Bought 2 lipo, one of them using many hours to balance

[waterproof]

Hi!

I bought 2 lipo battery today.
Tigerpower 2s 5400mah 35c hardcase.
The first battery used maby 1 hour and 15 minutes to full charge both cell.

Battery number two have use 3,5 hour and it not finish yet.
It goes from new 3,64 3,72 (unbalanced out of the box) and the one cell was balanced up to 4,20 just after 1 hour 15 min and the last cell was 4,10.. It goes slowly up from 4,10 but it have charge maby 2 hours just to get from 4,08-4,15 and it still balancing. Why is it using so long time to balance one of the cell?

Anyone know why a new battery do like that? I charge with 1c.

Happy for some answers :)

[longballlumber]

There is a bad cell in that pack. No question about it.

If those were new packs, I would be contacting the seller/manufacturer ASAP.

Later,
Mike

[waterproof]

Ok, could it be dangerous to try to use this battery? Its finish charged now, the one show 4.19-4.20 and the other 4.18

Yes its brand new.. Also try to discharge it with the computercharger, battery feels cold, it charge fast up again now the cell that using long time the first time have 4.18 when the other shows between 4.20

Edit: now the battery with issue is finish after 15 min discharge, its show 4.20 and 4.19
Is it still best to drive back to the store and change it with a new? Will it be a risk to try it to my boat?
Just purcase a new boat that i will try soon, but i dont want to take risk if it is that?

[kfxguy]

I would run it or cycle it a few times and see if anything changes. if not, a call to the manufacturer would be a good idea.

[waterproof]

Thanks for the support, its seems that the issue is fixed after a cycle with my charger, i guess its nothing to worry about now? Or could it be a risk? If i use it today in my boat and it last for a normal time and charges up again on normal time i will guess that it was so slowly just because the battery was new?
Would you still get refound or just use this since it not show issues now?

[waterproof]

I have try them in my boat now, everything seems to work but im a bit unsure why they are so unbalanced after use.
Battery nr one have 3.40 3.70
Battery nr two have 3.50 3.60
Stock miss geico 2x2s 5400mh about 13 min runtime.

The hobbystore say i could try to use them a couple of times and see if they getting better, or i get replacment, but they only have this type of battery in stock and i dont thing a new one will be better when i bought two?

[waterproof]

Today its going almost real bad with one of the battery.
The boat suddently cuttoff and i could only get it it in with minimal trottle and it just cutts and cutt before i got it in.

The battery have 3.04 3.70
Battery number two have 3.68 3.78
I must replace the first battery, but what about battery with 0,10 difference?

[siberianhusky]

If they were mine I'd replace both, have the voltage checked before you leave the store, all cells should be at 3.8v - 3.85v or very close to it. This is equal to about half charged. Some chargers use 3.85v others 3.8v for storage.
I always buy my batteries in pairs if they are going to be used that way, and keep them together. That way I know how many cycles and how much abuse each pair has seen. I think this helps to keep the internal resistance close to the same so they will discharge evenly (hopefully).

[waterproof]

Yes, when i charge them for the first time they both have around 3.68

The boat runs like it loose the connection to the remote so it was difficult to get it in and here i live its realy cold water right now :)
Do you know if this episode would affect the electronic in the boat or have it nothing to say that i used this bad battery?

[kfxguy]

get replacements. you have defective batts. what is tigerpower anyway? never heard of those before.

[waterproof]

I think they are the same as king Max.
The wierd thing is that the battery with 3.04 is going up in voltage, now its 3.22 and i have not charge it!
The hobby shop dosnt have any other in stock, im not sure if i would try 2 new, maby its better to get the money back and buy batteries from another store, its not many that have lipo with ec3 connector, is it ok to use ec3 to deans adapter to rc boats?

[siberianhusky]

Probably didn't hurt anything, you weren't able to run for very long and you did the right thing by bringing it right in and not trying again.
The cold water might have helped out, cooler is always better as far as the esc goes.
Many people have reported good luck with the plain blue Turnigy batteries from Hobby King. I've only had one set, they were OK for my setup at that time. A stock SV27r isn't really very power hungry. I really can't give you an honest opinion on how they work in higher power setups, never tried.
They certainly are cheap depending on shipping requirements.

[waterproof]

Ok, what could go wrong if i got replacment battery and it have the same issue and the volt drops under 3.0?

[siberianhusky]

If the batteries can't supply the load the esc will heat up very quickly and fail, depending on what part of the esc fails it could possibly damage your receiver and servos. Also the motor will heat up if it isn't getting what it needs, this can cause the windings to short or if it gets hot enough for the magnets to demagnetize.
Below 3.2 volts you are risking battery failure, they will puff up and basically not work right anymore. Once damaged there is no bringing them back. Not sure if they will go up in flames. Personally never seen a Lipo go up, back in the car days I had a Ni-cad cell blow.

[waterproof]

Ok i understand, the shop says if it goes under 3v it only destroy the battery and it will not charge up again.
That happend to me on a rc car, no fire :)

I got replacment battery today, and now it was 3.40 3.55 and the second was 3.65 3.70 so this seams better, it also runs 15-16 minutes so i got around 3 minutes more runtime.
The boat dosnt get hurt from the last episode there one of the battery gets low?
Because the boat goes to lipocutoff? The boat calculate the total volt from all 4 cell so it have got the power it needs
even that the one battery cell was 3.04? so were those other 3 cell higher that gives the boat enough to not stress the system?