Can you kill a battery by short circuiting?

Phil2008 · 14 Aug 2015 at 03:49

Today I replaced my UPS's batteries, but as fool as I am managed to touch both terminals of 1 battery on the metal floor of the UPS and the sparks flew. I carried on thinking no more about it and finished putting in the batteries.

When I tried the UPS it was dead wouldn't even turn on with the power cable connected and I thought thats it Ive killed the UPS when I shorted the battery on the floor of the UPS.

But amazingly when I tried the old batteries back in the UPS it worked. So Im guessing that 1 battery is dead, so I have ordered another battery as Im guessing they wont replace the dead one.

But I didn't think you could kill a battery from short circuiting it?

Rroff · 14 Aug 2015 at 04:01

Doesn't do a battery much good shorting it - even if you don't actually kill the cell itself the current can damage the terminals, etc. depends a bit on the type of battery - even a brief short can cause a Li-ion battery to discharge to below a certain voltage that kills the cell and longer shorts can cause more dramatic effects.

IIRC UPS batteries are usually lead acid which I don't know much about.

Phil2008 · 14 Aug 2015 at 04:40

Your not really suppose to change the batteries in the UPS I have, so basically you have to take the thing totally apart to get at the batteries. The case of the UPS is all metal as it even weighs a ton with out the batteries in.. Stupid design.

These are the batteries.... 12v, 34watts, 9A

http://www.sklep.orvaldi.pl/pol_pl_Akumulator-zelowy-12V-9Ah-CSB-HR1234W-F2-75_1.jpg[IMG]

[COLOR="Yellow"]**No hotlinking please**[/COLOR]

Tealc · 14 Aug 2015 at 05:22

If there are more than one battery it could just be that the one battery is so far out of balance with the others, due to the discharge, that the device won't power up.

How long was the battery shorting out? If even for a second it could have dropped 100A at 12V to ground which would have quite an impact on cell voltage.

You could try charging the battery independently of the others to bring cell voltage back up.

Phil2008 · 14 Aug 2015 at 16:44

Tealc said:
If there are more than one battery it could just be that the one battery is so far out of balance with the others, due to the discharge, that the device won't power up.

How long was the battery shorting out? If even for a second it could have dropped 100A at 12V to ground which would have quite an impact on cell voltage.

You could try charging the battery independently of the others to bring cell voltage back up.

It was touching for 2-3 secs and you can see the 2 burn marks on the UPS where the terminals has touched. I wish I had a volt meter, I was thinking of shorting it again for a split second to see if there's any power there.

I am amazed that the UPS didnt even power on with the mains cable connected, because its not using battery power at all when running from the mains.

KelDG · 14 Aug 2015 at 16:52

Yep you probably drained it dead, you effectively created a 2 second welder and its a good job none of your rings were included in the circuit. A ups usually uses lead acid batteries. If you have got a car battery charger you could give it a few hours charge and check the voltage on it (looking for about 13.5v) fully charged if I remember correctly. You may be lucky if you have not damaged the terminals or electrodes inside the battery.

Deep discharges really reduce the lifespan of lead acid batteries so you may have knocked off a couple of months useful life from it if it still works.

Phil2008 · 14 Aug 2015 at 17:15

I will probably bin it as I have ordered another battery now. I am going to put some tape on the terminals before installing the battery next time.

I touched the battery on the bottom lip when installing the first battery. You can see how much of the UPS you need to take apart to get at the batteries.. Then to top it off, the cover is all metal too

KelDG · 14 Aug 2015 at 17:21

Phil2008 said:
I will probably bin it as I have ordered another battery now. I am going to put some tape on the terminals before installing the battery next time.

I touched the battery on the bottom lip when installing the first battery. You can see how much of the UPS you need to take apart to get at the batteries.. Then to top it off, the cover is all metal too

Yeah get them taped, and again if you wear rings take them off. Google ring burn car battery if you have the stomach for it.

Phil2008 · 19 Aug 2015 at 14:43

Well I installed the batteries yesterday without anymore disasters and it appears to be working ok. I tested it last night and it lasts about 20mins with my pc setup (in sig).

I will have to keep my eye on it as it maybe getting warmer then normal . I think I will buy a new UPS when the batts die again, as it will be roughly 9-10yrs old by then. Plus Im guessing it hasn't any surge protection anymore, so I have it plugged into a surge protector.

Rroff · 19 Aug 2015 at 21:20

The capacitors in a lot of Belkin stuff seem to go after 10 years so probably a good call - dunno if its the case with their UPS but definitely plagues a lot of their network stuff.