Higher Ir on cell 4

[DannyH]

Just got 3 new optipower 5000mah 6s packs today. Have Charged 2 of the 3 packs so far and the Ir on cells 1,2,3,5 and 6 has been about 1.7mohms. However cell 4 has been 2.8 mohms on both packs. Am charging with a powerlab 6 charger on v1.07 firmware.

Is it likely to be a false reading due to the charger or a real reading and If real is this ok for brand new packs?

Man thanks

Dan

[sacko]

It's due to the extra 4mm bullet connection. It's fine..

[DannyH]

That's good news, was thinking it would be just my luck to get some duff packs

[cjcj1949]

When you take a reading for ir it needs to be taken directly off the cell that you are measuring. Usually the balance leads do that or the intercell connection is very short. As Sacko says you are including the connection wire between the two packs which adds a massive 1 milliohm. Shows how precise things have become. You should also note the temperature of the battery when you take your readings. If you hold the battery in your hand for a few seconds you'll see the ir dropping. It also drops just after charging, so a good idea to charge just before use.

[DannyH]

This may be a daft question but as the connection causes an increase in resistance does this mean that cell 4 will be more likely to go out of a balance in use? Also should the series connection in the cell be left disconnected when not charging or in use?