M109a3 batteries dying

[Last Man Standing]

I have an issue a need some help with. About 8 mo ago the truck started to turn over slow. I charged the 2 military batteries that came with the truck over night back to full power. I also replaced the batt terminals to ensure a nice fit. After a re install and a few days later things seemed ok. I got on the highway and drove about 8 miles to a fuel station, parked and fueled up. Got back in , turn on accessory key then pushed the button and....one slow turn and nothing....dead. A jump start later and drove home. I did the recharge thing again and it seemed fine for about 10 days and then DEAD. Got myself 2 new group 65 from advanced auto and did a nice install. Truck spun over very fast and off I went! This truck gets started about once a week foe 5-10 of run time. All has seemed well for a few months ..until 2 days ago...I let the truck sit for 2 weeks with no start up...got in..and it turned over a little slower than normal. I drove her down the road about 5 miles, parked for 5-8 min tops.. I did leave the accessory key on by mistake. Got back in and pushed the button...one slow turn...dead! Disconnected one battery, put cables on it for 5-10 min..reconnected and it fired right up. Another 2 days pass and all good. Got in the deuce today to fuel her up. Started right up without incident, all systems looked ok, and off to the same gas station same route I broke down at a few months prior. I got there, shut down, all systems off...fueled up...key on...pushed button..one slow turn and dead!!!!!! quick jump on batt and home I drove all P O d....lol

Any and all help would be grateful


Tim

 

[Jeepsinker]

Stop shutting it down until you are done with it for the day. Not being mean, that is just the best way to run one of these trucks. No reason to shut down a diesel for a fuel stop anyway. I leave mine running when I go in and shop at Walmart, when I go in to eat at restaurants, really anything. Check the battery voltage at the battery terminals with the engine running. You should see at least 28 volts. Sometimes the battery gauge on the dash is generous and will say all is fine when voltage is actually low.

And you should know by now that this should have been posted in the deuce forum, not here.
Mods please move this.

 

[Mike929]

Stop shutting it down until you are done with it for the day. Not being mean, that is just the best way to run one of these trucks. No reason to shut down a diesel for a fuel stop anyway. I leave mine running when I go in and shop at Walmart, when I go in to eat at restaurants, really anything. Check the battery voltage at the battery terminals with the engine running. You should see at least 28 volts. Sometimes the battery gauge on the dash is generous and will say all is fine when voltage is actually low.

And you should know by now that this should have been posted in the deuce forum, not here.
Mods please move this.

On the recovery of my M109A3 from Ft. Hood, they gave us a jump start and on the way back to DFW we left it running when we went into a Wendy's to eat. Brother didn't think twice about it, but it was a new experience to me. (i.e., I was a little uncomfortable)

Also left it running when we topped of the tanks, but that wasn't as weird to me for a diesel.

This truck seems to have a short of some kind that drains the batteries faster then the solerizer can charge them. Plan on putting in a battery cutoff as a short term solution to keep my batteries from being drained, and provide a basic security solution over and above the chain. Shouldn't be too hard to track down a short on a deuce, just been busy with my other trucks.

 

[gimpyrobb]

Sometimes the alt can have something go wrong in it and it will keep a drain on the batts. With the power switch off, check to see if there is a drain on the batts. If so, start with disconnecting the alt and see if it goes away.

 

[Recovry4x4]

OK, got it moved into the proper forum. Do you have a volt meter? Need voltage across both batteries with the truck running and with it off. We can go from there!

 

[huggy]

Yep, the alternators can be the problem for sure... I just got done jacking with one of the 3 cucv's I own now. The one I had the same problem with is a M1028 Dually I just got a few months ago. I replaced the alternators today and the problem is gone. I checked it with a test light as soon As I replaced them. Pulled the positive cable off and connected the test light to the cable and touched the positive post that it was hooked to, that when it was drawing the power out it lit up. Indicating a short. Well it was not doing it any longer. Take them off and have them checked by a reputable rebuilder. They can tell ya if they are the problem.

 

[rustystud]

Do you have a battery minder on your truck ? If not buy one. If you do, check the fluid levels of your batteries. You might be overcharging them. This can come from the alternator or battery minder. Either way, you should be checking the fluid levels monthly . At work we check the battery levels every 3000 miles (which happens every 15 days). It's also in the PM's .
On the opposite side, your alternator might not be putting out enough voltage. For proper charging on a 24 volt system you need between 28v to 30v (30v if using "Odyssey" style batteries).

 

[Last Man Standing]

I want to thank everyone for their input and ideas. After testing with multi meter..volts holding at 24.2 running or not with slight drops. As i was getting ready to pull the generator..to my surprise 2 out of the 3 bolts that hold the dam thing on are missing! it was hand loose and belts slipping when idle up! Looks like the last owner hmmmmm.... sheared of the top bolt in the water pump and just left it lined up loose. I removed the radiator to get at it properly. Drilled it out, used a tap and put in new bolts. While I was in there a changed the two belts as well. Did a re test with it running and WOW...28.6 volts!...I feel dumb.

 

[Jeepsinker]

Glad you got it fixed. Better than having to buy an alternator!

 

[Warthog]

Always seems to be the simple things. Glad you figured it out.

 

[Karl kostman]

I had a similar experience to yours concerning batteries draining it was on a 925A1 the batteries looked brand new so I just put the charger on them and slow charged them for a few days went out to start the truck it took right off and all is good right? NOT!!! After messing with this situation for a while I finally did a load test on the batteries, one at a time and found that 3 out of the 4 were bad, I pulled them out of the truck and found the dates, well even though they all looked brand new according to the dates they were all about 6 years old and 3 out of 4 were shot. I replaced the 4 with 2 new 6TLs and have never looked back! Glad you got your problem fixed!
KK