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How can i jumpstart my 5ton with 12v system

NovacaineFix

Member
662
1
18
Location
San Diego, California
Like Rosco said.

You can try to charge the batteries individually, but not as they are installed in the truck, at least not without disconnecting the cross-over cables that go from negative of 1 battery to positive of the other battery.
If the batteries are too far gone, they may not take a charge at all.

Check the surface voltage [voltage of the battery as it sits] with a voltmeter, should be at least 12.4 volts maybe 12.2 if it's cold. Then try taking a voltage reading with a small load applied to the batteries, if they drop below 11 volts, they are pretty much toast.

good luck
 

84crawling

Member
39
0
6
Location
Mt.Holly, NC
If it's the older 5tonn with stick pull start it with the f350..I did it with my deuce when the battery died in a parking lot.


Sent from my iPhone using Tapatalk
 

gimpyrobb

dumpsterlandingfromorbit!
27,786
755
113
Location
Cincy Ohio
Measure each battery and charge the one thats lowest first. Then charge the other. If they don't read 12.xx at rest(after charge), they are toast.
 

Trailboss

Well-known member
Steel Soldiers Supporter
1,577
138
63
Location
Norwood LA
You could use a jump cable from the F350 to boost one weak battery when starting, but unless you isolate the 5-ton batteries, you cannot use jumper cables to charge two 5-ton batteries from your two F350 batteries.

You could get the F350 running, then disconnect the second battery (careful to keep the positive lead wire from grounding), and use two jump cables to boost two batteries in the 5-ton without isolating the 5-ton batteries (only one 5-ton battery will charge, and the other battery will equalize slowly with the disconnected battery). If you have a 2-battery setup in your 5-ton instead of the stock 4-battery system, this might provide enough juice to start it.

The best bet is to use the 2 battery chargers to charge the 5-ton batteries 2 at a time. You don't need to isolate the batteries, just go from one charger to one battery.

I've changed my 5-tons to two type 31 batteries from the 4 stock batteries. I haven't done it yet, but I've kept in the back of my mind that I could use two 12 volt cars with two jump cables to boost one battery each from the separate cars to start my 5-ton with weak batteries.
 

wcuhillbilly

Member
421
5
18
Location
Devils Tower, WY
I cant vouch for the newer 5 tons with the electronics but my older 809 series is very easy. what worked for me when my mil batterys went south was to take the mil slave jump cable and remove the mil ends and add clamps like any other jumper cable. I found the battery on my Dually-Cummins that my alternator was dumping voltage into and attach to that battery, then I would attach the other end to just one battery.. actually didn't have to isolate the 5 ton batterys (however I did not turn on the 5 ton battery switch) and would charge each battery for a while. then I would attach to the battery that the trucks supply cable was hooked to. Now I would turn on the 5 ton battery switch and hold my tongue right, cross my fingers and toes, and light the fire.... worked for a while but I knew the OEM batterys were going south.

Final fix was to gut the battery box and weld the two together, forming one big box, remove the ribs in the bottom, line it with plywood in the bottom and install 4 Group 31 DEKA 1000CCA batteries. Fabb up a hold down and check/replace all the link cables that make the connections to the batteries and the truck.

Side note, (disclaimer) my Dually(sig line below) does not have the electronics of todays new vehicles, I have done this method while it had an ECM and was under the control of the notorious VP44 injection pump, and also now as its a completely mechanical P7100 pump on a 24v Cummins 5.9. The final trick was that I had swapped out the alternator to a Delco 22SI and not the factory Dodge Nippendenso or Bosch alternators
 

BR1

New member
4
0
3
Location
Clyde, TX
I've jumped my 5 ton with my little 4cyl. Toyota pickup and regular jumper cables. Positive on one battery, negative on the other battery, and then waited a couple of minutes; fired right up. I don't know if it makes a difference, but this was my scenario; the emergency engine stop wasn't working properly, I didn't realize that it was engaged, I had tried to start it multiple times and just ran the batteries down to low to crank the engine. My 5 ton only has two batteries. It's a work in progress and learning experience.
 

emr

New member
3,209
25
0
Location
landing , new jersey
Charge both batts same time in the truck, Remove nothing , U can jump with 2 batts using 2 sets of jumper cables, 2 separate cars will do this.. Its not rocket science , LOL Never have to remove anything to charge em in the truck with a batt charger on each batt, If you had only one batt charger you could just charge one at a time in the truck, Same thing, The second batt will take some charge but will NOT fully charge so you need to move the charger to the other batt when the first one is charged, This can be done with 4 batt set ups also.

FYI, The bad batt is the one that is at the end of the charging system . Charge that one first and make sure it will take a charge if you only have one charger, The last batt is never fully charged in these trucks, therefore they sulphate first and die first. these are not smart charging systems and I don't know of any smart charging systems in any vehicles, Its like filling a pool, There is over flow to the other batts, But when they are close to charge the resistance is strong enough to shut charging down, Because to fully charge the batts in back you would have to over charge the first batt, 973 219 4499 if U have any other questions, A good running truck does not need much of a boost in mild temps to start it, AKA The guy with the little battery in the Jap truck jumping His Mil Big batt truck,
 

74M35A2

Well-known member
4,145
330
83
Location
Livonia, MI
Two choices, as mentioned above:

1. Jump one or both parallel MV batteries from the running 12V truck, and crank. This will be 50% effective, and may be enough.

-or-

2. Disconnect MV batteries, and fast charge them from the idling 12v truck by connecting them all up parallel and going to lunch. Come back, disco 12v vehicle, connect up MV batteries as intended, and away you go.

I have witnessed a battery explode during just regular cranking right around freezing temps. I then understood why batteries are usually encased in a steel box. It sounded like a hunting rifle echoing through the woods, it was that intense. Nothing left but the cables that went to it. If a battery was discharged and then froze, it pushed all the plates around and is likely shorted out, and no good.

A battery is just an energy conversion device. It converts potential energy into kinetic energy. Think of how much energy is in that little box to crank over a big old 250 engine? Be scared and respectful of batteries, just like a running chainsaw. I hate batteries ever since witnessing this happen on my dad's 24v backhoe. At a minimum, wear safety glasses, look away, close your eyes tightly, or put the door in between you and the battery bank before cranking. I will never forget what I saw happen, completely unexpectedly. I wish all of you could have seen it to become scared too. I do HD starters for a living, and I hate batteries.
 
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