Lipo will not fully charge ?

[Rocker]

Anyone tell if one of my lipo is dead 

It charges up to about 90% (5 cells at 4.1and one cell at 4.2 ).The charger drops to 00.00 and it does not say fully charged but just will not fully charged the lipo .In the end the charger indicates "Out of time " I can put it back on charge but it just goes to 00.00 charge 

Anyone tell me whatvis going on .The resitance on all 6 c is 4 or 5 ????

[PeterF]

Can your charger do a balance without charging. If it can it will bring the high cell down to the same voltage as the others. Then discharge to storage voltage 3.85V per cell. If the odd cell goes back out of balance then it has probably reached end of useful life. If all cells remain reasonably well balanced at storage voltage then charge back up again and watch the voltage during the charge.

[Rocker]

Thanks Peter ,will do 

[Simon Chaddock]

Do watch out for some resistance in the balance plug and socket. You are looking at tiny voltage differences, 0.01V.

In such a case as yours I have found that just wiggling the balance plug in its socket suddenly causes the charged to stop showing "full" and 4.20 on all cells.

The LiPo is fully charged it is just the charger doesn't recognise it.  

[PeterF]

25 minutes ago, Simon Chaddock said:

Do watch out for some resistance in the balance plug and socket. You are looking at tiny voltage differences, 0.01V.

In such a case as yours I have found that just wiggling the balance plug in its socket suddenly causes the charged to stop showing "full" and 4.20 on all cells.

The LiPo is fully charged it is just the charger doesn't recognise it.  

Good point, if you have another measurement device check the battery with this as well as a cross check. I am currently looking into a battery with an odd cell and the cross check confirmed the imbalance was not due to the charger balance leads.

[Rocker]

I did what Peter said. I discarged the battery to 14% .Then balanced it and all the cell came back and then fully charge the battery and it is all OK now 

Thanks 

[MattyB]

1 hour ago, Rocker said:

I did what Peter said. I discarged the battery to 14% .Then balanced it and all the cell came back and then fully charge the battery and it is all OK now 

Thanks 

 

14%? That is pretty low. Instead of percentages, always discharge to a target V/cell - 3.2-3.3V/cell should be your target range, that leaves some safety margin if you make an error or temps are low.

[MattyB]

PS - Continue to keep an eye on that pack, as if it's gone out of balance once, it is more likely to do so again in the near future. Certainly never charge it in parallel with other packs unless you are happy all cells are in balance at the start point (and all cell voltages are within 0.1V of each other across ll the packs being parallel charged).

[Flying Squirrel]

3 hours ago, Rocker said:

I did what Peter said. I discarged the battery to 14% .Then balanced it and all the cell came back and then fully charge the battery and it is all OK now 

Thanks 

Just an observation - Myself and other club members with generic type lipo testers have noted that they often read 14%, far more than coincidence could explain, almost as if 14% covers anything from 10%-25%

 

[RottenRow]

37 minutes ago, Flying Squirrel said:

Just an observation - Myself and other club members with generic type lipo testers have noted that they often read 14%, far more than coincidence could explain, almost as if 14% covers anything from 10%-25%

 

Ha ha, this is a running joke between myself and a fellow club mate!

 

It doesn't happen with the 'original' version of those little black testers.. the ones branded 'Fusion Smart Guard' seem much more accurate. The others (I've seen several slightly different versions) all seem to be named 'Capacity Controller'; I've no idea how they control anything!

 

One that I had also showed a battery cell imbalance on the same cell in a number of packs, but only on a cold day. Clearly one or more sensitive components inside that one. It is no more, courtesy of a hammer.

 

The most accurate way to check individual cells would be to use a single voltmeter and read each cell in turn (at the balance plug). I do this occasionally just to check that my balance charger is indeed balancing the cells correctly.

 

Brian.