Mir Hussain

Hi there, I have not run my car over 9-10 months
Off course battery is dead (New one )
Now I was thinking, if I would do a jump start from Healthy battery or start off it. Then connect back the old dead battery to get charged up; while I was driving around?
I am not sure once engine has started it will be stay running if un hook the battery to swap out?

slowride94z

if the alternator is putting out correctly it should run

Mir Hussain

Only reason I have asked; cause I had a trip yesterday for 150 Miles in my Dodge caravan. So I thought once I would start the engine in caravan I will swap the battery and put dead battery off TA. Heck the second I unplug the negative Engine died!
I do non't want to same hoopla and found out I can't do with my TA either due to new electronics etc etc.........

shoebox

I wouldn't try it. It may fry the alternator. The factory manual says to NEVER (yes, in all caps) to disconnect the alternator battery terminal while the alternator is running. Disconnecting the battery would almost do the same thing (though the load of the car's accessories would still be attached). However, if you happen to let that battery cable end touch to ground, then there could be major damage to your car's wiring. It can't be that important that you would need to swap the battery while running, IMHO.

Mir Hussain

ok I won't do it

STRYKER

I can't speak for the F-bodies, but my caprice dies as soon as the battery is unplugged. I just tried it lol.

Fei

So there reason you don't do such things is that; the alternator senses how much power it needs to put out based upon the sensing wire. This sensing wire is attached to the postive pattery terminal. The lower the voltage it senses the more it puts out. What do you think would happen to the alt if it sensed zero voltage from the sensing wire?

Mir Hussain

Well with that line of reasoning now I know why my caravan died immediately when I remove the battery

charliediss

I have grounded out my alternator before using a box wrench...I think I started to weld the wrench to whatever it touched (I cant remember right now, however I do remember the sparks). This was in my younger, dumber days...just buy a new battery or trickle charge your old one.

sbs

Do they not sell jumper cables in Canada?

Mir Hussain

No they do not
They sell Booster cable
heeeee
Actually weak battery is so darn weak, It can't start with batter pluged in

ChickenScreamer94

Yeah, I wouldn't try to do this. Your alternator is just there to replenish the lost power from starting, and give a little more to run accessories. It will most likely kill itself after 150 miles of use like that. Either overheat or fry - both? You can report back if you want

Mir Hussain

150 Miles driving with Dead battery to charge
I was not going to drive 150 Miles without Battery

dangalla

the same exact thing that happens when you have a low battery charge condition or even just high load on the system - maximum alternator output. sure it could be bad for a long period of time but its really nothing different than normal operation

you will have no problem at all with the battery disconnected long enough to swap the battery - if it stays running

but, the better option would be to just remove the battery and charge it on a low amperage setting for a long time. if it is so dead that jumper cables are not helping chances are that the battery is just no good - and driving around is not going to help you or the battery.

ACE1252

Don't disconnect the battery with the car running. You could damage your ECU, Radio, and anything else electronic connected to it. I used to think you could do this, but was set straight by a gentleman on this board(I should have known better too...).

The problem is that the battery is providing the excitation field for the alternator's power generation. When you remove the battery, it becomes unstable and erratic....wild voltage swings can occur and could fry electronics.