SimonBryant

Hi Guys,

I'm looking to put on a E-tech 2 Cell 2400mA on a slow stick. It will have the Pixie 20p ESC, this will be powering a stock 300C motor (D Gearbox T-66, Prop 1180), ideally i would like to keep the JST connectors for the battery, would this be a problem with the JST connectors or should i upgrade them?

Advice would be much appreciated??

Regards

Simon

millet_flyer

My Feedback: (5)

It'll fly forever! The JST's will work fine in this application. Program the esc to cutoff at 6.0V. Good Luck!

SimonBryant

Hi thanks Millet,

I will continue to use JST connectors until i upgrade the motor, thanks again.

Simon

zagibond

Simon,

I bought a 1500 2cell for the same application.
I would bet that the 2400 will fly for almost an hour.
I would interested to hear how a 2 cell performs on the SS.

Where is mine? Left in the rain and dead after a very short test flight.

SimonBryant

Hi Zagi

I've been told that the 2400mA will give me approx 45-50 mins, the Battery should arrive today, so if its calm weather at the weekend i'll fly and time the flights....i'll let you know!!

Simon

zagibond

Great, I am interested in the performance with the lower weight of the Lipos and only 7.4 volts.
I have been flying my slow stick with 8.5 ounce 1700mAH 9.6 Volt NiMh. They are to heavy the Voltage is too high. I am afraid that 7.4 may be a bit low?
Let me know.

millet_flyer

My Feedback: (5)

With the 2s2p1500mah my SS flew for 65 min. Geez, my thumbs were done.

SimonBryant

Hi Zagi

Well i flew the new Litho setup at the weekend, WOW, incredible flight times, i was using a 1260 prop so it was probably drawing quite a few more amps that say a 1180, but i still has over 30 mins flight time, and as for power 7.4v was more than enough power, infact i flew 3/4 throttle mainly as i was scarred at burning the motor out. It has so much more power that those crappy NiCD and Nmhd.....i'm going to prop down to a 1180 after work, wind is forcast at 7MPH.

Also the Litho was not fully charge....so i would estimate another 10-15 mins giving me a total of around 40 mins...

Will keep you posted

Simon

SimonBryant

I decided to fly with the 1260 prop, a little dissapointed with the flight time, which was only 15 minutes with the 2S2P 2400mA, thought i would get much longer flying????

Any ideas??

Time Pilot

I think you should get more too. I get about 8 minutes of mostly 1/2 throttle with a nimh 650 pack with the same prop.

zagibond

Not sure what I am missing. Your first post looked like you had goood flight times, the second that you were dissapointed.
I doubt that a 7.4V will burn out the motor. I have burned up a few with 11.1V on my 3DX though.
I would imagine that the 2400 should give you plenty of flight time.
If my math is right 2400 mAh = 2.4 Amps for one hour, or 2.4 Amps for 60 minutes
I would guess that 3/4 throttle would use about 6 Amps with a 1260.
You should get 2.4/6*60 minutes ie. 24 minutes .
Mmmm something is wrong. Where is DR Kiwi when you need him?

SimonBryant

I'm just wondering if thats whats happened. I'm wondering whether the motor may be on it's way out, it would explain why i'm getting not as long flight times.

I have a spare motor so maybe i should try that.

I really think that with a 2400mA lith should give me more than 15 minutes on idle..

The other possible fact could be that the feild battery could be down on volts etc....and may require charging.

Simon

Dr Kiwi

Hi Zagibond - I'm here! And I believe I answered this question as best I could in another thread. I think I said that WOT with that combo would be 7A, so that should get Simon 20 minutes (or 30mins on 60-70% throttle). There is something else going on here - the battery may not be fully charged or the LVC may be incorrectly set, or there is a short somewhere!

Cheers, Phil

SimonBryant

Well something is going on....my flight yesterday was just 10 mins.....
i think the motor is damaged!!

??????????

SimonBryant

Hi All
It appears the flight performance is getting increasingly worse on each flight, here are the stats……..
This is what I have recorded since the first fight with the litho.

1st Flight charged @ 700mA – 4 hours until green charge light appeared. Flight was 23 mins on variable throttle.

2nd Flight Charged @ 700mA – approx 4 hours until green light charge appeared. Flight was 16 mins on variable throttle.

3rd Flight Charged @ 700mA – less than 3 hours until charge light appeared Flight was for 11.5 mins on low throttle.

4th Flight Charged @ 1200mA charged within 1 hour , left on charge for 5 hours. Flight was 9 mins on low throttle.

5th Flight Charged @ 700mA charged in less than 45 min : Will Fly Lunch Time For Results.

Something’s not right , I’m just wondering if it’s the battery that’s deteriatting.
Interesting don’t you think?
Simon

SimonBryant

Now I'm really confused as i've just done an 18.5 minute flight......really don't know whtas going on here?

Help?????

millet_flyer

My Feedback: (5)

That's a good one... Other than a poor connection, I don't know what else to tell you!!

sierra gold

I didn't notice you mentioning - what charger are you using on the LiPo?

Sierra Gold

Time Pilot

Simon,

My contribution to your problem. I'd change one thing at a time so you know if one was the problem.

- Check all electrical connections for a good connection and no shorts.
- Change motor and see if problem goes away.
- Check to make sure the pushrods and surfaces are not binding.
- Ensure servos are working smoothly and are in good repair.
- Prop balanced?
- Is shaft straight and gearbox working smoothly (Great planes suggests to put a piece of paper between the spur and the gear when assembling their gearbox. I start the screws for the motor, 'roll' a piece of paper in, and then tighten up the screws, then roll the paper out).
- Test the battery both after it is charged and discharged to see if the charger or the ESC may be the problem.

zagibond

Simon,
I would be curious to know what charger you are using.
What speed control. Really cheap speed controls use as many amps at 1/2 throttle as at wide and burn up motors.
I agree with time pilot. A bent shaft saps up power.

Dr Kiwi,
Thanks for the response. You are the man!

Time Pilot

Zagibond,

Cheap ESC's use as many amps at 1/2 throttle as at wide? Really? How does that happen?[sm=confused.gif]

And, (maybe more important), are the GWS ESC's (the 300 is the one I have) in this category?

If so, I suppose I can stop flying at 1/2 throttle thinking I'm extending my flight times!

Time Pilot

Simon,

If I recall correctly, you were able to do outside loops with your Slow Stick. Being a bit jealous, I thought I would change my setup as the best I could do inverted was a very slight climb with full down elevator.

After the change, I noticed my servos straining with 2/3 to full down--pushing against the tape and some of the foam, I guess. This would eat up more power. But as I was more concerned with servo failure, I put it all back the way it was and the will to be content that outside loops will be on my next mod should I destroy the horizontal stab.

But for you, this may be an area to investigate for leaking power.

zagibond

Simon,
No I don't think the GWS falls into that class.
There exists a ESC that comes standard with the Sky Scooter that causes the motor to chatter at below haf throttle. It gets the motor really hot and actually causes premature failure. I measured the Amp draw once on this ESC and found that it had no bearing on throttle position.

Honestly, I would be looking at my charger or batteries if I were you. Have you ever run your batteries too low? That will cause them to not hold a charge and act like you are describing.

If it were a bent shaft, too tight a gearbox or a bad motor you would see performance issues all the time.

SimonBryant

Hi Guys,

Appologies for my slow relpy as i've been on vacation this weekend.

Anyhow answers to your questions. First off I have the Castle Creation 20P Pixie speed controller.

The Battery is the E-tech 2400mA 2S2P and the charger is the E-Tec Apache 1-2 Cell Li-Poly Charger 1.2A.

The last flight time I had was this evening, this was based on a 12X6 prop and basically was just poodling around at approx 50% throttle with a couple of small full throttle blips (a few seconds at a time) FLIGHT TIME of 23 Minutes

I have replaced the motor and gear box to rule out a faulty or dying motor and replaced the whole gear and shaft to rule out a bent shaft as some say this saps battery time.

So with a flight time of 23 minutes does this sound correct with the current prop/battery/and amount of throttle applied or am i still loosing stick time somewhere... do i still need to look at the battery or charger.

Regards

Simon

PS:- Charging times seem to vary also!!!!

SimonBryant

Ok I've just put on an amp meter to test my amp flow and this is what i get.

Based on the 300C motor D Gearbox, 12X6 prop.

50% Throttle = 4.1 amps
100% Throttle = 6.2 amps