Article Next leap in battery performance for ebikes?

[KeithR]

Finally, I appreciate those who have said that having the right information is what matters. That's all I care about, not who is right or wrong. People will come here and we don't want them to learn dogma, we want them to have good answers.

I understand the motivation - it's not about being right, it's about making things right.

Why it provokes such hysterical, excessive reaction in some people mystifies me.

I'm neither pro nor anti either of the parties engaged in this discussion (I grew out of "sides" when I was still at school) - it's just a difference of opinion, FFS - and the tone of some of the tantrums on here is embarrassing.

 

[KeithR]

But I feel more sorry for Knut has has been unreasonably abused and felt the need to waste his time responding.

But what if CSJ's right?

Taking into account my admittedly limited "lay" understanding of the subject matter, nothing he has said leaps out as being glaringly off the mark: but 20-odd years of legal training and experience do allow me to recognise a strong, well-argued position when I see it...

 

[Waynemarlow]

Even in your acceptance of IR as an issue, you/re missing the point. When you go from 10s to 13s by adding cells, charge and discharge currents are unaffected but power is increased (because there are more cells). When you then normalize the cell count but keep the voltage difference, IR negatively effects charge and discharge in the 13s pack making the current less and power equal (because equal cell count).

The only thing that matters is cell count, as I said in the beginning.

That leaves us understanding that how well our bikes work is mostly dependent on how many cells our batteries have, and an important thing that some people fail to realize is that there isn't going to be any genre-busting bike with a teensy battery and big performance because low cell counts can't do that. Increasing voltage is a dream that says that we can get better performance out of fewer cells by rearranging some wires. That is false.

To put this into perspective and for all our nit picking here on quite infinitesimally small gains of battery capacity, the real story is power to weight ratios. Sure you can have your latest 102Nm motor running on increasingly efficient computer controlled motors, but the minute you put that combo in a 25kg bike with my lardy 92kgs parked astride it, then my mates converted 1998 Turner running on 26" wheels weighing all of 19kgs with his svelte 70kgs astride it, needs probably 2/3rds the battery capacity to do the same speed over the same ground.

Far far better to stop going to the pub for a month, stop eating fatty hamburgers on the way home from work and your last years battery technology is still going to get you further than this years latest and greatest.

 

[Akemtb]

Current chatter with respect to Watt hours per kilogram is the current standard or achievable density of 250 Wh/Kg to 400 Wh/Kg is anticipated in the next couple years. That would be a huge increase in the power to weight ratio not only for ebikes but EVs as well.

 

[Akemtb]

A link relating to my above post.

https://insideevs.com/news/440727/elon-musk-400-whkg-cells-not-far/

 

[Akemtb]

Coming soon, 3-4 years, 400 Wh/Kg cells:

Elon Musk: 400 Wh/kg Battery Cells Likely In Just 3-4 Years

Elon Musk has hinted that high-energy dense battery cells (400 Wh/kg) with "high cycle life" and "produced in volume", are not far away.

insideevs.com