6S LiPo Sensor

01082010206.jpg

Sensor for use with the FrSky Telemetry system.

Principle

Basic voltage divider connected to the two outer pins on the balancer connector on the battery.

For use with AD directly or 3.3V hub (3.3V max)

Max voltage in (25.2V) should give max 3.3V out

Schematic:

(As proposed by Bodmer)
(Cut GND line between battery and sensor, add 4K7 resistor in series to the output from the sensor)

Interpretation of Bodmers improvement

Conversion

Voltage divider using 10k and 68k resistors, plus 4K7.
24.95V on the battery gives a bytevalue of 248.
This gives a resolution of about 0.1V pr step, or 9.94 steps pr volt

Common Cell Voltages in bytevalue
Cell Voltage Pack Voltage Bytevalue
2.5V 15.0V 149
3.0V 18.0V 179
3.3V 19.8V 197
3.4V 20.4V 203
3.5V 21.0V 209
3.6V 21.6V 215
3.7V 22.2V 221
4.2V 25.2V 250

For use with a HUB (5V max)

Max voltage in (25.2V) should give max 3.3V out

Implementation

01082010206.jpg sensor_improved_1.jpg
sensor_improved_2.jpg 01082010207.jpg

6S_Voltage_Divider_original.png - Original Sensor Schematics (2.13 KB) Espen Solbu, 08/30/2010 07:48 pm

6S_Voltage_Divider_crop.png - Improved Sensor Schematics (2.59 KB) Espen Solbu, 08/30/2010 07:54 pm

01082010204.jpg (638 KB) Espen Solbu, 08/30/2010 08:00 pm

01082010205.jpg (605 KB) Espen Solbu, 08/30/2010 08:00 pm

01082010206.jpg (532 KB) Espen Solbu, 08/30/2010 08:00 pm

01082010207.jpg (538 KB) Espen Solbu, 08/30/2010 08:00 pm

6S_Voltage_Divider.png - Current Circuit (2.86 KB) Espen Solbu, 09/09/2010 11:22 pm

6S_Voltage_Divider_improved_bodmer.png - Interpretation of Bodmers improvement (5.17 KB) Espen Solbu, 09/13/2010 07:55 am

sensor_improved_1.jpg (48.1 KB) Espen Solbu, 09/18/2010 11:03 pm

sensor_improved_2.jpg (50.9 KB) Espen Solbu, 09/18/2010 11:03 pm