Battery charging problem and dealer's reply

[flobiwan]

I bought a brand new 2017 Ford Fiesta in October. After needing 3 jump starts, i called Ford but they couldn't take me for a week and, since it's important that i have a running car, i bought a new battery via AAA (cheaper than renting a car for a week).

The NEW battery also drained and i needed a jump start in a few days.

When i finally got the car into the dealer, he said the original battery was bad (not surprised as my 2011 Ford fiesta was also sold to me with a bad battery!).

Then, the mechanic said that when the AAA guy replaced my battery, he didn't program it so that's why the new batter didn't work right. Ford is giving me a replacement battery for free as it's under warranty (but they're not reimbursing me for the new battery i bought).

is it true that batteries need to be programmed now? I've never heard of that and it sounds fishy. And if true, is that why the new battery didn't hold a charge?

[Stealthee]

You're being fed a line of crap. A parasitic loss test needs to be performed to figure out what is causing the drain.

[flobiwan]

I had a feeling. Although, i don't know what the motivation is. I'm just going to bring the car back when it happens again since it's under warranty.

[Blue Bowtie]

On some vehicles, the BCM needs to be "updated" when a battery is replaced. This isn't actually reprogramming, but resetting a program flag in the BCM so the battery is recognized as new, and the controlled charging rate is reset to original parameters. On a BMW X5, for example, the body battery (separate from the starting battery) is charged at a controlled rate which is different for a new battery. As the battery gets older, the charging rate is altered in an attempt to maximize the life, but still maintain as full a charge as possible. If the battery is replaced but the flag is not reset, the new battery may not be charged at an appropriate rate.

[flobiwan]

yeah but the car is only 6 months old so i would think everything should still read as "new" anyway. I'll know over the next couple weeks if the car still has a problem.