The Stovebolt Site Forums The Shop Area The Electrical Bay 12 volt to 6 volt??

I am running a 6 volt system. I have a 12 volt jumper box. What can I do to reduce the voltage of my 12 volt jumper box, externally, to allow me to jump and run my truck off the box to get me home.?

No I don't want to convert to 12 volts!

No luck in finding a 6 volt jumper box, but would buy one if I could locate one.

Thanks in advance as always. .

You can jump a 6v vehicle from 12v battery. Just don't crank the starter too long.

Also, how often have you ever needed a jump start on any vehicle? If you're like most of us with old cars, you are intimately aware of every aspect of your vehicles' conditions and states of repair and likely aren't caught off guard by a dead battery.

I'm usually the one giving people jump starts in the parking lot or side of the road. I can't even remember if I ever needed a jump start in the last 25 years or so.

Remember also that you're driving a stick shift. Roll starting these trucks is pretty easy.

Great points, Otto.

I have a new battery and am trying to figure out the whole charging system.


I have some concerns about my charging system and don't want to become stranded. I figured if I had a jumper box to come to the rescue, I could still enjoy the truck until I get it all figured out.

Will a truck with a bad generator along with a dead battery, roll start?


Thanks

Probably not. You need at least some electricity to spark the plugs.

Have you tested your generator? With the engine running, put the volt meter leads on the battery posts. You should be getting about 7+ volts reading.

Be sure your battery cables are 00 gauge like welding cable. Make sure your ground cables are all clean connections.

I am reading 7.20 volts at a higher RPM, mid to upper 6s at idle.

Brand new braided grounds and 39 3/4 positive cable.

Maybe I am worried about nothing.

In the past I had a draw from the radio, which made me replace all of the items, cables and battery.
When the battery was dead the last time, the time of my current concern, I just put it on a charger before I checked for a draw. When I did check for a draw later, there was none.

Knowing it should be 7 plus helps alot.

Thanks

A vehicle with a generator can be push started and driven WITHOUT A BATTERY EVEN BEING CONNECTED! As long as the generator is polarized properly, it begins producing current as soon as it starts spinning. No battery required!

No, I'm not interested in getting into a long-winded technical discussion with a bunch of internet research gurus who have never worked on an actual DC generator, about why that happens! -If you're concerned about the battery going dead, you can also get a couple of 6 volt dry cell lantern batteries to hook up to the ignition system in parallel to get a bit more current capacity, and push start the vehicle. They'll be good for about 50 miles of driving before they go dead. Disconnect the battery wire at the voltage regulator and connect the dry cells there.

The normal charging system voltage AGAINST A FULLY CHARGED BATTERY should be 7.5 volts. You need to adjust your regulator, but be sure you slow charge the battery for a couple of days before making the voltage adjustment. Good luck!
Jerry

Interesting question.

Biggest risk when starting a 6 volt vehicle with a 12 volt vehicle is possibly burning out the gas gauge. A running vehicle may actually be at 15 volts.

I checked my NocoBoost with a voltmeter. It output is exactly 12 volts.

So, it's probably safer to start a 6 volt vehicle with the booster than with a running vehicle.

I have run 4 different 6 volt trucks converted to 12 volts for a total of 100,000 miles combined over a 35 year span without burning out a "6 volt" gas gauge. I don't think jump starting a 6 volt truck with twelve volts will hurt anything. Just don't turn on any lights or the radio while doing it.

So, I guess I was just unlucky to have my gauge burn out.

If I understand correctly, with a fully slow charged battery, adjust voltage regulator till my voltmeter reads 7.5 volts at about 2000 rpm?

Either that, or me and a bunch of other fellas who didn't worry about were all lucky.
I can see that going either way. That's how luck runs sometimes.

Just hook the 12v donor battery to the 6v dead battery only long enough to turn the starter.
Do not leave cables hooked up any longer than necessary to turn the starter motor. The battery will get hot and start to leak acid. I've been jumping 6v systems with 12v batteries for 55 years and have never burned out a gas gauge or anything else.

That's right. Just be sure the battery is fully charged, as the charging system voltage goes up as the battery approaches full charge. If you adjust the voltage to 7.5 against a partially charged battery, it will end up at 8V+ once the battery gets up to the proper specific gravity.
Jerry