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Jul 08, 2019, 09:10 AM
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Lynxman's Avatar
Originally Posted by wayne65
Hi: Joe
I was always told to have the ESC as close to the motor or as best as you can.
I have seen some setups with very long wires from the batteries to the ESC.

The ESC should be close to the batteries so that the input power wires don't have to be extended. Long input power wires will eventually cause the ESC to blow up, unless you add extra capacitors to the ESC (solder them as close to the ESC as possible, preferably where the original capacitors are soldered on the ESC as they are there for the same function). The three motor wires can be extended as much as is needed without problem.
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Jul 08, 2019, 12:38 PM
Registered User
Hi: Joe
sorry I told you wrong.
I have always seen long wires from the esc to the batteries.
Good luck
Hope it all works out for you.

Jul 08, 2019, 08:24 PM
Registered User
socshooter's Avatar

Thank you for the input. I did a bit of research and Lynxman is correct, the esc needs to be closer to the battery packs. Due to the distance of the esc to the motor, a capacitor needs to be installed. I ordered one from CC as recommended.

CC recommends installing the capacitor at 3 inches from the esc. Should it be closer?

Here's a link, good information.

I'll post a few pics once I get the parts,

Jul 08, 2019, 09:54 PM
Registered User
Lynxman's Avatar
Closer is better. They add to the existing bank of capacitors that the ESC came with. If CC says up to three inches then that should be fine.
Jul 09, 2019, 08:21 AM
homo ludens modellisticus
Ron van Sommeren's Avatar
Originally Posted by socshooter
.... Will the distance of the motor-esc-batteries effect the performance of the edf? ...
Yes, due to extra voltage losses in the extra wire, any wire. This is a resistance issue. To keep resistance, and therefore losses, the same, increase wire cross-sectional area with same factor as wire length.

Originally Posted by socshooter
... Is it a good idea to have the battery packs so far away from the motor (approximately 38-42inches)? ...
... Is it better to have the ESC closer to the battery packs or to have the ESC closer to the motor? ...
Keep ESC close to battery. This is an inductance (e.g. ignition coil) issue. Long(er) battery wires cause voltage spikes higher than battery voltage, same frequency as chosen ESC frequency, 8, 12, 16, 24 or 32kHz.

Motorside inductance, wire lengthening, is not a problem, since there's already a lot of wire in the motorcoils and there the inductance is needed to smooth the current. Current not smooth enough, more losses, more heat in the motor, less power handling, is why you increase ESC PWM chopping frequency. (Driving at constant speed to get somewhere is more efficient.).

Motorside: voltage chopping and smoothing of current

Originally Posted by socshooter
... CC recommends installing the capacitor at 3 inches from the esc. Should it be closer? ...
The closer to the controller, the more effective the capacitors.
Can't you just move the controller(s) close to battery(s)? Every added component is an extra point of failure.

Keep controller(s) close to battery if possible, and extend motor wires.
Keep the battery wires short, or else install extra capacitors, all on/near ESC.
Too long battery wires can kill ESC: precautions, solutions & workarounds - RCG
  • Example Four costly controllers consecutively cremated
  • Solutions I & II, rules of thumb
  • Problem
  • Rubbish! I have no problems.
  • Capacitor type & polarity (orientation!)
  • How & where (not) to add extra capacitors
  • DIY capacitor pack pictures
  • Capacitor & pack suppliers
  • Expert/manufacturer opinions, they all say the same ... & their rules of thumb
  • Explanation, water hammer/knock analogy, theory, references, measurements

Prettig weekend Ron
Without a watt-meter you are in the dark ... until something starts to glow
e-flight calculators watt-meters diy motor tips&tricks Cumulus MFC
Last edited by Ron van Sommeren; Jul 12, 2019 at 08:50 AM.

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