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

Budgreen's Sig:

1993 W350 club cab 4x4 5spd dually.
Homemade custom fuel pin, star wheel and smoke screw cranked. 366 spring, gauges n stuff

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?

NadirPoint's Sig:

'07 5.9 48RE
'91.5 12V G360

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.

---AutoMerged DoublePost---

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...

stkdram55's Sig:

Just an Inline 6 Cylinder

Only 2 defining forces have ever offered to die for you.....Jesus Christ and the American Soldier..
One died for your soul, the other for your freedom.

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.

diesel pap's Sig:

www.mightydiesel.com - Make Your Diesel MIGHTY !

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?

2000mA would be 2 amps...

and I don't need to disconnect it if the motor stays warm!

ps. I have a degree in electronics

so, after much playing the only draw I notice is for sure the radio/media controller which is minimal.

but in my playing around I did notice that after I remove the key the little buzzer under the dash is still going (cleaned my door switches so they work) is that normal or does it think they key is in? I may have an ignition related issue here.

sounds ignition realated to me josh. the buzzer is only on for the seat belts and the door as far as I know

440ctd's Sig:

96 2500 cummins 5.9L 12 valve jasper auto trans. ,guages: pyro, boost ,trans ... studed and ringed head, super HX40 turbo, stock injectors, exhaust: 4in downpipe 5in to muffler 6in tail end, silencer ring taken out.
79 ford f150 400ci 4in sus. 3in body 38" tsl's

Hey there,

my truck was doing the exact same thing with anywhere from 2 to 8mA of drain and I threw in a 'good' set of gently used batteries that load tested perfect on two seperate testers, but I was still having the same issue. So I was in a bad pinch one day stuck dead at work and got a lift to go pick up brand new ones and I put them in and havent had an issue since.

The batteries that were in when the whole problem started were only 1yr old if that and had an 8yr warranty on em so I took em in and got them tested. They were fine. So I charged them up and than left on the floor of my truck over night and took them in after work sitting in the cold all day as the first time the company load tested them they were fine. So I took em back to get checked and they failed and I got a new set. Now I have two sets of brand new batteries and problem solved.

atrd86's Sig:

05 F250 6.0L FX4 Lariat
---6" lift w/ 37" Procomp Xtreme A/Ts---Bullydog PMT---5" turboback---Airaid intake
---Throttlebody spacer---Full EGR Delete---In dash dvd---Alpine5x7's---JL10"sub ---Tinted18%

87 Samurai
---6"SPOA 30" mudders
05 R1 Track only---07Motovert Expert 125cc---07 CRF250R
08 Yamaha Phazer RTX

that'll be the experiment for tonight or another night. pretty sure all my batts are well within warranty