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 Posted: Nov 08, 2011 - 11:22 PM |
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Joined: Dec 11, 2007
Posts: 6980
Location: Cleveland, OH
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There are quite a few threads about battery chargers, especially about LiPo's.
EMS call today for an elderly patient who connected a heavy duty charger to a Lead Acid battery BACKWARDS and it blew up in his face.
Lots of "minor" hot acid burns, but no shrapnel wounds, and fortunately he was wearing glasses which protected his (single) good eye, (he already has one prosthetic eye, perhaps he is a slow learner...).
One can see where the case split open on both ends of the battery.
The charger is the large black box in front of the tractor's rear tire.
Just something to think about for everyone building battery chargers!
JC |
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Posted: Nov 08, 2011 - 11:40 PM |
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Joined: Jul 27, 2001
Posts: 7429
Location: St. Leonards-on-Sea (UK)
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| When I worked for Racal the battery on one of our manpack radios exploded whilst an officer was changing it during field trials, with him holding it between his thighs. Luckily, he wasn't hurt. SAFT eventually found that there was a design fault that could result in hydrogen being ignited by a spark caused by two conductors being too close together. |
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Leon Heller
G1HSM
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Posted: Nov 09, 2011 - 03:48 AM |
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Joined: Apr 24, 2006
Posts: 283
Location: Sydney, Australia
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I see 2 batteries in the picture - is it possible he connected these in reverse? (although i'm surprised it exploded before the wires melted).
Any charger worth its salt will have reverse polarity protection to prevent this sort of disaster. of course, if the charger is ancient it might not have this protection. |
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Posted: Nov 09, 2011 - 03:57 AM |
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Joined: Dec 11, 2007
Posts: 6980
Location: Cleveland, OH
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I believe he was connecting the battery to the very heavy duty battery charger, and had the wires crossed.
The charger is the large (muddy) black box in the background, more typical of a service/repair station than a home device.
The wires were stretched out, the Black, (Ground), wire was stretched out further and was adjacient the positive terminal on the battery. The positive wire was not stretched out as far, and could only reach the Negative terminal on the battery.
Bad news... Boom!
JC |
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Posted: Nov 09, 2011 - 05:43 AM |
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Joined: Nov 02, 2009
Posts: 3239
Location: Zelenograd, Russia
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More likely this is not a simple charger but a charger/starter (wire thikness and unit dimensions prove that). Such devices allow starting an engine with a totally dead battery (or no battery at all), thus supplying an output current up to hundreds of Amps limited only by transformer.
Moreover, many such devices have a 12/24 Vout switch which allows using them with truck batteries - so the switch could be in 24V position while a 12V battery was connected.
BTW to blow up a lead acid battery it's enough to feed it with relatively low current (0.8..1C). In normal conditions the charging current must not exceed 0.2C where C is a battery capacity in A*h. |
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Posted: Nov 09, 2011 - 02:40 PM |
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Joined: Apr 20, 2007
Posts: 6207
Location: Long Island New York
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Does not matter what the parameters are the end result is the same KABOOMIES!!
Jim |
_________________
Jim
I have decided that I am no longer going to plan anything in advance. In a court of law this is called Pre-Meditated, and does not look good for the defense.....
I am trying to 'C' the light. One function at a time.
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Posted: Nov 09, 2011 - 02:52 PM |
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Joined: Jan 09, 2007
Posts: 1919
Location: Arlington, Texas, U.S.A.
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DocJC wrote:
... elderly patient ... his (single) good eye, (he already has one prosthetic eye, ...
Could of described an uncle of mine. He acquired his prosthetic eye after loss of his eye, and his fellow U.S. Army gun mates, in north west France early August 1944 due to counter-battery fire. As a teen, I inquired him about his prosthetic eye; he pulled it out, did a fake fumble, and it was sliding across the floor towards me. He laughed at my mortified response. |
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Posted: Nov 09, 2011 - 05:15 PM |
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Joined: Nov 11, 2003
Posts: 4040
Location: Chicago Illinois USA
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| Can't be too careful with those things! |
_________________
Discursive design,
Torby
Some days, it's just not worth chewing through the restraints.
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Posted: Nov 09, 2011 - 05:19 PM |
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Joined: Sep 07, 2004
Posts: 2563
Location: New York State
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Red to red doesn't always work. I once bought a nice set of jumper cables and the two wires were molded together to form one cable. The whole cable was one color, but the clamps on the ends were red and black. It looked like the attached picture.
The first time I used it, I noticed more sparks than I was expecting when I made the last connection. I disconnected and inspected the situation. That's when I found the red clamp on one end was connected to the black clamp on the other, and vice versa. Fortunately no damage was done, and I had a rather easy time convincing the store clerk to exchange them.
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Posted: Nov 09, 2011 - 10:15 PM |
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Joined: Nov 11, 2003
Posts: 4040
Location: Chicago Illinois USA
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| Yikes! Maybe I'll check mine. |
_________________
Discursive design,
Torby
Some days, it's just not worth chewing through the restraints.
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Posted: Nov 10, 2011 - 08:40 PM |
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Joined: Sep 07, 2004
Posts: 2563
Location: New York State
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Torby wrote:
Locks are only temporary hindrances.
Are you from Chicago by any chance?  |
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Posted: Nov 11, 2011 - 07:11 PM |
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Joined: Jan 03, 2006
Posts: 4443
Location: Hemel Hemsptead, UK
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Had a look at the packing case for our kit today: big labels on it "primary lithium batteries - air freight only, not permitted on passenger carriers".
So what is so disposable about freight pilots? |
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Neil Barnes
www.nailed-barnacle.co.uk
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Posted: Nov 11, 2011 - 07:42 PM |
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Joined: Nov 11, 2003
Posts: 4040
Location: Chicago Illinois USA
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steve17 wrote:
Torby wrote:
Locks are only temporary hindrances.
Are you from Chicago by any chance?
See under my avatar  |
_________________
Discursive design,
Torby
Some days, it's just not worth chewing through the restraints.
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Posted: Nov 11, 2011 - 09:14 PM |
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Joined: Feb 19, 2001
Posts: 26102
Location: Wisconsin USA
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Quote:
...prosthetic eye; he pulled it out, did a fake fumble, and it was sliding across the floor towards me.
Growing up, across the road was a young family that had an older lady as a "nanny". She had one glass eye. One day my mother received a phone call from her and my brother and I were dispatched to the neighbor's house ... to search for the glass eye which had rolled away from her and she couldn't find it. |
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Posted: Nov 14, 2011 - 03:43 PM |
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Joined: Mar 07, 2001
Posts: 2376
Location: Stockholm, Sweden
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The fault of this is, IMHO, the battery manufacturers who can't even spend the $0.01 to the poles in an appropriate way.
Not even in the closeup pictures above, is it possible to see which pole is which. On neither of the two batteries. So how is a one-eyed elderly man supposed to see it?
A big red ring around the positive should be an absolute minimum. |
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/Jesper
http://www.yampp.com
The quick black AVR jumped over the lazy PIC.
What boots up, must come down.
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Posted: Nov 14, 2011 - 04:31 PM |
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Joined: Nov 11, 2003
Posts: 4040
Location: Chicago Illinois USA
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| Interesting observation! |
_________________
Discursive design,
Torby
Some days, it's just not worth chewing through the restraints.
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Posted: Nov 14, 2011 - 05:13 PM |
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Joined: Oct 02, 2007
Posts: 442
Location: Norway
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| There is markings on at least the black battery, not color coded, but moulded into the plastic. Both + and - pole is marked that way. On the grey battery i too cant find any markings. |
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Posted: Nov 14, 2011 - 09:11 PM |
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Joined: Jun 15, 2008
Posts: 1779
Location: North Carolina USA
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| Compounding that is the Ford 8N tractor originally had 6 volt positive ground. It seems converted to 12 volts negative ground (or maybe not) but there is still residual confusion every time you jumper such a beast. Your hands sometimes follow old memories when you are thinking of something else. |
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