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Old Sep 21, 2001, 10:56 PM
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Joined May 2000
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Jeti 70 amp brushless controller on 18 cells-- no problem

Hi all,
did some testing today again at the field.

Jet 45-3 and Jeti 70 amp opto brushless

Motor can take 20 cells all day long,
we know that.

Had to try the Jeti controller:

This is a geared ( 2:1) 45-3p driving
a 15 x8 :

20 cells -- won't start up..
I guess it's the gearbox or the heavy prop.
Will also try with belt drive.
Had the same problem with other configs.

18 -cells-- no problem .
It was warm ( 80) , but the controller
was NOT EVEN WARM!! ( 20 x 2400 ).
testbed was my trusty old LT 25.

So: 18 cells on a jeti 45 3p is not a problem
for 70 amp controller and motor.

To do:
try DD -- tomorrow.
Try GD with lighter prop-- Sunday.
Try belt drive --sometime next week.

Andre
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Old Sep 22, 2001, 05:35 PM
RIP Ric
Andy W's Avatar
Marietta, GA
Joined Jun 1999
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How about 100A peak?
That's what I need to know (I've been told it's OK)..
..a
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Old Sep 22, 2001, 05:38 PM
H2OFLY
Portland Oregon USA
Joined Feb 2000
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See, Bernard?

I'n NOT the only one who puts 20 cells into their LT-25!

Terry
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Old Sep 22, 2001, 09:55 PM
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Andy,
I tried to add a cell to my Hacker setup and the Jeti would shut the motor down after a short run. Specifics...B40-8S, 4.5:1 gearbox, cut down 12.8x13 RFM prop, 8-1250s (tried 9 and that's when I started experiencing problems). Suspecting too high current as the controller was barely warm after a very short flight. You might ask Sean Plummer about this, he told me he's done some not too gentle testing on the Jeti line and the 70 amp controller was the only one that did not care to be run over it's limit.
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Old Sep 22, 2001, 10:54 PM
RIP Ric
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Marietta, GA
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I will be trying this myself @ 100A or so.. just wanted to see who else had done the same..
..a
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Old Sep 23, 2001, 12:11 AM
BEC
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Quote:
Originally posted by Terry
See, Bernard?

I'n NOT the only one who puts 20 cells into their LT-25!

Terry
Well...... I'm not sure how to respond to that

Sounds like 20 cells didn't get off the ground.

Andreas,

Usually the upper cell limit on an ESC is set by the voltage the FETs can handle. You can get away with more cells when they're fresh because of lower internal resistance and therefore lower peak voltages. I expect Jeti are like most makers and conservative about the rating.

I'd be real curious to see if you can get 20 cells to start.

Scot,

Which controller are you using on the Hacker? I've run the 06 (as you know), the 30 and the 40 (both versions). The 30 runs warm at 30A. The 40 will take peaks over 40 easily. If the overcurrent protection in the brushless units is like their conventional ones, it doesn't kick in until you're around double the rating.
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Old Sep 23, 2001, 03:20 PM
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Hi Bernard,
I am using the 70 opto controller with the Hacker motor. I never measured the current with this exact setup so I don't really know if I'm exceeding the max current. But did measure it a while back when I was using a Kontroniks controller but with a different prop and on 8 cells it was somewhere around 60 amps...it's been a while so don't quote me on that. If what you say about over-current protection is true, perhaps I should try it again. When are you going to "test" your's Andy???
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Old Sep 23, 2001, 06:43 PM
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Quote:
Originally posted by ScotY
Hi Bernard,
I am using the 70 opto controller with the Hacker motor. When are you going to "test" your's Andy???
Ok all,
Voltage seems to be the limiting factor here.

Jet 45-3 will not start on 20 cells DD
using the Jet 70 Controller.
Will start on 18 cells, using a 12 x10.
Guess I have to play with the props...
was thinking of a 13 x 5.

Andre
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Old Sep 24, 2001, 10:28 PM
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Winston-Salem NC
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Andre,

Could you explain why the motor will start with 18 cells and not 20? (Is it the motor or controller, I'm still learning)

With your best Phasor setup for sport/aerobatic flying (5 to 8 min) how far are you away from performance like the OS 61FX or 91 4-cycle?

Marcus
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Old Sep 24, 2001, 10:49 PM
RIP Ric
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Marietta, GA
Joined Jun 1999
43,312 Posts
More than likely, controller. No reason for the motor to care about voltage, until the windings let out the blue smoke..

Test mine.. well, I'm unhappy with the glitching I was experiencing with the Sirius so I'm going to completely strip out the entire 12-cell system (radio, aileron servos, F12/L260C, etc.) and rebuild it with the 500/48 and the Jeti controller, new receiver, etc. The Kontronik motor is a 7-cell setup, although I'll probably run 8 (as I have so many great 8-cell packs). However, this project comes after: mystery acrobat on F27, F5D Vortex, Sokol rebuild on 1010/2, cutie wireless video on, and flea (say it isn't so), in no particular order. Or perhaps before some of them. I need a couple of months' vacation to get up to speed on my project list.
..a
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Old Sep 24, 2001, 10:51 PM
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Quote:
Originally posted by wrightmw
Andre,

Could you explain why the motor will start with 18 cells and not 20? (Is it the motor or controller, I'm still learning)

With your best Phasor setup for sport/aerobatic flying (5 to 8 min) how far are you away from performance like the OS 61FX or 91 4-cycle?

Marcus
Marcus,

It's the controller. Probably input voltage
limit. I use a Schulze 55 Bo on 20 x 2400 zapped
matched with the Phasor 45-3 driving a 12 x 10
and that's very convincing power, I would
say close to a 060 2stroke or a 91 4cycle.

What type of flying do you want to do?
The e-motor configs are many and best performance
comes from a good match of airframe,
motor and battery.

Andre
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Old Sep 25, 2001, 10:26 AM
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Winston-Salem NC
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Andre,

You are right that is very convincing power. If these things hold together it opens up a lot of avenues for conversions of glow ARFs and kits???

I mainly fly glow and gas but with some help from Ed L. (on the ezone) I built my first electric:

Senorita
MM on a MAT belt drive 3.6:1
12 x 3000 NIMh
11x9 electric MA prop

I am wanting to sell off some of my glow stuff and build a 60 sized Cap or G202 without breaking the bank (yes a convert in progress) and this sounds promising.

Marcus
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Old Sep 25, 2001, 10:58 AM
Visitor from Reality
United States, VA, Arlington
Joined Dec 1996
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Marcus
What you are after is feasible - AnnMarie Cross from Great Planes did an electric version of their Giles 202, which is a 60-ish model, on a MaxCim brushless and 20 cells. My CAP 232 from the GP kit is a little smaller than the Giles, but handles the same rig at 600 watts plus pretty well.

However - long term, the MaxCim stands up to flying constant aerobatics, landing so hot you can't touch the motor and folk only touch my packs once after landing.

Will the cheaper systems hold up to this kind of maltreatment? "Buy cheap, buy twice" is even more cutting when applied to expensive "cheap" stuff

Will a cheaper system really deliver, or do you really need a high end system knowing that it will take several years of utter abuse?

Why don't I fly Kadets and 4*40s on electric and get a glow powered F3A pattern ship running on cheap ol' gas rather than trying to melt RC2400s?

These, and many other questions, will only be answered in time.
(But the F3A on gas is mightily attractive )
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