O/T Dead batteries

Anonymous-0 · Nov 23, 2009

I have a 2006 F350 Diesel and every once in while I will go out to start it and the batteries wil be too flat to start. This has happened 3-4 times in last 2 months. I have disconected and recharged both batteries and they test as ok on a tester. Anyone else have this problem? My son has a 2007 same as mine and has happened to him. Ford even replaced the batterys once on warranty on his and still does it. No, I have'nt left anything on or ajar. Any ideas.
Thanks, Don from Canada

Lou from Wi. · Nov 23, 2009

I would disconnect the battery overnight to see if it is the alternator s internal regulator holding the circuit closed. 2nd try would be to pull leads off the alternator and then check remaining circuit with a volt ohm meter to see if it's still showing discharge through the meter.for a dead short. Hope this helps and hope you find whats causing such a drain. LOU

Anonymous-0 · Nov 23, 2009

There was just a thing on TV here about someone that was driving their car about 30 minutes a day just to keep the battery charged for about 15 years because noone could figure out what the problem was. It was traced to a relay that would operate a preheater which the car wasn't even equipped with. Can you disconnect the battery bable and put a multimeter in between without damaging anything electronic and start pulling fuses?

Dave

bjb in TX from Ne · Nov 23, 2009

My car did that one summer. Final time I gently wiggled the connection and it broke off. The battery post was corroded internally so there wasn't enough area to provide the current to crank the engine. It was a mess too, since it was a side terminal battery. Acid started spilling out.

Howard H. · Nov 23, 2009

My old '94 F250 will do the same thing... Work fine 95 times out of 100 - even after sitting for a month or so at a time, but then occasionally the battery will be dead as a hammer. It has always taken a charge and then been good again.

Since I also use the battery to run the winch on my tractor hauling trailer, I KNOW I have a good battery.

One guy told me a flaky alternator could do that - if it "stays open" or something along those lines... Didn't seem obvious as to what he was talking about, but I'd be curious as to anyone elses comments about that...

Also, I've gotten in the habit of pulling the key about halfway out to make positive I have the key switch completely off - it is dusty and worn enough - the lack of tactile feedback of the switch makes it tough to "feel" exactly where off is...

HH

RodinNS · Nov 23, 2009

Just because you didn't leave something on doesn't mean there isn't a phantom load of some sort or a short somewhere.
I'd unhook the batteries then stick an Ohm meter between the cable ends. See how much resistance is there, then start pulling fuses/breakers/relays until the load goes to zero. Then you found your problem.

I'd think it unusual for the OEM batteries to die like that in 3 years. Motorcraft's used to be good for 8-10 years unless they changed...

Rod

JDemaris · Nov 23, 2009

I have many like that. I have too many tractors and diesel trucks laying around that don't get used a lot. I finally broke down and bought cheap on-board battery maintainers and they work great. A $14 on-board 1.5 amp automatic maintainer can handle a pair of large diesel batteries, hooked in parallel, fine. I now have them on several tractors and both my diesel snow plow trucks. I got sick of jumping engines to start after they'd been sitting a few months. The maintainers will also make the batteries last a lot longer since they never drop below 13.5 VDC.

I also have the same problem on any of my newer cars and SUVs. For the ones that are backup vehicles that sit most of the time, I put in battery disconnects. My Dodge AWD Grandcaravan will go dead in a month if it doesn' get driven and the battery is hooked up. Now it can sit all winter and still start fine when I need it.

Zachary Hoyt · Nov 23, 2009

Those maintainers seem like a great idea. Do you know if they make them for 6V batteries as well? Thanks very much.
Zach

El Toro · Nov 23, 2009

You probably have a drain on the batteries. Could the regulator.. You can install a master switch in the ground leg so your battery is isolated from ground. The military has used master switches for years on their vehicles. Hal

JDemaris · Nov 23, 2009

If they do, I haven't seen them. I'd like to get one in 24 volt but haven't seen that either. My Allis Chalmers HD6 is 24 volts with two 12 volt batteries hooked in series. So, I have to unhook and use two maintainers on it.

Non mainstream stuff is usually available but costs much more. I just bought a 48 volt charger from Iota and it was almost $200. But, I've got a 48 volt battery bank with 16 batteries. Not much choice.

Name brands cost more too. Sometimes you get what you pay for and sometimes you don't.

Harbor Freight has these 1.5 amp high frequency maintainers for $14 each. Schumacher gets $40 each. So far, the HF units have been fine.

glennster · Nov 23, 2009

jd, battery tender makes a six volt version, i"ll post a link below. also oem tractor has a neat little tender for about 17 dollars for a 6v battery too.
6v battery tender

Howard H. · Nov 23, 2009

Well, if Don's problem is similar to mine, it is very intermittent.

It will sit for a couple of months in the winter and will start with no problem, usually, but once it had only been a couple of days - and then was dead...

HH

Anonymous-0 · Nov 23, 2009

I have seen soem of the older ford diesels that the glow plug relays sticks on intermittantly . suc the juice right out of a battery

Bill in Colo · Nov 23, 2009

I have two tractors and a truck with like problems, I've traced the problem to the alternators, so rather than replace I but a disconnect in the ground side

guido · Nov 23, 2009

Hello dcollins,
First test the batteries for self draining.
Remove all the cables Negative/s first.
Check battery voltage. Check the voltage 24 hrs later, it should be about the same.
A fully charged battery is 12.6V at 70 Degrees F.
So it tests 12.5 or more after 24hrs they are not self discharging. There are more tests you can do. Try this one and see what happens.
Guido.

guido · Nov 23, 2009

Hello dcollison,
First test the batteries for self draining.
Remove all the cables Negative/s first.
Check battery voltage. Check the voltage 24 hrs later, it should be about the same.
A fully charged battery is 12.6V at 70 Degrees F.
So it tests 12.5 or more after 24hrs they are not self discharging. There are more tests you can do. Try this one and see what happens.
Guido.

Brian Jasper co. Ia · Nov 23, 2009

The "Keep alive memory" in the PCM will draw about 15 milliamps which is enough to light a test light. Putting an ohm meter across the battery cables with the battery unhooked won't tell you anything as you will be measuring resistance across the PCM, FICM, and IPC not to mention other modules. You can use a digital ammeter in between one battery cable and terminal and measure the current draw. It may take up to 30 minutes for all modules to go to "sleep mode". If it gets down to about 15 milliamps, that's normal.
Wash off the tops of the batteries. If there is much acid/water on the top of the battery(s) current will flow through it and drain them.

Old Roy · Nov 23, 2009

Could take a test light and remove ground cable use test light between cable and ground terminal. if light comes on you have a drain ,remove fuses till it goes out.

RodinNS · Nov 23, 2009

You have fun changing the fuse in that ammeter when you actually find the load....
There is a reason why I use an ohmmeter.
You find the bad circuit by pulling the fuses and perhaps ascertaining what would be a normal draw for the ECM and radio memories.
Most ammeters I've had like to pop somewhere around 10 amps and if you have a real draw, that's often enough to burn the fuse. I don't know about you but that's a job I don't need.

Rod

RayP(MI) · Nov 23, 2009

I had one like that - "bout drove me crazy. Had an alternator rebuilt by a local back-yard rebuider. He did an nice job, replaced all the electronics. Every once in a while wife would come out of work to a dead battery. Kept searching, and found that when passenger door was opened after car was shut down, the draw from the courtesy light would trigger the alternator, and it would turn on the field coil, discharging the battery. Took alternator back, got new electronics, same problem... Seems that he got a bunch of defective voltage regulators. Scraped thru his junkbox, and found old regulator, installed, and problem solved. (Ford Bronco II)

barn E · Nov 23, 2009

I had 2 ford pickups(gasoline)that the pump relay musta been sticking because the fuel pump kept on going after engine was off. That will put a batt to sleep fast. Had diesel for 5 years and if you didn/t start ASAP, the batts would be dead. Good long recharge at 5 or 10 amps, like new again till next time. Dave

O/T Dead batteries

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