How to jump 24 volt with 12 volt

Columbia Basin, Ephrata, WA

Two pickups and two sets of cables is the fastest. Just hook one pickup to each battery as mentioned above and don’t let the pickups or any cables touch anything they aren’t supposed to.

I’ve also used one pickup. Hook cables up to first 12v battery and give it ten minutes, then remove both cable ends and switch them to charging the other 12v battery for another 10 min. It seems wrong to unhook your black jumper cable at the halfway point and then hook your red cable to pretty much the same spot, but it works.

Hey guy's,
It hasnt happened yet but, If my 09 runs out of charge and I need a jump will I be able to ask for a jump from a 12 volt vehicle? If so how would I hook up the jumper cables? If not, that sucks.

Thanks

I may be wrong but I think you can do it with two seperate 12v vehicles and 2 sets of jumper cables. Not 100% sure but I know the others will correct me if I am wrong.

You only need one vehicle to do it... Just hook the cables up normally, but ONLY to the FRONT battery on your 09... Shouldnt have any problems

Usually it is one battery that has died. Put the jumper cables across that battery. If both batteries are dead, then hook the second set of jumper cables from a second vehicle across the second battery.

You only need one vehicle to do it... Just hook the cables up normally, but ONLY to the FRONT battery on your 09... Shouldnt have any problems

Second this one.

If worst comes to worst with only 1 car available, I imagine hooking up to first battery in a normal manner then run the jumping car at a high idle for ~5 minutes; then hook up to second battery and do the same before attempting to start?

I actually did this, and was surprised that my cobalt jumped my m1009. I just hooked up the cables to the front battery. It took awhile for the juice to flow, but it finally started. I still dont know what drained the battery, and it hasnt happened again <knock on wood>, but yes no problems jumping with one car hooked up to the front battery.

The heavier the jumper cables the better. I have a set made out of welding cable and it will jump anything MV or civy. Using tiny jumper cables is asking for trouble.

Here's how to hook it up. You can hook it up either of these two ways. First hook it up to one battery and if it doesn't seem like that helps, switch to the other one. Just make sure you hook positive (+) to positive (+) and negative (-) to negative (-) with each battery.

WM is right in regard to cable size. Those little cables you buy at most chain stores aren't good for anything except maybe jumping off your lawn mower.

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Last edited: Feb 28, 2011

They are correct. Don't waste your money with crappy cables. Either make some cables out of welding cable or find some heavy duty jumper cables. I actually found a heavy duty set at Autozone. You are gonna spend some good money on them, but it will be worth it the first time you have to jump a vehicle.

Jumping a 24 volt system with a 12 volt system

I have a set of jumper cables that are 6 or 4 gauge wire, cant remember, but
over the years, I have had about 4 instances where people could not get a vehilce jumped using their 'cheap' jumper cables and I go over and put mine on there and it starts right up. The larger wire carries a whole lot more amps over to the 'dead' battery.

I am amazed to hear what you guys are stating above, I thought the diodes are something in the alternator would blow or melt if you hook a 24 volt vehicle to a 12 volt vehicle.

You mean I can jump start my deuce with my 12 volt Toyota 4Runner with the deuce batteries fully hooked up in series in their normal running 24 volt manner without messing up my daily driver yota?

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It's the other way around, mcmullag. Starting a 24V CUCV with a 12V car, not a deuce, or a deuce starting a 12v car or truck. The CUCV has two alternators to provide the military standard 24V, but most of the system is just a 12V civilian vehicle.

You can jump a deuce with 12v the same way you jump a CUCV with 12v. As long as you hook up the 12v source to an individual battery you'll be ok ("+" to "+" and "-" to "-" on each battery). In effect, all you're doing is replacing one of the deuce 12v batteries with the 12v jump vehicle.

I've done this before and haven't blown anything up.

Thanks guys, I thought CUCV's were totally 24volt throughout and I also forgot that they have two alternators.
So with my Toyota, I can't really jump start the deuce, I would have to disconnect the cable linking the deuce batteries in series and just ' charge' each battery individually with the jumper cables. Do I have that right?

I personally have jumped tractor trucks (24v) with my pickup (12v) before without any problems. Like we previously stated, its all in the way you hook up the cables and the size of the cables... You could jump your duece with your yota if you hook em up right.... Without having to unhook anything or charge them individually, unless you just want to

So with my Toyota, I can't really jump start the deuce, I would have to disconnect the cable linking the deuce batteries in series and just ' charge' each battery individually with the jumper cables. Do I have that right?

As I said above, you can jump your deuce with your 12v Toyota. Hook it up just like the diagram I posted earlier in the thread.

This is not the best for the CUCV or the deuce but it will work most of the time if that's all you've got. It won't work if both your batteries are completely shot but most of the time boosting one battery will get you going.

I personally have jumped tractor trucks (24v) with my pickup (12v) before without any problems. Like we previously stated, its all in the way you hook up the cables and the size of the cables... You could jump your duece with your yota if you hook em up right.... Without having to unhook anything or charge them individually, unless you just want to

Me to. I remember the looks on the people in the yard when I got the semi started by jumping it off of my little samurai.

I worked for an oil field trucking company for the last six years and have had to do it many times...

Yes, by hooking cables to one battery whether it is to the individual terminals or any of the other ways to isolate the circuit to one battery, you end up with your jumper circuit registering as a 12 volt circuit (12-14volts on volt meter) with your electrical on the 24 volt system intact.
No one has yet posted this on this thread yet; be absolutely sure if you do end up using two vehicles to assist that they DO NOT TOUCH. If they do, can you say 1000 amp/24 volt welding. This is a light show you can LIVE without.

Like said above it is usually only one batt that is dying, so if u have one car as a donor and a dead deuce,try it on ea. one, there are so many threads on this its silly, but here it goes, u can use one standard jumper cable and 2 deuces, make believe the 2 batts are only one, and just jump to the outsides, so its 24 to 24 simple, U can use 2 sets of jumpers one set on each batt, U can use 2 separate cars and 2 sets of jumpers to a deuce, u can put multiple battery chargers on each batt as long as they... meaning each output added together does not go over 12 volts, U NEVER need to remove any cables at all from the 24 volt system to charge with 12 volt batt chargers on each one, it is important to clean and pull your batts once a year and chege fully with a quality charger and rotate them in the box, one batt always takes more charge, yes it does, the batt getting the juice from the alt gets it first and over time the second batt becomes lasy or sulfated faster because it is always a little lite on charge, very very true in 4 batt systems also, there is usually one lazy batt, if they are not rotated, the best on board way to charge is with a batt charger for each batt, I always on the M925 put a 4 batt charger hooked on ea. one when stored, and keep a 24 volt charger desulphator screwed to back wall connected to back of slave , for emergencies, and will eventually put 4 charger desulphators along the back wall behind the passsenger seat,and hook one to ea. batt and then wire all ends to one plug, size of cables is important but u sure can use what U have, its like filling a pool, the juice is going over, even if they are junky, but be careful of over heating them,

Last edited: Mar 1, 2011

How do you get 24 volts from a 12 volt system?

To create a 24V system using two 12V batteries, you would wire the first battery's “+” positive terminal to the “-“negative terminal of the second battery. The remaining negative and positive connections get wired to the component you want to power just as you would if you were using a single battery.

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