Battery boost without slave cable

[Col Batguano]

M151A2 will not start battery charge shows yellow near red on the volt meter. How does one jump start the M151A2 without a slave cable ? Thank you. Rob

[Horst]

With jumper cables connect directly to the battery and ground.

151s without a heater don’t even have slave connector!

[Hambone]

Your boosting source will need to be 24v, so 2 12v batteries in series.

[Col Batguano]

Thank you for the replies. Forgive my ignorance, how does this work ? I know how to boost a car with a single battery but there are two separate batteries. Can someone explain the procedure/hook ups ? You will need crayons to draw me a picture lol. Thank you

[Mr. Recovery]

Just use 2 Batteries on the floor hooked up the same as the 2 in the mutt.

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[Mark]

2 Batteries connected in series, the 2 outside terminals + - are what you hook up like a 12 volt battery

[rickf]

Take two batteries, connect the positive of one battery to the negative of the other battery. Now available positive of the one battery and the available negative of the other battery are your 24 volts. IF you have another military vehicle that is 24 volts then it is basically the same as jumping a 12 volt car, Your hot cable goes on the positive terminal of the starting vehicle and the negative cable goes on the ground cable terminal of the starting vehicle. On the dead vehicle the hot jumper cable goes on the positive battery cable on the battery and the negative cable goes on either the negative battery cable terminal of the battery or a good ground on the vehicle.

[m3a1]

What I have read thus far might all be negated by a bad battery (or even two bad batteries). If you have a 12v charger to charge your batteries individually in the Mutt, make sure your vehicle's master power switch is off. Disconnect the jumper leads that connect the two batteries in the middle. This is not 100% necessary but more of a 'just in case' thing to do. Buy a load tester from Harbor Freight, if you don't have one. You should have one! Now, load test each battery. Yes they will probably both read low but if one has a fault (shorted out) it will show you that and you really ought to figure that out before wasting a bunch of time trying to jump start it. If both batteries read low, just charge each one up. At this point, if you have disconnected the jumper lead, you can charge each battery individually with a 12v charger without fear of getting your charging efforts involved with the rest of the electrical system (which may have a fault of its own, right?). Just remember, 'smart' chargers cannot be coaxed into charging your battery unless you have something like 3v minimum.

[Col Batguano]

Thank you very much everyone great information and clearly understandable for an old Grunt like myself ! Off to buy a charger and load tester.

[Col Batguano]

Battery load tester read that one battery needs replacing, the other is good to go. The battery charger 12v also indicated the battery was lame. Although I could get the lame battery charged enough to fire up the MUTT. The battery is obviously at the end of its life and probably will not hold a charge for long. My question is, do both 12v batteries need to be from the same maker, or can I have two different manufacturers 12v batteries used in the MUTT ? Thank you

[rickf]

It is best to replace the batteries in pairs so that they are equal in voltage and amperage. In any series hookup if you have one low battery then the charging system will be trying to bring the total system up to 28 volts and in the process it is cooking the good battery. And a hint on battery chargers, watch yard sales for an old fashioned marine or auto charger. Make sure it is an automatic charge type but NOT a digital charger. The old ones will charge the battery even if it has 1 volt in it and they will slow charge it for a couple days if need be and level off to a float charge when fully charged. I have brought several batteries back from the dead this way.

[m3a1]

I'll weigh in here because I found myself in a similar situation on several of my 24v vehicles. Rick is correct (and you often see a cascade of failing batteries in electric golf carts for this very reason...ask me how I know)...

...BUT...

Yep, you know I like big BUTs and I cannot lie!

You CAN get away with mix-n-match batteries for a while, if you wanna give that a shot and if your remaining battery is still hardy enough to take the beating.

Here's what ya do. Buy your new battery. Then, as soon as practicable, buy another just like it and put it in the Mutt. Then, you'll have a matched set and all will be well. Keep the second old battery around for a back-up. I have several batteries laying around here that I've kept after experiencing the same circumstances you are experiencing. I use them for running portable electric winches and what have you. One was made in 2002! Yeah...it's 22 years old!!!!

Point is, your present situation is not all bad and the storm has passed for now.

Plus...you now have your very own load tester...which is a must-have item for anyone running multiple batteries.

Cheers,
TJ

[Col Batguano]

It is decided then ! I will replace both batteries with the same maker and as suggested keep the good one as a spare. Thank you for the help guys, love this site ! Great support and information. Have a great day. Rob

[glcaines]

As Rick mentioned, always buy the batteries in pairs. However, always check the dates on the batteries. Several years back I purchased two new Interstate 6TLs for my M35A2. After checking the dates I found that one of the 6TLs was 2 years older than the other. I returned both batteries and had to wait 3 weeks for replacements with similar dates.

[Col Batguano]

As Rick mentioned, always buy the batteries in pairs. However, always check the dates on the batteries. Several years back I purchased two new Interstate 6TLs for my M35A2. After checking the dates I found that one of the 6TLs was 2 years older than the other. I returned both batteries and had to wait 3 weeks for replacements with similar dates.

Thank you