Disconnected battery while engine was still running

[M104]

Hi everyone. Today i had to help a friend by jump starting his car. Unfortunately, the wires were a little short and it pulled my negative terminal off while my car was still idling. It looks like it didn't harm anything but i'd like to know how bad it is, what should i keep an eye on and if any of you actually had issues after doing the same mistake. The terminal was disconnected for maybe 20-30 sec max. The car is my wife's 2006 Peugeot 407 2 liter.

 

[CapitalTruck]

Used to do it regularly back in the day (when ultra poor and had to do some interesting parts distribution between my group of friends' vehicles). I would bet no damage...but I wouldn't make it a habit.

 

[wlk]

I wouldn't worry about it.

 

[zrxkawboy]

Not a good idea on modern cars, but if any damage was done, I'm guessing it would be evident right away.

 

[SC Maintenance]

Not a good idea but the stories of impending doom are exaggerated I believe. Yes it can hurt something but I don't think as often as some would want to believe. Modern controls are pretty fast acting and your battery is the sink.

I would check to make sure its still outputting enough volts at charge and if so not worry about it.

 

[Bottom_Feeder]

It's totaled.

 

[M104]

I would check to make sure its still outputting enough volts at charge and if so not worry about it.

I'll check the alternator as soon as i get home.

 

[Lubener]

I'll check the alternator as soon as i get home.

I wouldn't worry about it if you are not getting any charging or check engine dash indications.

 

[oil pan 4]

Hi everyone. Today i had to help a friend by jump starting his car. Unfortunately, the wires were a little short and it pulled my negative terminal off while my car was still idling. It looks like it didn't harm anything but i'd like to know how bad it is, what should i keep an eye on and if any of you actually had issues after doing the same mistake. The terminal was disconnected for maybe 20-30 sec max. The car is my wife's 2006 Peugeot 407 2 liter.

If it didn't fry anything immediately it's probably fine. I've heard disconnecting the battery when there's little to no other electric loads can cause a voltage spike. I just figured I'd best not test it.

 

[SOHCman]

Had to do this one time to get a parts store reman starter to stop trying to start the engine. Some kind of internal short, and learned to get OEM starters instead.

 

[dishdude]

You'd know right away if it caused any damage.

 

[Starving Electrician]

Electronics are digital in that they are either working or not haha. Sorry lame joke. With that if it was going to be a problem it would have been a problem already.