Back to Bike.

Hi-Power Cycles: Cadillac AM2.4, BMC 600 W geared hub at 51 V

  1. Main
  2. Events
  3. Conclusion
  4. References

by Jérôme Daoust.  Revised 2008/11/19

 


Main (Top of Page)

Configuration

Part

Source

Warranty

Retail price

Cadillac AM2.4 bike with street tires.

Purchased used

 

Depends on the deal you find. Retail is 1600 $US.

BMC 600 W motor with custom wiring and connectors

Hi-Power Cycles

1 year

1200 $US

Battery: LiFePo4: 51.2 V, 20 Ah: 1024 Wh, 19 lb. With 40 A controller.

Hi-Power Cycles

6 months

1699 $US

Controller: Upgrade from 40 A to 48-50 A.

Hi-Power Cycles

6 months

80 $US

Straight battery support post.

Hi-Power Cycles

 

80 $US

Cycle Analyst DPS (direct plug in + speedometer cable).

Hi-Power Cycles

 

145 $US

 

 

 

Total: Bike + 3204 $US

 

About Hi-Power Cycles

·         They are located in Chatsworth, California, USA. You can initiate contact by email and take it from there. Chris Hunt is the full-time manager and I also met 2 of his employees who help him assemble and ship ebikes: Derek and Greg.

·         Availability: Chris has answered many of my questions by email and also over the phone. Him and 2 others of his team met with me on a Sunday, to have me demo a bike similar to my desired setup. They bravely let me go full blast, jump curbs, ride on asphalt and sand and brake to the fullest.

·         See References for related online discussions.

 

Motor

·         Noise level:

o   When testing a demo bike with similar setup to my desired configuration, I noticed some grunt when starting (let’s say below 5 mph) but noise level was low above that. So this motor will not draw unwanted attention when used alongside cyclists or pedestrians. Not totally silent like an E+ (gearless motor), but not a concern either.

o   Derek, Hi-Power Cycles, 2008/10/30: The newest motors we have tested exhibit no start up noise.

·         DirtDad writes on 2008/10/29 (source): The differences (between the old 400W BMC and the 600W BMC) are improved materials and construction: Composite gears, Silver/Teflon phase wires, bigger stronger batteries, tighter tolerances, etc. The casing has the same external dimensions. But much of the shell was simply made and unnecessarily thick. So it was thinned out in non-structural areas. The end result is a motor that is the same weight and size that delivers more power. The differences may not sound like they add up to much, but the proof is in the results, this little motor really flies.

·         The custom 12 gage wires from the battery stop before the rear axle because their diameter would be too large to enter.

·         Torque arm was secured by a U-bolt. Not elegant but functional.

 

Battery

·         It is a LiFePo4 chemistry, 51.2 V with 20 Ah à 1024 Wh of energy.

·         Chris Hunt, Hi-Power Cycles, 2008/10/26: LiFePo4 compared to LiPo offers:

o   More thermal stability and general robustness.

o   Tolerant to full discharges.

o   Offers more constant voltage during discharge.

o   More cycles (longer life).

·         Fast charge time:

o   Derek, Hi-Power Cycles, 2008/10/30: There is a possibility of 1 hour charge times with the 10 Ah battery you test drove the bike with, if you used a 10 amp charger. For the 20 Ah battery you elected to buy, you would need a 20 amp charger to do so (don't know if they make a charger like this). A 2 hour charge time on the 20 Ah battery is not out of the question though and is very feasible (even when the battery is fully depleted). 

 

Controller

·         Chris Hunt, Hi-Power Cycles, 2008/11/5: We have a new 48A-50A controller that is an absolute animal on acceleration and hill climbing. Your battery system (LiFePo4, 51.2 V, 20 Ah) can easily sustain 70A continuously. So, upgrading the controller for higher current is a viable option.

·         Chris Hunt, Hi-Power Cycles, 2008/11/9: Despite having the new 48A-50A controller, we recommend you limit current to 40A through the Cycle Analyst.

 

Bike

·        Plush long-travel dual suspension.

·        Low transport weight (easy battery removal) of 45 lb (20.5 kg).

·        Gearing is not well adapted to the high speed of this bike.

·        Under hard braking, the front wheel spokes contact the brake caliper bolt heads under hard breaking. Chris Hunt, Hi-Power Cycles, 2008/11/9: This is a problem with all Cadillac AM2.4 bikes, but we believe we found a solution.

·        Unable to use lower (bigger) gears on rear derailleur, but this should be easily adjusted at a bike shop. Still, this reveals no prior testing.

·         Rolling resistance:  There seemed to be significant resistance when pedaling without the motor, but can only guess at the source (maybe front brake).

·         Rear brake make noises under moderate braking.

 

Performance

·         Speed:

o   On 2008/10/26, I measured 32 mph (my GPS) on a demo bike (same model) with 40 A controller and a partially drained 51.2 V LiFePo4 battery.

o   On 2008/11/9, I measured 34 mph (from Cycle Analyst) on the bike limited to 40 A current. Not sure if speed was calibrated.

·         Range:  To be determined.

·         Suspension:

o   I did not measure yet, but there is at least 4” of plush travel in front and back. Riding fast over road irregularities was comfortable, so I am satisfied.

·         Throttle:

o   The twist-grip on the right half-grip provided a good level of control.

·         Brakes:

o   I did some hard stops from high speed with a demo bike with similar setup to my desired configuration, and the cable-operated (not hydraulic) disk brakes did a good job of slowing me down in a controlled manner. Hydraulic brakes could be a better choice for downhill racers, but for my recreational needs, this is plenty good.

·         Compared to:

o   Crystalyte X5304 hub motor.

§  Chris Hunt, Hi-Power Cycles, 2008/11/4 (source): All tests were done with identical 51.2v LiFePo4 10AH battery, 40A controller and 215 lb rider.
Video: Hill climb battle (10.9% average grade).
Video: Race on the flatlands.

 

BMC 600 W

Crystalyte X5304

0 to 100’ (30.5 m) time

4.90 s

5.60 s

0 to 200’ (61.0 m) time

7.38 s

8.61 s

0 to 300’ (91.5 m) time

10.12

11.16 s

Top speed

33.2 mph ( 53.8 km/h )

30.4 mph ( 49.2 km/h )

   


Events (Top of Page)

2008/10/26

·         Chris Hunt and 2 others of his team met with me, to have me demo a bike similar to my desired setup.

2008/11/9

·         Tested the bike which was configured to meet my desired setup. Enjoyed acceleration, speed, but inability to change rear gears (probably easy to adjust) revealed no prior testing. Front wheel spoke to brake caliper interference not eliminated prior to re-testing despite my request to be corrected. More high-bikes are available (like the KHS XCT555), but I don’t want to take that route and will consider other options.

 


Conclusion (Top of Page)

Good:

·         Plush long-travel dual suspension.

·         Good performance: Acceleration and max speed of 33 mph.

·         State-of-the-art battery system (LiFePo4).

·         Low transport weight (easy battery removal) of 45 lb (20.5 kg).

·         Low noise level and normal bike appearance (read stealthy).

Neutral:

·         The motor is new, so it needs to prove itself over time.

·         Workmanship is adequate: Does not look home-made, but not production-level either.

Bad:

·         Gearing is not well adapted to the high speed of this bike.

·         Under hard braking, the front wheel spokes contact the brake caliper bolt heads under hard breaking. Chris Hunt, Hi-Power Cycles, 2008/11/9: This is a problem with all Cadillac AM2.4 bikes, but we believe we found a solution.

·         Hard seat, but there are inexpensive aftermarket comfortable seats.

 

Summary of how other ebikes compare:

·         EMS E+ Mountain:

o   Good: Silent.

o   Good: Resale value.

o   Bad: Slightly more expensive.

o   Bad: No rear suspension.

o   Bad: Heavy at 65 lb. And batteries are in front wheel.

o   Bad: Heavy front wheel contributes to more unsprung weight.

o   Bad: Standard battery in front wheel has limited energy.

·         Optibike 800Li:

o   Good: Motor is part of the sprung weight, instead of typically being in the rear wheel.

o   Good: Reliability record from riders who use it for daily commuting.

o   Good: Resale value.

o   Good: Well adapted gear ratios.

o   Bad: More expensive (more than twice)

o   Bad: Unable to remove batteries (higher transport weight, unable to swap packs)

o   Bad: Noisy. Not a problem for the rider but gets unwanted attention on beach bicycle paths.

For a more detailed comparison for this recreational rider: Best electric bike decision matrix (open with Microsoft Excel). What is a decision matrix.

 


 References (Top of Page)

Definition:

·         Unsprung weight.

Company:

·         Hi-Power Cycles

o   Discussion (Tidal Force): What is your experience with Hi-Power Cycles?

·         BMC (Brushless Motor Corporation)

o   Discussion (Endless-sphere): BMC motors, anyone willing to say where they come from?

Bike:

·         Cadillac AM 2.4

o   Discussion (Endless-sphere): Please recommend a bicycle to add a motor to...

Motor:

·         BMC 600 W

o   Hi-Power Cycles: 600W BMC "Thunderbolt" kit with BMC Controller.

o   Discussion (Endless-sphere): Important announcement! Newly developed BMC motors!!!

o   Discussion (Endless-sphere): BMC 600W vs Crystalyte 5304 @72V.

o   Discussion (Tidal Force): Newly developed BMC motors Options

o   Discussion (Tidal Force): BMC Thunderbolt 600W showcase video

Battery:

·         Hi-Power Cycles: 51.2V LiFePo4 High Performance Battery System

o   Discussion (Tidal Force): Hi-Power Cycles: 51.2V LiFePO4 Battery System Options

·         Monitoring:

o   Cycle Analyst.

Study:

·         For this recreational rider: Best electric bike decision matrix (open with Microsoft Excel). What is a decision matrix.