Stefan Mikes
Gravel e-biker
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- Mazovia, PL
Why do the top manufacturers embrace 36 volt/ 250 watt power systems?
- Thread starter mata2maui
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Gionnirocket
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Small correction in the wording.
Amperage dictates wire size... I believe how you want to describe it is that the smaller wire can carry the same wattage using a higher voltage as less amperage is needed.
In general higher voltage is more efficient, that's why Europe uses 220v in homes.
The US decided 110v was safer in homes. In a commercial/industrial environment the US uses 277/480v systems.
As mentioned earlier higher voltage also adds performance. That's why the tool manufacturers are now in the +80v range now.
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mschwett
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whoops yes, fixed!
linklemming
Well-Known Member
Doesnt really proof anything
If you take that 36V motor and run it at 48V without any circuitry to limit power, it will produce more power.
https://ebikes.ca/tools/simulator.h...&bopen=true&batt_b=B4816_GA&cont=PR&cont_b=PR
Here is a good article, especially when comparing a 36V and 52V system
https://ebikes.ca/learn/power-ratings.html
If perhaps your argument is....at a limited power setting(i.e. 240W), there isnt much of a difference, you would be correct (mostly). I changed the speed of the 48V system to match the speed of the 36v system (which uses same power). The efficiency is basically identical. There would be additional losses in the 36V system not calculated in this simulator in the power wires. power circuitry (i.e. FETs) and the IR of the battery all of which would generate heat.
https://ebikes.ca/tools/simulator.h...R&autothrot_b=true&throt_b=10.999644106207965
If this is indeed your argument it seems silly and focused around your euro-centric view of the world which doesnt apply to probably 90%+ of the users on this site. Despite the size of the euro ebike market as you claim, it doesnt apply to most users here and doesnt negate the physics of electrical motors.
I love my 2021 Turbo Levo (36V), its great for a class 1 strictly offroad MTB and I have no use for more power unless traveling to the trailhead. My 52V DIY ebikes (mid and hub drive) outperform it in every other metric by significant margins.
With the 750W limit in the US, 48V is a better fit and why it has been chosen outside of the euro-spec bikes
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Stefan Mikes
Gravel e-biker
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- Mazovia, PL
How odd the system engineers at the largest e-bike brands seem to have different design criteria from yours.
Gionnirocket
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Design criteria or doing what they can within the restrictions they need to comply with.
1 donkey power isn't much headroom
Stefan Mikes
Gravel e-biker
- Region
- Europe
- City
- Mazovia, PL
mata2maui
Active Member
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SL line looks to be the exception to the rule , but they run only a 240 volt nominal motor with a the 325Wh 48v battery (and claim a range advantage over industry standard 625Wh 36v batts due to their batt being light weight), so not much of a power advatage for larger riders regardless of 48v battery.Incorrect. Specialized also offers a 48 V/240 W motor on its SL line.
The reasons of the 250 W nominal (and up to, say, 565 W peak power) with maximum 4x Rider's Boost Factor are:
Interestingly, Stromer is a Swiss brand but it conforms to Euro rules, except they make 45 km/h (28 mph) e-bikes allowed both in Switzerland and the United States.
- The European Union being the biggest e-bike market in the world (outside China)
- The Euro regulation requiring a regular e-bike (treated equally with traditional bicycles) be limited to 250 W nominal
- The Euro regulations also read "not more than 48 V"
- A widely accepted industrial rule (in Europe, not in China of course) that the bike assistance shall not exceed the human power more than 4 times (otherwise it is a moped or a motorcycle)
- No throttle, pedalling only
- A less powerful e-bike can be more lightweight
- In case of mid-motors, a 250 W nominal, 85-90 Nm motor is more than enough for either fast ride on the flat or steep climbs.
The reason Specialized has opted for 48 V in the lightweight less powerful SL line is the 48 V battery of capacity of 320 Wh will be as long as the e-bikes bottom frame tube but actually very slim, giving SL e-bikes a stealthy look.
No, it is the domain of the mass produced Chinese cr*pware.
Certainly you can ask Zen E-Bike in Canada to build such an e-bike for you. With a Chinese motor of course(Zen also builds e-bikes based on Bosch system, which is Euro).
linklemming
Well-Known Member
Exactly, 36V is fine for the lower power euro-spec bikes which is where all these systems are designed. I am in no way arguing that. Designing lower voltage electronics is also cheaper since higher voltage components usually cost more.
The point I am making is that this is ONLY valid in europe which 90%+ of the people on this site could care less about (even moreso about poland).
48V is a much better fit for the US 750W limit
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linklemming
Well-Known Member
Arguments always arise when Stefan tries to contradict simple physics by using the 'call to authority' argument philosophy
https://www.intelligentspeculation.com/blog/argument-from-authority
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Stefan Mikes
Gravel e-biker
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- Europe
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- Mazovia, PL
Our Hawaiian OP wrote:
The fact is the premium brands are "Euro-centred" while the $2,000 rubbish comes with high voltage systems. Has not been the "e-bike fire" issue discussed recently?
Please explain lemming why the big brands use either 36 or 48 V systems. Also help me understand why there are ten times less e-bikes in North America than they are in Europe. And how that affects the business of the big brands.
Just a clarification first.
- 240 W motor
- 320 Wh, 48 V battery.
fooferdoggie
Well-Known Member
if you fart we will argue about it.
linklemming
Well-Known Member
Its always fun to see how you choose to categorize and select 'facts' to prove your weak arguments. 'Call to authority' seems your preferred debating technique. I prefer well established physics.
No doubt the "ebike fire" issue is real and probably related to cheaper bikes with less quality control. I dont own any of those bikes(and never will). To characterize any bike that isnt one of the big 4 (motor wise) as garbage is too simplistic....but hey if that works for you..go for it. There could be many reasons besides your simplistic presentation...for example bad bms, chargers, charging practices or construction. I would need more info before making any further assumptions.
All ebikes use the same basic cells (really cheap ebikes might use cheaper mismatched cells or even 'clones'). As an example my Bulls and iZIP Moda (both Brose based 2018 designs) use samsung 35E 18650 cells. I have a pack from EM3EV with the same cells. These days the panasonic GA 18650 cell which I also have (used in teslas for awhile) seem a better choice supposedly due to ability to have more charge cycles. Newer bikes are coming with 21700 cells which are better still.
I only own batteries with individually fused cells. My assumption is all the big 4 motor manufacturers do this. I use EM3EV batteries which come with this feature. The older/cheaper method of using nickel strips to connect cells can have serious consequences. Ebike battery packs are built of parallel groups arranged in series (i.e. 14S 6P). If any cell in a parallel group shorts, all the adjacent parallel cells will dump their current into the shorted cell causing it to overheat and possibly catch on fire. This is something no BMS can protect against. For the same battery capacity, the argument could be made that a lower voltage pack would require more parallel cells and therefore would be more prone to fire for the case of a cell short. These days QC on cells is pretty good with the brands like panasonic and samsung.
I dont need to explain your 'Call to authority' approach to debating 36V vs 48V systems by speculation of the big 4 as its EE 101 stuff. The use of 36V could be for alot of things For the low power limit of 250W euro-based bikes, 36V is good enough only requiring about 7A for 250W and would be more cost effective. Would 48V be better..absolutely(from a pure engineering perspective) although the companies probably did a cost analysis and figured 36V would suffice (which it does for lower wattage euro-based bikes). There is also potential legacy issues. Many of the earlier ebikes were 36V and since 36V is fine for lower powered euro-bikes, why change. For my 36V Turbo levo, 36V is fine for offroad.
Legacy is real but not always the best solution over time (change horse to donkey to determine euro-bike equivalence)
http://www.astrodigital.org/space/stshorse.html
Another 'Call to Authority' on the euro market being 10 times the US market. My point (which you choose to overlook) is that this site is not composed of 10x the users from europe compared to the US, so basically 90% of the users here dont care about your euro-centric views. Why dont you go hang out in euro ebike forums instead of polluting EBR with your euro-snob attitudes. Better yet, grab some tissues and hand lotion and review your strava stats.
Dont be a Stefan
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linklemming
Well-Known Member
fooferdoggie
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no I fart on the tandem clearnig the after burners my wife has to suffer that.
mata2maui
Active Member
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Best farting scenario is on a bike in motion cuz your never down wind...unless on a tandem!
fooferdoggie
Well-Known Member
if my wife complains I ask if she wants me to slow down.
Gionnirocket
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Old news but...
www.cpsc.gov
Specialized Bicycle Components Recalls Electric Mountain Bike Battery Packs Due to Fire and Burn Hazards (Recall Alert)
Consumers should immediately stop using the recalled electric mountain bikes and contact Specialized Bicycle for a free repair. Specialized is contacting purchasers directly about the recall. Consumers should not charge the recalled battery pack or expose it to wet conditions until it has been...
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