2005 prius battery health

Hello, I recently bought a used 2005 Prius w/ 78k miles from a private seller. I've been reading the forums (which were extremely helpful for a newbie like me btw) and came across some posts that seem to suggest that the hybrid battery is more likely to go bad after 10-12 years. I haven't had an issue so far driving about 600 miles since getting the car, and mpg is avging 38-41 mpg (backed up by both computer and hand calculation)

Question: I was wondering if the traction battery is at a point in it's life that I should invest in one of the grid chargers (like Hybrid Automotive) to keep the battery balanced and at capacity. I am aiming to keep the Prius for at least 3 years, so I'm not sure how worthy it would be, and if the battery is in a state where it needs that upkeep.

I attached some graphs from testing the traction battery with the Hybrid Assistant app. It seems to claim I have only 2-3 Ah of capacity (when nominal is 6.4Ah), but it may be a bit faulty, I haven't tried to do in-depth hand calculations yet to verify that measurement.

Test 1: Initial SOC @ >60%, drain with AC on high, headlights on, defroster on, radio on till ICE kicks in to recharge. Stopped when ICE stops


Test 2: Initial SOC @ >60%, drained with AC on low, stopped when SOC is >10% lower than initial SOC. Compressor alternating on and off during this time.


Test 3: Driving on highway with SOC and battery values being recorded. You can see max deltas on the second graph. A lot of transient measurements here.


Thanks all!