Thread: New Product ESR / IR Meter fo Lipos
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Old Dec 06, 2012, 01:32 PM
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Originally Posted by orlbuzz View Post
Having just purchased a Blade mCPx V2, I now have a need to check 1S lipos. My friends and I have ordered the 6 lead pigtail parallel charging lead. It occurred to me that I could cut the UM connectors with leads out of the pigtail and make up a harness to create a 2S, 3s, etc., battery by connecting them in series and (observing polarity), connect a Deans connector. I could then take a balance connector and insert it's leads in the appropriate places between each cell.

These cells will be 200 to 300 mAh each. Is my thinking correct that this would be the same, (using 200 mAh cells, for example), as a 3S, 600mAh battery?

I realize the UM connectors and the leads will add resistance not found in a assembled battery pack with soldered tabs, etc., but as a tool for comparison, would this work and not overload the individual cells with the pulse?
If I understand correctly you are making up a 3S battery from 3 individual 200 or 300mAh cells in which case it would be a 3S200 or 3S300 pack respectively

The meter is rated for 500 - 6000mAh packs and the minimum limit is based on the max IR the meter will read in "CELL" mode which is specified as 25 milliohms although in practice it will read up to about 30 milliohms.
If you try to measure a cell with an IR of over 30 milliohms then the system will saturate and you will get an optimistic reading.

The pulse will not cause any damage to a small cell because it is so short but the reading will not be reliable if it is >30milliohms.

Incidentally, the extra resistance of the connectors would not affect the readings.
The voltage sensing leads take no current so that they measure the voltage at the cell with no added voltage drop. The current pulse only passes through the power leads.

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