Charging system

[manvstaco]

Hello all! I just recently received two m998 Humvees from Govplanet, one with 3,700 miles on it that runs(did run lol) and one that is 50k unknown atm but in great condition.
The one I'm working on it started and ran just fine but would go in the red zone(maxed out) for the charging gauge, then you could hear a click after you hit the throttle and it would go down in the yellow( the alternator would stop charging and just run on batteries). I did a voltmeter test off the leads on the alternator and was getting 24v, and nothing on the 14v post, I took this as an indication that my voltage regulator might have crapped out on me so thought it was a good idea to charge the batteries over the next few hours. Connected the charger to one battery at a time to keep things at 12v(was dumb and didn't disconnect them from the humvee?) The charger box did it's deal and indicated that both batteries were bad at end of charge(weird they were just working?) Disconnected the charger around 11pm and check things this morning and what do you know? Two dead batteries.. just swapped out the batteries from the other humvee(they are much newer and held a charge without the charger saying they're bad)and all I get is clicking from the smart start box with no glow plug light illuminated. 19v across both posts when installed.

Did I fry the smart start box because of how I charged the batteries possibly? I do have another I can try if that's the case

I did accidentally leave the hood up and got about 4 inches of snow on all the wiring under the hood, maybe that's the issue I hope? lol sorry for all these noob questions. I put about 10k on one of these during my 2003 iraq deployment but was stuck running security with the maintenance team wrenched on them so I'm clueless.
Any feedback is appreciated
Will post pictures soon!

 

[jeffy777]

I like to be a little focused on my problem (cause I am a stupid nuub) and you are introducing problems. There is no doubt there are tests to check the smart box. You may have fried it. But first what I would do is get a 24V Charger. I bought and used a Schumacher SE-3000 1.5-200 Amp Manual Fleet Battery Charger which has a 24 volt system on it. Be careful you hookup the cables correctly. I imagine Humvees are generally the same and they are two 12V in series. So it is the Negative that is not connected to the other batteries positive and and the positive that is not attached to the other batteries negative. (At least that is what I have done.) Mine started after about an hour of charging.

 

[Action]

jeffy777,
the negative of one battery is the negative for the system.
The positive of the other battery is the positive for the system.
The positive of one hooks to the negative of the other.

manvstaco,
is anything hooked up to the 14v stud on your alternator? If not, it should have a wire hooking it to a stud on the regulator.

 

[jeffy777]

There is probably someone better to answer the question. But I am headed home and I will try to get some time to look at the manuals to see if I understand 14v stud. If you get the batteries fully charged and it starts and runs for a few minutes and then run down. Then it is probably your alternator. But I have read the grounding is a big issue with the HMMWV and you may have a grounding issues that is causing all of this.

Hopefully one of the smart people on the board respond. I am a nuub too. So the blind are leading the blind right now and that is probably not the best idea.

 

[kfrosty]

Man,

I had an alternator that was similiar, it would start in yellow, go to green and then red and come back. At some point it would hit 32v's.

When you hooked up the charger, was it a 24v or a 12 volt charger? If 12, did you disconnect the positive to negative cable?

Check the batteries individually, they probably should be above 12 if they are good. if they are under 12, charge them individually and see if you can get them to hold a charge above 12.

As for the box, make SURE you disconnect your batteries before switching them out or you'll fry the other one.

If running, your alternator should be putting out around 27 volts, not 24. So if you were reading 24v running I would suspect the alternator may be bad.

Personally if you have a good alternator and good box, I would start with that. If you get 27ish volts at the alternator, make sure you are getting it at the batteries as well when running.

 

[manvstaco]

Thanks for the relies so far guys! I'll go at it again tomorrow morning and see I can accomplish. I have a sneaky suspension I might have a couple bad batteries and out of the 4 I'm sure I can get two working properly.
First things first, I'll make sure I can get the voltage up to 24v or 12v per battery. I have the batteries disconnected and charging them individually since I can only charge 12v currently. {pictures as promised!

 

[manvstaco]

Well, I got her started and now I'm troubleshooting the charging system. 24v at the batteries when not running, 33v at idle, then up to 38v when I hit the throttle. I have the 200 amp alternator so it's not adjustable correct? What should I do next? Do I need to replace the voltage regulator on the top of the generator? anything free I can try? My other humvee has the smaller adjustable generator on it so I don't think I can swap the two without changing out the wiring harness? more pictures

 

[jeffy777]

Nice going. Good looking rigs.

 

[jeffy777]

Ok, the batteries are charged and it runs. Great job. I would not assume you have a charging issue or any other issue. The guy at Gov Planet when I picked up my HMMWV said they get it going. Meeting the commitments of certificate of what they said when you purchased them(period). This is kind of a hard issue because you buy and so many months later you pick it up. They may have just jumped it with another HMMWV and got it started. When you picked it up it had been turned over and was in a good technical position (residual fuel pressure, warm engine, oil well circulated) for starting(requiring little amps). So you got it and a battery was bad or low and you started it up and it behaved as any old vehicle with a very low battery.

Are the gauges acting weird after the HMMWV warms up now that you have two conditioned batteries in it?

 

[manvstaco]

I still have yet to see the temp gauge move, but I am feeling some heat from the heater when it's on for a bit. I haven't really ran it for more than a couple minutes at a time as I don't want to damage anything with the voltage being too high.. So yesterday when I was fiddling with things it would disable the charge entirely running only on batteries when I had one bad one installed, but now it will at least stay stay charging @33v idle now that I think I have two good batteries installed. each battery still reads 12v when I check them, do you think it's possible i still have some crappy batteries and that's why it's overcharging? I'm seeing it go as high as 38v when I give it throttle.

 

[Action]

33v - 38v is too high. Bad things can happen if you continue to over charge batteries.

It may have no effext on the 28v output, but the 14v tap should be grounded if not being used. Run a wire from it to one of the four regulator mounting bolts and check the volts at battery again.

 

[jeffy777]

I have never read the voltage on my batteries while running. I would imagine you would get a false number as the voltage would appear odd because you were not looking at the voltage of the batteries but looking at the voltage of the operating vehicle which may swing. If the vehicle is in good shape can you drive it around the neighborhood, like 10-15 minutes and then park it start it tomorrow. What does the voltage dash gauge say while running awhile. You may not have a problem other then the battery was old.

 

[manvstaco]

Yesterday the voltage gauge was pegged at max in the red zone when the batteries were super low on charge then it would stop charging all together after i hit the throttle. Now, today with the batteries charged which I believe to be "good" I have the voltage gauge in the low red zone around 33v @ idle with my multimeter. I'm still wondering if the batteries are not doing what they should and it's wigging things out.

So you guys think I should try grounding out the 14v post on the voltage regulator then and check the voltage at the batteries again?
Is 33v to high to drive around the neighborhood for 10 minutes or so to see if the thing starts behaving better?

 

[ryanruck]

Yesterday the voltage gauge was pegged at max in the red zone when the batteries were super low on charge then it would stop charging all together after i hit the throttle. Now, today with the batteries charged which I believe to be "good" I have the voltage gauge in the low red zone around 33v @ idle with my multimeter. I'm still wondering if the batteries are not doing what they should and it's wigging things out.

So you guys think I should try grounding out the 14v post on the voltage regulator then and check the voltage at the batteries again?
Is 33v to high to drive around the neighborhood for 10 minutes or so to see if the thing starts behaving better?

If you suspect bad batteries, take them to your local auto parts store and have them tested. Individually they are 12v and no different from any other car battery (aside from being AGMs) and, the test equipment will indicate if there's any issues. Since you're getting 24v measuring just the battery voltage my gut says there's an issue with the regulator. I'd start with the batteries and go from there however since testing is free. 5v high is getting a bit "hot" for 24-28v systems which will have some built in natural tolerances. 38v is definitely too high. I wouldn't drive it around with those types of voltages until I had the issue ironed out or you risk burning things out which can get expensive quick. New and used replacement dual voltage regulators are all over and aren't all that expensive compared to what it would cost you to replace components burned out from overvoltage.

A side suggestion, I would suggest that instead of just grounding out the 14v output, get some 0 AWG wire and connect it up to the rear battery as it was designed to be. You've got the dual voltage setup, I don't see any reason to not take advantage of it since it will allow you to safely run 12v accessories on your truck without causing battery imbalance.

For what it's worth, my truck came with the 14v stud not connected to anything either and my truck did not have the issues you're describing. I hooked it up to the rear battery for 12v accessory use. When the warm weather rolls around again, I will be installing a 12v power block in my truck.

 

[Action]

if you have the military 6TL batteries, check the water levels.

 

[Retiredwarhorses]

Your regulator is shot....your going to blow up your batteries if you keep running it at that voltage.
27.5 is where you should be.....it's not adjustable on the 100/200amp.

 

[manvstaco]

Roger that.. So I just need to replace this one component before proceeding?

 

[ryanruck]

Yes but no links to eBay listings so you might want to delete that.

And shop around. That price is high.

 

[mechanicjim]

on the alternators manufactures website are troubleshooting guides for the alternator/Regulator, also the installation instructions.
the website is "http://www.ceniehoff.com" the documents are under the Service and Support link at the top.
N1225/N1387 Alternator Installation Instructions (II225A)
N1225-1/N1237-1/N1505-1 TG (TG0017B)

 

[manvstaco]

Swapped out the batteries and voltage regulator for new, problem solved thanks guys!