Jump starting battery

[Joe Flanagan]

I've seen conflicting answers on whether it's OK to jump a 6v battery with a 12v. I don't want to kick up a rumpus but I would like to hear opinions. Just be thankful I'm not asking about ZDDP and other additives.

Also, if I have to use a 12v to spin my engine because it's newly rebuilt, do I risk damaging anything?

I believe I fixed my leaking gas tank.

[Fireball]

I'm under believe that the consensus is, starter stands the 12V without a doubt. So what I would do in your situation, use the 12V directly to starter solenoid. That way you avoid risking the whole harness?

[aero3113]

Keep the lights off and I think you my have to disconnect your amp gauge(Not 100% positive on the gauge)

[Young Ed]

I agree to be safe I would jump to the starter solenoid. 12v can be necessary if your rebuild is really tight.

[kencombs]

As others have said, the starter is not a problem, nor is the amp gauge. But, the others do care about voltage. So, direct to the solenoid or starter would be best.

[1949P17BC]

Do it all of the time make sure everything is off. Dont grind, grind, grind and grind. Just enough for it to catch. once its starts unhook. Also if it won;t start I let everyting cool down between tries

[greg g]

Connect the negative from the 12 v to the starter side of the solenoid. With the ign swithc i the run position. Ground the positive jumper to the engine. this will engage the starter without passing the 12v through the battery or the solenoid.

[Plymouthy Adams]

and as Greg method points out, that by touching the block last to make the connection the heavy arcing is not on soft copper or lead components..

[Joe Flanagan]

Thanks, everyone. I'm going to try it with my new 6v first. I had been keeping it indoors until a few days ago and then made the mistake of putting it in the car. Temps have been going below freezing here and a battery guy told me today that it probably won't be at full strength as a result.

[Rodney Bullock]

Hey Joe, I know you wanted to start the motor today however it's to cool the winds are at 50 mph. remember once you start it you have to stay with it and moniter it for 20 min. Good days are ahead in fact monday will be 53 degress. I have your ZDDP here with me. I wanted to bring my Plymouth over when you started your for car to car support. I have been down the country and it ain't pretty:mad:

[Joe Flanagan]

Yeah, Rodney. I don't even want to be outside in this. Tomorrow's supposed to be better. I might try it then. Wouldn't be so bad if it weren't for the wind. We've got trees down over here.

[Rodney Bullock]

Man that's tough, No tree over here just front porch rails:( I know I am going to have to have it fixed in the spring. There goes my plans for a Hemi motor:(I will have to get that stuff rebuilt or find a new place to live. Oh well it could be worse right;) A tree could have fell on my car again right:D life, Your lucky to get out of it alive.

[55 Fargo]

Warm thats battery in the house carry it out and crank that baby too life. I start my engine at cool temps all the time.

Your engine is begging to be fired, now go get at her......

[Joe Flanagan]

Rockwood, that's what I done. "The wind cries Mary," man, I haven't heard that line in AGES.

[garbagestate 44]

When I do the 12 volt assist, I begin cranking with the 6v and then connect the 12v. Also, If you have one of those sisson chokes, The 12v jump will eventually make the unit too hot to touch so it might be advisable to disconnect it and have an assistant work the choke manually given the expensive replacement cost if you fry it.

[Joe Flanagan]

Thanks for that. I really don't want to fry that thing. I just checked my battery and it reads 6.31 volts so I guess I should be OK with that.

[Johnny S]

Joe, I haven't done it for a long time but back with my first '49 I used a 12v battery to jump start it probably once a week during the winters. That didn't cause any issues at all. I didn't have any accessories on and I didn't grind it very long .... 'cause I didn't have to. It started right up pretty much every time quite quickly. Very important to have the cables connected right.

[Oldguy48]

Years ago, when a P15 was my transportation to college, jump starting it from 12 volts was necessary on a routine basis during cold weather. That thing absolutely refused to start when the temperature dropped, unless starting fluid, 12 volt jump start, a dipstick heater, the planets were in perfect alignment, and a stroke of luck were involved. I realize now that there were probably a lot of things on that vehicle that needed correcting that I was not aware of at the time, but jump starting from 12 volts never harmed it.