Can you change a battery while the car is running?

[-westy-]

^^ probably a stupid question, but I need to fit my spare battery, and I can't bump start the car once its in.

The car will start with the current battery, I'm just wondering if you can change a battery when the car's running.

Thanks

 

[Dr_Evil]

only 1 way to find out.....

 

[happytechie]

if the car is running the alternator (unless it's dead) will be charging the battery

 

[Trifid]

The battery is recharged by the alternator so I don't see why you can't...

(My car knowledge isn't very vast so I take no responsibility for what happens .)

 

[-westy-]

Well, my spare battery is totally dead. So i can't get the car started to charge it..

 

[Dr_Evil]

Well, my spare battery is totally dead. So i can't get the car started to charge it..

then how would you start it in the first place?

 

[happytechie]

Well, my spare battery is totally dead. So i can't get the car started to charge it..

then take the battery out of the car and charge it

 

[Dr_Evil]

then take the battery out of the car and charge it

even better, leave it in there and charge it!

 

[-westy-]

then how would you start it in the first place?

using my old battery It starts the car fine, just doesn't hold charge for very long.

And I don't have a battery charger

 

[Jonny69]

I haven't tried with a car with an alternator but you can if it's got a dynamo so my guess is yes. Only one way to find out though...

Beware the alternator is going to kick in full pelt on a flat battery so expect it to go BZZZZT when you connect up the live

 

[killsta]

Can't you stick the flat battery in then jump start it?

 

[Dr_Evil]

alternatively - cut a squared hole in the bottom of the chassis, in between the pedals and the driver's seat.

Can't you stick the flat battery in then jump start it?

not if it's dead flat - i tried that once and it didn't work. The battery needs to have a very small charge left to do this.

 

[DingleBerry]

no you can't. Its a bit of a problem with narrow boats. If you leave an alternator running for any length of time without anyhting connected the voltage regulator fries itself. Whether the instruments are enough to help it not die I don't know. But I've seen labels on alternators telling you not to disconnect the battery while its running. I wouldn't.

 

[James_200sx]

Dont as you could damage the electrical system on the vechical.

Charge the spare with some jump leads or

jump your car after it has been done or

move your car to steep hill and change it there then use mavity to bump it.

 

[-westy-]

Oh well, I did it anyway

the revs dropped a bit when I touched the live cable, so I just pulled the throttle linkage until I had a fast idle.

Sorted, cheers!

Can someone RTM my post so this can be locked/deleted please