Older but no Wiser

[Billhook]

A pearl of wisdom from an oldie is that there are many occasions when you should be wise and you are not because you think you know everything 

Years ago in the farm workshop we had a tractor battery on charge all night

The next day the mechanic was grinding some metal, luckily for him at the far end of the workshop, when a spark caused an almighty explosion which ripped the battery apart and sent bits of battery and acid flying all over the place

Again to show how old I am when I was at school we never wore protection in the chemistry lab even when dealing with concentrated acids which were all lined up in front of our work surface in glass jars

The teacher decided to show us the explosive combination of oxygen and hydrogen when mixed in the correct proportions 

He bubbled the mix through some fairy liquid and a large bubble was floating in the air which he unwisely lit

The following explosion was enough to shatter some beakers and move the acid bottles though thankfully did not break them,

So yesterday having forgotten all my hard earned knowledge I tried to start the Stiga mower having left the battery on charge all night but the solenoid would not work

Being impatient I bridged the terminals with a spanner which of course caused a spark

The result was a huge explosion that even made my wife come running out of the house from the far end

Bits of battery plastic hit me and a fine spray of acid . Luckily I was wearing a thick jacket and gloves, but the acid changed the colour of the gloves from yellow to red

i think that is what might have happened to the skin on my face but again I was lucky to be near the Belfast sink which I had only installed a few days ago and which had a spray nozzle.

I was surprised as the mower was out in the open and not enclosed in a shed but I know differently now!

Hope this confession may help some of you from making the same mistake 

[silky fox]

You have been lucky Bilhook.Good tale to share if it prevents a similar event.And you are ok[emoji106]

[Daniël Bos]

We've had a similar explosive bit of fun on the farm.

Now all the batteries are charged in a wee box outside with forced ventilation.

[Sawchip]

53 minutes ago, Billhook said:

A pearl of wisdom from an oldie is that there are many occasions when you should be wise and you are not because you think you know everything 

Years ago in the farm workshop we had a tractor battery on charge all night

The next day the mechanic was grinding some metal, luckily for him at the far end of the workshop, when a spark caused an almighty explosion which ripped the battery apart and sent bits of battery and acid flying all over the place

Again to show how old I am when I was at school we never wore protection in the chemistry lab even when dealing with concentrated acids which were all lined up in front of our work surface in glass jars

The teacher decided to show us the explosive combination of oxygen and hydrogen when mixed in the correct proportions 

He bubbled the mix through some fairy liquid and a large bubble was floating in the air which he unwisely lit

The following explosion was enough to shatter some beakers and move the acid bottles though thankfully did not break them,

So yesterday having forgotten all my hard earned knowledge I tried to start the Stiga mower having left the battery on charge all night but the solenoid would not work

Being impatient I bridged the terminals with a spanner which of course caused a spark

The result was a huge explosion that even made my wife come running out of the house from the far end

Bits of battery plastic hit me and a fine spray of acid . Luckily I was wearing a thick jacket and gloves, but the acid changed the colour of the gloves from yellow to red

i think that is what might have happened to the skin on my face but again I was lucky to be near the Belfast sink which I had only installed a few days ago and which had a spray nozzle.

I was surprised as the mower was out in the open and not enclosed in a shed but I know differently now!

Hope this confession may help some of you from making the same mistake 

Nasty !!!

Do you happen to know if its the amount of time after being on constant charge and the gasses given off in those circumstances that can give this sort of result ?

You would think that a battery being in a enclosed place in a car (for example) would cause a bad risk from the charging it gets from the alternator to keep it within voltage.  

[gary112]

1 hour ago, Billhook said:

A pearl of wisdom from an oldie is that there are many occasions when you should be wise and you are not because you think you know everything 

Years ago in the farm workshop we had a tractor battery on charge all night

The next day the mechanic was grinding some metal, luckily for him at the far end of the workshop, when a spark caused an almighty explosion which ripped the battery apart and sent bits of battery and acid flying all over the place

Again to show how old I am when I was at school we never wore protection in the chemistry lab even when dealing with concentrated acids which were all lined up in front of our work surface in glass jars

The teacher decided to show us the explosive combination of oxygen and hydrogen when mixed in the correct proportions 

He bubbled the mix through some fairy liquid and a large bubble was floating in the air which he unwisely lit

The following explosion was enough to shatter some beakers and move the acid bottles though thankfully did not break them,

So yesterday having forgotten all my hard earned knowledge I tried to start the Stiga mower having left the battery on charge all night but the solenoid would not work

Being impatient I bridged the terminals with a spanner which of course caused a spark

The result was a huge explosion that even made my wife come running out of the house from the far end

Bits of battery plastic hit me and a fine spray of acid . Luckily I was wearing a thick jacket and gloves, but the acid changed the colour of the gloves from yellow to red

i think that is what might have happened to the skin on my face but again I was lucky to be near the Belfast sink which I had only installed a few days ago and which had a spray nozzle.

I was surprised as the mower was out in the open and not enclosed in a shed but I know differently now!

Hope this confession may help some of you from making the same mistake 

Could have been so much worse for ya,lesson for all of us there

[Bob_z_l]

Every day a learning day...or re-learning.

 

A Very Valid point, However I suspect this is an "over-charging" issue or a damaged cell.

 

The newer intelligent chargers moderate charge rate as the voltage on the cells comes up.

 

A quick google came up with.... 

http://support.rollsbattery.com/support/solutions/articles/816-hydrogen-off-gas-ventilation

**************

Through calculations we can show that 1 AH of over charge will in fact produce 0.42L of hydrogen gas PER BATTERY CELL. Also for every volume of hydrogen a ½ volume of oxygen is produced (H2 O)

**************

Nearly .5 litre per cell x 6 is no insignificant volume if not ventilated.

The article does indicate gas production is because of overcharging... As the battery cell voltage reaches 2.35 VPC the majority of gassing begins.

Probably with these older units a duff cell meant others were receiving more charge. Boom.

 

 

[Billhook]

I vaguely remember that the ratio of hydrogen to oxygen had to be exactly right to result in an explosion.  We used to burn hydrogen in the lab with no explosion

[Rob_the_Sparky]

Yes, the water is breaking down so it releases the right ratios for a big boom.  From the photos I'd guess that most of the boom came from gas inside the battery so may well happen even with good ventilation.

[AJStrees]

And what of the bridging terminals with a spanner?

Did the spanner stay the same?

[Peasgood]

My Dad has blown loads of them up yet he still charges them next to the bench when using a grinder.