Mike leroy
Active Member
This article provides background information about electric bicycles that exceed 35mph -- without pedaling. The HPC Revolution is compared against the ZERO FX motorcycle. Electric bicycles are encroaching into electric motorcycle territory due to NMC battery chemistry in lithium-ion batteries.
Some benefits of NMC over conventional li-ion batteries follow. For a technical comparison, compare the graph of the Sanyo batteries in the previous link.
In my personal situation, competing with car traffic is the most significant issue when considering a bike for road use. A fast bicycle levels the road against cars in ways that traditional eBikes are incapable of.
In my opinion, high performance bikes need to be designed around the battery -- above and beyond -- all other considerations. Powerful and customizable batteries enable new motor capabilities. Fast eBikes need double the voltage (i.e., 76V) of conventional batteries. Most home electrical outlets are 110V! The bicycle frame and stealth design are heavily influenced by battery size and weight characterisics.
How useful is a 60mph bike with a 20 mile range and six hour charge time? Batteries are currently the weak link in any eBike system. Batteries deserve most attention and not dismissed like an ugly ducking.
Lithium-ion batteries become unusable after a few years of recharging. Battery and replacement cost is a significant, if not the most expensive, part of the total eBike cost.
Powerful battery packs typically have individual Battery Management System (BMS) chips for every battery cell (i.e., 48), rather than one BMS chip for the entire pack, as typically found today. Battery packs suffer from the weakest link principle. In other words, one rotten apple spoils the bunch. Individual cell BMS chips are a huge advantage. Companies like Polaris, that manufacture many vehicles, i.e., cars, motorcycles and eBikes, utilize individual cell BMS chips to optimize performance and prevent disaster.
Ragone Charts are the most common way to compare battery performance. Think of a Ragone Chart as comparing a sprinter's speed (vertical axis) against a distance runner's endurance (horizontal axis). Ragone Charts indicate how long an electric battery can operate at the peak output. If you ride at high speeds, then voltage is more important than amperage. To carry a heavy load up a steep hill, great torque or high amperage is required.
Ragone charts help you match your riding style to the appropriate battery chemistry. NMC is unique lithium-ion technology because only NMC can target either specific energy (capacity) or specific power.
Replacing the chainring with a Schlumpf gear box is worth considering when 35mph speeds are attainable. The gear drive is similar to a motorcycle gear box. Increase hill climbing or speed gear ratios by 2.5 times. Some compensating gear ratios are needed to accommodate the 80 pound weight. Consider reducing chain twist under high loads by using a cassette with a minimal number of gears, e.g., 7 or 8. Consider replacing the chain at frequent intervals, e.g., every 1,500 to 3,000 miles. Chain change, as opposed to oil change.
Also consider the Grace One.15 Pinion P1.8 gearbox approach, rather than a rear dérailleur. I prefer the Pinion, which is designed by ex-Porsche engineers. Grace utilizes the Gates Carbon Belt, rather than a metal chain. Durability, cost and safety are serious considerations.
Although this bike is ten times more powerful than a typical eBike, it also is twice as heavy. Synchronizing gear ratios to PAS profiles will optimize energy consumption and ease physical exertion.
The most effective way to increase your battery range is to set your Power Assist Levels (PAS) as low as possible. Also, conserve your battery by restricting high loads to uphill only. Optimize gear ratios to achieve pedal and battery efficiency. I suppose battery range can be doubled with careful energy economy.
HPC Revolution Sport is an off-road bicycle. The web page indicates that all models can be made street legal with the Cycle Analyst. In which case, I would simply set power to 1kW when I need to comply with motor vehicle laws. If the 3.5kW is the antidote for suburban car traffic, then I would register the eBike with DMV as a motorcycle.
HPC is the only electric bicycle manufacturer, that I know of, offering NMC batteries for their eBikes. Please inform of any other NMC bikes sold today.
HPC Battery Management System(BMS) may not be optimized. Bicycle NMC batteries now sell for a premium. Heavy hub motors necessitates strong rims, e.g., triple-walled rims. The 12.6 pound, gearless, 1 kW HPC motor may need triple-walled rims. AlexRims Supra BH may not be strong enough to support extra weight. Some downhill rims, like Spoon, are triple-walled.
Zero FX has an long history in electric motorcycles. The entry-level ZERO FX ZF2.8 is a:
.
.
.
Some benefits of NMC over conventional li-ion batteries follow. For a technical comparison, compare the graph of the Sanyo batteries in the previous link.
- About half the weight
- Much further range (i.e., battery distance)
- Chemicals are much less expensive
- Should last about twice as long as traditional li-ion batteries.
In my personal situation, competing with car traffic is the most significant issue when considering a bike for road use. A fast bicycle levels the road against cars in ways that traditional eBikes are incapable of.
In my opinion, high performance bikes need to be designed around the battery -- above and beyond -- all other considerations. Powerful and customizable batteries enable new motor capabilities. Fast eBikes need double the voltage (i.e., 76V) of conventional batteries. Most home electrical outlets are 110V! The bicycle frame and stealth design are heavily influenced by battery size and weight characterisics.
How useful is a 60mph bike with a 20 mile range and six hour charge time? Batteries are currently the weak link in any eBike system. Batteries deserve most attention and not dismissed like an ugly ducking.
Lithium-ion batteries become unusable after a few years of recharging. Battery and replacement cost is a significant, if not the most expensive, part of the total eBike cost.
Powerful battery packs typically have individual Battery Management System (BMS) chips for every battery cell (i.e., 48), rather than one BMS chip for the entire pack, as typically found today. Battery packs suffer from the weakest link principle. In other words, one rotten apple spoils the bunch. Individual cell BMS chips are a huge advantage. Companies like Polaris, that manufacture many vehicles, i.e., cars, motorcycles and eBikes, utilize individual cell BMS chips to optimize performance and prevent disaster.
Ragone Charts are the most common way to compare battery performance. Think of a Ragone Chart as comparing a sprinter's speed (vertical axis) against a distance runner's endurance (horizontal axis). Ragone Charts indicate how long an electric battery can operate at the peak output. If you ride at high speeds, then voltage is more important than amperage. To carry a heavy load up a steep hill, great torque or high amperage is required.
Ragone charts help you match your riding style to the appropriate battery chemistry. NMC is unique lithium-ion technology because only NMC can target either specific energy (capacity) or specific power.
Replacing the chainring with a Schlumpf gear box is worth considering when 35mph speeds are attainable. The gear drive is similar to a motorcycle gear box. Increase hill climbing or speed gear ratios by 2.5 times. Some compensating gear ratios are needed to accommodate the 80 pound weight. Consider reducing chain twist under high loads by using a cassette with a minimal number of gears, e.g., 7 or 8. Consider replacing the chain at frequent intervals, e.g., every 1,500 to 3,000 miles. Chain change, as opposed to oil change.
Also consider the Grace One.15 Pinion P1.8 gearbox approach, rather than a rear dérailleur. I prefer the Pinion, which is designed by ex-Porsche engineers. Grace utilizes the Gates Carbon Belt, rather than a metal chain. Durability, cost and safety are serious considerations.
Although this bike is ten times more powerful than a typical eBike, it also is twice as heavy. Synchronizing gear ratios to PAS profiles will optimize energy consumption and ease physical exertion.
The most effective way to increase your battery range is to set your Power Assist Levels (PAS) as low as possible. Also, conserve your battery by restricting high loads to uphill only. Optimize gear ratios to achieve pedal and battery efficiency. I suppose battery range can be doubled with careful energy economy.
HPC Revolution Sport is an off-road bicycle. The web page indicates that all models can be made street legal with the Cycle Analyst. In which case, I would simply set power to 1kW when I need to comply with motor vehicle laws. If the 3.5kW is the antidote for suburban car traffic, then I would register the eBike with DMV as a motorcycle.
- 3.5kW hub motor
- 80 pounds or 44W per pound (typical 350W / 40 lbs = 9W per lb.) ~ 5x power-weight ratio.
- 50+ mile range at 20mph
- Capable of speeds over 45mph
- 78V electrical system (double conventional eBikes)
- 12.5 AH, UN 38.3 Certified Battery available in different capacities
- ? Nm torque
- $7000
HPC is the only electric bicycle manufacturer, that I know of, offering NMC batteries for their eBikes. Please inform of any other NMC bikes sold today.
HPC Battery Management System(BMS) may not be optimized. Bicycle NMC batteries now sell for a premium. Heavy hub motors necessitates strong rims, e.g., triple-walled rims. The 12.6 pound, gearless, 1 kW HPC motor may need triple-walled rims. AlexRims Supra BH may not be strong enough to support extra weight. Some downhill rims, like Spoon, are triple-walled.
Zero FX has an long history in electric motorcycles. The entry-level ZERO FX ZF2.8 is a:
- 28kW motor
- 247 pounds ( 113.4W per pound)
- 35-mile city range
- 70mph sustained speed
- 102V
- 2.5 kWh battery, 2,500 charge cycles
- 95 Nm torque
- $13,300
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