Title: Battery Detection Test
- Whenever the EVM behave from non-charging mode to charging mode would mean the battery detection flow chart is applied.
- 8mA discharge current is a constant current.
Test Setup:
1) Set power supply to 12V, 3A.
2) Set DMM to DCI, 10A Range, Fast Mode.
3) Set E-Load to Resistance function with 8 ohm resistance.
4) Connect DMM to PC by USB.
5) Connect the entire instruments as show in Figure 1 below.
Test Sequence:
1) Ensure EVM is under non-charging mode, Current reading is 0A.
2) Start collecting reading from DMM using SCPI “READ?”
3) Close E-load to allow EVM start charging.
4) Stop Data collection from PC.
Result:
|
|
Expected Reading |
Result |
|
Before start |
0A |
0A |
|
First 1s |
-8mA |
112mA |
|
End |
125mA |
112mA |
Discussion:
1) Base on the flow chart, EVM will first apply 8mA discharge current for 1s. Thus the DMM should read a -8mA at first.
2) The DMM have a spec to read 19 data per second, thus we can ensure the DMM performance is good enough to catch the -8mA within the first second of current flow.
Conclusion:
- The EVM does not apply the battery detection flow chart as the 8mA discharge current was not detected.
- The flow chart is invalid.
Question: what happen if a fully charged battery is detected?