Battery problems

It was marked, sealed for life, I guess than when it "unsealed" itself, that was the end of its life!

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More seriously, any ideas what could have happened? This is a battery that is used in my Landrover (in series with the "normal" battery) to give me 24v for the diesel heater. It comes out about once a month for charging (I've charged it this way in the same place on the same charger for the last 2 years).

It was put on charge a couple of days earlier on a 12v, 5A (trickle) charge, I came into the workshop yesterday to find this!

I have since charged a similar battery (same type) without any problems.

Cheers

Peter

Reply to
puffernutter
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Looks like something ignited the venting hydrogen. Is your battery setup causing circulating current at some point, resulting in overcharging? I had something similar happen with a charging battery.....

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Alex

Reply to
Alex

It went *BANG*!

Just as well you weren't anywhere near it battery acid is not nice on your skin or clothes. Hope you have washed everything down with plenty of bicarbonate to neutralise the acid or things *will* fall apart over the next week or so...

How much current does the heater take? My suspicion is that the battery has been seriously overcharged...

5A for 48hrs is 240AHr, that doesn't look more than about a 80Ahr battery to me. I doubt the explosion was due to a sudden failure of the casing due to pressure build up as batteries have pressure relief systems, so that leaves a hydrogen explosion but I wonder what set that off? Any automatic power switching in the charger?
Reply to
Dave Liquorice

A high-resistance fault between 2 cells became hot enough during charging to ignite the hydrogen. I've seen it happen a few times over the years and it makes a fecking mess of the workshop (expecially with a large one like a 624). After the spray of acid costing me a ne wpaintjob on a car I now charge batteries outside behind the workshop, in a cage to stop them getting nicked.

Reply to
EMB

Mm, I have been trying to rescue a battery that has got a cell down. Left it on a 2-3A charge for a couple of days. Forgot to check it yesterday, this afternoon I found that the high resistance had broken down a bit and it was taking about 10A and rather warm. I charge batteries with the stoppers out, which tends to prevent any Hydrogen buildup. Still got one cell with low gravity, so given up on it and thrown it away.

Alex

Reply to
Alex

Bit tricky to take the stoppers out on a "sealed for life" battery... B-)

There is more to bringing a duff cell back to life than simply bunging the battery on a simple charger. Have a google, there is plenty of info out there.

Reply to
Dave Liquorice

Charging batteries indoors can be dangerous if there's a chance of the hydrogen produced getting trapped somewhere and then ignited by a spark. It's a common occurrence in commercial garages which have a badly designed 'battery room'.

As a matter of interest is your charger an old model?

Reply to
Dave Plowman (News)

Mmmm. I've lost count of the number of "sealed for life" batteries that I've taken the stoppers out of to check gravities and top up with acid/water as required. Peel the label off the top that says "sealed for life" and lo! the stoppers are underneath.

The only truly sealed lead-acid batteries are the likes of the Optima and the dry-cell lead acid batteries. And even they have pressure relief vents to let out excess gases.

Alex

Reply to
Alex

I wouldn't call 5 amps a trickle charge, maybe got a crack in the case through manhandling it quite a lot by removing to charge? Low electrolyte level and arced across the top of the plates? If it's 2 years old it was probably knackered anyway and due for replacement. To trickle charge I use not more than 1/2 an amp over a couple of days, that always seems to work and doesn't cook the battery, and as someone said earlier it's not hard to work out, a totally flat 80 a/h battery would take 40 hours at 1/2 an amp. I reckon it was just overcharged.

Martin

Reply to
Oily

I think should clarify a couple of things, the charger is an "old fashioned" transformer/rectifier (the only electronics are the silicon diodes!) also it was on the 5A setting (it has 5A, 10A and 20A fast charge settings), it was actually taking between 1 and 2 Amps.

Cheers

Peter

Reply to
puffernutter

The only time I've seen that happen was in a garage on Anglesey when I had popped in for something and was standing in their workshop where they had a car battery on charge - the charger was one of those big ones on wheels and was being used to put in a rapid charge to get the car going. The battery exploded without warning and showered everything in sight with bits of plastic and acid. I was about 20ft away and got away with a few holes in my jeans, but I'm glad I wasn't standing next to it.

Reply to
Rich B

I did exactly the same to an old 4cylinder MF35 but it was my fault in that I gave up and removed the clips from the terminals whilst the charger was still live, the spark initiated the explosion, luckily I wear glasses but it cost me a pair of Levis.

That's why it is recommended that when using jump leads you attach the negative (assuming this is earth) leads to earth points away from battery terminals and place them last then remove them first.

AJH

Reply to
andrew heggie

Or clip the terminals to the battery *before* plugging in to the mains, and remove them *after* unplugging the charger. God knows how many times I have had my head under a bonnet and have struck the charger leads together "to see if it's working". Lovely shower of sparks. I shouldn't have any eyebrows left, by rights.

Those with rings you can attach permanently and just plug the charger in via a connector are a bloody good idea, for convenience as well as safety.

Reply to
Rich B

That explains things. Old basic chargers like this continue to charge after the battery has fully charged and cause the battery to gas freely - they should not be used unattended with low maintenance types. They will also deplete the electrolyte if they're left on after the battery reaches full charge. They can be modified to constant voltage charge, though.

Reply to
Dave Plowman (News)

...and 5A 12V is 60W into the battery isn't going to encourage cool-ness.

Steve

Reply to
Steve Taylor

On or around Sat, 29 Dec 2007 00:48:46 +0000 (GMT), "Dave Liquorice" enlightened us thusly:

then again, yer typical 5A charger a) doesn't supply 5A to start with and b) the current drops off as it reaches full voltage.

I favour something making a spark and the H mixture just happening to be volatile.

Reply to
Austin Shackles

snipped-for-privacy@davenoise.co.uk...

And then another 120 hours at 1/2 amp? :-) AL

Reply to
al

True enough most cheap/older car battery chargers are very crude, fine for vented cells but not really suitable for use with modern sealed for life batteries.

Any way the thing that the OPs battery was sat looked more like a commercial heavy duty battery charger... Could be wrong though.

Batteries only really gas once they are being over charged...

Reply to
Dave Liquorice

OK ignore my other post...

If you can trust the meter. The meter on my lump of iron and diode charger can be made to read almost anything from 0 to 4 A depending how you knock it and its orientation. I've never actually put a decent ammeter in series with it to see what is actually happening, it's just a "something is going in" indication.

How flat was the battery when it was put on charge? 2 A for 48hrs will fully charge a *totaly flat* 80AHr battery. I doubt this battery was totaly flat when put on charge hence it will have been overcharged and thus gassing nicely. B-)

Reply to
Dave Liquorice

I thought a spark would be necessary because the autoignition temperatre of hydrogen in air is 500C. Except this is a mixture of hydrogen and ogygen, so it could be a lot lower and impurities, especially if there is any phosphorus in the battery, could actually ignite at room temperature.

AJH

Reply to
andrew heggie

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