TP820CD under charging.

[Grumpy]

I'd suggest 'suger lumps' as a not totally accurat analogy as to how a battery 'fills up'. No analogy is perfect but imagining the battery as a container being filled with water is probably more accurate. It doesnt really matter how you pour the water in, the volume of water that will fit in the container is the same providing it's filled to the same level.

If the voltage of the battery is the same (4.2V per cell after settling) when the battery comes off both chargers then both chargers have 'filled' the battery exactly the same. Resting voltage indicates charge state.. PERIOD.

[SGD]

I'd suggest 'suger lumps' as a not totally accurat analogy as to how a battery 'fills up'. No analogy is perfect but imagining the battery as a container being filled with water is probably more accurate. It doesnt really batter how you pour the water in, the volume of water that will fit in the container is the same providing it's filled to the same level.

If the voltage of the battery is the same (4.2V per cell after settling) when the battery comes off both chargers then both chargers have 'filled' the battery exactly the same. Resting voltage indicates charge state.. PERIOD.

Quite agree with you on the analogy and better one would be a viscose liquid on a sponge, it takes time to be absorbed and time to get it fully saturated.

I'd prefer if the end voltages were expressed as 4.200V because as you have already shown even 0.05V can make a noticeable difference and this way reduces the possible margin of difference to such a minimum it's not worth considering.

[Granpappy]

I could see this thread was going to deteriorate lol..... at the end of the day it is just a "toy" helicopter.... who cares, go out fly it and enjoy yourself

Frustration maybe..... Deterioration definitely not. Who cares?...... I do. Those who don't care needn't follow the thread. Toys? That's subjective. I consider it an investment for my leisure time and any investment should be made with guidance and solid information.