d8veh said:
cycleops612 said:
I am skeptical of the volume proportion of the fancy 18650s on the market that you represent as the norm.
Do laptops use LiFePO4? Do electric vacuum cleaners or lawnmowers use LiFePO4? There's a reason that the answer is no. In fact I can't think of a single battery powered domestic device that uses LiFePO4.
I can show you 100 different OEM bikes that use 18650 cells in their batteries. I challenge you to show me 3 OEM bikes that use LiFePO4. I don't want to sound big-headed, but for your information, I work with various OEM brands to help them develop new ebikes, so I know what's going on in the industry (Europe).
Yes, 18650s serve ok for 250w EU bikes, but thats about the limit of bottle 18650 batteries.
Yes, I know my style doesnt win any friends. To some extent i provoke, on thin ice, to get answers. Sorry folks, but its the best way i can figure.
I say again. I am not convinced. You guys never address the issue holistically from the consumers viewpoint. Maybe on paper, by your chosen criteria 18650 is better, but u guys happily sell bottle batteries of 18650s to mostly occasional users. A 1c 12ah 18650 panasonic 36v bottle pak wont even power a 350w properly more than a few minutes. Put it aside for a few months, its quite possibly ruined. You guys dont replace failed batteries (warranty is a nonsense given shipping rules, more than its worth). all they want is an easy sale. Of course they, like you, sell the conventional wisdom. Educating punters means lost sales.
(an 18650 is 560gm, a lifepo4 pouch cell is about 250gm per 10ah, so do the math, its not huge - at best, 170gm vs 250gm, at premium 2500ms, its 200gm vs 250gm and most commonly at about 1500ma chinese cells, its heavier at 333 gms.). Each result, if dubious claimed voltages are believed, should be factored a bit due to the 1/3 highre voltages at full charge, but averaged out given rapid and continuous voltage drop of 18650s, this edge ought be at least halved.
e.g. Nobody even seems to admit the fundamental flaw that the last 20% of 18650 limn is a flat out lie. Its useless dead weight, yet its counted as capacity? Right there alone is a 20% fudging of weight, cost & capacity. I may be wrong (and am happy to be proved so by someone who addresses arguments as they should), but this has to be the fifth time i have said it, yet all simply recite the alleged sexy bits about 18650s (largely, as here, its "the conventional wisdom"), and ignore what seems a blatant and ~universal deception. It has been universally ignored by the fanboys, so i have to assume its correct.
This alone would make a 10ah lifepo4 equal a 12ah 18650 rig in capacity, and negate most if not all weight "disadvantages". Then you have; c rates, durability, longevity, fully usable til empty (a half empty 18650 is nothing like a full one, unlike the identical~ abilities of a half full lifepo4), fault diagnosis, fixability, simple construction.
18650s are great - for slow constant, piddling applications, but would you make a car battery out of torch batteries? Tessla use ~7000? get real. Do you really think that sensible.
They are fine for small jobs, not big batteries and for EV bursty demands. A single cell lifepo4 can be 100 ah or more vs an absolute max of about 3.2 ah in scarce (snapped up by apple etc.) premium 18650s. For argument sakes, the fanboys treat this as the norm, whereas sub 2 ah is?
It doesnt make sense intuitively does it? a big battery made up of scads of tiny ones? Good luck finding the inevitable bad ones among that rats nest of groups and subgroups of cells.
Similarly, all have avoided is my often put point: How on earth can 18650 cells be properly charge managed, if as certainly seems the case, only groups of 18650s are managed, not each cell as in lifepo4 (how do you manage 7000 cells in a tessla - forgetaboutit?)
I regularly hear lifepo4 is heavier and dearer, but, honest apples with apples comparisons please.
It is nothing like a given that industry knows best for consumers.
Laptops are not ebikes. Weight and ideal c rates are way different. Laptops dont have to accelerate out of trouble or climb hills hauling 100+ kilos..
Cars have softened us to expect big bills, but personally, i would prefer a battery that serves, neglected, for a decade, over a prima donna which serves a few years if no storage lapses of procedure occur. The learning curve for lifepo4 is simple. ~There isnt one. Those real costs to be factored in where i come from.
- nah - lifepo4 4 this twice bitten 18650 former customer.
