dek1581 Posted November 29, 2012 Share Posted November 29, 2012 just want to be prepared but is it possible to jump start a positive ground firetruck with a negative ground vehicle? common sense says to simply reverse jumper wires but i don't feel like blowing an alternator... Quote Link to comment https://www.bigmacktrucks.com/topic/28585-jump-starting-positive-ground-vehicle/ Share on other sites More sharing options...
rsb502 Posted November 29, 2012 Share Posted November 29, 2012 yes just use the positive on the positive terminal and the negative on the negative terminal on the battery and the powered vehicle doesnt know that the non powered vehicle is positive ground, 12V D.C. is still 12V D.C. positive or negative ground. If its a 24V vehicle that becomes more of a challenge and involves removing the ground cable from the powered battery ( vehicle wont be running) and applying the jumper cables to the 24V battery side( this is using two pairs of 12V 31S950 batteries in series to make 24V) actually what you are doing is just adding CCA's to the batteries that are on the truck, if they are completely dead I have never been able to make it happen(not for lack of trying). Quote "Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin"If your gonna be STUPID, you gotta be TOUGH" "You cant always get what you want, but if you try sometimes you get what you need" Link to comment https://www.bigmacktrucks.com/topic/28585-jump-starting-positive-ground-vehicle/#findComment-148541 Share on other sites More sharing options...
MACKS Posted November 29, 2012 Share Posted November 29, 2012 Not likely to happen but make sure the vehicles are not contacting each other. Quote Link to comment https://www.bigmacktrucks.com/topic/28585-jump-starting-positive-ground-vehicle/#findComment-148545 Share on other sites More sharing options...
mowerman Posted November 29, 2012 Share Posted November 29, 2012 dont know if you got all that,,,just hook them,,red on red black on black,,,do not reverse them,,,and you can generall do it with a car....bob Quote Link to comment https://www.bigmacktrucks.com/topic/28585-jump-starting-positive-ground-vehicle/#findComment-148546 Share on other sites More sharing options...
rsb502 Posted November 29, 2012 Share Posted November 29, 2012 Not likely to happen but make sure the vehicles are not contacting each other.good point, if they were and the cables were hooked it could make a neat light show, and some welding noises in the cantact area. (not likely on newer plastic bumper crap) Quote "Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin"If your gonna be STUPID, you gotta be TOUGH" "You cant always get what you want, but if you try sometimes you get what you need" Link to comment https://www.bigmacktrucks.com/topic/28585-jump-starting-positive-ground-vehicle/#findComment-148553 Share on other sites More sharing options...
609albert Posted November 29, 2012 Share Posted November 29, 2012 as BULLDOG said don't let vehicles touch, I installed a plastic caution tag on my mack fire truck as a warning and instructions for jump starting. Quote Link to comment https://www.bigmacktrucks.com/topic/28585-jump-starting-positive-ground-vehicle/#findComment-148565 Share on other sites More sharing options...
fxfymn Posted November 29, 2012 Share Posted November 29, 2012 Albert,Did you get my message about the stanchions?Carl Quote Money, sex, and fire; everybody thinks everyone else is getting more than they are! Link to comment https://www.bigmacktrucks.com/topic/28585-jump-starting-positive-ground-vehicle/#findComment-148604 Share on other sites More sharing options...
dek1581 Posted November 29, 2012 Author Share Posted November 29, 2012 yes just use the positive on the positive terminal and the negative on the negative terminal on the battery and the powered vehicle doesnt know that the non powered vehicle is positive ground, 12V D.C. is still 12V D.C. positive or negative ground. If its a 24V vehicle that becomes more of a challenge and involves removing the ground cable from the powered battery ( vehicle wont be running) and applying the jumper cables to the 24V battery side( this is using two pairs of 12V 31S950 batteries in series to make 24V) actually what you are doing is just adding CCA's to the batteries that are on the truck, if they are completely dead I have never been able to make it happen(not for lack of trying).like i said before never tried this...so if there are two batteries side by side in series to make 24v, put one cable on positive(red) of one battery and other cable on negative (black) of other battery? and why are you disconnecting negative cable (to ground) of jumper battery? always jumped vehicles with engine running but if this is better way fine... Quote Link to comment https://www.bigmacktrucks.com/topic/28585-jump-starting-positive-ground-vehicle/#findComment-148646 Share on other sites More sharing options...
MACKS Posted November 29, 2012 Share Posted November 29, 2012 good point, if they were and the cables were hooked it could make a neat light show, and some welding noises in the cantact area. (not likely on newer plastic bumper crap)Don't ask me how I know,lol Quote Link to comment https://www.bigmacktrucks.com/topic/28585-jump-starting-positive-ground-vehicle/#findComment-148661 Share on other sites More sharing options...
609albert Posted December 1, 2012 Share Posted December 1, 2012 carl ,I only would need one side to do, a double rail stanchions and end pieces will work. Quote Link to comment https://www.bigmacktrucks.com/topic/28585-jump-starting-positive-ground-vehicle/#findComment-148826 Share on other sites More sharing options...
fxfymn Posted December 2, 2012 Share Posted December 2, 2012 Mike Yarnall has a set for you. You need to contact him. Quote Money, sex, and fire; everybody thinks everyone else is getting more than they are! Link to comment https://www.bigmacktrucks.com/topic/28585-jump-starting-positive-ground-vehicle/#findComment-149067 Share on other sites More sharing options...
rsb502 Posted December 3, 2012 Share Posted December 3, 2012 like i said before never tried this...so if there are two batteries side by side in series to make 24v, put one cable on positive(red) of one battery and other cable on negative (black) of other battery? and why are you disconnecting negative cable (to ground) of jumper battery? always jumped vehicles with engine running but if this is better way fine...ok is the truck 12v or 24v, i get that its positive ground and to jump a positive ground 12v truck you just need to put pos to pos neg to neg on the batteries, to jump 24v positive ground it gets tricky at best with a 12v vehicle if its doable at all. The reason to disconnect the neg on the powered vehicle (12v) when trying to jump a 24v is so that the 24v vehicle doesnt fry your 12v system when it starts. best to go get a jump box that does both 12 and 24v I have one and it works great. Quote "Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin"If your gonna be STUPID, you gotta be TOUGH" "You cant always get what you want, but if you try sometimes you get what you need" Link to comment https://www.bigmacktrucks.com/topic/28585-jump-starting-positive-ground-vehicle/#findComment-149180 Share on other sites More sharing options...
dek1581 Posted December 3, 2012 Author Share Posted December 3, 2012 ok is the truck 12v or 24v, i get that its positive ground and to jump a positive ground 12v truck you just need to put pos to pos neg to neg on the batteries, to jump 24v positive ground it gets tricky at best with a 12v vehicle if its doable at all. The reason to disconnect the neg on the powered vehicle (12v) when trying to jump a 24v is so that the 24v vehicle doesnt fry your 12v system when it starts. best to go get a jump box that does both 12 and 24v I have one and it works great.thanks for the info! Quote Link to comment https://www.bigmacktrucks.com/topic/28585-jump-starting-positive-ground-vehicle/#findComment-149218 Share on other sites More sharing options...
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