6437 km (4000 miles)

A quick update since it's been nearly a year: The last crash took some wind out of my sails, and the MS that put me in the chair keeps progressing, but the past 1400 km have been fairly uneventful with the rubber side staying down.

• The Q-211 front tire finally gave out with a slow flat and cords showing.  Lifetime: 3629 km
• The larger 36 V, 11.6 Ah battery started cutting out, perhaps due to unbalanced cells, so I reverted back to the original 6.6 Ah one.  Lifetime:  5050 km (about 250 cycles assuming 50% depletion)

Screenshot from the VESC phone app (Android).  The electronic FREEwheel is active to improve coasting and reduce torque chatter.  The throttle holder is keeping MAXimum forwards throttle until I press reverse.

Replacement Q-211 tire before mounting.

5000 km (crash)

The past two km chiliads (since 3000 km) were notable for two accidents, keeping the rate at a stubborn one per 1000 km.  First, a minor low-speed tip-over that occurred while playing tag with a relative on roller skates.  Some people take pride in playing hard.  The second was more troubling:

Near the top speed (23 km/h), I lost steering control and crashed diagonally into a curb, causing the wheelchair to flip. I think the left Firefly attachment had separated from the wheelchair, and the right clamp by itself was too weak (picture below), causing the loss of steering. 

I don't know why the left connection let go.  Perhaps I forgot to flip the quick-release lever or the pins weren't fully seated or resonance caused the mechanism to disengage. Just before the crash, I rode over a rumble strip whose vibrations must have caused the final separation. It would be wise to check for any self-loosening in the future and maybe add latch retainers.

Fortunately, the bruising and road-rash are temporary.  I replaced the trashed right-side attachment clamp, but my wheelchair is crooked now, with the right frame leg bent back by about half an inch and downward by a quarter inch.  Considering my usual routes, the consequences of veering sideways uncontrollably could have been a lot more serious.

On a positive note, the QIND Q-211 tire continues to last beyond 2400 km with no visible cords. The front axle has stayed tight since switching to the VESC controller nearly 700 km ago, despite heavy use of regen-braking.

3000 km, KT-LCD3 display, etc.

Spring flowers are blooming, the sun is shining, and I've started putting distance onto the Firefly again.  It's important to get outside, despite the many warnings about COVID-19 from politicians and public health busybodies.  Their science is tentative and fraught with conflicts of interest, and their claims - hypocritical as they may be - of valuing safety above all else do not reflect my values.  Fear, i.e. focusing on worst-case-scenarios, is a choice that I reject.  Life is for living.

I'm using a new KT-LCD3 display, which works as a drop-in replacement for the original KT-LCD5 after setting the various parameters.  The LCD3 shows power in Watts, which maxxes out at about 550 W for me.  I really wanted to know the maximum power.  The display also shows ambient and motor temperature, but unfortunately the motor field does not measure anything, and the ambient value is inaccurate.

Update: After this post I reverted to the original LCD5 display and spooled the LCD3 odometer distance onto it, using the documented communications protocol.



Together, the old (2730.5 km) and new (273.6 km) odometers add to 3004.1 km and 286.1 hours for the following statistics:

• 2 years ownership
• Several hundred trips enabled by the Firefly
• Scores of friendly compliments
• 10.5 km/h (average speed)
• 3 worn out front tires (current one seems like a winner)
• 2 significant mechanical issue:
• Loose axle nut
• Shims for the wheelchair frame attachment are slippery.  If used, inspect regularly and check bolts for tightness.
• 3 tip-over accidents (sideways)
• Turning onto an uphill ramp.  Too much speed and off-camber.  Kind bystanders tipped me back up.
• Riding up a steep and narrow temporary ramp, losing traction near the top, fishtailing backwards, and tipping over the side.  Relying on momentum rather than traction to get up steep slopes is dangerous.  The result of not reaching the top can be an extended loss of control, because sliding friction is less than static friction.  Rear wheel braking could help, because the rear wheels have a lot more traction (but engaging them while moving backwards could make the vehicle flip).  Reversing up steep slopes can be safer.
• While going around an illegally parked truck.  Always cross drop-offs at a perpendicular angle, even when annoyed.
• 1 empty battery (later replaced with a larger one)
• 1 flat rear tire (from a thumb tack)
• 1 flat front tire
• 0 collisions

Tip-over accidents are a recurring theme, because any safety gains due to skill and experience seem to be cancelled out by higher speed and reduced caution.

2000 km (1243 miles)

This milestone (kilometerstone?) occurred a few weeks ago.

Other numbers:

• 442 days (ownership)
• Several hundred trips enabled by the Firefly
• 191 hours, 51 minutes (total time).  The hundreds digit is not shown in the display.
• Scores of friendly compliments
• 10.4 km/h (average speed)
• 3 worn out front tires (current one seems like a winner)
• 2 significant mechanical issue:
• Loose axle nut
• Shims for the wheelchair frame attachment are slippery.  If used, inspect regularly and check bolts for tightness.
• 2 tip-over accidents (sideways)
• Riding up a steep and narrow temporary ramp, losing traction near the top, fishtailing backwards, and tipping over the side.  Relying on momentum rather than traction to get up steep slopes is dangerous.  The result of not reaching the top can be an extended loss of control, because sliding friction is less than static friction.  Rear wheel braking could help, because the rear wheels have a lot more traction (but engaging them while moving backwards could make the vehicle flip).  Reversing up steep slopes can be safer.
• While going around an illegally parked truck.  Always cross drop-offs at a perpendicular angle, even when annoyed.
• 1 empty battery (later replaced with a larger one)
• 1 flat rear tire (from a thumb tack)
• 0 collisions

1000 km

Other numbers:

• 99 hours, 42 minutes (total time)
• 10.1 km/h (average speed)
• 202 days (ownership)
• Several hundred trips enabled by the Firefly
• Dozens of friendly compliments
• 1 significant mechanical issue:
• Shims for the wheelchair attachment are slippery.  If used, inspect them regularly.
• 1 tip over accident
• while going around an illegally parked truck.  Always cross drop-offs at a perpendicular angle, even when annoyed.
• 1 worn out front tire
• 1 flat rear tire (from a thumb tack)
• 0 collisions
• 0 empty batteries