smoking batteries

[porkysplace]

You started this thread
923a2 wiring voltage question A month or so ago and never updated it , did you install the 12v lights ?

Depending on how they were wired it could be part of the problem.

Edit; this thread will give you directions to the electrical trouble shooting section and schmatics
[h=1]m939 series schematic[/h]

 

[mcmud]

You started this thread
923a2 wiring voltage question A month or so ago and never updated it , did you install the 12v lights ?

Depending on how they were wired it could be part of the problem.

Edit; this thread will give you directions to the electrical trouble shooting section and schmatics
m939 series schematic

Yes, I did the install. I pulled a single (16gauge I believe) wire to a fuse block and from there to the lights. The lights work great, I have never had any issues with them. I will check the schematics after i post this reply. I just had the chance to check all the voltages with a digital multi-tester. All of the volts seem right. The batteries individually are all just slightly above 12 volts which I understand is normal. I then tested the two series, running at 24~ volts. I then turned the engine on and let it warm up and run. got to 26.9 for the first bank and 27.1 on the second. The dash gauge stayed with in the green marks also. Could this have just been a fluke thing?

 

[juanprado]

Put a load test on the batteries. It could have 12v and drop down under load. Need to have 2/4 good batteries that load test ok before checking alt voltage/regulator.

Harbor freight sells a cheap battery load tester & voltmeter that I call the bread toaster as it has open coils and heats up when it does the load test. Perfect for browning your toast when camping

 

[mcmud]

I was thinking of installing a small bank of voltage meters. One for each battery and one for each bank, 6 total. I know it's a lot but this way I can keep real time info on all of the connections. I figure better to be safe than sorry. When I checked the voltage yesterday everything came back within spec so I don't really know where to start with this now. I guess just keep a very close eye on the battery gauge and watch and check for smell while I drive.

 

[juanprado]

You might only be reading surface voltage on the batts, that does not tell you if the battery can handle the amps it was designed for.
I have seen 12.5 volt battery drop to almost nothing when a load is a applied.

 

[mcmud]

I used the multi tester, is that the same? The voltages stayed the same between them all connected, disconnected, on and off, running cold and hot, with all the lights and the cb radio running too. I'll see about the load tester at harbor freight when I get off work. Is that different than what I used to test?

 

[porkysplace]

I used the multi tester, is that the same? The voltages stayed the same between them all connected, disconnected, on and off, running cold and hot, with all the lights and the cb radio running too. I'll see about the load tester at harbor freight when I get off work. Is that different than what I used to test?

No it is not the same , post #1 of this thread has a link to what you need .
[h=1]New 85 M1009 24V 6.2L owner starting issues?[/h]Adding a small bank of voltmeters would be counter productive in my opinion as it will give you that many more places for problems to occur . You need to find the cause of the problem ,which may involve a lot of troubleshooting.

 

[SCSG-G4]

Since both the banks of batteries are hooked to the same thing, there should not have been any difference in the voltages. If you are consistently getting 26.9 on the first bank and 27.1 on the second bank, you have a weak battery in the first bank. And what has been posted about surface voltage and discharge voltage is spot on. A battery that reads good under a very light load may drop almost to zero when placed under a starting load. And when both banks are hooked together, some of the power you want to go to the starter instead goes to the failing battery, which drops the overall voltage too low to start the engine. Then when you do get it started, the alternator tries to bring things back up to full charge as quickly as it can, which results in overcharging the good batteries, causing them to boil over.

 

[mcmud]

That makes sense. Would the truck have trouble starting if one bank is bad? It starts immediately every time and drives perfect. What is the procedure to find out which one is dead if they all test within normal volts for me? Should I test amps?

 

[porkysplace]

Take out all the batteries make sure they are fully charged and load test individually.

 

[mcmud]

Ok. I'll try to get to that tonight and post the numbers. If not tonight then Friday evening

 

[mcmud]

So I checked everything I could think of. I checked the volts on the batteries, both in series and separate. I checked the load test on them too, both while hooked up and taken apart. I checked the charging system as well while running, both warm and cold, at idle and high sustained rpm's. I, against the advice of this column, drove it to see if I could recreate the problem and I couldn't. The battery meter on the dash stayed at the mid to low part of the green section. As far as I can tell, it's running fine now. Could this have been a fluke? Just a one time thing?

 

[Artisan]

Are the batteries strapped down solid? Is it possible when you went for that cruz
one or more of the batteries jumped up and caused issues?


FWIW I have a Big Cam 400 in my M916 and w/ 2 Sears B-14 Batteries it starts FAST
and it spins QUICK while doing it. Just 2 Sears batteries...