LOL, you still shouldn't have paid the six grand for the battery, sorry...but okay.
At 255K it didn't really owe you guys anything anyway. Cheers on the garage queen condition and appearances but at two hundred and fifty five thousand miles, if it were me I'd have thrown in a budget refurb or reman unit and call it good for another two or three years.
Reman units run about 1500 to 2000 bucks and you get a pretty decent life out of them for the most part.
Yes, I know about the battery switcheroo process, it's not all that scary as long as you respect the 200 volts dealio.
To be honest, it's changing and cleaning the battery vent fan that pisses me off, it's almost as labor intensive as swapping out the damn battery, at least on a Gen II model anyway.
I wish they'd have made the ventilation fan a modular pop-out/snap-in unit so people could clean the fan every six months with five minutes worth of DIY, like changing an engine air filter.
You shouldn't have to dismantle most of the rear interior just to clean a stupid squirrel cage fan!
The NiMH cells in the Prius battery pack don't like to regularly forced all the way up to 100% every single time you charge but 85-90% is golden, with some occasional one hundred percent charges spaced out after a run down to 45-50%.
As far as I know, the "ONE BAR" condition does NOT represent zero or even close to zero, it IS actually representing approximately 40-45%...that is the "artificial low" charge status indicated by "one bar".
And it is, as you probably know, based on voltage readings, not current.
Like your wife, I too was driving an awful lot in city traffic and like your wife, my driving did not always have enough long highway drives either.
But the battery has held up. I just hate the lackluster performance of the vehicle, especially when compared to my daughter's Chevy Volt, which is actually pretty fun to drive for what it is. It's not a Tesla but it has enough oomph "to get out of its own way".
My experience with NiMH and Li-Ion batteries is not from the automotive circles but instead from my career as a director of photography.
I started out in 1983 with a mix of gel cell lead acid and Ni-Cad battery packs and "battery belts" for my camera gear, then graduated to Nickel-Metal Hydride, then moved into Lithium-Ion and we've all "been friends" all along and I've learned the idiosyncracies of each system.
And I've had to train my crew in the proper care and feeding of these batteries as well, because as you said, if they aren't maintained and charged properly, the life expectancy drops.
But seriously, I think the ladies in your fam did okay because you did get 255 thousand miles out of that pack, which is pretty good.
Most Prius taxicabs will get 250-350 thousand miles out of one before swapping them out.
And from what I can gather, those taxi fleets are not buying the six thousand dollar OEM units either, because generally speaking after the second battery pack reaches the end of useful life, so has the taxicab.
You guys did pretty well. Maybe they could have squeezed another fifty thousand out of it, maybe not, but 255K is nothing to be ashamed about!