New batteries - cheap junk?

I’m just trying out a couple of batteries purchased cheaply.
Testing, both on a discharger and in the aircraft seems to show a terrible performance - they give about 1000mAh and show 50% charged, in the air a very gentle 2 minute flight uses 40% (a throttle heavy flight usually uses about 60% in 4 1/4 minutes, and takes about 3500mAh to recharge.
In both instances (discharger and in flight the pack only seems to take 1200-1400mAh to recharge.

Basically the two batteries seem to have the capacity of a 2000-2200mAh pack rather than 4500!

I’ve had other cheap 4500mAh packs previously, at less than half price of other makes and been more than happy with them.

would this seem to be a fair call to return them?

i know the whole buy cheap, buy twice logic but a performance seeming to be less than half a decent package seems astounding and indeed atrocious!

Edited By Ian Whittaker on 22/11/2020 22:14:49

What brand these batteries? Please

Dave

I think that we need more information before making any judgement.

What is the 'C' rating of the batteries?

What current are you drawing at full throttle?

How old are the batteries?

What sort of charger are you using?

On the face of it, these batteries are rather sad, but we need the extra bits that I have listed to make a proper diagnosis.

Tom

Regrettably, it is all too easy for a manufacturer of Lipos which have "questionable" quality to simply wrap their dreadful product in a label which displays some outrageously optimistic numbers.

We are a trusting lot, so it isn't until we put the batteries "under the cosh" that their deficiencies are revealed.

. . . and then there's that wonderful moment of realisation that we've been had.

Hi Tom, thanks for your thoughts.

The batteries are marketed at 60C

Im unsure of the current, although after a flight no battery has ever been any more than slightly above ambient. They are used in a helicopter, which although certainly current happy is a purpose designed set up, with motor, esc and power train as set out and indeed supplied by the manufacturer. The recommended cell capacity is 2600 to 5200, so I’m not pushing any new boundaries.

The batteries are new.

They are being charged on a Sky RC e680 - a 80w device so at 3.4A (max), although I actually set it at 2A.

I’ve actually contacted the seller who has immediately offered a refund, which I’m happy about. Im not sure if I’ve just received two from a duff batch or if the actual design is actually pitiful!
I have had in the past used a cheaper, smaller than normal pack, a 4500mAh pack marketed by Ripmax (from memory) and found it ideal. Yes, the remaining capacity was slightly less on landing but that’s to be expected as it’s a smaller capacity anyway. It just meant I had about 30% remaining as opposed to 40 - not a problem. I’d still be using it but it got damaged during an ‘uncontrolled arrival’...

Edited By Ian Whittaker on 23/11/2020 09:21:55

Your first post quoted a throttle heavy flight of 4.25 minutes requiring a 3500mAh recharge. That suggests an average current of about 50amps. Hardly an onerous task for a 60C 4500!

Dick

A reasonably happy ending then.