Need some help diagnosing a possible bad alternator or a phantom intermittent parasitic draw that is killing my battery. It’s a 2014 F350 6.2 gas engine, 52000 miles, completely stock with nothing aftermarket and no extra electronics.

Went to start and battery was dead.

Charged overnight, drove around normal for a day, parked.

3 days later battery is dead again.

Replaced battery with new Napa Gold battery.

Charged overnight, checked voltage = good. Checked charging system with battery tester = good.

Drove around normal running some errands for the day and then parked again.

3 days later with no usage battery is dead again. So I assumed a possible parasitic draw.

Charged overnight again. Voltage = 13v. Charging system = 14.65v with dmm.

Hooked up dmm in line between + battery post and cable to truck, unplugged hood light and zip tied hood switch closed, flipped door latches closed with screwdriver, locked and armed truck using the key fob, waited an hour and then started monitoring the amp draw watching for a parasitic draw. When truck is asleep its drawing a steady .013 milliamps. I used the voltage drop test with a dmm and checked every fuse in the engine box and inside cab box. Every one reads zero. Over the course of watching for three days I’ve noticed a pattern where about once every 60 minutes there is a current draw spike up to 2.16 amps momentarily and then it starts to drop back to .013 in about one minute. Sometimes this same spike happens again after about 20 minutes and sometimes a third time after about 5 minutes and then sometimes it will stay asleep for a couple hours but then do it again. Each time I see it it’s the same spike and then back to rest pattern. Whatever this is leads to about .10 amps lost in battery charge every 24 hrs which doesn’t correlate to killing the battery every three days as before. I’ve checked for signs of moisture and water inside along the a pillars , the windshield, the headliner, down around the control modules on the firewall and all are dry and clean. I’ve checked all the fuses and relays with a IR thermometer each morning and all are the same ambient temperature as everything surrounding.

I redid all of the same as above with the dmm in line between the – battery post and cable from truck and observed everything the same.

So unless there was something else going on earlier (maybe a stuck relay or something) I’m leaning towards possibly the alternator is intermittently not charging as it should? If I understand correctly from the internet and youtube university this is smart alternator controlled by the computer and to test correctly I’ll need more advanced testing equipment. Unless someone can tell me how to do it with a standard dmm. I have noticed that when reconnecting the power cable to the battery there is a definitive pop or arcing sound that comes from the alternator. I’ve also noticed the same sound, sometimes occasionally, sometimes repetitively, and sometimes not at all coming from the alternator while the truck is running. Is this normal or is this a sound of something bad in the alternator? I’m thinking it might just be cheaper to replace the alternator with a new one and hope it fixes the issue rather than take the truck in to Ford for a long drawn out and expensive diagnosis. Any thoughts and input is appreciated. Thanks.

 

you could look at this website www.highoutputalternators.com
I bought one from here 140 amp for my 2001 7.3 diesel

I just re-visited the website.
Now I am thinking they sell primarily for diesel engines, but also list alternators for Many vehicles.

 

.013 ma isn't enough to kill a battery in 3 days. Reason why it might jump to 2+ amps after a couple of hours I can't say as those trucks have over 1/2 dozen computers in them. If you alternator is working intermittently you should receive a message on the dash when it is having issues. The pcm sends a voltage reading to the alternator and the alternator alters its charging accordingly. You might have a bad regulator in the alternator or a bad ground. I had a Chrysler that wouldn't charge recently and it was the pcm failing to command the alternator. A new pcm cured that issue.

I would suggest you take out a Alldatadiy subscription or similar from another site to get the information on the wiring for the alternator and instructions on how to diagnose. You can diagnose most of the charging issues with a DVOM, that's the special tool you need. If you think it could be the alternator killing battery you can certainly disconnect it and see what happens after a few days.

Other than that I suggest you hit the books. G'luck.

 

Try pulling PCM related fuses while it is sitting. See if you still have that odd current spike.

I have also seen radios do weird things while a vehicle is off... Not to mention aftermarket remote starters, security systems, etc etc

 

I've done a few of these over the past 3 years. Outside of a bad alternator, for the vehicles that had actual voltage spikes a couple of them had a bad wiper motor. The ECU (these cars didn't have a BCU) kept trying to turn on the wiper motor. I've also found a few aftermarket backup cameras that were spliced into an 'always hot' wire by bad (Best Buy) techs.

If you have a thermal imager, it can be faster to find the root of your problem than pulling fuses (which often wakes up the ECU so can take longer to diagnose). If the voltage spike is high enough the thermal imager should catch it.

-- Dave

 

I have some weird problems myself,, 1999 f350 7.3 .. I bought a newer fuse box to replace because of fuse # 15 was some how loose causing the GEM to get energized when the connection touched.. I have heard tel that a GEM turns on and off when sitting there. If I don't use my truck for days that may deaden the Batt. As a test I took a piece of wire and jumped the fuse. My doors stopped locking and unlocking and interior lights stopped blinking.. So problem#1 hopefully solved with out getting a GEM..
Now problem #2 The starter will crank at any time!!!! when the engine is on or off.. I'm going to probably purchase a GEM to complete this fiasco.. The dealer wants $700 for a GEM replacement WTF Its only a plug and play.....!!!!!!!!!!!!!!!
This is my tale ....

stevo