Dying battery, less hp?

[714_2er]

Battery (7yrs old) finally starting to fail, replaced it today and now my car seems to be slightly more "fluid" in the mid to top range.

Placebo effect or does a failing battery really affect performance?

[tracer bullet]

Generally speaking when you are driving you are using alternator power, the battery just starts the car. That's way oversimplified but I'm pretty sure you're imagining things.

[Ric in RVA]

Does pulling battery reset adaptations?

I think it does.

If so that is what you are feeling...

[JimD]

I think it also depends some on how the battery fails. My wife's shorted or something and would not take a charge at all. Too jumping on both ends - battery and under hood - to start. The dash was all lit up when it ran. I wouldn't be surprised if she was on the backup tune it uses when there are check engine messages (although it had none). If it goes to the backup tune it probably affects power.

[MightyMouseTech]

When the battery is in good condition, it only charges the battery when decelerating. Think of it as a light hybrid kind of mode. Below 80% charge, it will charge while normal driving. So car probably thought the battery was weak and charging it during accel as well.

So yes, it can affect performance.

[The Wind Breezes]

I've heard of batteries causing some mysterious behavior but it's rare. And the alternator saps less than 2 kilowatts max from the engine, all things considered including inefficiency. Generally it would pull quite a bit less even when charging the battery. That's like 2.5 horsepower MAX, not nearly enough for you to notice unless you can hear people whisper from 10 miles away or detect earthquakes minutes in advance.

[ianc]

Pulling the battery does not reset adaptations. This must be done manually.

ianc

[brytom]

Pulling the battery does not reset adaptations.
If you didn't register the battery for replacement, nothing has changed. The vehicle will continue to charge your new battery like the old one.
Which brings me to my last point, register the battery. I don't know of at home solutions, someone can chime in there. We had an incident where a technician twice replaced a battery and shipped it without registration. Both cars started coming back at 6 months to a year with weird electrical issues. They car will continue to not keep a full charge/ 80% charge on the battery. It will start charging the battery to 50-60% as time goes on. Doing this on an old battery is fine, doing this to a new battery will decrease its life. On top of having other issues.