Those of us who have been using Lithium-Polymer batteries for a while are probably aware that they are changing. How so?:
My theory on this one is that the battery manufacturers are having to ensure that their cells live up to their claims. Kokam claimed 7/10C discharge rate, while E_sky claim 10C, Hi-Model 20C and Mystery 15C.
Mystery cells behave like Kokams. They run out of power about halfway through the expected discharge but will recover after a rest (you can repeat this several times).
The E_sky and Hi-Model cells give much better performance for a longer period, when they will suddenly run out of steam. They do NOT recover, until recharged.
Mystery cells are similar to the Kokams (I had assumed that these were new to the market, but perhaps I'm wrong). Even when new, they don't match the performance of E_sky and Hi-Model cells which seem to be a vast improvement on earlier types (though heavier). So far, the E_sky and Hi-Model cells show no loss of performance over 20 cycles or so. The Mystery cells are already showing signs of fading after just 10 cycles.
There is one other difference: The cells which recover after a rest (Kokam, Mystery, etc.) all show around 3.8 volts per cell even when pushed to the point where they won't fly the model. The newer types (E_sky, Hi-Model) register as low as 3.2 volts when pushed to the same point.
|Maker||Capacity (mAh)||Weight (grams)||Discharge rating (C)||Comment|
I now have a couple of 2 cell packs of Fullriver 800 mAh cells from Indoor Flyer. I have had good results from this manufacturers cells in smaller sizes, so had to try them. These are substantially bigger and heavier than other cells of similar capacity. The trend continues.