Yet another HV thread (Gen 3 - Prolong, New Prius Batteries, new OEM?)

Eager noob here! I recently bought "Orpheus," a 2010 with 160K miles. In the spirit of long-term investment, I bought him expecting to replace the HV battery at some point in exchange for keeping him 5-10 years. I'm lucky to live in range of Boulder Hybrids and discussed HV batteries with Paul while I had the car in for routine maintenance. According to him and Torque News, I'll get a P0A80 code if a cell block hits 30 milliohms of resistance or there's a voltage difference of 0.75V between blocks.

I already suspected my battery wasn't long for this world; I'm getting rapid SOC fluctuations on the road (how rapid is bad?), and the ICE has started kicking on and idling even when stopped / driving slowly with several battery bars left. (The battery doesn't lose charge overnight, though.) Accordingly, I got an OBD scanner and the Dr. Prius app and found 5 cell blocks at 29 milliohms and a voltage difference of 0.36V (screenshot attached).

After admittedly spotty research on PC and other places, I'm figuring these are my best options:

1. New OEM battery from Toyota -

1a. Installed by Boulder Hybrids. That's what Paul recommended, but he estimated $2800 for the battery and the job. That's a darn sight better than a dealer but I was hoping to do far better still.

1b. Bought and installed by me, if I can find one for sale. How would I avoid the core charge? Does that mean I just purchase the individual cells?

2. Use Hybrid Automotive's Prolong now for preventative rebalancing before the battery goes.

2a. Boulder Hybrids has a professional Prolong kit, and they'll rebalance my battery with it for ~$450 to buy me a year or two.

2b. I don't think that's worth it, as a home Prolong kit wouldn't run me much more than one professional rebalancing, and I could keep rebalancing my battery once or twice a year as I've seen people on PC doing. That might buy me more than two years, maybe?

3. New Prius Batteries. I like the idea and most people on PC seem happy with it (and also seem to think it'd work with Prolong when the time comes). I can't find too many data points for long-term/heavy use, though.

I'm not planning on buying a whole reconditioned battery - it's "just a band-aid" as people say and much more expensive than the Prolong band-aid.

Sorry for the wall of details - if you made it through all of them, thanks!

So, my questions:

I. Is my battery on the way out, as I suspect?
II. With the battery as far along as it is, how much good will Prolong do? Am I right that regular rebalancings (with a home kit) will do measurably more good than rebalancing once?
III. Any advice/caveats on my "options" or better options I haven't considered?

 

Thanks! I'd thought pretty hard about Green Bean just because of that warranty. I don't like that it voids the warranty if I (or the shop, I presume) do anything to it myself, but I suppose the point of the warranty in the first place is that I don't need to.

 

Shows how much I actually know about this. Thanks.

I hadn't before you replied, but I decided it was worth the money. Ran both full battery and life expectancy tests twice because I wasn't sure what I was doing the first time. Results attached. Not sure what to make of the inconsistent full-battery results, but I suppose the life-expectancy results speak for themselves.

 

Several months or $4K? Big yikes.

Thanks @fotomoto and @The Critic for the warnings. I guess it can't hurt to DM Toaster, see if anything hasn't miraculously changed in a month, and grab the first pack I can find before things get worse (with my battery and the world)?

Big, fat yikes. What a time to live in.