I have done a search but I didn't see a clear answer to this question. I want to make sure that if I do this, I don't cause any damage to my system. So if I'm jumping a 12v vehicle with my 24v system what's the correct and safe procedure?
Jumping 24v to 12v
- Thread starter Martin White
- Start date
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Martian, i'm not one of those people that throw a "huge baby fit" when someone doesn't search first before asking a question but if you haven't already there was a very good post awhile back(seeems maybe 3 or 4 months back) about jumping 24V systems. If you can find it, it's a good read.
https://forum.ih8mud.com/showthread.php?t=57213 for one discussion on boosting a totally 24V vehicle.
Edit...your HDJ81 goes to 24V for start only, correct? The below method is for a 12V vehicle to a 12V vehicle. It is to be done with both vehicles off. Then start the boost vehicle after connections are made. No reason it would not work when using your HDJ81 as the boost vehicle...just make sure you are not using chassis ground on your (the boost) vehicle.
Hook up the positive (red) of the cable to the positive pole of your battery (boost vehicle). Hook up the other positive (red) clamp to the positive pole of the 12V car being jumped. Hook up the negative (black) clamp to the negative pole of the same battery of the boost vehicle, then hook up the other negative (black) clamp to chassis ground of the vehicle being jumped. Start the boost vehicle, let it run for a while, then start the vehicle that is being jumped. Disconnect in reverse.
hth's
gb
Edit...your HDJ81 goes to 24V for start only, correct? The below method is for a 12V vehicle to a 12V vehicle. It is to be done with both vehicles off. Then start the boost vehicle after connections are made. No reason it would not work when using your HDJ81 as the boost vehicle...just make sure you are not using chassis ground on your (the boost) vehicle.
Hook up the positive (red) of the cable to the positive pole of your battery (boost vehicle). Hook up the other positive (red) clamp to the positive pole of the 12V car being jumped. Hook up the negative (black) clamp to the negative pole of the same battery of the boost vehicle, then hook up the other negative (black) clamp to chassis ground of the vehicle being jumped. Start the boost vehicle, let it run for a while, then start the vehicle that is being jumped. Disconnect in reverse.
hth's
gb
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wussyPup
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You want to use the battery on the driver's side that has the chassis ground; not the one on the LH side with this protective cover:
-Steve
-Steve
No need to call him Martian....
Martin, just remember that the 2 batteries are in series, so the first one puts 12V out of the positive terminal and the second one (the one that connects to your vehicle's starter etc) is 24V.
Hook up to the first battery only, ground the negative clamp at the dead vehicle.
No need to call him Martian....
Martin, just remember that the 2 batteries are in series, so the first one puts 12V out of the positive terminal and the second one (the one that connects to your vehicle's starter etc) is 24V.
Hook up to the first battery only, ground the negative clamp at the dead vehicle.
This is true if you are grounding to the frame of the 24volt vehivle, but if you measure the voltage bewteen pos. and neg. posts on either battery it will still read twelve volts. I may be mistaken, but I don't see why you can't boost off of the high side battery as long as you ground to the neg. post and not to the frame???
I never ground to the frame on the "booster" end, ground to the frame of the "boostee"...the dead car.
Why take the chance that after connecting the positive lead to the 24v terminal, you accidentally touch the negative terminal to the chassis and run 24 volts out to the dead car? Wouldn't it just be smarter to play it safe and use the first battery in the series?
Why take the chance that after connecting the positive lead to the 24v terminal, you accidentally touch the negative terminal to the chassis and run 24 volts out to the dead car? Wouldn't it just be smarter to play it safe and use the first battery in the series?
Just random but whats the real point to hooking to the frame anyways? I've always just hooked right to both terminals, in the correct order, but it seems ya get a faster charge.
Spark, slight chance of explosion from hydrogen gas which can have formed around a battery that has been discharged, or from fluid lose. Hence hooking up in the sequence explained. This ensures the discharged battery is fully hooked up before given juice from the booster vehicle.
When working with 24V it behoves some understanding, and educated choices made. Chances are slight of an issue, however it is present. Good ventilation helps reduce possibilities; however does take away the obligation to attempt correct hookup/unhook sequence to minimize chances of an issue.
hth's
gb
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Steve - am new to LCs and don't have the manuals - so just want to confirm. Mine came with dual-battery setup. Is the primary battery on all 80LCs (US/JDM) the one near the power steering reservoir)?
And the battery that should be used to jumpstart another rig is on the left side (near the air filter).
See pics (not mine but from other MUD posts)
1st pic - primary (red-battery - not to be used for jumpstarting)
2nd pic - secondary (yellow-battery - the one to use)
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I agree with iron giant and greg b. Each battery is 12 volts... in series they are 24, but you can pick either one to jump from if you connect to the terminals. The battery is 12 volts. Just check it with a volt meter... it will tell you so.
wussyPup
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If you connect to the terminals and not to the chassis, then yes, use either.
If you connect to the chassis, then use the battery that is directly grounded to the chassis; for a JDM that will be the one near the coolant reservoir on the driver's side (RH). The pics you posted don't look factory (looks nice though).
I don't think any of the US market 80s came with the 12V run/24V start configuration.
Here's a pic of mine with the battery not to use in the foreground:
If you connect to the chassis, then use the battery that is directly grounded to the chassis; for a JDM that will be the one near the coolant reservoir on the driver's side (RH). The pics you posted don't look factory (looks nice though).
I don't think any of the US market 80s came with the 12V run/24V start configuration.
Here's a pic of mine with the battery not to use in the foreground: