Cells Database

The cells database (CELLS.EDB) characterizes Nickel-Cadmium cells.


CELLS is a description of the selected cell (up to 20 characters). These cells are mainly Sanyo. The most popular are the N-1700SCRC and RC2000 for sport flying, and the KR-600AE and N-500AR for the smaller "Speed 400" models. This brand has a proven track record. Cells with an 'R' in the suffix are especially suited for the high charge and discharge rates needed for electric flight. Other cells have a higher energy to weight ratio but at the expense of higher current handling and/or charge rate

MAH is the typical milliampere-hour capacity of a cell. This basically means that the cell can supply that many milliamps for one hour before the voltage drops substantially. This is generally higher than the manufacturer's rating, but will vary as a function of the charge method, discharge rate, and temperature. This number is used to estimate the motor run time at the calculated battery current. MAH is normally measured assuming a cutoff voltage of one volt or less. With high cell-count packs you can't afford to let the pack get down this low per cell without risking damage to the lower-capacity cells. You can expect the capacity of a higher cell-count pack to appear less due to the higher probability of a spread in cell capacities.

mOHM is the equivalent cell resistance in milliohms. The lowest resistance is obtained with end-end soldered cells. Cell resistance should include the resistance of the cell interconnections. The original data assumes minimal (end-end soldered) resistance. Bars or heavy braid will be somewhat more (+0.5 milliohm) and welded tabs could be substantially more (>1 milliohm). You can measure this yourself with a good DVM, ammeter, and load. Basically you need to measure under load and no-load voltage quickly so that chemical processes do not interfere. Use at least a 10-amp load. Cell resistance is voltage difference divided by load current divided by number of cells. See our web site for information on end-end packs.

DIA. & HGT. are cell dimensions in inches and are informational only.

WGT. is weight of the cell in ounces. This number is used in calculating the plane weight. When the cell type is changed, the plane weight is adjusted automatically.

MAH/OZ. is informational. It is the capacity of the cell in MAH divided by the weight in ounces. Use this to appreciate the capacity versus weight tradeoffs that you must sometimes make.

COMMENTS are allowed at the end of the line.

PTR is a somewhat bizarre alphanumeric pointer assigned to this data entry for reference by the PLANES database. There is a small chance that two entries will have the same pointer and thus "confuse" the program into selecting the wrong one. This can generally be fixed by making a slight change in the description.