PowerLab 8 V2 - Cell voltage monitoring problem - HeliFreak
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Old 12-26-2016, 03:39 PM   #1 (permalink)
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Default PowerLab 8 V2 - Cell voltage monitoring problem

Hello,

I bought a powerlab 8 v2 with MPA parallel board 3 months ago and have been using it without any issue since then. Yesterday, I was checking my 6S lipos using Fluke 115 multimeter for cell voltages and started charging them to put them in storage (charging single pack at a time). I monitored each cell voltage and noticed all cell voltages were same in CCS voltage monitor and the charger display. I stopped the charging and check the cell voltages again using the multimeter and they were certainly not equal. When I charged the pack using my hyperion charger, it showed the different voltages for each cell.
Now, I am questioning if the powerlab charger is detecting the cell voltages correctly. I do not feel safe using the charger anymore.
Have anyone seen something like this?
Any comments or suggestions would be appreciated.

Thank you.

Heon
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Old 12-26-2016, 06:39 PM   #2 (permalink)
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Sometimes my PL8's do that all the cells are the same, and sometimes not. Usually in the beginning of a charge mine may be a slight bit different, after a few minutes charging they all get even... Maybe your meter is out of calibration???
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Old 12-26-2016, 11:46 PM   #3 (permalink)
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How far off is it?

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Old 12-27-2016, 10:35 AM   #4 (permalink)
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Thanks for the comments! The cell voltage reading for all 6 cells stay the same from the beginning to the end. When I monitored the cell voltages using my meter (Fluke 115), the lowest voltage cell was 10mV off from the voltage reading from the powerlab 8 v2. Also, cell voltage sequentially increased by 2mV from cell 6 to cell 1 (or cell 1 to cell 6), making the highest cell voltage number within 2mV difference from the powerlab voltage number. The same voltage variations were measured right after charging finished using the meter. The same thing is happening when I am charging 2S Lipo. This time, the voltage difference after charging is ~10mV from cell 1 to cell 2.
My biggest problem is the powerlab 8 v2 is not showing these voltage differences. It seems the charger is trying to balance each cell during charge. I can see the bypass % number changing for each cell but the voltage is off by ~10mV from lowest voltage cell to highest voltage cell at the end of the charge.
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Old 12-27-2016, 02:26 PM   #5 (permalink)
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Quote:
Originally Posted by haha0606 View Post
Thanks for the comments! The cell voltage reading for all 6 cells stay the same from the beginning to the end. When I monitored the cell voltages using my meter (Fluke 115), the lowest voltage cell was 10mV off from the voltage reading from the powerlab 8 v2. Also, cell voltage sequentially increased by 2mV from cell 6 to cell 1 (or cell 1 to cell 6), making the highest cell voltage number within 2mV difference from the powerlab voltage number. The same voltage variations were measured right after charging finished using the meter. The same thing is happening when I am charging 2S Lipo. This time, the voltage difference after charging is ~10mV from cell 1 to cell 2.
My biggest problem is the powerlab 8 v2 is not showing these voltage differences. It seems the charger is trying to balance each cell during charge. I can see the bypass % number changing for each cell but the voltage is off by ~10mV from lowest voltage cell to highest voltage cell at the end of the charge.
The reported voltages are averaged across several samples, and may change significantly once the charge current stops.

In the end, something in the 10mv range is completely insignificant when it comes to battery charging.
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Old 12-27-2016, 05:16 PM   #6 (permalink)
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The reported voltages are averaged across several samples, and may change significantly once the charge current stops.

In the end, something in the 10mv range is completely insignificant when it comes to battery charging.
Thanks! I've used charger without any issue. I was just questioning what I've seen is normal.
Thanks again guys!
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