M923A2 - Are all 4 Batteries required to start the engine?

[sold4less]

Could I get away with just 2 batteries to start the engine? Any wiring diagram for this setup? Thanks for you help.

 

[rhurey]

Yes, only 2 are needed.

Depends on the battery size, but even 2 of the original 6tmf's are enough to start it.

 

[sandcobra164]

I start an engine nearly twice the size with two batteries. Anything under 50 degrees requires about 30 seconds of cranking for the NHC-250. I've read the 8.3's in the A2's are much easier starting so I'm sure you'll be fine with two batteries so long as they are 750 CCA or above.

 

[big block 88]

Been done several times on here. Do a search and read.

 

[kdaniels]

Brought both of my 5 tons (M923-M923A2) home on two batteries. Like Sandcobra stated ...cold weather will hurt you with only two as far as cranking time goes.

For two Batt's your red (main) cable goes to one positive terminal and your ground (black) cable goes to your second batt's NEGITIVE terminal, then use one of your left over short sections to connect to your remaining positive and negative terminal's. You will need to look at your cable and terminal positions to get your batteries in the proper position so that your cables work out right. It's very easy to do, but these aren't like AA batteries in weight so watch your fingers.



SEMPER FI


keith

 

[tobyS]

We seem to always have one of four that will not hold a charge. Take the terminals loose and check voltages. Use the highest 2 and charge them if you have a chance. They connect in series + - + -. Remove everything else, including the slave port wires.

I've found some slave ports with corrosion up in them where the poles are in close proximity and they "leak" across a short surface in humid environment, which will drain a battery. Keep them hooked up if you are using slave cables but check to see if there is corrosion first.

Until the very coldest of weather, 2 should work fine. I use 2 of the 8D 1400 cca bus batteries when I replace them....good deals on them at Oreilly.

 

[Coffey1]

Cold weather two battery start works better with your ether bottle.
Hit button for 3 seconds she will start.

 

[Ue413]

I almost always use two. I have two as a back-up that I will use to help (connected with jumpers) in cold weather. The newer turbos hardly ever need the help, just the nhc250

 

[74M35A2]

I run 2 group 31 conventional semi-truck batteries on my 8.3 in MI. It starts great, even down to negative temperatures. They are very low cost, and free up a bunch of room. Batteries more than 5 years old should be replaced even if it seems they crank OK. The 8.3L fuel stop solenoid is weak in that as system voltage drops during cranking, the fuel stop solenoid moves to the engine stop position, causing a no start situation. Cranking speed will seem fine when this is happening.

I did 2 group 31’s and a civilian alternator years ago, and have not looked back. Don’t need a battery charger, slave jumps, etc....

 

[lindsey97]

2 group 31's work good, but are taller. Be sure to secure your batteries, and insulate the posts to avoid contact with the seat lid. My personal favorite for space and cranking amps is (2) Interstate MTP-65. They give 1000ca each, and are shorter than group 31's. Interstate also has a very good warranty; I have gotten 5-6 years of use out of a set, sometimes more.

Consider fixing/verifying that your ether assist works, and also install a coolant heater into the engine block. Quick, simple, and very effective.

A2 trucks work better with 2 batteries than a NHC-250 equipped truck, but the NHC-250 is a 14 liter engine versus an 8.3l in the A2 variant.

 

[simp5782]

I went to 8d's. Two of them from batteries + bulbs is 265 for the pair. I carry 2 extra in case of emergency and jump starts on remote trucks. I have also tested the battery capabilities as far as endurance. I can run on just the two 8Ds for 100mi with no alternator charge. With lights on and heater unit on low and still be able to restart after shutdown.

Sent from my SM-G935P using Tapatalk

 

[guyo]

Could I get away with just 2 batteries to start the engine? Any wiring diagram for this setup? Thanks for you help.

I did it on my m923 a2 and I love it. The stock Napa replacement batteries are just as crappy as the ones we had in the military. I used two huge R.V. batteries and it starts and never leaves me wanting a jump. I have had it this way for 2 years now flawless.