Older but no Wiser

[htb]

Had the same 20 yrs ago, had one blow the top off whilst I was leaning over it. Luckily no burns as head 1st into a water butt. Glasses /beard/ wooly hat and boiler suit helped. But my left ear damaged, ear ringing for a week, now hearing aid in that ear.

[Billhook]

3 hours ago, AJStrees said:

And what of the bridging terminals with a spanner?

Did the spanner stay the same?

It was actually an old pair of pliers, slightly seized so they stuck open at the right distance with insulated handles

 

I think that the Hindenberg Airship only burned with no explosion in spite of the huge amount of hydrogen released

[AJStrees]

2 hours ago, Billhook said:

It was actually an old pair of pliers, slightly seized so they stuck open at the right distance with insulated handles

 

I think that the Hindenberg Airship only burned with no explosion in spite of the huge amount of hydrogen released

Crikey!. Well good luck on getting a new battery and hope that doesn't happen again. 

 

Probably there is some H&S regulation on touching a battery and what sort of protective gear one should be wearing while dealing with them.

 

Maybe someone will invent a course on care of machine and car batteries some time. 

[openspaceman]

2 hours ago, Billhook said:

I think that the Hindenberg Airship only burned with no explosion in spite of the huge amount of hydrogen released

The hydrogen from the ruptured bags went upward and only burned as fast as oxygen diffused into it, your oxygen and hydrogen were premixed as they were produced at anode and cathode of in the same cell.

 

I did the same with our old MF35 in 1972, I knew both batteries were knackered so I was in the habit of sticking the starter boost on my oxford welder across the terminals I disconnected the clips before switching the welder off.

[AJStrees]

The hydrogen from the ruptured bags went upward and only burned as fast as oxygen diffused into it, your oxygen and hydrogen were premixed as they were produced at anode and cathode of in the same cell.
 
I did the same with our old MF35 in 1972, I knew both batteries were knackered so I was in the habit of sticking the starter boost on my oxford welder across the terminals I disconnected the clips before switching the welder off.

Yes if there had been an explosion on the Hindenburg, then I doubt there would have been any survivors.

[AJStrees]

The hydrogen from the ruptured bags went upward and only burned as fast as oxygen diffused into it, your oxygen and hydrogen were premixed as they were produced at anode and cathode of in the same cell.
 
I did the same with our old MF35 in 1972, I knew both batteries were knackered so I was in the habit of sticking the starter boost on my oxford welder across the terminals I disconnected the clips before switching the welder off.

Talking of MFs, I am slowly refurbing (with the help of a friend that knows what he’s doing) our MF 135, think it’s a late 60’s model brought back over from Italy about 15 year’s ago.

Battery is fine on it though luckily

[Billhook]

On 04/03/2020 at 22:38, openspaceman said:

The hydrogen from the ruptured bags went upward and only burned as fast as oxygen diffused into it, your oxygen and hydrogen were premixed as they were produced at anode and cathode of in the same cell.

 

I did the same with our old MF35 in 1972, I knew both batteries were knackered so I was in the habit of sticking the starter boost on my oxford welder across the terminals I disconnected the clips before switching the welder off.

Thinking more on the subject, I am now convinced that it makes little difference having a well ventilated room for the battery charging

For it to explode as it did the exact explosive mixture must have been created inside the cell of the battery where there is no ventilation unless you remove the caps which does not seem possible on many modern batteries 

But there again maybe they are sealed for protection against explosion 

Anyway what ever my theory, do not create a spark near a charging or newly charged battery until it has settled down 

[Chalgravesteve]

6 minutes ago, Billhook said:

Thinking more on the subject, I am now convinced that it makes little difference having a well ventilated room for the battery charging

For it to explode as it did the exact explosive mixture must have been created inside the cell of the battery where there is no ventilation unless you remove the caps which does not seem possible on many modern batteries 

But there again maybe they are sealed for protection against explosion 

Anyway what ever my theory, do not create a spark near a charging or newly charged battery until it has settled down 

Exactly.  For the battery casing to rupture as it has done, the explosive mixture must have been contained within it. In my view, had the explosion occurred externally to the battery, the shock wave might have knocked it over but if there was enough force to break the casing from an external explosion you would have a bit more damage to yourself than red dots on gloves......

[Daniël Bos]

The battery won't explode unless the combustible mixture within is exposed to a source of ignition.

What most likely happened in your case was that there was a cloud of combustible gas in the air, near the battery. This cloud got ignited by the sparks, the flamefront will have either travelled to the inside through the battery's vent tube/holes, or the cloud combustion was so powerful it cracked the case getting the ignition to the perfect explosive mixture contained within.

 

Ventilation won't do anything to remove the combustible gasses inside a battery.

But if there is no way for the source of ignition to reach those gasses there is no explosion. The forced ventilation of our box removes any potential build up of gasses near the battery, so if there is any sparking there is still no explosion as there is a "buffer" of (non combustible) air all around the battery.

To prevent sparking, the charger is only powered when the door is closed (simple door switch with a relay).

[roys]

Time for my confession.

I was a 1st year apprentice 39 years ago, as a 1st year apprentice I was sent with the “battery” man for the day, we went to his workshop which is about the size of a double garage where once a week or so he would get a sort of sit on battery driven road / floor sweeper in to give a battery service to.

This consisted of scraping of the white furry stuff from the hundred odd terminals on the battery bank, then check and top up the levels.

Well anyway, It was my first time on this job (my defence), we both went to the workshop, sweeper waiting outside, he opened up and drove the sweeper in, lifted the lid on it showed me the mass of furry terminals, told me he was away for a shit with the Sun newspaper under his arm and would be back in an 30 minutes and I was to get battery cleaning. My ppe consisted of my overalls nowt else, I looked about to see what I  could use to clean the fur off with, ahh a wire brush, perfect, mmm,  these batteries are about 6” square with copper bars between them, when I started brushing a wee bit of sparking occurred, but they were cleaning up a treat.

Well 5 mins into my excellent cleaning job, boom, felt my face wet, no idea what had happened, but fortunately there was a sink in the shop so I washed my face, and had a look at what had happened. I was surprised to be able to see the plate tops on one of the cells, looked about the shop and abviously by design the top had blown neatly off in two halves on one of the many cells, so I gathered them up and clicked them back onto the cell top. Continued my cleaning with a cable tie end, which was not nearly as effective. My tradesman man came back and was well impressed with how clean I had got the battery bank.

Fast forward 3 weeks when my overalls came back from the wash, and I couldn’t work out why they were full of holes, took a wee while to twig the events of 3 weeks previous and how acid effects cotton overalls.

Oh how we laughed.

Edited March 6, 2020 by roys