new to the whole m37

[heavyp36]

I know this might sound stupid but can you jump a 24 volt system with an 12 volt vehicles

[Sal]

Are both battery's dead or just one? You can jump it if one is bad by putting your jumpers across the bad one but if there both bad or missing your out of luck. I wouldn't connect a battery until you first check to make sure the pos. (+) isn't grounded or other wiring is shorted.

Sal

[heavyp36]

So what your saying is i just need two new batteries. ......and is their any special kind ?

[Sal]

No.. You can use any 12 volt battery's that you may have.

Sal

[Carter]

Use a VOM to check each battery while disconnected and separated from each other to determine which has low voltage. Then reconnect them and then put the jumpers on the low or dead one just long enough to start the M and have a friend take the jumper off the 24V set fast or the 12 V battery in the car/truck being used as helper vehicle will most likely explode from the surge of 28.5 VDC being put out by the M's generator.
A better solution would be buy a new set of batteries.

[Cal_Gary]

Welcome aboard HeavyP! Lots of sound advice here along with a bunch of great folks-glad to have you with us!
Gary

[carolinamv]

Is your truck still 24V? Might sound like a dumb question but a lot were changed to 12V and you said you were new to M37's. I assume yours has two batteries

[m15256]

Use a VOM to check each battery while disconnected and separated from each other to determine which has low voltage. Then reconnect them and then put the jumpers on the low or dead one just long enough to start the M and have a friend take the jumper off the 24V set fast or the 12 V battery in the car/truck being used as helper vehicle will most likely explode from the surge of 28.5 VDC being put out by the M's generator.
A better solution would be buy a new set of batteries.

Carter,
I have a tremendous amount of respect for your wealth of M37 knowledge but this time you made a mistake. A 12 V battery is constructed of 6 2V cells. Another battery (jumper) hooked to it in parallel will never sense more than the total voltage in those cells even if it is in series with other batteries. I worked on a ship with a 120 V DC system made up of 20 6V batteries and could meter each one as if it was standing alone by contacting the plus and minus terminals. You can jump a 24V system by connecting to the more dead of the two batteries (as long as the other has some charge) without the danger of sending 28.5 volts back to the jumper vehicle.
Rick