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I've had a constant plague of random dead battery issues over the last few years. Truck works, runs, drives fine all day, week, month, etc. Get home park it and it's dead th enext AM. At first I thought is was simply batteries going bad but now I know it's not. I just changed the battery in it and it's back to the same problems. It'll do it with or without a phone charger plugged in the power port, other than that everything is fine.
Any ideas? I bet I've put close to 6 batteries in the damn truck since 2013... I've heard mention of a battery management system? Shops are baffled and don't know what to do...
How long does it sit between long (30+ minute) drives? Which one the trucks in your signature are you talking about? Have you been able to check the voltage output of the alternator?
At any point have you used an external charger or battery maintainer on it?
How long does it sit between long (30+ minute) drives? Which one the trucks in your signature are you talking about? Have you been able to check the voltage output of the alternator?
At any point have you used an external charger or battery maintainer on it?
It's the 2013 F150 in my sig. Never used a battery charger or maintainer. And I've never checked the voltage from the alternator. But I can jump the truck off, it'll start and run fine. If I let it run for about 20 mins it'll crank back up just fine and operate fine for who knows until it does it all over again.
The truck will sometimes get driven for hours on end and sit for at least 10 hours before it gets driven again. Every time this has happened I've gotten in the truck in the AM and the battery is dead. I mean nothing works. No remote unlock, no dash lights, etc. Just like the truck doesn't even have a battery in it.
Sure sounds like one of two problems at this point. 1) alternator not charging battery properly or 2) parasitic drain. #1 is probably easier to diagnose. Voltages would be a good place to start on both.
I'm positive it's not the alternator. Because right before the truck was parked it was moved around the yard a few times and cranked fine each time. Next AM, dead...
big question is could it be this battery management system or what ever it's called that's in these trucks and needs to be reset after a battery replacement...?
It's the 2013 F150 in my sig. Never used a battery charger or maintainer. And I've never checked the voltage from the alternator. But I can jump the truck off, it'll start and run fine. If I let it run for about 20 mins it'll crank back up just fine and operate fine for who knows until it does it all over again.
The truck will sometimes get driven for hours on end and sit for at least 10 hours before it gets driven again. Every time this has happened I've gotten in the truck in the AM and the battery is dead. I mean nothing works. No remote unlock, no dash lights, etc. Just like the truck doesn't even have a battery in it.
I am going to say the BMS has aged out the battery and isn't charging correctly. If you have access to forscan you can reset the BMS easily. If you don't there is a work around, unplug the hall effect sensor on the negative battery cable and leave it off. This will give you 13.6-14.3 nominal charge voltage. Remember these BMS systems will only attempt to charge when downshifting otherwise they float charge. It's not a good system overall but it does save some fuel. However if the battery goes flat dead the battery will never be the same and should be replaced. The quality of the replacement batteries should also be considered.
Unplug that sensor and be done with it. #10 in the following pic, you can leave the ring on the battery cable. DO NOT unplug the one on the positive cable.
No it will not pop a warning light on your dash. The only thing it'll do is allow your alternator to charge all the time like they've been doing for near 100 years.
I would suggest if you unplug the connector put a small freezer bag over each connector and tape them shut so water and dirt doesn't get into the connector wiring. You'll probably want to reconnect it if selling or other reasons later.
I would suggest if you unplug the connector put a small freezer bag over each connector and tape them shut so water and dirt doesn't get into the connector wiring. You'll probably want to reconnect it if selling or other reasons later.
I folded mine over on itself and wrapped it with electrical tape in several layers. Should last for as long as the harness itself.
RLXXI, thanks for the information and graphics. Great post.
I haven't had any such problems with my '14 that I purchased new. But, I now know a "fix" if that gremlin rears its head.
