I think a few folks have invested in good battery chargers for their packs, but I suspect a lot of us have just been using the cheap generic Chinese chargers that are sometimes included with a new battery pack. I've been using mine for about 3 years now, but it never occurred to me that it might need some occasional adjusting. During the last 6 months, after switching over to my current controller and cycle analyst, I noticed on a few occasions that the fully charged pack voltage was higher than 58.8V for my 52V pack. I don't charge to full very often, so I saw this happen during the last few times that I did. I had concluded at the time that my CA was reading voltage slightly high, and put the thought off for another day, thinking I would calibrate the CA.
This weekend, I charged to 100% to allow the pack to balance, and noticed the CA was reading 59.28V, so I got out my meter to measure it. Sure enough, the charger's voltage had drifted over time and was reading high. The CA was right. I took the charger apart and adjusted down the voltage to 58.8V. I checked the voltage a few times after assembly, cycling the charger on and off a few times and it remained at 58.8V. Anyway, it didn't occur to me that these cheap chargers could drift that much, but maybe something to check once in a while.
This weekend, I charged to 100% to allow the pack to balance, and noticed the CA was reading 59.28V, so I got out my meter to measure it. Sure enough, the charger's voltage had drifted over time and was reading high. The CA was right. I took the charger apart and adjusted down the voltage to 58.8V. I checked the voltage a few times after assembly, cycling the charger on and off a few times and it remained at 58.8V. Anyway, it didn't occur to me that these cheap chargers could drift that much, but maybe something to check once in a while.