Serial Data Output
The extra small pad labeled TX is now enabled for serial data transmission, at 9600 baud, ascii formatted, tab seperated values which look like the following:
Ah V A S D
0.031 37.31 17.85 21.2 0.413
0.042 38.22 7.45 21.2 0.452
0.048 38.25 5.85 21.2 0.487
You can select whether the data rate is at 1Hz, suitable for general purpose data logging, for 5 Hz, which is fast enough to capture the dynamic response of an EV during acceleration and such, and do all kinds of vehicle performance analysis.
The output is 0-5V CMOS level, so directly compatible with other microchips, but to read it with a PC you would need an RS-232 level shifter. Fairly soon we'll be designing a plug-in circuit with a SUB-D connector on the end to allow for direct connectivity to a computer or PDA, and further down the line hope to offer an SD memory card writer, so you could ride around and all the trip data would be stored on a small memory chip.
Combined with the additional low voltage and current limiting features of the CA, this allows for some interesting possibilities. For instance, you could purchase an inexpensive bicycle trainer stand and use it as a stationary load for your ebike, then completely discharge the battery pack at constant current by running the hub motor on the stand, with the CA recording the discharge profile on a PC and maintaining the constant current discharge. No need for massive load banks, and you can test up to 100V or 200V battery packs without even removing them from the vehicle.