repinfl

My Feedback: (40)

I purchased a Great Planes Eletrostik ARF that came with an Electrifly Silver Series 45 amp brushless ESC and a Great Planes Rimfire 42-40-1000 outrunner brushless motor. I also purchased there ElectriFly 11.1V 3200mAh 20C BP Series LiPo Battery at the same time. Everything worked GREAT! Later I purchased some batteries fron Hobby King, (Turnigy and Zippy) trade names of same type as the ElectriFly but much cheaper! They were 3300 mah 20C to 35C. When I try to use these I have a problem. If I advance the throttle very slowly all is OK BUT when I advance the throttle quickly the motor stops and there is a LOUD growling noise. When I reinstall one of the ElectriFly batteries, and I have more that one, they work with no problem. HELP! Thanks, Robert

TheWoodCrafter

My Feedback: (1)

That is a strange problem.

Your new batteries are 3S LiPo, Right? You are sure?

repinfl

My Feedback: (40)

Yes they all are 3S 11.1V amd vary from 2200 to 4000 mah but all are 3S!
They vary from 20C to 45C whereas the Great Planes batteries are all 20C.
Can not find anyone that know the solution. The system ARMS correctly and
will work if I SLOWLY advance the throttle but not if I advance fast. Yet
everything works great with the Great Planes batteries!!! I am trying a lot
of things and next I am going to switch complete radio systems from Futaba
to Airtronics and see what happens. Any advice would be great. Robert

TheWoodCrafter

My Feedback: (1)

Did these new batteries charge O.K.?

Have you/ can you measure the voltage of these new packs?

It would be interesting to see the voltage of these batteries when you see this happen and compare that to the old batteries when it works fine.

repinfl

My Feedback: (40)

All batteries charged OK. I use a Hitec X4 charger and then I check them with a battery detector LCD6 which gives me the voltage of each cell and they are all right on! I think that I am "barking up the wrong tree" as I just switched to an all Airtronics system from Futaba and all works fine.
I had tried two new Futaba receivers with the same results so tried Airtronics and it works with all batteries. Still do not see why Futaba worked with the Great Planes battery but would not work with the Hobby King batteries. Next I am going to try a completely different Futaba system, new transmitter and receiver and see what happens. Thanks for the interest.....Robert

pilotpete2

I think your symptom is due to the new batteries having a higher "C" rating and delivering higher voltage under load than the older Great Planes 20C batteries. Higher voltage at full throttle would be pushing the motor a little harder, possibly triggering off a timing issue with the ESC/motor combination. Does the ESc have different timing options?
Pete

Jezmo

+1 on Pete's post.

guver

My Feedback: (325)

I think it is the opposite problem , voltage too low when advancing the throttle too quickly. Possible trouble is connectors,adapters,small wires,long wires,bad/weak cell(s)

It may be hitting the LVC when throttle is blipped. To confirm put one of the problem packs on with about 20-50% charge to see if the trouble goes away. OR y in 2 problem packs in parallel. OR check voltage during the trouble if you can on both packs.

Walt Thyng

My Feedback: (9)

Capacity has nothing to do with voltage. I.E. a higher discharge rate LiPo does NOT affect the voltage that the motor sees. The discharge rating is only a possible rate that is determined by the motor/prop combination.

It sounds to me like a low voltage problem, though given your assertions, I'm not sure why. Check wire sizes, connector and how they're attached to the battery leads.

I use a variety of HK packs and find them completely acceptable (with the exception of one that arrived with a bad cell).
Walt

TheWoodCrafter

My Feedback: (1)

That is why I suggested he measrue the voltage while it is happening.

guver

My Feedback: (325)

I'm not sure of the actual current this electro-stik pulls, but ALL of the above mentioned packs may be borderlined "not quite enough current capability". My limited experience with GP BP packs tells me they are not quite up to par w/ their ratings. My limited experience with HK packs tells me the same.

Walt Thyng

My Feedback: (9)

I agree with Guyver. Youse gets what youse pays for. Over stressing HK packs can bring some surprises. Once again the 80 % rule applies: Limit anything you do with your batteries to 80% of the given parameter and you should be okay.

TheWoodCrafter

My Feedback: (1)

There is nothing wrong with HK LiPos.

They have been stressed to hell in helicopters for several years  now . They stand up just fine.

He needs to put a volt meter on that particular battery to see what's going on.

repinfl

My Feedback: (40)

A little update on my problem...GP Electrifly 2100 20C 12.1V @ time of test.
Watt meter readings=11.2V - 25amps - 220watts.

Turnigy 2200 20C 12.1V @ time of test.
Watt meter readings=11.3V - 33amps - 370watts.

Being VERY new to this, I really do not know if these reading are good or not.
The Batteries probably need a recharge after all the testing I have been doing
these last two days. I will recharge and run the drill again and thanks for all
the input and if anyone can tell me if these readings are good or not would help
Robert

TheWoodCrafter

My Feedback: (1)

So these readings are when the batteries are connected to the ESC and you are operating the throttle?

Is the Turnigy reading when the motor is stalled?

repinfl

My Feedback: (40)

These readings are when the battery is connected to the ESC through a Watt meter and throttle has been advanced SLOWLY to full so the motor does not stall.

TheWoodCrafter

My Feedback: (1)

And the Turnigy is providing more current.

I think Iam going with Pete's idea here.

Re-program your ESC.
It may not be the timing issue but Iwould re-program using that battery and see what happens.

repinfl

My Feedback: (40)

Can NOT time an Electrifly Silver Series ESC.
I switched from Futaba to Airtronics and have
no problem at all with Airtronics. Motor does not
stall at all with Airtronics!!!! I have fired
off an e-mail to Futaba Support to see what they
have to say. Thanks for the help and I will keep
posting here if I come up with a solution so that
it may help someone else. I think it may have something
to do with the throttle settings on my Futaba transmitter
and I am looking into that, maybe I can solve it myself.
Robert

Goldenduff

Hello, I too run Futaba and had a similar problem- was intermittent and seemed to go away when loaded (in flight). Obviously not a stategy to use with your pride and joy. I waggled the wires to the motor before flights so not sure if that's the cure! (? dodgey motor connections?).

I have found Futaba's support to be excellent and eagerly await any news!

Thanks

repinfl

My Feedback: (40)

Do not understand "waggled the wires to the motor before flights so not sure if that's the cure! (? dodgey motor connections?)."
Robert

Goldenduff

Waggle, a technical possibly Scottish word for wiggle/move- I basically moved them right/left then pushed them further in. Seemed to work!

TheWoodCrafter

My Feedback: (1)

LOL

I think I remember my Grandmother using that word.

repinfl

My Feedback: (40)

I may have found my problem! The Airtronics transmitter was already set up for
this same airplane that I have at my Summer home and it worked perfect with this airplane.
However the Futaba transmitter is new and I just set it up and left the throttle trim
"as is" which was CENTER. When I set the Digital Trim for throttle to absolute low things
worked correctly. Waiting to see what Futaba says.

guver

My Feedback: (325)

My theory is out. It is wrong. The voltage readings are fine and not stressed. The 2 different volt readings also do not quite make sense (11.2 ans 11.3) The current and power do make sense. The 11.2 really should be around 9 volts.

James c harrell

My Feedback: (18)

I have found that on futaba I have to run with the throttle trim at dead bottom or they will cut out on hard accellerartion. Don't know why but the trim doesn't affect the top-end performance at all. I replaced the recievers in a couple of Parkzones' with Futaba 2.4 and they would cut out till I moved the trim. No problems since.