average holding 5-6 charging cycles with original charger

After about two months the battery was no longer charged with the appropriate charger (was when measuring the voltage tester jew. Deep discharge) even though it was handled with care, ie never stored in an empty state and removed always after the ride from the RC car and charged. So we needed within a year 5 of these batteries, incl. A "Power Battery" (same problem).
This hobby is now to expensive.