The birth of the battery data logger

The interface has changed from only recording voltage data to recording various real-time parameters of the battery (including temperature, current , capacity, power, etc.). The interface is as shown below.

This recorder is passive and works by taking power from RS232. It consumes less than 2mA and is only half the size of a palm (6.3cm*5.6cm). It also communicates with the computer through the RS232 interface. The basic functions are as follows:

1. It can simultaneously record 8-channel voltage (e.g. , the voltage of each cell of 8 ...

2. All parameter curves (voltage, current, temperature, capacity, power) during charging and discharging can be generated

3. The voltage range is adjustable (20V if not adjusted), the current range is up to 10A, and the maximum measurement error is 0.2% (limited by the A/D conversion accuracy, I will improve it to 0.02% accuracy later)

4. It can be used as a voltmeter, ammeter and thermometer.

5. The scanning speed is adjustable and can be set arbitrarily from 0.5S to 5S.

In version 1.2 I will add output control function, which can control the power supply (or charger) and electronic load, so that it can be used to measure the cycle life of the battery.

In version 1.3, the frequency meter function and duty cycle calculation function will be added. (Used to detect the PWM of the charger circuit )

The signal generator function will be added in version 1.4. (It's just for fun, it would be a pity if it's not added.)

In addition, please contact me, JIMKPC netizen, I will give you a 1.2 version multi-function data recorder for free. (I owed him a favor before, now I return it.)
The figure below is the parameter curve generated by the data recorded by the recorder when the 18650 battery is discharged. The coordinate unit is second, the capacity unit is Ah, the power unit is Wh, the voltage unit is V, the current unit is A, for the convenience of display, the temperature is the Celsius value after dividing by 10. Because the range is 20V, the voltage curve is not smooth enough. After I changed it to 5V range, the curve is perfect.

The following is the circuit schematic diagram, share with you (please indicate the source if you reproduce the original from Power Network)