boiling batteries.

[tankie88]

I know my altenators are putting out a bit to many volts.But lately my batteries have begun to boil even after only driving a few miles.The rear battery boils more than the front battery.So i take it something in the altenator/s has thrown it hand in?Any body any ideas??

 

[CCATLETT1984]

what voltage are you getting at each battery?
if its more than 14V you need to have the alternators fixed, or you will start blowing and melting things.

 

[devilman96]

Yep... One or both of the voltage regulators is headed for the rubbish bin... Best find out what one it is quickly or it will be both for sure... Let me know if you need an alternator, I export..

 

[Michael]

I believe that you should see 14.4 to 14.6 volts at each battery. Anything less than 14 is undercharging. Be sure to use a quality digital voltmeter. From the TM20:

VOLTMETER IN RED (OVERCHARGE) ZONE (ALL EXCEPT M1010)
Step 1. Start engine. Check voltage at left and right alternators at positive (+) terminals.
Voltage should not exceed 16.0 at left alternator or 31.8 at right alternator.
If voltage is over 16,0 at left alternator or 31.8 at right alternator, replace
alternator. (See paragraph 4-2)
If voltage is correct, replace voltmeter. (See paragraph 4-9)

 

[acetomatoco]

Each alternator is independently internally regulated...check the output of each and replace the one which has the bad regulator.. as they are 12V units with isolated ground any local alternator shop should be able to fix it for about $35 Vermont Prices...

 

[tankie88]

I take it this is the offending item??.....

 

[Michael]

That is the voltage regulator as far as I know.

 

[ida34]

That is the voltage regulator.

 

[tankie88]

Right chaps,changed both voltage regulators,batteries still boiling and onboard volt meter still in the red.Any ideas??????

 

[gasser]

Check the voltage-sense wire; it's the red wire out of the "two prong" that goes into the top of the alternators. This is the 12v feedback to tell the alternators regulator to keep it at the 14v or so. If it's not making the connection, your regulators are going to put out the max ...

Also, when the truck is running, what do you get at each battery?

HTH,

-graham

 

[tankie88]

just tested both batteries while running..front batt,14.6 rear batt,14.7.Wiring to both altenators all tight.Onboard volt meter still in red.I wonder if all is ok but the onboard voltmeter is playing up.

 

[gasser]

14.7/8 is definitely the higher part of what I would consider safe then. However, across both batteries, it should not pass 29.6.
Well, something is not all OK because your batts are frying, but it could a previous condition with them that is now surfacing. Try swapping the location of the batts and if you got some extra ones to try out, put them in the mix and see if they boil over. However, 14.7 on each *should* not cause them to boil .. unless, again, if they are bad from the get go ....

-graham

 

[tankie88]

Is there any relays or gharging panel under the dasboard? After my M1009 starts up the lights flicker and there is a clicking sound coming from the drivers side under the dash or on the bukhead,while this is happening the needle on the voltmeter goes from in the red to in the green(click) and back to red.Anyone any ideas????

 

[gasser]

I believe that is the glow plug relay (just on the otherside of the bulkhead) ... you will *experience* that for a few cycles ... maybe for a total of 20 seconds or so. That 'red' is the draw side, not the over-charging 'red' that you are also experiencing, right ?

The alternators do have a set of the generic 4-plug relays, that are right under the dash, over in the STE plug area.

 

[tankie88]

Right chaps,1st thing in the morning..i get in and turn on ing(glow plug light on)..wait(glowplug light goes out)...start...(voltmeter in green)....click from somewhere(lights flicker,voltmeter in red)...click(voltmeter in green)...seconds later click..(voltmeter in red) and stays there. iv've swopped the relays around ..no change.GRRR.

 

[Michael]

If you mean that your dash volt meter is staying in the red on the high side, then it could be that the clicking that you hear is the glow plug relay coming on and the load of the glow plugs is causing a voltage drop that is pulling the voltage down into the green and when they turn off it is going back into the high side red. It is normal for the glow plugs to cycle on and off for a few times until the engine warms up.

The real question is whether your charging system is putting out excessive voltage or not. It will take precise voltage measurements with a quality digital voltmeter to be for sure. The numbers you gave before do not seem to be too high therefore I am thinking your gage is broken.

 

[tankie88]

But a broken gauge won't make the batts boil..will it???

 

[CCATLETT1984]

NO

 

[Michael]

Applying 14.7 volts across a good battery won't make it boil excessively either. Just how much boiling are we talking about? It is normal for a battery to bubble as it charges. If it is bubbling a lot at 14.7 volts it is either discharged excessively or has gone bad.

 

[tankie88]

truck running,i get 14.62 on the rear batt and 14.20 on the front batt.