Battery explosion.

[rtronics]

For interest, here is my battery which exploded one day. It was under trickle charge from an electronic type charger, which still works. The battery cell caps were not removed for charging, but I don't know why it blew up.
Ray.

 

[MikeHalloran]

There's a fair chance that it blew _because_ the caps were not removed.
Or something else.



Mike Halloran
Pembroke Pines, FL, USA

 

[Skogsgurra]

Were they vented caps?
Charge rate may also be important. Was this the first time you used this charger on that battery?

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[badservo]

Looks like a hydrogen explosion due to spark, possibly due to corrosion on posts or a fault inside the battery. I seen a battery do that before when someone had bumped the charger clamp when charging a weak battery, top came right off just like your battery.

 

[waross]

Been there, done that, got the tee shirt.
I would guess that this battery was in service for several years with the charger permanently connected and no maintenance whatever.
When I started installing standby gen-sets the battery would last for several years and eventually fail and there would be a power failure and the set wouldn't start. Then I started spec'ing electronic chargers. The extra charge gave a little more life to a failing battery, but I started getting calls;
"There was a power failure, my set wouldn't start and the battery exploded."
I started disconnecting the electronic chargers. The drama and the danger was not worth the slight extra battery life.
I never had a battery blow up on a set WITHOUT an electronic charger.
I could speculate as to the reason; Possibly a low electrolyte level (many of the batteries were sealed, and battery service is not on the minds of most homeowners) and a hot spot or spark from the starting current. At this point the charger is likely producing an oxygen-hydrogen mix in the top of the cells.
I would detour past a grocery store on the way to these calls to pick up a couple of packages of Baking Soda to neutralize the spilled acid. (Mixed with water of course.)

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[itsmoked]

The battery plates are VERY fragile. As an aside: Heavy things that are fragile.. Wanna see steep freight charges? Of the nine levels of freight tariffs that's the highest, but I digress.

The fragile plates are just pressed-on materials that make up the electrodes. When you stick a battery on a charger, float or otherwise, and set the knobs to Ignore or Fahgetaboutit the result is electrolyte that drops below the tops of the plates. After a while the pressed-on material gets so dry and brittle that slabs of it, (see the tan sticks in the picture?), actually peal off and either fall to the bottom to short that cell out, or lean over and touch the opposite plate causing a spark. If it's in gas. Ka-blooie! Don't be there when it happens. Always wear safety glasses when working near or spending time around big LA batteries. Also review where a source of running water is for flushing off any face dissolving acid should the need suddenly arrive.


I had the other form of plate failure recently. After working my way across Death Valley dirt roads we started up a steep highway to a campground. We noticed steam coming out of the hood of our diesel sub and pulled over. In a few seconds I realized one of the batteries had failed with a shorted cell after the rough roads. It was being furiously 'charged' by the 150A alternator and the other other battery at probably about 400A. They were determined to charge it back up to 14V even though the battery was now only a 10V battery since one cell was shorted. That caused severe pucker-factor trying to get the cable off that boiling battery all the while expecting a big bang and a hot acid bath.


Keith Cress
kcress -

http://www.flaminsystems.com

 

[Skogsgurra]

Death Valley - the right place!

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[waross]

Hi Keith. I agree with your assessment of the failure mode.
I have experienced one failure and been aware of two other failures from excess current such as you almost had. As the electrolyte boils, steam pressure builds up and blows out the side of one or more cells. The explosion is not as violent and there tends to be little shrapnel but it is still a dramatic event.
The explosion that I witnessed resulted from a short caused by a pinched battery cable. The other two were the result of attempted starts of a diesel engine with a 24 Volt starter. A relatively small battery from a pickup truck in series with an 8-D battery for 24 Volts. The 8-D forced too much current through the smaller battery with the resulting steam explosion.
I'm glad you were not injured.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[btrueblood]

Driving thru Death Valley in a diesel sub? Didn't realize those things were amphibious -- did you torpedo anything?

 

[waross]

Would that be a Sub(urban) or a Sport Utility Behicle. grin (auto correct?)

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[mikekilroy]

Is there a consensus then that using small 10-200ma 'float' chargers/supplies on auto size 12v batteries is a really dangerous thing to do?

In have not blown any of my batteries up yet and have probably 10-15 of them in various old motor homes, antique cars, farm & timber equipment, and even under workbench for the ham radios...... many of which remain clipped on a simple 12.5v 50 amp crude power supply thru a 12 gauge romex run through barns. I am sure I don't check the electrolyte level often enough, but I never considered I was in danger of a hydrogen explosion by doing this.... this 12.5v is below what is required to pump the cells up to point of pulling any significant current; just trying to keep batteries from freezing in the winter or going too soft to start something from sitting 2-3 months.

I never considered this dangerous, but question myself now.

 

[rtronics]

Its only a small charger, 4 amps max, supposed to drop back to trickle charge automatically, and yes it was on continuous charge, but I look after it myself, so the electrolyte was definitely above the plates.
The theory that a clip lead fell off, causing a small spark, that ignited the oxy-hydrogen mixture, is the one that I regard as most likely, especially as the clips are super flimsy. And the caps are ventilated with a small hole, not that tower structure you see on true standby batteries.
The explosion was heard by my neighbour who lives about 400 yards down the road.
Luckily there was no one nearby, and the cleanup did involve a couple of packets of baking soda liberated from the kitchen pantry.
That battery was a Caterpillar make, from some earthmoving machinery, and I was using it as a general purpose 12 volt source.
It could still send 600 amps into the diesel starter motor.
I am seriously considering moving to sealed LA batteries because being near the open ones makes me nervous these days.
Ray.

 

[mikekilroy]

not sure if I would think "sealed LA batteries" would be any better. Now THOSE I've seen get so hot I have been amazed I never had a fire - when a cell or two short inside and so the charger in the UPS tries to pump full amps into them to bring voltage back...