this might be a long post so please bear with me... also i planned to make this post a few days ago ,,,but then decided to wait  for a new charger and then ask for help.

so here is the prob:::: \

i use only 3s batteries... i also have been using a cheap clone imax b3 charger that i bought for 300 bucks.

NOW i have 5 tattu batteries and 1 kypom and one gens ace battery.
the tattu batteries are new less than 10 cycles on em...... all others also in good conditon-- no puffing nothing.

i have always balance charged my batteries , and  on the few occassions that i check voltage post flight ,i have never dropped em below 3.8 volt

OF THE 3 CELLS IN ALL THE BATTERIES . the first cell is taking forever to charge. i mean, the last 2 cells charge up quickly to 4.2 volts but the first cell  IN ALL THE BATTERIES (YES ALL) charges at a crawling pace. the voltage increases to 3.78 volts and then after an hour to 3.8 volt and then to 3.83 and so on.- very slow ..
if my batteries were of large capacity i could have considered it as 'charging' but 2 of them are just 650 mah 3s and they take forever to charge too...

I CONCLUDED THAT THE CHARGER WAS FAULTY AND ORDERED A NEW ONE...
now i got a original skyrc 3s charger from robu.in , hoping that the problem will stop..
no use... my battery has been charging all afternoon and its first cell is lingering around 3.9 volts the other two cells hit 4.2 volts a long time ago....

now the battery has a problem..YES?!!!..but why only cell number 1 in all the batteries??  

it isnt a issue of balance either coz.... yesterday i spent like 24+ hours and finally got the voltage right on all 3 cells...had a flight today and the problem persists..

Has the internal resistance of cell number 1 in all the batteries increased??  but then why only cell number 1? HOW DO I MEASURE INTERNAL RESISTANCE ... is it just the simple resistance that may be measured on a multimeter ?? i suppose not coz internal resistance shows itself when battery under load....so thats a deadend.

more importantly what do i do now? i  am going hiking in the himalayas in 48 hours and had planned some fpv

any help .... direction... will be very much appreciated...

meanwhile i remain online  look for answers on various forums...

is there anything else i need to provide to better help u understand my problem..please let me know...
regards.

i have one more question.. does a bad charger have the capacity to destroy the internals of a battery...i suppose the answer is yes..but then why only cell number 1 on all batteries...

but i checked the out voltage on my cheap charger across all pins....its 4.16- 4.19 volts , so i dont see how that can harm a battery

The same issue also happens with me, i also have 3s batteries, everyone when I use my bitch turnigy accucell 6 lipo charger it charges 1 cell at 3.8 to 3.9 volt while 2nd and 3rd cell reaches to 4.28 to 4.3 and that dangerous so I calibrate it such that all will have 3.9 overall voltage but again it takes lots of time to balance it event sometime it takes 4 to 8 hrs
So while struggling with this issue I came across the youtube channel called as rcmodelreviews from where I designed 1s charging wire and decide to charge lipo battery cell individual but again it takes more time to ake it balanced
Then decided to have icharger 106b+ and everything changes some rc hobbyist told me it happens when cell eges. But icharger came and all cell are at same voltage

And that's my personal review

Actually there are two versions of turnigy accucell 6 one had ir measurements technology and other don't have it. After all I was having other charger but one of my friend on rcindia from which I bought 2 3000mah 3s lipo has ir about 17,18,35 milliohm and it is considered as having ir greater than 6 to 8 depending on temperature condition is very bad or cell is dying. At that time I don't have much knowledge about internal resistance in lipo so I bought them from him. Later on after using icharger and by checking their ir on it ., I was surprised it showing 3,4,2 which is good enough that's why I don't believe in others anymore

Then decided to have icharger 106b+ and everything change..
You mean your problem got solved?
Its interesting. I am discharging  2 cells in mine... will charge them  all again lets see

Ofcource after using icharger problem is solved. Just tried to help you. You can laugh at this or use it choice is yours. Sorry to have commented on your post. You can delete it.,😔😕

Relax mate... not laughing... actually i am considering buying a smart charger now... Seeing that it worked well for you.
But i am still interested in understanding what the problem is.... It intrigues me.

Thanks but it's almost 3 to 4 years i was using turnigy accucell it does not charges lipo correctly may be several things are included
1) internal resistance of cell may get increase (do not use multimeter to measure ir directly it may damage lipo and multimeter)
2) lipo and charger terminal ( connectors) resistance may be the reason
3) icharger has voltage calibration at balanced port also but other don't have it so that other charger only calibrate total voltage and not balance port
Or may be other reason that I don't know
But you can check one thing try to discharge all cell at equal lets say
3.8 volt and charge each cell individually at same current and note the time for all cell if any one cell takes longer time then it must have high ir. You can have try this.

Yes that is exactly what i thought.. discharge all...then charge all...it should work...otherwise ir is high.👍

Here's a possible explanation, from what I think has happened.

Your previous charger had a problem, particularly with the 3rd balance pin. Due to which, maybe the probable cause, it would've resulted in a mild short or something like that; every time you charge it.
When this thing happens over a period of time, the chemistry gets disturbed, and the internal resistance increases. In other words, that particular cell had an accelerated wear.

If it were a short at the output end, the internal resistance on all of the three cells changes, and you won't notice a thing when charging. Probably a higher charging time.


What I've said is highly theoretical, and happens maybe once in a million times. But since you've used a fake charger, it just increases the probability.


What I think you should do is, get a good multimeter and measure each internal resistances. If it were different, this might be the possible scenario.


Hope that helps.

Quote from: Aravind298 on April 29, 2018, 12:04:05 AM
Here's a possible explanation, from what I think has happened.

Your previous charger had a problem, particularly with the 3rd balance pin. Due to which, maybe the probable cause, it would've resulted in a mild short or something like that; every time you charge it.
When this thing happens over a period of time, the chemistry gets disturbed, and the internal resistance increases. In other words, that particular cell had an accelerated wear.

If it were a short at the output end, the internal resistance on all of the three cells changes, and you won't notice a thing when charging. Probably a higher charging time.


What I've said is highly theoretical, and happens maybe once in a million times. But since you've used a fake charger, it just increases the probability.


What I think you should do is, get a good multimeter and measure each internal resistances. If it were different, this might be the possible scenario.


Hope that helps.

yeah this is exactly what i wanted to know... possible reason...yes a cheap charger i think could have been the culprit..

also i noticed the cheap one charged my cells to 4.26 volts... while the sky rc charges to a safe 4.20-21 volts.

i remember my wise part telling me to not to cheap out on buying a good charger,,,, should have listened
i have managed to get one of them to balance after an  overnight charge.
suddenly i love my lipos a lot more .