Originally Posted by
RCoffroadracer
the reason they don't suggest an extension on the battery i'm thinking, is because you can fry a lipo battery with one short of the + and -. ...
It's because long battery wires create voltage spikes that are
higher than battery voltage.
At same frequency as user selected
Pulse Width Modulation frequency, 8, 16 or 32kHz.
Too long wires batteryside can kill ESC over time: causes, precautions, solutions & workarounds - RCG
Length of battery wire between packs counts too.
Keeping/tying/taping the plus and minus battery wires close together also helps reduce wire inductance (
table).
You could take this a bit further by removing the insulation of one the two wires, reducing the distance between the copper cores even further.
Contents - Two problems
• Voltage spikes higher than battery voltage: transistor / powerFET / die breakdown.
• Current through input capacitors too high: caps overheating/popping/exploding.
• Nonsense Ron, I never had problems with long battery wires.
- Example: four costly controllers consecutively cremated
- Solution I: simply lengthen the motor wires instead
- Solution II: add extra capacitors, rules of thumb
Calculation spreadsheet
- Capacitor type and polarity/orientation!
- How & where (not) to add extra capacitors
All capacitors as close to or on controller, do not distribute along batterywires.
- DIY capacitor pack pictures
- Capacitor & pack suppliers
- Expert/manufacturer opinions & their rules of thumb
They all say the same ... noise_reduction_101, switching_power_supply_design_101.
- Cause, explanation, water hammer/knock analogy&
, theory
References
- Measurements & scope traces
Vriendelijke groeteen
Ron
• Without a watt-meter you're in the dark ... until something starts to glow •
• E-flight calculators • watt-meters • diy motor tips&tricks • Cumulus MFC •
