded
smoke. I immediately unplugged UPS from live power and battery power.
Smoke appears to have originated from some square caps near the
regulator ICs. Any ideas on why the new batteries coudl cause this?
they were direct from APC.

 

[Brian Friedl]

Well, last time i checked, I am not colorblind, and know the difference
between black and red! I assure you polarity was correct.

 

[David]

The second cause of blowing UPS's is people replace them with the UPS switch
still turned on and many times the computer devices still plugged into the
UPS and/OR the UPS still plugged into the AC outlet. Either scenario will
cause quite a large arc and blowing of the board.

The batteries should only be replaced with the unit unplugged from ac power,
the power switch in the off position, and all devices unplugged from the
outlets on the unit as an added precaution (not to mention the extra ease in
turning it upside down without the extra cables hanging off it).

David

 

[James Sweet]

Well, last time i checked, I am not colorblind, and know the difference
between black and red! I assure you polarity was correct.

I think people are overlooking a fairly obvious possibility, the UPS failed
on it's own with the dead batteries still installed. Installing new
batteries gave it a fresh source of internal power to cause further damage
due to the fault. It's probably fixable, but some troubleshooting knowledge
will be needed. Worst case you could buy a new UPS that uses the same sort
of batteries and keep the new ones you bought as spares.

 

[Brian]

The batteries should only be replaced with the unit unplugged from ac power,

the power switch in the off position, and all devices unplugged from the
outlets on the unit as an added precaution (not to mention the extra ease in
turning it upside down without the extra cables hanging off it).

I could see this being true, except there was no load, and the ups is
hot swappable. (Also, on SmartUPS, the batteries slide out the front
of the unit.) There was no load at the time, because I was having
problems with it turning off at random times because it would go on a
self-test and die because of the dead batteries. All that was plugged
in was a monitor, and I unplugged that too because I couldnt see the
screen!

So back to my question. Should I pay $80 for APC to send me new
batteries and a warranty or just go out and buy a all new unit for
double that cost? Perhaps this is fixable, as I have knowledge in SMPS
repair and design, however I have heard that APC refuses to provide
prints for their units.

 

[DaveC]

Worst case you could buy a new UPS that uses the same sort
of batteries and keep the new ones you bought as spares.

Except for the fact that lead-acid batteries don't store well without a
trickle charge on them.

 

[James Sweet]

Except for the fact that lead-acid batteries don't store well without a
trickle charge on them.
--

Trickle charge isn't hard though, just use an old 12v wall wart with a small
automotive lightbulb in series.

 

[Brian Friedl]

True, but i suppose I could swap out batteries every 3 months? Would
that work? or perhaps hook up the two batteries in parallel? (I think
the latter would require modifying the charging circuit?)