Zippy Pack 2x6s 2650mAh 40C Problem after less than 10 cycles on a Trex500

[santomotion]

Hi,

I use a 2x3s 2650mAh 40C on a Trex500. I´ve used them under 10 times and no 3D flying at all, so they are almost new. I´ve put them into the heli today and right after lifting and changing the curve it seemed like the ESC was going into lipo cut off phase because the motor was not pushing.
I´ve tried other pack and work fine so it´s not a heli problem.
Voltage is over 4Volts in every cell
I´m quite surprised since they have been working fine and they are almost new.

Any reason you could think of?

Did anybody had problems with similar packs before?

Cheers!

[acidla]

That is strange, i have the same zippy packs also used on my Trex500, 12 packs to be exact and no problems so far. Half of them are really old and still they perform relatively well.

[santomotion]

The only think I could think of is that on one flight I overraned them and the voltage went down to 3,2v, but after that they've been working alright, and that was a one time only.
I would understand the low performance if one or more cells were at low voltage, but they're all above 4volts so it must be that under workload some "brake down", is that possible? How could I check that?

[ChrisB]

A suggestion as a possible cause that I have seen many times would be voltage drop under load,the Pack charges to 4.2v ok per cell but when loaded one or more cells will drop out.

[santomotion]

A suggestion as a possible cause that I have seen many times would be voltage drop under load,the Pack charges to 4.2v ok per cell but when loaded one or more cells will drop out.

I think that's exactly what happens. Is that due to a factory problem? Could I claim a new pack or something? I'm going to email the shop to see what they say....

It's quite disappointing to get a new pack and not being able to use it being so new.

Could you think of any reason for that to happen?

[ChrisB]

I think it's certainly worth contacting the shop and sending it back for them to test if they allow it.

Normally I have seen this in older packs but I have found the Zippys to be much shorter in lifespan but I am still talking 30 plus cycles.

I think it comes down to QC at the factory and a bit of luck,I think the cheaper packs carry more risk of failure but for sure they can also be very reliable for some,I think as you move up thru to the more expensive packs the chances of a duff pack greatly reduce but you almost certainly will have some support from the supplier.

[p4ddy]

I've never used Zippy's only turnigy & in my experience i've found they do not like to go over or even bang on 80% discharge. If you went slightly over then you've probably knackered one cell. You can't send them back either as the warranty only allows you to send un modified & unused & i think uncharged lipo's back. I myself would use Turnigy's next time instead of Zippys. I have old Revo packs for my logo & although they say 4.205 each cell the esc will go into LV cut off within seconds of take off but these packs are very old & well used.

[santomotion]

Hi,

I charged both lipos and I could only put in around 300mA, I´ve put them today back on the heli and surprise... they´ve worked completely fine! I don´t understand why.
Could it make any difference they way they were charged? I think last time I charged them at 1,5C aprox. (4A, they are 2650mA) instead at 1C as I normally do, that´s the only difference I could think of.