Sudden battery death?

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99WhiteC5Coupe

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Fizzy

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Our 2023 started giving a message a few weeks ago that the battery charge is getting low. I checked the voltage with the engine off over about a week and it shows 12.0 - 12.1 if it has sat for a few hours. Using either a full charger or a trickle charger it would go back up to 12.6 - 12.8, but after a few hours it drops back down again.

I have an appointment tomorrow at the Ford dealer. Will be interesting to see what they decide. Any thoughts welcome. It is 18 months old. It gets driven daily usually 15 - 20 minutes at a time. We have done two long trips in it, and every month or so it gets driven longer distances, say 30 - 60 minute trips. In the same driving I have never had a battery issue on any other vehicle.

When I replaced the battery on our 2020, the factory Motorcraft H7 AGM battery had a sticker on the side saying “36 month warranty” or something. And there’s also a sticker showing manufacturing date.

Incidentally, I replaced it with a Costco Energizer H7 AGM battery. 10 year warranty! First 5 years full refund, second 5 years prorated refund. Crazy - basically free battery for life.
 
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DieselMonk

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I got about 6 years out of the H8 AGM in the F150 Babystroke. Started to use more fuel than usual, shortened the distance to the next DPF burn and I end up with an almost dead battery every 2 weeks. Also the auto start stop quit after 2nd day of charging the battery and some other quirky things were going on then.
Put new H8 AGM battery, reset the BMS and truck returned back to normal. Was shaking my head what a battery can do to a modern vehicle.
 

jjscsix

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Our 2023 started giving a message a few weeks ago that the battery charge is getting low. I checked the voltage with the engine off over about a week and it shows 12.0 - 12.1 if it has sat for a few hours. Using either a full charger or a trickle charger it would go back up to 12.6 - 12.8, but after a few hours it drops back down again.

I have an appointment tomorrow at the Ford dealer. Will be interesting to see what they decide. Any thoughts welcome. It is 18 months old. It gets driven daily usually 15 - 20 minutes at a time. We have done two long trips in it, and every month or so it gets driven longer distances, say 30 - 60 minute trips. In the same driving I have never had a battery issue on any other vehicle.
Follow up to my own post. The dealer determined that my battery was bad and they replaced it. My dealer service was excellent.
 

Paddler

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I replaced my battery today after it wouldn't start the car. I connected a charger to the cables while I did so, but the dealer said I need to reset the battery management system. How does one do that? My dealer charges $200/hour for labor.
 

AJ82

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I replaced my battery today after it wouldn't start the car. I connected a charger to the cables while I did so, but the dealer said I need to reset the battery management system. How does one do that? My dealer charges $200/hour for labor.
From the '22 manual (page 405):

Battery Sensor Reset
When you install a new battery, reset the
battery sensor by doing the following:

1. Switch the ignition on, and leave the
engine off.

Note: Complete Steps 2 and 3 within 10
seconds.

2. Flash the high beam headlamps five
times, ending with the high beams off.

3. Press and release the brake pedal three
times.

The battery warning lamp flashes three
times to confirm that the reset is
successful.
 

Paddler

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From the '22 manual (page 405):

Battery Sensor Reset
When you install a new battery, reset the
battery sensor by doing the following:

1. Switch the ignition on, and leave the
engine off.

Note: Complete Steps 2 and 3 within 10
seconds.

2. Flash the high beam headlamps five
times, ending with the high beams off.

3. Press and release the brake pedal three
times.

The battery warning lamp flashes three
times to confirm that the reset is
successful.
Thanks! Done.
 

GlennSullivan

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From the '22 manual (page 405):

Battery Sensor Reset
When you install a new battery, reset the
battery sensor by doing the following:

1. Switch the ignition on, and leave the
engine off.

Note: Complete Steps 2 and 3 within 10
seconds.

2. Flash the high beam headlamps five
times, ending with the high beams off.

3. Press and release the brake pedal three
times.

The battery warning lamp flashes three
times to confirm that the reset is
successful.
Does anyone know if this applies to 2015-2017 (Gen 3B)
 
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