5 ms·

Is this a problem due to bad cell quality control? Car-sized lithium batteries are lasting 200,000+ miles. Why aren't e-bike batteries?

lallysingh 1y ago
How many cycles does the ebike battery go through in 200k+ miles? An EV car does ~300 miles/cycle. So 200k miles = 667 cycles.
- gonzo41 1y ago
  i get about 90km of range from a 500Wt Bosch battery. Thats running at full power the whole time.
  - jacquesm 1y ago
    That is amazing performance. I usually get about half that.
    - gonzo41 1y ago
      I usually ride faster than the motors limit, so it's really just acting like a push, and most of the battery is spent dragging me up a really big hill i live on. Everywhere I ride down in town is pretty much flat.
  - ul5255 1y ago
    With 600Wh battery and Shimano Steps E5000 in lowest support level I can easily ride 250km/charge
- jve 1y ago
  Cycles is not the only variable in play here: - Depth of Discharge - how often you go from full to low battery? Going twice from 80->30 (which accounts to a single cycle) is much better than single 100->0 cycle - Thermal management - what are cell temperatures when battery is being charged? Maybe it is charged in direct sunlight? This will kill battery pretty fast. At what temperatures are the cells when driving the ebike? - Ebike/scooter probably being charged to 100% more often than necessary. - Did you leave your battery at winter completely discharged or fully charged in your garage? Bad. TLDR: Info I gathered about reading how to take care of Lithium NMC batteries which are so widespread.
adiabatichottub 1y ago
Battery service life depends on many other factors besides just manufacturing quality: time, operating temperature, number of charge cycles, charging parameters, etc. On top of that, each cell design is optimized for some set of operating parameters: load, energy density, specific energy, price. It's all variables, so you'd have to narrow that question down quite a bit to even hope to have a reasonable answer.
infecto 1y ago
I imagine it’s partly due to bad quality control and engineering. No active cooling, probably a not well optimized battery management system. The batteries probably have more shock from lack of suspension. On the user side folks may not be keeping them optimally charged.
analog31 1y ago
In my experience, virtually everything is less reliable on a conventional bike, than on a car. Many of the consumable parts last a couple thousand miles at most. This may be due to differing user expectations, or the fact that a bike is more sensitive to added weight. As a rider, it's not objectionable because everything is also more maintainable by a reasonably handy person. I'd rather fix the bike once in a while than ride a permanently heavy bike. What I can't guess is how this translates into expectations for the components of an e-bike. There must still be a limit to how much size and weight a rider is willing to tolerate. On the other hand, maybe a high quality battery would last a long time and not need service, but the market isn't ready to believe it.
- ehnto 1y ago
  I think that you got it right, expectations for cylcing are different. Even avid cyclists could never hit the kilometres travelled by your average car user in a year. Being a lot more expensive as well cars need to last longer for the cost benefit math to make sense. If your car broke every in 10,000kms you'd be livid, out of action constantly. If your bike breaks down, you can probably fix it that afternoon if not on the spot. Worst case you can probably walk it the rest of the trip. That's where the e-bike is crossing barriers a bit. People will ride them much further, and getting the e-drivetrain repaired can be a real time and money sink. So you want it to be reliable, more reliable than the rest of your bike even.
  - wiether 1y ago
    > Even avid cyclists could never hit the kilometres travelled by your average car user in a year. According to different sources, the average kilometers travelled by motorists are under 25k km/year (including Europe & US). You'd be surprised by how many amateur cyclists ride more than that each year.
    - urban_winter 1y ago
      > You'd be surprised by how many amateur cyclists ride more than that each year. You wouldn't. As an 8k km/yr cyclist with a lot of cycling friends, I can tell you that 12.5k/yr is extremely high for an amateur. Sure, there are some, but a truly tiny proportion. 8k/year eats bikes, BTW. I used to wear out rims regularly before I switched to disks and chains/sprockets didn't even last a year (on a fixed gear bike).
throwup238 1y ago
Battery cells are generally binned like many ICs and the best cells go to cars and other high margin, high performance, or safety critical goods. The lower quality ones go to more cost conscious markets like the ebikes, where problems in quality control can definitely show up, especially if the OEM isn’t careful in how they spec the deliverables QA on the battery manufacturer’s side.
- CorrectHorseBat 1y ago
  How are ebikes not in the high margin category? The Bosch batteries sell for €1000/kWh at the pack level. I think it's the BMS, Batteries in cars usually get used between 20/80% and have active cooling and heating while ebikes don't.
  - throwup238 1y ago
    High margin means stuff like aerospace, defense, and biotech - although a more accurate phrasing might have been “high value add”
numpad0 1y ago
discharge rates
oulipo 1y ago
(Gouach co-founder here) Car-sized batteries last long because they have so much redundancy, that even when multiple cell fails, you barely notice it. It's very different in a smaller e-bike battery packing 40 or 80 cells. Cells aside, cars have very good suspensions, and their batteries have been designed with very pricey component to eliminate shocks and vibrations. On e-bikes, most batteries will have to sustain those, and we've seen a LOT of commercial batteries who were out of order for a simple $5 electronics component which was broken, and which couldn't be replaced because the battery was not made to be repaired (soldiering, glue, etc)
Saris 1y ago
They last about the same number of cycles, but a cycle on a car is 250-350 miles, a cycle on a typical ebike is 20-40 miles.
- fulafel 1y ago
  Ebike BMS will also drive the batteries harder (allowing to reach deeper empty/full states) since their design lifetimes are shorter than cars.

lallysingh 1y ago

How many cycles does the ebike battery go through in 200k+ miles? An EV car does ~300 miles/cycle. So 200k miles = 667 cycles.

gonzo41 1y ago
i get about 90km of range from a 500Wt Bosch battery. Thats running at full power the whole time.
- jacquesm 1y ago
  That is amazing performance. I usually get about half that.
  - gonzo41 1y ago
    I usually ride faster than the motors limit, so it's really just acting like a push, and most of the battery is spent dragging me up a really big hill i live on. Everywhere I ride down in town is pretty much flat.
- ul5255 1y ago
  With 600Wh battery and Shimano Steps E5000 in lowest support level I can easily ride 250km/charge
jve 1y ago
Cycles is not the only variable in play here: - Depth of Discharge - how often you go from full to low battery? Going twice from 80->30 (which accounts to a single cycle) is much better than single 100->0 cycle - Thermal management - what are cell temperatures when battery is being charged? Maybe it is charged in direct sunlight? This will kill battery pretty fast. At what temperatures are the cells when driving the ebike? - Ebike/scooter probably being charged to 100% more often than necessary. - Did you leave your battery at winter completely discharged or fully charged in your garage? Bad. TLDR: Info I gathered about reading how to take care of Lithium NMC batteries which are so widespread.

adiabatichottub 1y ago

Battery service life depends on many other factors besides just manufacturing quality: time, operating temperature, number of charge cycles, charging parameters, etc. On top of that, each cell design is optimized for some set of operating parameters: load, energy density, specific energy, price. It's all variables, so you'd have to narrow that question down quite a bit to even hope to have a reasonable answer.

infecto 1y ago

I imagine it’s partly due to bad quality control and engineering. No active cooling, probably a not well optimized battery management system. The batteries probably have more shock from lack of suspension. On the user side folks may not be keeping them optimally charged.

analog31 1y ago

In my experience, virtually everything is less reliable on a conventional bike, than on a car. Many of the consumable parts last a couple thousand miles at most. This may be due to differing user expectations, or the fact that a bike is more sensitive to added weight. As a rider, it's not objectionable because everything is also more maintainable by a reasonably handy person. I'd rather fix the bike once in a while than ride a permanently heavy bike. What I can't guess is how this translates into expectations for the components of an e-bike. There must still be a limit to how much size and weight a rider is willing to tolerate. On the other hand, maybe a high quality battery would last a long time and not need service, but the market isn't ready to believe it.

ehnto 1y ago
I think that you got it right, expectations for cylcing are different. Even avid cyclists could never hit the kilometres travelled by your average car user in a year. Being a lot more expensive as well cars need to last longer for the cost benefit math to make sense. If your car broke every in 10,000kms you'd be livid, out of action constantly. If your bike breaks down, you can probably fix it that afternoon if not on the spot. Worst case you can probably walk it the rest of the trip. That's where the e-bike is crossing barriers a bit. People will ride them much further, and getting the e-drivetrain repaired can be a real time and money sink. So you want it to be reliable, more reliable than the rest of your bike even.
- wiether 1y ago
  > Even avid cyclists could never hit the kilometres travelled by your average car user in a year. According to different sources, the average kilometers travelled by motorists are under 25k km/year (including Europe & US). You'd be surprised by how many amateur cyclists ride more than that each year.
  - urban_winter 1y ago
    > You'd be surprised by how many amateur cyclists ride more than that each year. You wouldn't. As an 8k km/yr cyclist with a lot of cycling friends, I can tell you that 12.5k/yr is extremely high for an amateur. Sure, there are some, but a truly tiny proportion. 8k/year eats bikes, BTW. I used to wear out rims regularly before I switched to disks and chains/sprockets didn't even last a year (on a fixed gear bike).

throwup238 1y ago

Battery cells are generally binned like many ICs and the best cells go to cars and other high margin, high performance, or safety critical goods. The lower quality ones go to more cost conscious markets like the ebikes, where problems in quality control can definitely show up, especially if the OEM isn’t careful in how they spec the deliverables QA on the battery manufacturer’s side.

CorrectHorseBat 1y ago
How are ebikes not in the high margin category? The Bosch batteries sell for €1000/kWh at the pack level. I think it's the BMS, Batteries in cars usually get used between 20/80% and have active cooling and heating while ebikes don't.
- throwup238 1y ago
  High margin means stuff like aerospace, defense, and biotech - although a more accurate phrasing might have been “high value add”

numpad0 1y ago

discharge rates

oulipo 1y ago

(Gouach co-founder here) Car-sized batteries last long because they have so much redundancy, that even when multiple cell fails, you barely notice it. It's very different in a smaller e-bike battery packing 40 or 80 cells. Cells aside, cars have very good suspensions, and their batteries have been designed with very pricey component to eliminate shocks and vibrations. On e-bikes, most batteries will have to sustain those, and we've seen a LOT of commercial batteries who were out of order for a simple $5 electronics component which was broken, and which couldn't be replaced because the battery was not made to be repaired (soldiering, glue, etc)

Saris 1y ago

They last about the same number of cycles, but a cycle on a car is 250-350 miles, a cycle on a typical ebike is 20-40 miles.

fulafel 1y ago
Ebike BMS will also drive the batteries harder (allowing to reach deeper empty/full states) since their design lifetimes are shorter than cars.