Lipo's and capacity
 

As Lipo batteries die, do they loose capacity? I usually run 5 min runs with about 2 mins of warm up laps so my batteries are rarely fully discharged. Yesterday I decided rather than charge between rounds, I'd run the same pack for two qualifiers. Late in the 2nd qual, my radio was complaining about low voltage (I have a nomadio set to tell me when they get to 14 volts) so I babied it around the track and never actually hit the LVC but I was darn close. Anyway when I got them on the charger, it said they were at 9% and it proceeded to put only about 3800mAh back in...they are 4900's...does that mean my batteries after 3 seasons of racing are starting to go? Might they rebound?

From what I've seen with mine, yes, they start to loose capacity as they get older and build the number of disch/chrg cycles. The most used ones I've had were for 18th scale and were 1500mah. After a little more than 100cycles thery were charging to only low 1200's after being run to 6.2v cutoff. When new, they would routinely see 1575, a drop of 20+%.

I assume IR goes up as well as they age, although not to the point with NiMhs.