Jumping a 24 volt with a 12 volt

[mcmullag]

full flow of the 24 volts

Thanks fellers. I will try this tomorrow as I have one bad battery and am waiting on a replacement. I am just amazed that hooking cables up to one battery as M16ty states, will really work without messing up my daily driver. Makes no sense to me that a 12 volt vehicle may hook up to one 12 volt battery on a fully connected 24 volt vehicle without blowing/melting/disintegrating something on the 12 volt vehicle.
Safety glasses will be in place, charge card for repairs to toyota will be ready, and/or bus schedules will be studied so I may get to work......

 

[littlebob]

As long as you isolate it to the one 12v battery your OK. If there were 24v to an individual battery of 12v it would be spectacular I'm sure. Radios and 12v accessories are added to golf carts(mostly 36v) all the time by just isolating two of the 6v batteries. If your still unsure take a voltmeter and put it across the two points you want to connect to.

 

[Stan Leschert]

If you are really FUBAR, and both batts are dead, disconnect the cable that runs between both batts. Hook booster vehicle to batt #1 and boost for 5 min. Keep the connecting cable off and then boost Bat#2 for 5 min. Unhook donor vehicle, put the connecting cable back in and you should be good to go. Initiate ignition sequence!

This worked when I was in the Oil Patch.
Sometimes a little gentle persuasion in the form of SMALL amounts of ether speeded the results! SMALL!

 

[NICK_M1009]

Thanks

First off thanks to EVERYBODY for their feedback on this. I'm kinda on the fence when it comes to jumping my 09. I would really feel bad if I asked someone for a jump and burned something up on their vehicle. I seen a few people actually did it them selves and it makes me feel better about it. Thanks again...


Oh, I read someone was going to try it this morning with his yota, I wonder what happened?

 

[m16ty]

This will work but I can't stress enough to make sure you hook the cables up correctly. This can end very badly ( I've had a battery blow up in my face and it's no fun) if you don't hook it up exactly as it has been described in this thread. If you read through the post and look at the drawings I posted and still are not exactly sure how to hook the cables up, do not try it. I just don't want to see somebody get hurt or tear something up because they weren't paying enough attention and "thought" they had it hooked up right.

 

[hdmax]

As stated here, one vehicle! There is a remote chance maybe one in a thousand that one 12 volt powered vehicle will not start a 24 volt powered vehicle.
Back in my military days we jump started M60A3 tanks with a M151 jeep. (Those are a 6 battery setup being jumped by one.)

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

 

[hdmax]

Not only that, but have you ever seen burns from a battery that exploded? That is not pretty, so don't try two vehicles to jump start a 24 volt powered vehicle unless you know exactly what you are doing. Someone will most likely get hurt, not to mention what can happen to one or more of the charging systems.

In most cases the battery is not DEAD, it is just much to weak to start the vehicle. (Even if it will not crank, it stall may have several volts.)

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.

 

[destroked]

Thanks fellers. I will try this tomorrow as I have one bad battery and am waiting on a replacement. I am just amazed that hooking cables up to one battery as M16ty states, will really work without messing up my daily driver. Makes no sense to me that a 12 volt vehicle may hook up to one 12 volt battery on a fully connected 24 volt vehicle without blowing/melting/disintegrating something on the 12 volt vehicle.
Safety glasses will be in place, charge card for repairs to toyota will be ready, and/or bus schedules will be studied so I may get to work......

Why does this make no sense? This is basic DC electrical theory, no scholars need apply.

Take a few moments to read up on series and parallel dc circuits. You can group together 4 batteries to in series to make 48 volts dc, but if you connect to the terminal lugs on each specific battery's neg and positive terminals, you will only have 12 volts at each one. This is how A/C transformers work to give various voltage outputs, you simply tap off of the coil windings at various points to increase or decrease the output you need.

 

[maetl]

Works fine!

For newcomers to this situation like me, I just wanted to confirm that the methods here do work (Thanks, guys)

The battery closest to the firewall (rear battery) was dead on my M1009.

I jumped it with a 2002 Chevy Blazer by hooking on to the other battery, closest to the head lights (front battery).

After about four to five minutes on high idle, my CUCV was able to crank right up while still attached to the 12v jump vehicle.

Disconnected the cables, let it idle about 30 minutes, drove it around, and all is well. Nothing caught fire--nothing exploded in my face

 

[tennmogger]

Little skinny jumper cables work fine to boost charge a battery from another vehicle, given time.

There are two ways to "jump start" a vehicle. The most common (as posted above) is to use high current and the energy of the remote battery to do the cranking. That for sure takes high current cables. But, in a pinch even little Radio Shack alligator clips can do the job. Just remember the same energy is conveyed by high current for a short period as for low current over longer time.

If your big truck draws 500 amps during starting but only takes a second or two of cranking, you can use the big cables and handle 500 amps for a few seconds. Or, use the slow boost method to put the same energy into the dead battery, say 10 amps for 50 minutes. Lots of cheap jumpers handle 10 amps easily.

In an emergency, being running in an hour is better than walking.

PS, that's how those little typically 7 AH booster packs work, they charge the dead battery so you can start off it.

 

[Riverbend]

My CUCV has both batteries side by side at the front, which one would I put the cables on the first one, or the second one

 

[Rustyshackelford]

My CUCV has both batteries side by side at the front, which one would I put the cables on the first one, or the second one
View attachment 697003

Whichever one is dead. Most likely the one that is connected to the ground.

 

[CUCVFAN]

One closest to the radiator appears to be supplying the 12V for you.

 

[Riverbend]

10-4, Thanks