Originally Posted by
cutting42
Well if we are being precise (or pedantic ;-) ) the max voltage overstates the requirement as the LIPO charge cycle is only done at MAX amps for the early part of the charge as you can see by watching the display during charging. By the time the batteries get over the spec voltage (3.7v per cell) the charger does not dish out the full amperage so in reality calculating as I did is pretty accurate which is why the calc max amps for 4s was the same as the observed - 3.3A
We are kind of splitting hairs here, we agree on the premise that the 50W charger cannot deliver 6 amps into a 4s battery but can into a 2s.
All of the lipo chargers I have, of several brands, charge at full amperage all the way up to 4.2 volts per cell. Then begin the CV portion and start decreasing the amps. For the vast majority of the charge cycle the cells are above the 3.7V nominal, a lot of it is above 4V even. The voltage rises quickly and significantly when charging.
Nominal voltage is intended as a representative voltage during discharge, while under load when the voltage sags or drops. Opposite of charging.
If the amps are dropping around 3.7V per I suspect it is due to power limiting, as correctly alluded to by previous posters. A 80W charger would not be able to maintain 6 amps on a 4S to full voltage. Would still charge it, and probably work fine for many, but it would take longer and is under powered to a degree.