Originally Posted by
Rodney
If you are not reading 4.2 plus or minus .01 volts after a full charge, I'd suspect that your volt meter need calibration. The 4.2 volts is a chemical fact, not an adjustable or varying value that can only vary with temerature and then by a very small margin.
Actually that's not quite true. The chemical "mix" can vary, such that a lipo mild mix might result in 4.1v or so, and a "hot mix" around 4.35v.
To add to the confusion, most everyday use DVMs read 4.2v to two decimal digits, and add +/-1 LSD +/-/ the full scale accuracy spec.
In other words a DVM reading of exactly 4.20v might mean that the actual voltage is higher or lower.
To combat this, I bought an inexpensive "standard" that puts out a reference voltage of 4.2000 v This allows me to determine the actual
reading of a dvm with 4.2000 v input. That DVM can them be used to compare a chargers voltage reading against the DVM's reading.