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Old Jun 15, 2002, 10:13 AM
Ain't Dutch? Ain't Mutch!
Kimble_Schmitz's Avatar
Southampton, UK
Joined Oct 2001
3,384 Posts
Jeti brushless power lead lenght

I have a Jeti 40-3p BEC (gold) brushless motor controller. In the short guide that came with it, it said not to exceed over 20cm wire lenght from batt to controller.

Now i have a battery pack where the cells are configured side by side. One power lead has to be longer then they other to reatch the controller. In doing so my one lead will exceed that 20 cm with 10 more cm's.

Is this going to be a problem?! I read about voltage indused power spikes and god knows what that means. I only now that it is not good and can cook your ESC.

Also what pole should have the longer lead, the + or the - pole?
I know that electrons travel along the negative pole out of the cell and then return back into the cell over the positive pole. But who cares?!

I don't want to bust my ESC, is there enything i can look for on the test run?!
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Old Jun 18, 2002, 10:20 AM
Ain't Dutch? Ain't Mutch!
Kimble_Schmitz's Avatar
Southampton, UK
Joined Oct 2001
3,384 Posts
OK, so there aren't many of you how have a Jeti or know much about it.

I did the test and it performed ok. The total lenght of the - wire is 27 cm and the + wire is 39 long.

20 cm does seem a bit short, i gues they underastimate their own product

My 3 motor wires are 9 cm long, you could call that short.

Nothing got hot or made smoke. I used 8 cells and tested it at both around 30 and 40 amps.

I timed 8x 30 second runs and let the motor cool down 30 seconds in between.
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Old Jun 18, 2002, 11:03 AM
RIP Ric
Andy W's Avatar
Marietta, GA
Joined Jun 1999
43,312 Posts
I didn't reply because I've never had to lengthen the leads, and I've never had a pack with a "long lead" as you describe (all my odd-number of cell packs have a cell across the end, so both leads start at the same end of the pack). Plus I keep all leads short for losses, as much as potential damage.

My F16, however, has an Aveox L30uP in the tail, and the leads from the pack to the ESC are about 20" EACH. That makes 40" total. Never had a problem..
..a
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Old Jun 18, 2002, 03:28 PM
BEC
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Auburn, Washington USA
Joined Jan 2001
12,937 Posts
This is a matter of some controversy.....and you get different answers depending on which maker you ask. Most prefer you lenghten on the motor side.

What will happen, if it fails, is that the capacitor on the input side of the ESC will explode. The gold Jetis have a bigger capacitor there than the white-labels. A friend of mine blew the capacitor on a white label while testing with a Whattmeter in line (which, of course, is more length).

Part throttle is where this will happen, not a full throttle.
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Old Jun 18, 2002, 10:55 PM
Tasmanian Tiger
DeanW's Avatar
Hobart, Tasmania, Australia
Joined Aug 2000
273 Posts
I asked Jeti the same sort of question and this is what they had to say-

If you use 300 mm between controller and battery it is no problem. If you
need more than 300 mm it is necessary to add capacitor between red (+) and
black (-) wires at 50% of length. If it is nescessary I send you capacitor
( special ) to add it to the wires.


Best regards J.Tinka


They sent me 4, 35V, 220uF, 105 dec C, electrolytic capacitors like this.

Cheers

Dean
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Old Jun 19, 2002, 07:13 AM
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DavidWillis's Avatar
Keighley,West Yorkshire, UK
Joined May 2001
50 Posts
DeanW,
good info !
Also be sure to use an 'LXY' type (see your pic)

This designates the cap as a low impedance type - very important.

David
www.fly-electric.co.uk
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