CUCV-II/CUCV2 battery issues

[reliabledan95]

To any one whom might know, I have a cucv2 and I'm having issues with my battery's draining. I've gone threw about 6 battery's in the last year or so. This problem is starting to be a hassle . The last time I changed out my battery's I checked my alternator and it had gone bad, so I changed it out. But the problem is that my battery"s are still draining . I starting to think it might be a relay, but I'm not sure were to look. If anyone knows about how I can fix this issue please HELP.

 

[blueblaze]

I'd start pulling fuses and checking the battery for the drain to see which circuit is the cause.

 

[Stonepicker1]

How bad is the drain? If it takes 3 or 5 days to kill the batteries, you will need to move the "blackout switch" down from the up position. Just flip it up before you drive.


http://www.steelsoldiers.com/showthread.php?116374-CUCV-II-won-t-start

 

[Warthog]

How bad is the drain? If it takes 3 or 5 days to kill the batteries, you will need to move the "blackout switch" down from the up position. Just flip it up before you drive.


http://www.steelsoldiers.com/showthread.php?116374-CUCV-II-won-t-start

Very true.

Stonepicker for the right price I can tell you how to fix it.
You will however loose the B/O function

 

[Humvee1538]

Mine had the same problem, replaced the black out light switch and solved the issue.

 

[reliabledan95]

So it's the switch the one that goes to service lights and black out lights

 

[Nico]

Hi!
I got the Draining Problem also.
I fixed fuse problem on the Resistor that cause the "no charge" issue for the Passenger batt. (14,4V on the passenger batt. while engine / gen. running.)
But i still can`t start after a few day`s without charging the battery`s first.
Warthog, as far as i understand you bypassed the B/O light`s to prevent the draining of my truck batt. aren`t you?
I bought 2 of the CTEK Monitor Battery Sense for each Battery to check what is the status easy with my i phone.


After a few days of testing it showes that passenger Batt. is still the problem:

This is the Passenger batt. after a night without connected to a batterycharger:



Any idea what to do next.

 

[bikeman]

For what it's worth, the CUCV II/Navy Chevy truck that my unit in Korea picked up from DRMO, had a master kill switch in it. The drain was bad enough that if you left it for a few hours you could get to a no start condition.

 

[Stonepicker1]

Hi!
I got the Draining Problem also.
I fixed fuse problem on the Resistor that cause the "no charge" issue for the Passenger batt. (14,4V on the passenger batt. while engine / gen. running.)
But i still can`t start after a few day`s without charging the battery`s first.
Warthog, as far as i understand you bypassed the B/O light`s to prevent the draining of my truck batt. aren`t you?
I bought 2 of the CTEK Monitor Battery Sense for each Battery to check what is the status easy with my i phone.
View attachment 638326

After a few days of testing it showes that passenger Batt. is still the problem:
View attachment 638327
This is the Passenger batt. after a night without connected to a batterycharger:
View attachment 638332


Any idea what to do next.

I had a starting issue with my crew cab and it was the OPTIMA Yellow battery on the 12 volt side. It was 3-1/2 year old battery and would go dead after two days(6 months ago it would go dead after 4 or 5 days). Load test showed weak after I recharged it.
Put a new OPTIMA Battery in and no problems now.

Blackout switch, terminal corrosion are somethings to look at.

 

[Nico]

Thx 4 the reply Stonepicker, i changed from red to yellow top about 5 month ago. My batterycharger got a recond funktion the passenger side got 13.1 V After that procedure. That should be enough. But what is sucking only the right batt. Dry, since warthog has bypassed the blackout lights? I thought someone solved that Issue already.

 

[Stonepicker1]

Could it be the Alternator draining the battery? bad Diode or something.

 

[Nico]

i`ll check that. i am also going to pull some fuses. thx

 

[Nico]

No significant draining measured in the fuse box. Maybe the Converter...

 

[Stonepicker1]

No significant draining measured in the fuse box. Maybe the Converter...

I thought the converter only got energized when the ignition was turned on.

I switch the Service Light switch to "ALL OFF" and after 6 month with the truck not being started. The truck will start right up.

If I don't move the Service Switch, my Crew Cab CUCV-II truck it will have a dead battery in about 9 to 12 days.

 

[Warthog]

With the B/O switch in the ON position there is an added relay under the dash the gets energized. I had the same
issue on my CUCV2 and made a bypass of the B/O switch. Didn't have any more issues of the 12v side draining the battery

 

[Nico]

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