Shouldn't all e'cycles be made with 18650's? BMS??

[4LivesPerGallon]

To my knowledge, the ONLY good EV-model is the Tesla.

With two wheel, so far, it seems to be the Taiwan-made Gogoro. And, in China, the NIU N1 made by the Baidu boy-genius.

These all use 18650's from Panasonic, I believe.

But, where is the BMS that operates the 18650's (homebuilt or in 12V-looking packs) with Tesla-like precision, in series/parallel blocks?

If I'd like to change my 1/2 Group U1 12V batteries with Panasonic 18650's inside, which proven product to buy?

Our group's experience with 40AH "12v"Thundersky's was that their C-Rating, under load, dropped fast after charging.

The Chinese 12V LIFEPO4 "1/2 Group U1", from 2012, have a lower C-Rating now than they were, when new. The capacity seems to be OK, but the lowered C-rating observed means that the e-cycle has to go slower, or else the battery just "runs out of breath" and needs to rest.

 

[amberwolf]

I wouldn't want 18650s; too many connections to break under vibration on the roads here. (if they were free I'd use them....but I wouldn't go out and buy them, unless my other choice was RC LiPo--I'd rather use the 18650s. )

On my primary bike CrazyBike2 I'm still using EIG NMC 20Ah prismatics, in a home-built pack using EIG hardware, which work fine for my applications. (wish I had more!).

A123 20Ah prismatics on the trike, in an EM3EV pack, which also work fine. (just wish it was higher capacity)

 

[neptronix]

Pouch cells would certainly be more ideal than hundreds of tiny cells with hundreds of tiny connections.
18650's currently have the best chemistries right now though, in terms of energy density.

But pouch cells don't require so much work to assemble, and take less space.. Potentially, they could be lighter as well.

I don't understand the current fetish with 18650's. I think it is driven mostly by Telsa. Must be nice for them to have an automated laser tab welding facility.. you and me don't have the ability to utilize such a thing.

 

[wesnewell]

In answer to the subject line, that's a big fricking NO IMO.

 

[Voltron]

Horses for courses... all the battery types have their special thing that makes them more optimal for one application than another. I'd say if your build valued high fire safety, high redundancy factor, easily configurable shape, and medium c rate, and you have the technical skills to do it,18650s are a fine choice. But maybe something else is important to you like extreme c rate, or simple construction, or you really really like big gray rectangles or something, then maybe hundreds of little cells aren't your thing.

 

[Voltron]

That's all said as the new owner of a 280 cell 18650 pack to manage now... So maybe I'm just selling myself on them..lol.

 

[kdog]

I was wondering why 18650's predominate so heavily over 26650's. The only benefit I can see is packing factor... This is of course beneficial in a small space like an ebike frame but with a larger battery why do 18650's still remain popular?

 

[Hillhater]

I was wondering why 18650's predominate so heavily over 26650's. The only benefit I can see is packing factor... This is of course beneficial in a small space like an ebike frame but with a larger battery why do 18650's still remain popular?

Price vs performance.
The result of producing huge volumes of18650 compared to 26650s. Initially for the laptop market, and now for portable tools and Tesla etc.
.

To my knowledge, the ONLY good EV-model is the Tesla.

With two wheel, so far, it seems to be the Taiwan-made Gogoro. And, in China, the NIU N1 made by the Baidu boy-genius.
.

Your comments are flawed...!
Tesla may be one of the best EVs, but it's not the only good one.
Nissans Leaf with pouch cells if a very good vehicle, together with the award winning BMW i3, and the GM Spark and Volt are highly regarded also.
2 wheels ?.....forgotten the Zero. .?
Ebikes ?... Many, many very good products from Europe with in frame packs.

 

[999zip999]

YES.

 

[dogman dan]

18650's now popular again because they hold a lot more capacity, than the 2008 version of lifepo4 18650 cell. And yeah, they do pack tighter than a larger diameter cell.

Spot welding them so they don't disconnect the first time the package is dropped during shipping is merely a technical quality control problem. But one they did not worry about on those shitty lifepo4 packs of 2008.

For home builders of batteries, It would be great if good cells came in 3p, 4p, 5p, etc, all spot welded up for you ready to go. Then simple to solder a few series connections to a convenient protruding tab to make a 10-20 ah pack. Better still if they came with a short wire soldered on at the factory.

 

[mistercrash]

Shouldn't all e'cycles be made with 18650's? BMS??

Now, I'm thinking yes. Even using plastic spacers to hold the 18650 cells 2 mm apart will yield a smaller battery than prismatic pouches from EIG, A123 or Hobby King. Wether they be LiFePo or Lipo. Spot welding them together is becoming easier with the help of guys like riba who offer a good spot welder for a reasonable price. High quality cells are also offered at a reasonable price by guys like okashira. (He's out now but working hard to get more). So for now, yes but who knows what is coming in the near future.

 

[Voltron]

Except for the C rate... a much as I'm enjoying my 18650s, even with the balancing, fire hazard and dud rate of RC lipo.. I sure wouldn't mind some 30 or 40 C rating. But not everybody needs that of course...

 

[Hillhater]

Except for the C rate... a much as I'm enjoying my 18650s, even with the balancing, fire hazard and dud rate of RC lipo.. I sure wouldn't mind some 30 or 40 C rating. But not everybody needs that of course...

Well, there is still the A123 M1 option for high C rate.
....but then you trade off capacity and cost.

 

[markz]

Why are pouches better then can? Stirctly in the space saving angle. Drop a pouch on its corner its done right?
I would have assumed the other way around, cans are better then pouches. But I'd prefer safety then space saving. I really have no space saving requirements.

 

[spinningmagnets]

I was wondering why 18650's predominate so heavily over 26650's

The global market for cordless tools (using high-current 18650's) is absolutely huge, compared to 18650's used in E-bikes. China has millions of E-bikes, but...the predominant battery is still the lead-acid. I don't know why Tesla didn't use 26650's in a honeycomb pattern, but...they did what they did...which ended up being good news for the E-bike world.

There has recently been a big improvement in 18650 cells, the 3500-mAh, NCR18650-GA, Panasonic-Sanyo cell is expensive for now, but...a small 5P pack (rated for 10A per cell) provides 50A, and 17.5-Ah. A 12S pack like that would be only 60 cells, so that's incredibly small!

A year from now we might start seeing the battery volume of that size Watt-Hour of battery pack cut in half by solid state batteries (SSB). In 2008, ES members were harvesting cells out of huge piles of new cordless drill packs (DeWalt/Makita) to build a pack with decent current and safety.

 

[Hillhater]

I was wondering why 18650's predominate so heavily over 26650's

. I don't know why Tesla didn't use 26650's in a honeycomb pattern, but...they did what they did....

Probably because large volumes of high capacity, high power, 26650s were not available at that time.
And 18650s were by far the better choice, being the cell used by most laptops for some years by then, with huge production capacity ( consequently low cost) and better kWhr/kg .