Gone Brushless-Help please

[Kelly]

Hello

I have gone brushless with my Ripmax lecky Spit.Not wanting to fork out for a lipo battery and charger I was told I could still use my 9.6v Ni-cad batterys.

well I charged the battery as normal followed the switch on instuctions with the esc,lots of beeps. throttled up and at 3/4 throttle the motor cut out? pulled the throttle back then added power same thing.

Motor specs are Thunder Tiger Ripper 36 series
Over-tech P series Bec Controller.

Would It be better to invest in lipos.

Very new to electric flight would value any advice to resolve this problem.

Thankyou all

Kelvin

[Phil Meredith]

sounds like the motors drawing more than its got in the bank, and no overdraft, i would suggest a lipo pack, im sure timbo can advise you better on the correct setup when he sees the thread,

[GrumpyGnome]

Hi Kelvin, not much to go on but here are a few suggestions:

1) Drawing too many amps for the ESC to cope with - try and get hold of a WattMeter. Remedy, change prop or ESC
2) Cells can't cope with the load so voltage drops below the Low Voltage Cutoff (LVC) at the ESC. Remedy new cells or decrease the load by changing the prop
3) LVC set too high on ESC. Nice easy remedy - correct the ESC settings.

If you can get a hold of one, a Watt Meter will let you see amps and volts so makes checking 1) and 2) very simple.

I prefer my Spit with MiCad/NiMh to be honest - struggled to get a Lipo heavy enough in and I hate adding lead !

GG

[Alistair Taylor]

I've experienced this with a brushless motor controller.

It was a 70 amp controller, and on plugging in a 9.6V nicad and connecting it to the Axi 2820/10 motor I wanted to use it with, it would beep, and make the motor turn over at up to 1/2 - 3/4 throttle, then the motor would cut out.

I tried everything, eventually deciding to read the instructions....

The controller was rated for 12 - 16 NiCad/NiMH cells, or 4S - 5S lipos. So while the 8-cell NiCad pack gave out just enough volts (freshly charged) to persuade the controller to start up, as soon as I drew any amps, the volts dropped back to 9 ish and the controller cut out.

I will probably end up using this controller with a 600W cheapy brushless and 16 cells (two 8-cell packs connected together) in a 100" glider.

Hope this helps

AlistairT

[scott cuppello]

I run the Ripmax Spit with;

E-Flight 0.10 Equiv outrunner

12x6 prop

45A ESC

3600mah 11.1v Lipo

and it is stunning! I think with the brushless, you won't get the benefit until you go lipo. Yes you have to add weight to the nose, but in terms of performance, it's worth it!

[Kelly]

Hi everyone

Thanks for all the info to date,just had another look at the ESC info it is 40A and it can be programmed for different voltages using a system of beeps, to cut off when voltage drops below a specific value also lots of other things I do not understand,
eg:- positive and negative turn of the motor/setup of PWM mode etc etc up to a max of 16 beeps???
I will have a go at setting it up using the beeps from what I understand of the motor prop size it should work but I probably don't undertand that either:-)?
If that does not cure the problem I will try smaller prop.It is looking like the old current account(pardon the pun) may get another bashing for a couple of lipos and a charger.

Many thanks
Kelvin

[scott cuppello]

Just one thing Kelvin, with the extra performance, don't launch at full throttle if you are pulling the big prop, go 3/4 throttle, there is a risk it will torque roll when you launch!

[Kelly]

Hi Scott

Thanks for the advice.Launching is the time you miss some help when you fly on your own,the reason I decided to fit a brushless was the lack of power during a nil wind launch its very difficult to give it enough speed and it takes time to get your hand back on the stick(failed to launch both attempts at nil wind launch)plus I am a bit rusty after 30 plus years since I last flew R/C models,my excuse.
I have foud a few sites dedicated to electric flight,If anyone could recommend books/websites on the subject I would be grateful.
I am considering joining my local club to do my A certificate although I need something with wheels,may buy another spity and fit a set of wheels,is it possible to fit retracts,I am upgrading to 6 channel in the near future(more account bashing).

Thanks Scott and everyone else,this is a good forum.
Cheers
Kelvin

[Kelly]

Hi
Set the ESC to 8 beeps = low voltage cut off when falls to 55% of starting run voltage,and it works tested to full power on several short test runs,seems to have cured it.Have to see how many minutes flying time I get with this setting.

Cheers

Kelvin

[scott cuppello]

Oooops, get my info right, motor is an E-FLight 0.15, not 0.10! Actually wish I'd used the 0.25, would drastically reduce lead in the nose, more power [not needed], but longer duration as a result of more power. Also, you MUST use MG servo's in aileron and elevator!

[Kelly]

I was wondering if it would need MG servos after lots of items flew about the living room in the blast from the prop.
The elevator seems a bit flimsy thinking of beefing it up in the middle.
Lots of time before the good weather returns