SO.. in an attempt to not hijack the other thread of not charging the battery I am starting this one.


it's been getting cooler out and i'm starting to notice some problems with the battery. the one that was in the truck would die from time to time, eventually found out it was a bad cell after it blew a cap off so I replaced it charges fine, no problems and load tests well. come out on any morning cold enough for the grids to run and it's sitting at around 8v?!?! barely runs the grids much less turn the truck over, if I plug it in so the motor is warm in the morning it's at around 12v and starts no problem, I looked for drains and found my sub amp always on so I fixed that and don't see anything other than very small drain, like for the radio memory etc. I know for a fact it's not the grids killing it when they come on because I checked it before I even put the key in..

any suggestions on where to start on this? it's really screwing with my head!

45* and below - dead
45* and below plugged in - not dead

btw, this happens at work also if it sits the 9hrs in 40* or colder weather

 

depends on your luck just maybe a new bad battery if it was myself with the luck i have i would of got the only bad new battery in town

 

What is the CCA rating (cold cranking amps) of your new battery?

 

it's from another truck I have, load tested it before it went in so I know it's still good. now that i'm thinking about it, maybe the previous owner hot wired the grid controller and it runs just sitting at night.. the truck was a wiring nightmare when I got it!

so much as to say the heater control died so the fan was on a switch hanging under the dash, rear lights were bypassed to just the trailer plug.. etc. etc. maybe I missed something when I went through it.

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1000CCA

There's not enough draw to even come close to killing it overnight.. but if it's cold out it's almost fully drained in the morning, when it's hotter out it's perfectly fine.

like I said i'm pulling my hair out trying to figure it out, usually it turns out to be a constant draw (not there) or a crap battery (load tested good)

 

did you replace both batteries or just one?? Im assuming first gens have two like every other years...

 

only has provisions for 1 commercial size one, I found it odd but seems to do the job until now

 

when you get it fig out let me know. my 91 is doin that. when its cold battery will drain. it stayed charged all summer.

 

Have you confirmed there is a non-running draw on the battery or not? Put a voltmeter on it before and after disconnecting it at the main terminal. There should be zero to negligible difference in the readings.

 

Actually, you want to put a meter in-line and check for a current draw.

Yes there is a draw, but it's in the miliamps range, mainly the radio constant for memory is my best guess. but a draw like that would take weeks to kill it as low as it gets.

diesel pap: I'm gonna be playing with it quite a bit, will update here when I find the cause, because I will since I'm good like that

Things i'm gonna start with.

1.) wiring for grids and controller
2.) starter solenoid
3.) ?

 

Disconnect the battery until you found the amp draw. That way you can find out easily if the battery isn't able to hold the charge too.
How many milli amps draw do you have 20mA or 2000mA?