it's the age-old cycling method. With NiMH, much of the capacity is lost, but still exists at the 0.8V potential through additional material phases at the terminal - meaning it can never be used in the normal 1.0V+ range. By cycling the cells repeatedly, this lower range of capacity is consumed. When charged, the proper material phase is restored to the terminals and that capacity is again available above 1.0V+. Any time you see "reconditioned" that's what's done. "Decrystalized" just sounds FANCY!

One thing I will caution you on... The FEH cells are VERY misleading. They cycle like a dream and can regain a substantial portion of its 5.5Ah capacity; HOWEVER, they are tricky as ****. One thing that won't improve is self-discharge, i.e., the ability to hold a charge. Builders often make the mistake of conducting short-term testing and fail to realize this issue... they'll send out a pack that works for a few months, and then it fails like yours has.

 

Gotcha, I appreciate the information. It's too bad nobody seems to offer these packs with new NiMH cells in them. I assume they're manufactured and have to exist somewhere. I know GreenTec has packs with "new generation cells" with a 36 month warranty; I used their chat and they confirmed these "new generation cells" are indeed still used; but it's also a $4K pack which I simply can't justify for this car.

I'm thinking my best course of action for now is to get a pack with the best warranty/price ratio I can.

 

I'm 99% certain some Chinese suppliers are making 5 cell FEH sticks. IMHO, you will have better results with a quality reconditioned or as-removed healthy salvage pack. The data indicating that the Chinese cells are inferior to the original Panasonic/Sanyo cells is overwhelming.

"new generation" just means they're using 2010-12 cells in the older packs.

Make SURE your replacement pack can manage the cooling system. A 2010-12 pack will not.

There's a BCM self test in Forscan that will operate the fans and cycle the blend door. That should confirm the cooling system can be managed.

 

Figured I'd post an update here. I pulled the trigger and bought the $1300 refurbished battery from the local hybrid shop w/ a 2 year warranty. So far so good! Noticeable MPG improvement, and it sit for 3-4 days with no change in the battery status on the power flow display. Time will tell with the longevity, but as of now, I'm happy with it.