Jump start positive ground car

[mmotors]

What is the best way to jump start a positive ground car from a negative ground car?
Thank you

 

[AUSMHLY]

Others will chime in, so I hope I'm not wrong.
Positive to positive, negative to negative on the batteries.
Don't let the cars body touch each other.

 

[GregW]

Yep.

 

[mmotors]

Thank you. Next time I won't feel so worried when hooking them up.

 

[tahoe healey]

I remember something about which terminal is connected last being important but I don't remember what. just don't let a loose clip hit the bumper.

 

[RestoreThemAll]

OK, so would one of those battery jumper boxes be a better choice? We have one from Sears and paid I think $20.

Can you push start a Healey safely? I have a BJ7 and recall push starting it several times in the 1970's. That doesn't make it a good idea. Could it hurt the OD?

 

[Bob_Spidell]

Usually, you want to connect the ground last--and away from the battery, if possible--in case there's any hydrogen gas around the battery and you get a spark.

 

[Keoke]

OK, so would one of those battery jumper boxes be a better choice? We have one from Sears and paid I think $20.

It would be OK provided the car's battery is not absolutely dead.

Can you push start a Healey safely?

Yes if you are on a good hill or have a bit of extra help'

I have a BJ7 and recall push starting it several times in the 1970's. That doesn't make it a good idea. Could it hurt the OD?

No you should not hurt the OD as it's switch should be disengaged
Fwiw----Keoke

 

[Johnny]

Others will chime in, so I hope I'm not wrong.
Positive to positive, negative to negative on the batteries.
Don't let the cars body touch each other.

Hmm, lets see, you're hooking your neg battery terminal(hot) to a neg battery terminal (grd) in a car, possibly running. I would think you would get a big SPARK!

Unless the donor battery is out of the car (disconnected) I wouldn't do it.

 

[Bob_Spidell]

Hmm, lets see, you're hooking your neg battery terminal(hot) to a neg battery terminal (grd) in a car, possibly running. I would think you would get a big SPARK!

Nope. There is no absolute 'ground' (except maybe for AC like in your house). In fact, the more correct term is 'common,' for the common frame the accessories are 'grounded' to. That's why you don't need a special battery in a positive ground car: just connect the positive terminal to the chassis instead of the negative. I've jump-started neg-'ground' cars with my pos-'ground' BJ8 several times.

If you think about it, since electricity travels in a circuit both terminals are 'hot;' it's just that one terminal is made common so that it's convenient to (electrically) attach things like starters and generators to it (else you'd need two cables to all electrical components and everything would have to be thoroughly insulated). IOW, the chassis is used as part of the 'wiring' of the car.

If you connect neg-pos battery terminals from a negative ground car to a positive ground car and connect the two chassis you're connecting the circuits in series and you'd get 24V across your components (similar to connecting two 6V batteries in series to get 12V). Your starter would spin like crazy ... for a couple seconds. If you connect neg-neg and pos-pos you're making the connection in parallel, which combines the available current from both sources but the potential (voltage) remains the same (12V).

You will sometimes get a little spark when you make a neg-neg or pos-pos connection, which is why you should make the last one to the chassis away from the battery.

 

[why]

no different than any other car, push start with ignition on and pop clutch in 2nd or 3rd gear, or just connect like battery terminals to like battery terminals with jumper cables being careful that giant alligators on cables touch nothing other than terminal, donor car running or not running, OD or any other electical on or off, just like a Chevy,