Is my lipo faulty ?

[Caravan9927]

I bought a new 3s 4200mah lipo from a UK retailer and on arrival one cell was only 0.85 v and the other two were 3.5 v each. Although I felt the depleted cell was faulty and possibly dangerous, the retailer did not think there was anything unusual about this, so I bowed to his suggestion that I give the battery several charges at low trickle to see if that would correct it

I have now given the battery three charge/discharge cycles on half C using my PROLUX Balance charger and on average the results are :-

Fully charged............4.16/4.16/4.24

Discharged (ie after my esc powers down @ 9.6 v) ....... 3.38/3.40/3.66

I am prepared to accept a discrepancy between cells of .01, .02 or even .03 when charged and discharged but not as above.

However, before I return the battery I would like to know what others think. Am I right in returning it or is the discrepancy I describe normal for a new battery ? Any comment would be much appreciated.

[Maxpoly]

Definitely 100% return it.

A cell at 0.85v is effectively dead and not only is trickle charging a cell like that dodgy, you will never get the life out of it and it will never balance as well.

Your figures post discharge are also way out from each other as you say.

Andrew

[handthrottle]

Trust Andrew....

[Ashley Davis]

yep, agree, that's *******

[Unsung Hero]

yep, agree, that's *******

Is that a technical term
J

[Pipistrelli]

Is that a technical term
J

It is when Ashley uses it!

[Si Goodchild]

...that's *******

My exact thoughts. And I'm supposed to be an engineer!

[Caravan9927]

Thanks all of you. I'm sorry I posted in the wrong section but nevertheless got the answers I needed. You have confirmed my worst fears so will be sending the battery back asp.

Merry Xmas to you all.

[cjcj1949]

The man in the shop is completely wrong. Many chargers will not charge a cell below a certain voltage. There is a reason for that. I don't fully understand the lithium chemistry but I have seen the fires and I know that lithium is very reactive. LiPos are bad enough when treated properly let alone when they are defective. The man in the shop is often wrong. I find that if they won't listen, asking them to put it in writing usually works well. The magic words are 'not fit for purpose'. The person you are dealing with is putting other people at risk and is probably criminally irresponsible.

There is a 80% rule that experienced people follow. Only use 80% of the battery's capacity if you want it to last.