Electronics / Controllers: July 2009 Archives

My little Piaggio-EV is back up and running. I made the following mods:

  • My replacement HV-110 is now installed in an external plexiglass box with (much) better airflow and forced as well as passive air cooling. The forced cooling is on full all the time rather than the temperature variable fan that I used to have.
  • Extra caps (470 uF x 6) soldered in parallel with input leads
  • (Slightly) beefier wiring used -- 8 gauge rather than 12 ga
  • 75 amp Andersen PowerPoles used instead of 30A
  • Wiring shortened a bit
  • Thermometer probe directly on caps to monitor heat

So far, it seemed ok. After my ride to work this morning, the caps heated up a bit -- from 17°C ambient at the beginning to 37°C ambient at the end of the 5 kilometer ride. I'm working on getting even more cooling in there.

6 amps used. 30 watts/kilometer average energy expenditure.

My project has expanded to use standard size servos (link back to my micro servo comparison). Here's a little table that I'm using to compare various options.

TowerPro MG930Digital36.2x15.2x28.7 mm26g0.14sec/60°3.6 kg/cm0.11 sec/60°Metal$16
Hitec HS-225BB Analog32.4x16.8x30.8mm27g0.14 sec/60°3.9kg/cm0.11 sec/60°Nylon$20
Hitec HS-225MG 31gMetal$30
Hitec HS-5245MG Digital32.0x17.0x31.0mm32g0.15 sec/60°4.4kg/cm0.12 sec/60°Metal$48
MKS DS9660Digital35.0x18.0x28.0mm35g0.13 sec/60°3.7 kg/cm0.10 sec/60°Metal$57
Futaba S9650Digital36.0x15.0x29.0mm26g0.14 sec/60°3.6kg/cm0.11 sec/60°Nylon$65

The conversion for torque from kg/cm to oz/in is to multiply by 14.7. So a servo with a torque of 1.0 kg/cm has an imperial torque of 14.7 oz/in.

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This page is a archive of entries in the Electronics / Controllers category from July 2009.

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