The below is a copy-paste from Radical RC Frequently Asked Questions section:
If you have an Accucycle and you think you have a bad battery understand that what I'm telling you is you've been throwing away good packs for along time probably. Test your rig, send it in for calibration or replace it with an accurate setup and you'll be way ahead financially before long. THE ACCUCYLE IS NOT BAD! Many of them have been shipped to customers out of calibration. CALIBRATION IS THE ISSUE. And I've been told that Hobbico/ Hobby Services has provided excellent service fixing the out of adjustment units. It is also possible that any cycler can drift over time. Just because a device was once in calibrated only means it was "once" in calibration. Test it to see if it is now
There is a calibration procedure that is simple and easy to follow. If you own a digital volt/ohm/ampere meter, you can pretty easily calibrate it yourself. I'll try to dig out the process and post it.
CGr.