Preemptive HV Battery Replacement?

Hi there! First off, so glad PriusChat exists. Already it's helped me tons in my three months as a Prius owner.

Second, I'm unsure whether to go ahead and replace my HV battery on my 2009 Prius, 140k miles. I bought the car somewhat discounted knowing that it had a "weak" battery (as my new hybrid specialty mechanic told me). Supposedly my battery could last me anywhere from 2 weeks to 2 years.

I haven't been able to find any answers about whether driving around (and I drive a lot for Uber) on a weak battery is a bad idea. For the most part, I can deal with the inconveniences of having a weak battery, like being conservative with the AC while parked -- but might it be taxing on the rest of the car's components to drive on a weak HV battery? Am I losing out on gas mileage or acceleration? (I'm currently getting around 40 mpg.) Having not driven a Prius with a newer battery, I'm not sure what to expect from the car.

Thanks! I look forward to hearing from anyone.

 

Thanks Jeff! I've heard varying opinions on reconditioning HV batteries, but I'll add another vote to the "pro" side though! Thanks!

 

Sure, although I'm a little fuzzy on the diagnostics my mechanic ran...it was a few months ago. I believe they have a slew of tests that gauge the battery. I'll check my records to see if I have any specifics on what they did.

As for my own observations, the battery charge indicator thingy on the MFD fluctuates between 2 and 9 bars in a matter of minutes, usually after starting the car for the first time in a day or two, after running the AC for a few minutes while not driving, or driving uphill for more than a few minutes.

Also, compared to my sister's 2010 Corolla, my acceleration is a bit pokey.

Does that help?

 

Thanks. Yeah, I kinda assumed a battery replacement is imminent. Any thoughts as to the harm in driving until the battery dies completely or if I should go ahead and replace it?