Car Battery Replacement

[Galaxy01]

I had my car battery replaced by a battery shop the other day.

I was a bit surprised that he removed the old battery while the engine was running and then put in the new one.

I read somewhere that doing so may damage some electronic circuit/components in the car.

Any experts here to shed some lights on this?

Cheers

[zqwerty]

With most cars having an on board computer these days, if the battery is disconnected and replaced without using a backup battery all custom settings made by the customer will be lost, that's what happens with my Mercedes anyway.

So leaving the car running would achieve this result of backing up the battery voltage whilst it is being changed.

May be this is why they left the car running but it sounds a bit risky to me what with all the transients at the time of switch over.

[Galaxy01]

I remember the last time I replaced the battery, the guy plugged in a small back up battery into the lighter socket and then replaced the battery, of course, with the engine OFF.

I was a quite surprised that the battery shop guy, being a professional in their trade did that way. Hopefully, nothing goes wrong with my car.

In future, if my battery needs replacement, do you think that I should request them to plug in the back up battery, rather than leaving the engine running while replacing it?

[zqwerty]

I think you should insist on it and so will I when I get my battery replaced in the very near future.

[allblack]

I had my car battery replaced by a battery shop the other day.

I was a bit surprised that he removed the old battery while the engine was running and then put in the new one.

I read somewhere that doing so may damage some electronic circuit/components in the car.

Any experts here to shed some lights on this?

Cheers

I'm curious, what type of car and the name of the company that did the battery?

[Agent_24]

I had my car battery replaced by a battery shop the other day.

he removed the old battery while the engine was running and then put in the new one.

I read somewhere that doing so may damage some electronic circuit/components in the car.

Yes, it can, depending on how old your car is, what make etc.
Maybe he knew yours would be fine. Or maybe he didn't give a shit / always done it that way bro, which is probably more likely. Some people are "cowboys".

Recommended way if needing to keep settings is using a backup device while the battery is swapped, with the engine off as you have mentioned others doing.

Hot swapping isn't recommended with modern cars.

[jim157]

i had to jump start the mercedes the other day, thought the old batterys on the way out, priced up a new one $475...i park it facing downhill now so i can clutch start it