EBike Quick Charge: Ultra-fast charging battery to substitute for Specialized SL Extender battery? Logarithmic Charging Strategy.

BikeMike

Active Member
This post explains my intent.

I talked with Specialized Boulder at length. They could not answer my question. I am looking for a "Touring Battery", "Opportunity Battery" or "Logarithmic Charging Battery". A battery that can quickly recharge several times per day, without concern for range. Riding 200 miles per day would be ideal. Ideally, the battery would recharge during a food break. Whole Foods is ideal because they are part of the EVgo.com car charging station network. Don't confuse several daily recharges with several Extender batteries. I don't want to carry five Extender batteries for a 200 mile range.

Opportunity charging is charging the battery whenever power is available or between partial discharges rather than waiting for the battery to be completely discharged. It is used with batteries in cycle service, and in applications when energy is available only intermittently.

I am not convinced that the Specialized SL battery pack is the tool for my goal. I am under the impression the electrical system is designed to make the bike as easy to ride as possible, rather than make it go as fast as and/or as far as possible. An excellent balance of compromises is difficult to achieve.

The "Logarithmic Charging" use case is:
  1. Ride for two hours as close to 25mph as possible
  2. 30 minute charging break (30% to 70% charge)
  3. Repeat until exhausted


Venn2.png

Venn diagram to analyze battery compromises.​

A - Capacity
B - Charging Rate
C - Convenience

Label the intersections to specifiy your needs.

S - Symmetry a 1:1:1 ratio of equally balanced factors

AB - Practical, Highly Inconvenient, Typical charging rate.
  • The internal Specialized SL Battery Pack seems positioned inside AB.
  • Battery pack can only be removed by first removing the bottom bracket motor

BC - "Touring or Opportunity Battery" or "Logarithmic Charging"
  • Fast charging rate, Small battery capacity, Convenient
  • Permits battery balancing for bike packing load and wind conditions
  • About 40 mile range, or less than one minute charging per mile.
  • The perfect solution is the Extender with a 6A charger.
    • 3.5 amp-hour battery will charge in 30 minutes.
  • Recharge battery frequently (several times) during a single ride, while taking a break, e.g., food or drink.
  • Specialized in Boulder could not tell me whether the Extender battery will charge at 6A.
I don't need continuous power. I don't mind unpowered pedaling for ten miles. A light bike, with unnoticeable motor drag like the Specialized Creo SL is fine. My goal is high average speed, i.e., 22mph minimum, over the entire elapsed time period.

I desire a bike that goes very fast over a very long distance. Think Tour Divide.

SC - Highly convenient, low capacity, very slow charging rate
  • Specialized SL "Extender"
  • External bottle cage
==========================================================================================================

My personal motto is: follow where the evidence leads you. I arrived at a much different place than where I originally started.

1593947181969.png

My Actual Requirements

A: Portable, Full Function 10 Amp Charger
  • High(3) C Batteries designed to charge within one hour, not 1C.
  • Charger weighing less than five pounds
  • Needs a carrying mechanism, e.g., bosses, rack, bikepacking bag, inside frame, etc...
  • Allows for programmable charging, e.g., overnight as well as immediate
  • Allows charging level to be passed as a parameter
  • Displays exact charge level and time to charge different levels
B: 28 mph Speed Limiter

C: True hybrid eBike

  • Almost Imperceptible Decoupled Motor Resistance
  • Functions similar with or without power

S: My Dream Bike - realizable in the foreseeable future

BC: Specialized Creo SL
SA: Haibike FlyOn Adventure
AB: JuicedBikes with 3C battery pack cells. Doubt 8Fun motor can be decoupled?

==============

Modular electrical system a la Egoe style (https://uncrate.com/nestbox-camper-module/ ). Zip tie plastic milk cartons, stacked upon each other.
  1. Camper designed around electrical system.
    1. MB diesel Sprinter, 4WD (suspect too high for parking entrance)
    2. Toyota Sienna AWD
      1. Appliances and water accessed from rear door that provides shelter
  2. Electrical system dictates camper livability. Minimal requirements:
    1. Subfloor with radiant heater
    2. Outlets to power electric blanket and appliances
    3. Lighting in ceiling or walls
    4. Water heater
    5. Recharge eBike battery
      1. Specialized Creo SL Evo does not require continuous power.
    6. Small electric refrigerator
  3. J1772 outlets(two to four) to charge camper battery from EV stations in 30 minutes
    1. 720 aH @ 12v = 60w. 72A ( J1775 80A max), 1C = 10H full charge time. 3C = 2 hours.
    2. Accessible from rear door to avoid EV station conflict
  4. How much sailing hardware is appropriate?
  5. What can I learn from Ford projects?
  • Fast charging battery system:
    • 540W of solar panels (3)
    • 3500W Pure Sin Wave Inverter (2.5 hours of driving to recharge battery)
    • 5kW diesel heater
    • eBike (2' x 6' x 3.5' space)
    • Lighting
    • Small induction stove
    • Small Microwave
    • Refrigerator same dimensions as stove
    • Water heater for shower, food prep, constant covid19 hand washing.
    • Sound system
    • Internet Connection
    • Heating, Cooling and Ventilation
      • Tradeoff between roof exhaust fan and solar panels
      • Carbon monoxide detector
 
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Sierratim

Well-Known Member
Sounds like you'd like an 'ultrafast' charge extender battery. Maybe in 5 years, but not today. Battery University discusses limits to fast and ultrafast charging here; https://batteryuniversity.com/learn/article/ultra_fast_chargers . Basically, high charging rates decrease battery life, even with batteries and chargers that are designed for fast charging.

Work being by Tesla et al is developing and commercializing fast and ultrafast charge battery chemistry. This will eventually trickle down to ebikes.
 

BikeMike

Active Member
Sounds like you'd like an 'ultrafast' charge extender battery. Maybe in 5 years, but not today. Battery University discusses limits to fast and ultrafast charging here; https://batteryuniversity.com/learn/article/ultra_fast_chargers . Basically, high charging rates decrease battery life, even with batteries and chargers that are designed for fast charging.

Work being by Tesla et al is developing and commercializing fast and ultrafast charge battery chemistry. This will eventually trickle down to ebikes.
Specialized told me the same. I am willing to pay for a disposable battery that might only last one season.

I need to track down this chemistry:
Lithium Titanate may be the exception and allow ultra-fast charging without undue stress. This feature will likely be used in future EVs; however, Li-titanate has a lower specific energy than cobalt-blended Li-ion and the battery is expensive. (See BU-205: Types of Lithium-ion)

Nickel-cadmium is another battery chemistry that can be charged in minutes to 70 percent state-of-charge. Like with most batteries, the charge acceptance drops towards full-charge and the charge current must be reduced.


This table about battery chemistry is what I was hoping to find:

TypeChemistryC rateTimeTemperaturesCharge termination
Slow chargerNiCd
Lead acid
0.1C14h0ºC to 45ºC
(32ºF to 113ºF)
Continuous low charge or fixed timer. Subject to overcharge. Remove battery when charged.
Rapid chargerNiCd, NiMH,
Li-ion
0.3-0.5C3-6h10ºC to 45ºC
(50ºF to 113ºF)
Senses battery by voltage, current, temperature and time-out timer.
Fast chargerNiCd, NiMH,
Li-ion
1C1h+10ºC to 45ºC
(50ºF to 113ºF)
Same as a rapid charger with faster service.
Ultra-fast chargerLi-ion, NiCd, NiMH1-10C10-60 minutes10ºC to 45ºC
(50ºF to 113ºF)
Applies ultra-fast charge to 70% SoC; limited to specialty batteries.
Table 3: Charger characteristics. Each chemistry uses a unique charge termination.
 
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Sierratim

Well-Known Member
Specialized told me the same. I am willing to pay for a disposable battery that might only last one season.
Probably too small of a market to expect a product offering. You could build your own pack that would get close to what you want but interfacing it to your Specialized bike is an unknown.
 

BikeMike

Active Member
Probably too small of a market to expect a product offering. You could build your own pack that would get close to what you want but interfacing it to your Specialized bike is an unknown.
Would i need to get an electrical interface specification from Specialized, or is the interface standardized?

I love my mechanical Specialized Diverge because it works so well on varied terrain. Specialized told me i am better off using my Diverge.

An eBike becomes very desirable with a "Touring Battery". I need a small, convenient, fast charging battery. I don't need large capacity. I just need to recharge within 30 minutes, every 50 miles (2.5 hours), or so.

I don't need continuous power. I don't mind unpowered pedaling for ten miles. A light bike, with unnoticeable motor drag like the Specialized Creo SL is fine. My goal is high average speed, i.e., 22mph minimum, over the entire elapsed time period.

I desire a bike that goes very fast over a very long distance. Think Tour Divide.
 
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Sierratim

Well-Known Member
I'd guess that the interface is proprietary to Specialized. My Specialized recognizes the battery charger and even turns the bike off going into charging mode automatically. Specialized ebikes that accept extender batteries also recognize the difference between the charger and the extender battery. This 'handshake' could be as simple as pin configurations in the charger vs the extender connectors or as complex as firmware since the main battery has firmware as well. Specialized doesn't make this info public, but as a minimum you would need to know how this 'handshake' takes place.

Storing enough energy in 30 minutes to go 50 miles is a tough spec, depending on terrain and your fitness level.
 

BikeMike

Active Member
I'd guess that the interface is proprietary to Specialized. My Specialized recognizes the battery charger and even turns the bike off going into charging mode automatically. Specialized ebikes that accept extender batteries also recognize the difference between the charger and the extender battery. This 'handshake' could be as simple as pin configurations in the charger vs the extender connectors or as complex as firmware since the main battery has firmware as well. Specialized doesn't make this info public, but as a minimum you would need to know how this 'handshake' takes place.

Storing enough energy in 30 minutes to go 50 miles is a tough spec, depending on terrain and your fitness level.
I am a software developer. I know how to interface hardware, given a spec.

I estimated what i think i need in watts: 80. I would configure the bike power levels to achieve 22mph so:
  • Set three power modes to 05%, 17% and 33%.
  • 5% rather than turing off power
  • 20:1, 4:1 and 2:1 human-to-motor power ratios for 240 watt Creo motor
 
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CityExplorer

Well-Known Member
Your thinking is not really right; a larger capacity battery does not necessarily mean it will change slower, proper capacity is measured in Wh.

A typical 48V 20Ah (960Wh) battery can be charged safely just as fast as a typical 48V 10Ah battery (480Wh). The 20Ah battery only takes longer if you use a charger better suited for the 10Ah battery. If the battery is designed correctly to allow a full nominal charge rate and you have the matched charger then you don't need to worry about charge time as they will be the same.

Of course chemistry plays a role, as does the design of the cell, for example an 18650 vs 21700, or punch, and there is the CV phase of a full charge that makes charge times non-linear so change in cell capacity and design have non linear effects as internal resistance will be different between different cell designs.

However; same cell; same voltage battery; you're charge time is not dependent on capacity if you can supply a nominal charge rate as dictated by the battery. You will hit a limit with cable-sizes at some point, a typical consumer battery would probably hot the limit on charge electronics first as things scaled up, but you don't need to go that far.
 

BikeMike

Active Member
Your thinking is not really right; a larger capacity battery does not necessarily mean it will change slower, proper capacity is measured in Wh.

A typical 48V 20Ah (960Wh) battery can be charged safely just as fast as a typical 48V 10Ah battery (480Wh). The 20Ah battery only takes longer if you use a charger better suited for the 10Ah battery. If the battery is designed correctly to allow a full nominal charge rate and you have the matched charger then you don't need to worry about charge time as they will be the same.

Of course chemistry plays a role, as does the design of the cell, for example an 18650 vs 21700, or punch, and there is the CV phase of a full charge that makes charge times non-linear so change in cell capacity and design have non linear effects as internal resistance will be different between different cell designs.

However; same cell; same voltage battery; you're charge time is not dependent on capacity if you can supply a nominal charge rate as dictated by the battery. You will hit a limit with cable-sizes at some point, a typical consumer battery would probably hot the limit on charge electronics first as things scaled up, but you don't need to go that far.
You know more than me on this subject. I try to simplify reasoning. All I want to do is use a 6A charger with a 3.5 ah battery to complete in 30 minutes. How do I achieve that?

Zero Motorcycle solution:


https://www.zeromotorcycles.com/accessories-en-us.pdf



QUICK CHARGER

The 96-volt Quick Charger can be used either for motorcycle quick charging or off-board power pack charging of 2013- 2020 Zero Motorcycles.

Motorcycle quick charging

One Quick Charger provides an additional 1 kW of charging capability. When used with your motorcycle’s integrated charging system, this approximately doubles the amount of energy flowing to the power pack during charging. As a result, the charge time of a Zero motorcycle is reduced by around 50%. To charge even faster, multiple Quick Chargers can be purchased and used with a Quick Charger Y Adapter to reduce the charge time further.

Off-board power pack charging

The Quick Charger can be used to charge power pack modules when removed from the motorcycle. The ZF2.8, ZF3.3 or ZF3.6 Power Pack Modules, used with the Zero FX, Zero FXS and Zero XU motorcycles, require the Power Pack Module Charging Adapter when the power packs are charged off-board.
 
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Ebiker01

Well-Known Member
Most likely the Creo battery BMS won't accept 6amps charge.

3.5ah and 6ah , that is 2x C ratio , very , very bad for the battery, assuming the BMS doesn't stop it.

Safest is 0.5C rate as in 12.6amps with 6amps charger. That's why Specialized Creo is very badly engineered , the battery is small and can't take fast charge.

The Zero has a huge battery amps, can probably charge it at 20amps .
 

Sierratim

Well-Known Member
You can connect a 6A charger to any 3.5Ah lithium battery pack. It will shorten its life as @Ebiker01 noted. It also runs the risk of overheating the battery with undesireable consequences (fire, explosion, etc). Your call.

I wouldn't recommend such a high charge rate on a standard pack. You can build a pack that would be safe enough. It will still have a relatively short life at significantly more than a trivial cost.
 

CityExplorer

Well-Known Member
You know more than me on this subject. I try to simplify reasoning. All I want to do is use a 6A charger with a 3.5 ah battery to complete in 30 minutes. How do I achieve that?

......

Do you want to charge 'a' 3.5 Ah battery in 30min or do you want to charge 'this' 3.5Ah battery in 30min ('this' being a specific battery that already exists)?

If you are trying to charge the Specialized SL 3.5Ah battery in 30min, then forget about it, it isn't happening. If you want to make a battery that you can push 3.5Ah into in 30min, that's a different story.


ps.... 3.5Ah is a useless amount of energy for an e-bike so forget all about that number. Figure out how many Wh you are going to use between stops and start there.

If you are looking at that crap because you want to use off the shelf parts, then you are probably wasting your time with that battery and should be looking elsewhere. There is no magic here, if you are using typical cylindrical Li-Ion Cobalt cells then you have to stick to 1-1.5C rate for your charge, and don't forget the CC phase means it takes longer than simple math indicates. There are tricks such a Quick charging for the first 1/2 or so of the charge cycle and other things that may be possible depending on the cell used.

Go look at the weight of the Zero battery, if you make a good battery for your ebike you can charge it very fast. They are not doing anything special, just following the basic rules they did not invent any new secret fast charging, I don't even think they use a fast pulse charge.

People would love to charge their Teslas in 30min also, but hey it takes a bit longer; Surprisingly a super charger can do pretty good in 30-60min, they use the same charging rules (more or less); it's all in the design of the battery.
 

BikeMike

Active Member
Do you want to charge 'a' 3.5 Ah battery in 30min or do you want to charge 'this' 3.5Ah battery in 30min ('this' being a specific battery that already exists)?

If you are trying to charge the Specialized SL 3.5Ah battery in 30min, then forget about it, it isn't happening. If you want to make a battery that you can push 3.5Ah into in 30min, that's a different story.


ps.... 3.5Ah is a useless amount of energy for an e-bike so forget all about that number. Figure out how many Wh you are going to use between stops and start there.

If you are looking at that crap because you want to use off the shelf parts, then you are probably wasting your time with that battery and should be looking elsewhere. There is no magic here, if you are using typical cylindrical Li-Ion Cobalt cells then you have to stick to 1-1.5C rate for your charge, and don't forget the CC phase means it takes longer than simple math indicates. There are tricks such a Quick charging for the first 1/2 or so of the charge cycle and other things that may be possible depending on the cell used.

Go look at the weight of the Zero battery, if you make a good battery for your ebike you can charge it very fast. They are not doing anything special, just following the basic rules they did not invent any new secret fast charging, I don't even think they use a fast pulse charge.

People would love to charge their Teslas in 30min also, but hey it takes a bit longer; Surprisingly a super charger can do pretty good in 30-60min, they use the same charging rules (more or less); it's all in the design of the battery.
The Specialized charger is 3A. No 6A charger is available from Specialized to charge their battery in half the time, like Zero offers for their motorcycles. A fast charging external battery is The most important component in an eBike to me. I am willing to compromise on all other parts of the electrical system . I am willing to pedal unpowered. I do not require continuous power.

I don't want to make a battery pack. I am unskilled in making things. I want to buy a plug compatible 160 wh fast charging battery to substitute for the Extender, that can charge in 30 minutes. The battery should fit in a bottle cage, like the Specialized Extender.

Specialized battery interface is obviously proprietary. I don't know if it possible to work around their black box, or not. I find absolutely no detailed information. Obviously, warranty concerns are important.

I had electrical theory classes in college. I understand the concepts. I don't have working knowledge. I am frightened to take chances with electronics or electrical components.

I am not overly concerned about economy. I am OK with a battery that only lasts one season. Economy is the easiest aspect to compromise on.
 
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Stefan Mikes

Well-Known Member
Region
Europe
City
Brwinów (PL)
I think all these considerations are pointless as the Specialized battery is custom, their batteries are indeed computers that only allow Specialized chargers dedicated for specific battery system (the UI-400, UI-500 and UI-600 batteries are one system for Vado and Como, M2-500 & M2-700 is another system for Levo and Kenevo, and SL1-320 with the Range Extender is the third system for SL e-bikes). Specialized won't tell you anything because they will not reveal their trade secrets and are not interested to talk with you on the details. Their policy is simple: Want to ride far? Go buy as many as several Range Extender batteries, have them charged and carry them with you. Specialized are not interested you don't want to carry 5 extenders for 200 miles.

For some reasons you're talking about an SL e-bike. I'll tell you what. My brother was capable to ride my "heavy" Vado 5.0 with 20/20% Support/Max Motor Power setting. He made as many as 90 miles on a single UI-600 Specialized battery. Were he carrying a spare battery in the pannier, he could make 180 miles safely on a heavy bike. His experience was "I'm riding a bike that behaves as a regular mechanical one except I can ride 19 mph into the wind".

So simple.
 

BikeMike

Active Member
I think all these considerations are pointless as the Specialized battery is custom, their batteries are indeed computers that only allow Specialized chargers dedicated for specific battery system (the UI-400, UI-500 and UI-600 batteries are one system for Vado and Como, M2-500 & M2-700 is another system for Levo and Kenevo, and SL1-320 with the Range Extender is the third system for SL e-bikes). Specialized won't tell you anything because they will not reveal their trade secrets and are not interested to talk with you on the details. Their policy is simple: Want to ride far? Go buy as many as several Range Extender batteries, have them charged and carry them with you. Specialized are not interested you don't want to carry 5 extenders for 200 miles.

For some reasons you're talking about an SL e-bike. I'll tell you what. My brother was capable to ride my "heavy" Vado 5.0 with 20/20% Support/Max Motor Power setting. He made as many as 90 miles on a single UI-600 Specialized battery. Were he carrying a spare battery in the pannier, he could make 180 miles safely on a heavy bike. His experience was "I'm riding a bike that behaves as a regular mechanical one except I can ride 19 mph into the wind".

So simple.
Right. I just want bonus power to compensate for wind and bikepacking load. I call it a "foul weather" bike. Specialized fancies it as a training bike.

The main appeal to me is the Diverge geometry. A great balance of compromises for mixed terrain.

I am content with my Diverge. I don't see Any reason to upgrade to what Specialized offers without fast charging. A fast charging Extender is the only electrical feature i require.

The idea is very similar to Future Shock. A configurable amount of vibration absorbtion is very valuable. Shock absorbtion incurs unwanted weight and power loss. hardtails have some advantages over full suspension mountain bikes.

I am a software developer. You'd be surprised how easy some computer systems are to fool. My guess is the plug socket uses standardized components. customized communications are often easy to interface with. Think OBCD in cars. OBCD is the same thing as an eBike controller. You can edit the entire car database from OBCD with a cell phone. I've taken advantage of it when it comes to car registration.

Likewise, all battery cells come just a handful of suppliers.

Power and status information are the main things an eBike contoller wants from a battery. I know very little about Specialized eBikes, or any eBike. I hope they license accessory interfaces to third parties. Someone will reverse engineer it, if they dont.

I am wary of buying into the Specialized platform. I remember when their batteries were faulty due to potting. Epoxy is tricky to work with. I remain skeptical of Specialized. I find several faults in the Creo.
 
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BikeMike

Active Member
Probably too small of a market to expect a product offering. You could build your own pack that would get close to what you want but interfacing it to your Specialized bike is an unknown.
I understand what you mean, now. Ultrafast charging will take years to reach Specialized. Specialized has a custom system. Much easier and faster for bike manufacturers to resell stock batterty packs from industry suppliers.
 

dblhelix

Well-Known Member
Would i need to get an electrical interface specification from Specialized, or is the interface standardized?

I love my mechanical Specialized Diverge because it works so well on varied terrain. Specialized told me i am better off using my Diverge.

An eBike becomes very desirable with a "Touring Battery". I need a small, convenient, fast charging battery. I don't need large capacity. I just need to recharge within 30 minutes, every 50 miles (2.5 hours), or so.

I don't need continuous power. I don't mind unpowered pedaling for ten miles. A light bike, with unnoticeable motor drag like the Specialized Creo SL is fine. My goal is high average speed, i.e., 22mph minimum, over the entire elapsed time period.

I desire a bike that goes very fast over a very long distance. Think Tour Divide.
The connector was Rosenberger for the Specialized Turbo series. Don’t know about the current line-up but should be very easy to find out.

 

BikeMike

Active Member
I found this covid19 airplane simulation so revealing, that i feel everyone show be aware of it. The momentum of air the key to understanding how covid19 is so infectious. Walking spreads virus particles further than coughing.