Why don’t refurbished Prius battery sellers show cell specs?

Warranty is only a useful number for a company large enough that you expect it to be around so that it can honor that contract.

 

it's probably the same batteries, the extra money you pay for a longer warranty is insurance

 

There are ebay sellers who offer individual Prius modules (not the entire HV pack) where they disclose the mAh capacity.

mAh is much more important than "open circuit voltage" (which is stated by almost every vendor of used Prius modules). They all say their modules are "7.5V or higher." But that only means you won't be getting a module with a shorted cell inside it (those never get higher than 6.2V).

I'm about to buy some spare modules for my 2005 Prius. I'm searching for modules advertised as "5,000 mAh" at the minimum. I also found one ebay vendor offering used modules which are 5,500 up to 6,000 mAh. That's about as good as it gets. The rated capacity of a brand new module is 6,500 mAh. These do cost more ($56 USD each), but could be worth it if most of the existing modules in your pack are >5,500 mAh.

Toyota Prius Hybrid Battery Module Cell Very High Capacity 5500-6000 mAh | eBay

 

The Ah capacity only means something if the discharge load is part of specs, but you can be sure the load is very small if they are advertising in mAh. The new module capacity is 6.5Ah, so that should be a min load to measure capacity to see how close to the hr it can supply.
The next important part is start test voltage and under load end test voltage, and the test must be at a constant load, no waiting for recovery time, then starting the load test again, a time stamped graph of the modules performance that shows voltage and load current, then it would be believable ...... sort of, you just need to have a method of ensuring the test data was the module you bought and not some new module or even a different chemistry.

Unless the modules have been rehydrated, there is very little chance they will have a near new capacity

T1 Terry