Morris Minor Owners Club

The advice given by BMC very early on in this thread was to disconnect the small wire and then connect the battery. If the solenoid contact were closed there would be a very large current - more than 200 amps on an M35 starter - and a consequent very large spark as the battery terminal was connected,

The location of the solenoid is irrelevant because the advice given was to reconnect the BATTERY and I've no doubt that a person taking that advice would do so AT THE BATTERY TERMINALS.

BMC gave the same advice that 99% have given.

The issue has been resolved without an exploding battery and still great eyesight, so no worries.

If anyone is really interested in safe practices for connecting a battery as per fully approved processes in a major blue chip automotive firm... Nothing more than you'd expect.

As for care of a battery (and yourself) during and after charging a lead acid battery this is fundamentally the same hazard severity but a totally different statistic for probability. During and soon after charging it is worth to take care as there is a probability of explosive gas mixture being present and small risk of igniting it. Some workshops go to the length if having a completely separate area with tight controls for charging lead acid batteries.
For those who like to weld through a puddle of brake fluid to see if the safety warnings are true... You're more than likely to find the same thing, but as there's hundreds of millions of cars these days, there are people out there who inadvertently managed to get the conditions just right with brake fluid mist, battery gases etc.. Any injury that is easily avoided is always one injury too many.
Anyone who's been on courses about electrical equipment for use in hazardous areas would recognise the same thing about the almost mythical explosion in a flour mill. Recreating it is very very hard but in just the right conditions the worst can happen.

I am probably banging my head against the wall here but I wonder if some of the posts would be as smug and condescending if "the worst had happened".

As a matter of interest I have received a pm from someone who claims:

"I have deliberately attempted to create this situation many times over and failed. Despite that I am fully aware that it is possible in the right circumstances."

Why would you????????????????????????

A battery under charge gives off HYDROGEN. This is one of the most explosive gases that most of us will come across in our everyday lives. I have a friend who ran a garage business in Leicester for about fourty years with no problems until one day he was charging a battery and there was a spark and now he only has one eye. He now has the battery charger inside his workshop and the batteries to be charged are in a well-ventilated "kennel" outside. Where the two wires go through the wall are two isolating switches. He can still earn a living with one eye but his philosophy is that it might be a bit awkward if it happened again......

Scary story - and yes - charging batteries can be a risky business - if they are overcharged and allowed to 'gas'.