Jump start battery, what connections?

[central52]

If I want to jump start my 6 volt battery on my 47 coupe, where do I put the connections from my 6 volt battery charger? The positive ground thing confuses me. And if I'm on the road, and need a charge from a 12 volt car, again,where do I connect the cables? Ed

[Merle Coggins]

Positive to Positive... Negative to Negative

The positive ground thing means nothing to the battery

[BobT-47P15]

Merle is right on the pos to pos, etc thing.

When I jump a 6 volt battery from a 12 volt car, I attach one cable to the 6 volt, then try to have a helper to start the 6 volt car while I touch the cable to the second terminal only long enough for the car to start.

That way it does not get the 12 volt jolt for very long. I would touch the second cable to the negative side. Just my method.

[Dennis_MN]

If I want to jump start my 6 volt battery on my 47 coupe, where do I put the connections from my 6 volt battery charger? The positive ground thing confuses me. And if I'm on the road, and need a charge from a 12 volt car, again,where do I connect the cables? Ed

This is Minnesota talk, getting a Jump elsewhere means something entirely different.

1. six volt to six volt is just like Merle said, + to + and - to - . We who are experienced at getting a jump, hook up the battery lead first, then we hook up the ground to a bumper or some other connection away from the battery to avoid a potential explosion. In the case of my pickup, my battery is under the floor so I connect the Neg - lead from the charger or another 6v battery directly to the connection on the starter, then I connect the Pos + lead to the bumper.

2. My neighbor came to my rescue once with his 12volt pickup and he connected his positive terminal to my negative terminal (starter) and then hooked up the negative terminal to my bumper. I asked him why he crossed the polarity and he said because it reduced the voltage. I think that he connected the batteries in series instead of in parallel. Anyone else have any insight on why he crossed the polarity?

Glad you asked the question

Dennis

[Niel Hoback]

Something you need to do before you hook up the cables: make sure everything electrical is turned off. Lights, radio, heater fan. Don't open the passenger door while you're jumping.

Don't turn the ignition on until you are ready to crank.

Disconnect the 12 volts as soon as possible after the engine starts so avoid burning the points.

The idea is to use 12 volts the absolute least time possible.

[Norm's Coupe]

You didn't say what kind of transmission you have. If you have a manual transmission, just put it in gear, hold the clutch in, turn the key on and get the car rolling. Doesn't have to be rolling very fast, just moving, then pop the clutch and the car should start without a jump.

[kevin h P15]

2. My neighbor came to my rescue once with his 12volt pickup and he connected his positive terminal to my negative terminal (starter) and then hooked up the negative terminal to my bumper. I asked him why he crossed the polarity and he said because it reduced the voltage. I think that he connected the batteries in series instead of in parallel. Anyone else have any insight on why he crossed the polarity?

Glad you asked the question

Dennis

Dennis -- When you & your neighbor did this, did you push the starter button? Or did the engine roll over when he connected the ground cable? If the later, he was using his battery to just turn the starter - bypassing the 6V battery and your starter solenoid. This is a slick way to protect his & your electrical system. Only works if you enough to juice left for a hot spark. Also helps since the motor rolls over a little faster with the 12V. Reversed polarity works since starters have field & rotor connected internally - always spin the same direction.

If you pushed the starter button, he was charging your battery backwards. So you were starting on positive 12V & then running on negative 6V (I think). For short time OK, but could heat up the battery & shorten life. Possibly burn gauges problems too (?). Neg to neg, pos to pos better even with 12 to 6v.

my 2 cents.. kevin

[central52]

Thanks again, guys. Lots of useful information in the replies. Ed

[Dennis_MN]

Dennis -- When you & your neighbor did this, did you push the starter button? If you pushed the starter button, he was charging your battery backwards. So you were starting on positive 12V & then running on negative 6V (I think). For short time OK, but could heat up the battery & shorten life. Possibly burn gauges problems too (?). Neg to neg, pos to pos better even with 12 to 6v.

my 2 cents.. kevin

Button? My truck has no steeeenking button. Nope, I pushed the starter rod with my foot to engage the starter. The hook up to the starter is just a convenient spot to connect to the battery because the batter is under the floor. I like the series vs paralell theroy myself.

Dennis

[Merle Coggins]

As Dennis says, the trucks don't have a start button to a solenoid. Instead the starter is engaged manually with a foot actuated lever. So the only to connect a jumper battery will power the entire system.

Now, as for reversing the polarity. That WILL NOT reduce the voltage. I don't know where he learned that, but it is WRONG. Reversing the polarity through a battery can damage it severly, especially if connecting 12 volts to a 6 volt battery. I think you got lucky, Dennis.

When jump starting a 6 volt, positive ground system with a 12 volt negative gound system, I highly reccomend connecting it only long enough for the engine to start, and don't let the vehicles touch. You should still connect + to + and - to -. And it most likely will create sparks, so connecting away from the battery is a very good idea. Best case would be to connect the Negitave jumper cable to the negative post on the battery or starter / starter solenoid, then have one person engage the starter while the other person touches the Positive jumper cable clamp to a good ground point away from the battery. This should cause the engine to crank quite fast and start easily. As soon as the engine starts, remove the Pos jumper cable. I have used this technique many times to start 12 volt machines with a 24 volt jumper pack.

Merle