damaged lead acid batteries in UPS systems-advice needed

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calling

Joined: 03 Nov 2009
Posts: 5

03 Nov 2009 16:45 UPS battery damaged

Hi,

I have a UPS system which uses sealed lead acid batteries 12V 100Ah.
All the batteries are damaged and I can't understand why. They all have lead sulfate in the negative terminal.
Can anyone explain me why did this happened?

Thank you.

Last edited by calling on 04 Nov 2009 13:18; edited 1 time in total

Audioguru

Joined: 19 Jan 2008
Posts: 1149
Helped: 95
Location: Toronto area of Canada

03 Nov 2009 22:10 UPS battery damaged

A lead acid battery gets sulphated if it sits uncharged for a few months. It will self-discharge by itself in a few months without being charged.

Maybe the charger is broken.

pranam77

Joined: 22 Apr 2008
Posts: 1073
Helped: 94
Location: Mangalore(India)

04 Nov 2009 7:48 UPS battery damaged

Battery's get damaged probably due to over charging , or insufficient charging, or passage of time. You didnt mention how old are the battery's. Cheers

calling

Joined: 03 Nov 2009
Posts: 5

04 Nov 2009 9:54 Re: UPS battery damaged

pranam77 wrote:

Battery's get damaged probably due to over charging , or insufficient charging, or passage of time. You didnt mention how old are the battery's. Cheers

The batteries are about 1/2 year old I think.

What I think that is strange is the fact that all the batteries have the same problem. The protection around the negative terminal burst and the mixture of lead sulfate with sulfuric acid got off the batteries.

rajudp

Joined: 27 May 2006
Posts: 239
Helped: 10
Location: India

04 Nov 2009 13:06 UPS battery damaged - lead sulfate in the negative terminal

for 6 months you will get warranty

pranam77

Joined: 22 Apr 2008
Posts: 1073
Helped: 94
Location: Mangalore(India)

04 Nov 2009 13:43 Re: UPS battery damaged

rajudp wrote:

for 6 months you will get warranty

No...naturally the said problem is not a manufacturing defect to claim a warantee.

calling wrote:

The batteries are about 1/2 year old I think. What I think that is strange is the fact that all the batteries have the same problem. The protection around the negative terminal burst and the mixture of lead sulfate with sulfuric acid got off the batteries.

Check out what is the output voltage of the charger. Also let me know what load is driven by the batteries? And too confirm that the vent plugs of all cells are well ventilated to emit the gasses. Cheers

calling

Joined: 03 Nov 2009
Posts: 5

04 Nov 2009 14:57 Re: UPS battery damaged

pranam77 wrote:

Check out what is the output voltage of the charger. Also let me know what load is driven by the batteries? And too confirm that the vent plugs of all cells are well ventilated to emit the gasses.

The batteries are sealed so I think they do not release the gasses (correct me if I'm wrong). I can't do the measures you're asking =(. I just need know what are the possible causes of the problem but as I don't understand a lot of batteries I came here to see if someone could help me.

For what you've said the possible causes of this problem can be excess of voltage in the output of the charger or overload? Couldn't it be a manufacturing defect or is it normal that the protection around the negative terminal burnt.

Can you also explain me why did it happened only in the negative terminal and not on the positive too? Cheers

Last edited by calling on 04 Nov 2009 15:55; edited 1 time in total

pranam77

Joined: 22 Apr 2008
Posts: 1073
Helped: 94
Location: Mangalore(India)

04 Nov 2009 15:42 Re: UPS battery damaged

calling wrote:

The batteries are sealed so I think they do not release the gasses (correct me if I'm wrong).

Every battery when charged, releases toxic gasses. If the battery is a sealed one, there will be small vents through which the gases escape.

calling wrote:

Couldn't it be a manufacturing defect or is it normal that the protection around the negative terminal burs..

It is not normal to get a terminal burnt off. You may contact the supplier to see wether he honours the warantee for the same and also you may get better solution from him for the problem.

calling wrote:

I can't do the measures you're asking =(. I just need know what are the possible causes of the problem but as I don't understand a lot of batteries I came here to see if someone could help me.

Without measuring i coudnt figure out whatz the prolem. I am sorry...may be you'll get some better answers.

Audioguru

Joined: 19 Jan 2008
Posts: 1149
Helped: 95
Location: Toronto area of Canada

04 Nov 2009 16:14 UPS battery damaged

First the batteries were suphated which happen when a lead-acid battery sits for months without a charge.

Now the problem is completely different: the "protection" burst and the negative terminal is burnt. The batteries are now leaking sulphate and acid?

calling

Joined: 03 Nov 2009
Posts: 5

04 Nov 2009 16:37 Re: UPS battery damaged

Audioguru wrote:

Now the problem is completely different: the "protection" burst and the negative terminal is burnt. The batteries are now leaking sulphate and acid?

They are leaking a white paste which I think is a mixture of lead sulphate and acid. But only from the negative terminal (all of them).

Audioguru

Joined: 19 Jan 2008
Posts: 1149
Helped: 95
Location: Toronto area of Canada

04 Nov 2009 16:54 UPS battery damaged

Lead sulphate is a material that is deposited on the lead plates of an old battery. It is not a paste.

I think the white paste is the electrolyte gel in a sealed gel-cell battery. The battery is completely sealed and normally does not produce gas.

I think the UPS over-charged the batteries which caused gas which exploded the sealed case around the negative terminals.

A gel-cell battery is supposed to be charged to a lower voltage than a wet-cell battery. If you replaced wet-cell batteries with gel-cell batteries then you are to blame for the damage.

If the UPS is also only 6 months old then the UPS manufacturer should fix the charger in the UPS and should replace the damaged batteries.

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calling

Joined: 03 Nov 2009
Posts: 5

05 Nov 2009 9:34 Re: UPS battery damaged

So you think the problem is on the charger and not on the battery?

Couldn't it be a manufacturing problem? For example a weak sealed case around the negative terminal?
And why do you think it happened only on the negative terminal? Cheers