Unbalanced LiPo

[ChrisH]

Hi all,

OCD taking over again (Gary...).

After an incident involving a gentle landing in an oil seed rape field after I ignored the flashing red led I decided to get some cheap alarms. Working on the principal that if I can';t see it I should be able to hear it in a similar circumstance I got 3 off ebay.

Thought I';d see how my assortment of LiPo';s measured. They give a rolling set of readings (on a 3S) of cell count, overall voltage and then individual cells. I have 4 5000 3S batteries, two Nanotech and two others. Three of them read within 0.01V across the 3 cells. One Nanotech records 3.95/4.19/4.19 on all three alarms. I put it back on the balance charger but no difference.

Question is: the fact that one cell exhibits this difference in voltage, is it on the way out or is this normal? 

[Biffa]

I';ve never tested mine, but I would be a little dubious of the accuracy of these alarms.

Have you checked the battery with a multi meter?

[ChrisH]

Steve,

I understand that but all three showing exactly the same difference on just one battery? The other three are within 0.01 per cell.

Not checked individual cells with a meter but the overall voltage is Ok.  It';s just that it';s odd on one battery and I don';t want to risk a crash if it';s a bad one!!

[Balders]

I use/rely on lipo alarms all the time.

If in any doubt, check the balance ports with a decent voltmeter, but sounds to me like you';ve got a dead/duff cell on that lipo.

[ChrisH]

Think it';s going to get sidelined.

Not risking that much kit up in the air relying on one £30+ battery that is giving slightly dodgy readings. Only had about 5 flights on that one battery. Maybe swap it for the one on the FPV screen... 

[Biffa]

Think it';s going to get sidelined.

Not risking that much kit up in the air relying on one £30+ battery that is giving slightly dodgy readings. Only had about 5 flights on that one battery. Maybe swap it for the one on the FPV screen... 

Probably the best idea.

Out of curiosity I was just looking for my little alarm to see how it compared to my meter, but I can';t remember where I put it last

[ChrisH]

I';m not so worried about the absolute accuracy but the fact that 3 alarms read the same on all 4 batteries raised my concern for this "high tech" battery.

Label it and use on the base station. If it fails on that nothing crashes as I use it for video alignment not full fpv!

[Biffa]

I';m not so worried about the absolute accuracy but the fact that 3 alarms read the same on all 4 batteries raised my concern for this "high tech" battery.

Label it and use on the base station. If it fails on that nothing crashes as I use it for video alignment not full fpv!

The four Nano Tech Crappo Tech packs I have are all buggered. I certainly wont be buying any more.

[ChrisH]

Steve, expensive lessons we seem to be learning. Suckers for advertising splurge,  I';m sticking to Overlander or Zippy from now on. My oldest batteries and still good.

[Biffa]

I have some Zippy';s and they are great. They have and still do take loads of abuse.

The Crappo Techs were bought after numerous recommendations - go figure

[Hands0n]

Is it just the Nano Tech that are in question here? Getting a strong vibe that Zippy and Overlander are the biz. 

I';ve started out with Turnigy 3S 2.2 - have three of them now, and they all seem to be pretty consistent and within only a few .0x difference from time to time. I make a point of always Balance Charging them given what I';ve read and being in no particular hurry. And then no more than 2.2amp of charge current.

[ChrisH]

Danny, I have two Nanotech batteries. One gives me this problem the is other fine (so far). On a percentage failure rate not good but a small sample size! Look at other posts for views on the Nanotech but lets just say I won';t be paying the premium price for them in future! 

[coastersteve]

I';ll be honest, my 3 X 2650 Nano Tech';s have been fantastic. They always come off cool, hold their voltage during flight and are happy being charged at 2C. My Quad pulls around 25A in hover and all my Zippy';s come off warm and my 3000A/Hr Zippy has puffed massively. All I use that now is adjusting settings in the house.

I';m not sure how much of it is marketing, this video is impressive.

https://www.youtube.com/watch?v=KvIaLN4AVlE