EV Mode 2 charging O-PEN

You can add to that list, a Granny Charger is safe if no one touches the vehicle whilst it is connected to the charging lead.

Around forty five years ago a lorry driver working for our local aggregate merchant was burnt and lost an eye connecting jump leads to a lorry battery.

He could not start the lorry so fetched a battery out of the workshop that had been charging overnight, put the leads on the spare battery then leant under the lorry bed and connected the lorry battery.

As well as being flat the lorry battery it was assumed it was also partially frozen as it was the middle of the winter, the battery exploded with enough force to blow a hole in the steel bed of the tipping wagon, which I saw myself I also saw the burns the driver received and he lost an eye.

Ever since then I have always put the leads onto the flat battery first, then stood back and connected the fresh battery.

Granny leads really need a similar approach, plug the lead into the vehicle to be charged then stand back and plug the lead into the wall socket, then when charging is complete disconnect at the wall first.

But in reality people will touch the vehicle whilst it is charging. 

That's a bit like disconnecting the earth side of a battery before "live" (could be pos or neg).

I have never heard of a frozen battery - what is the freezing point of reasonably strong sulphuric acid? Perhaps there was a duff cell?

That's a bit like disconnecting the earth side of a battery before "live" (could be pos or neg).

I have never heard of a frozen battery - what is the freezing point of reasonably strong sulphuric acid? Perhaps there was a duff cell?

It was a 3.5 ton tipping wagon with a steel bed, the battery did a proper job of blowing a hole in it on an exceptionally cold morning.

Full strength battery acid wont freeze at any temperature likely to be found in the UK. However in a deeply discharged battery the acid becomes more dilute and it can freeze in severe weather. In polar regions it can be worth removing a vehicle battery and bringing it inside overnight. Alternatively many vehicles have an electric engine block heater in severe climates, some models include a small heater to warm the battery, and also a trickle charger for the battery.

Most businesses and homes have outdoor 120 volt, 15 amp outlets for engine block heaters.