Buk___ said:
But then the C-rate stuff cropped up and I do not 'get' that yet.
C-rate is a way to describe how much current you can draw from a cell. 1C means 1x the Ah capacity = how many Amps you can draw, so a 4.4Ah cell with a continous 2C "c-rate" can handle 8.8A without major voltage sag, internal heating, or cell damage. A burst c-rate of 3C for a 2Ah cell would be 6A for a few seconds or less, usually, while the same cell might handle 1-2C (2A to 4A) continuously, for example.
And sellers too-frequently lie about both the capacity *and* the C-rate of their cells and packs. You'll see stuff like Ultrafire (and other *fire) cells that give capacities of 10Ah or even 20Ah in a single 18650, which is currently far from possible, and might list C-rates of 5C to 10C that could probably set the cell on fire from the heat generated...assuming the cells even worked at all when you got them
since those *fire cells are typically recycled garbage rewrapped as if they were new.
The pouch cells you link to could actually be genuine; the page says MOQ is only 1, but they probably charge some exorbitant handling or shipping fees; you'd have to check them out to see. It's also possible that their C-rate is very low, which just means you ahve to parallel a number of them to draw much current from them. You'd have to determine how much current your controller needs to pull from your pack, under the loads (hills/weight) you'll be putting it under, for the continuous length of time you have to do that for.
Regarding assembly, one problem with pouch cells is that they usually need to be constrained equally across their large flat surfaces, such that they dont' swell up with gas formation inside, when used at higher (for their specs) currents. They may have to be constrained no matter what their usage is.
My present packs are pouch cells, but they're also mounted in the hardware the manufacturer designed for that purpose, which makes it easier for me to package and handle them without worry. Iv'e still killed one cell with overdischarge accidentally, puffed it up right good. :/ (but I think it took actually reversing it to do that to this one--hobby RC cells I've puffed up just sitting there. :/ ) The problem with the ones I use is they're expensive and have to either be gotten used from someone else (like mine) or in large quantities from the manufacturer.
If you know anywhere in your area that scraps out electric or hybrid cars, the packs from those are often still usable at least in part, and may have cells you can use for your own pack.
But the DIY and other costs may still make it cheaper to buy prebuilt from a trusted seller.
(trusted, because I think we see more "crappy battery" problems here on ES than anything else. )
As yet I do not understand the difference/significance of the sinusoidal vs non-sinusoidal controllers? Nor have any notion of what if any difference there is in cost.
Probably not much cost differnce. Sine controllers are generally going to be a lot quieter with typical motors vs trap controllers. Might also be more efficient (cooler) depending on the motor/etc.
I'm looking to extend my excursion range, but I live (nearly) at the top of one of the highest hills in my county, which means I tend to be going down hill outbound whatever direction, and thus hit the wall when returning.
.
Just keep in mind that if you setup a system that uses regen for braking that you won't want to (or possibly be able to) use it going down that hill outbound, if you start out fully charged. Won't matter if you use any of the geared hub motors or middrives, just DD (direct drive) hubmotors.
Buk___ said:
Amberwolf. You're crazy! But you know that
Yes, yes I am. Muhahahahaaaaaha..heha..:chokes:
You're also talented, dogged, persistent, and original. I envy you all of those. (But not the dayglow
)
I dunno about original, but I'll grant the others (even if my talents are rough and strange).
At the time, dayglo paint was the best way to be seen on a "regular" bike in daytime, and even at night under most lighting conditions (especially with white LED or fluorescent/UV downlighting).
Nowadays I don't bother with that due to the size of my contraptions being large enough in daytime to ensure most drivers go around me rather than over or thru me, or attempt to run me off the road. (I have a feeling most of the ones that consider it decide not to as it might actually damage their vehicle to hit me). At night I'm so well lit that the only way they wouldn't see me is if they were driving with their eyes completely closed for the mile before they got to me till after they'd passed me some distance.
but in the last 30 years I've seen exactly one discarded (probably stolen, broken and dumped) bike and when I went back past there a few days later -- I was out walking with the wife when I saw it -- it had gone.
This past decade has seen the recyclable junk curbside diminish severely here, too--but until so many people became desperate enough for money to do pretty much anything for easy money like that, there used to be a lot of it. I still find them at yardsales and such, but not much curbside.
Essentially what I am saying is that I simply do not see much in the way of discarded stuff where I live.
Yeah, it makes it hard to do what I like to do; much of what I use these days comes from work or friends/acquaintances that remember I might be able to use something....
but I used to do a lot of dumpster diving until they made it illegal (too many idiots making messes instead of cleaning up after they were done).
Having read a few of your threads (here and on your own site), my take from it is that the only really successful build was when you bought (albeit at a knock-down price) and designed-for-purpose hub motor. (I cannot see anyone gifting me a similar bargain.)
It was certainly longer lasting than my friction drive made from the skate wheels and radiator fan motors--but I think if I'd had better batteries and more clue to what I was doing, I could've made that one work out better and last just fine.
CrazyBike2 was successful enough as a powerchair motor chain drive...but I had little idea what I was doing and was learning as I went--I hadnt even found this site yet, IIRC. I think if I were to go back and retry that (I still want to) it'd be a lot better built--partly cuz the frame wouldn't be so bendy (the cause of most of the destruction of parts was derailing due to misalignments under torque).
Sure, you learnt a lot and had some fun from building the wiper motor/fan motor chain drive/friction drive early attempts; and we your readers learnt a lot from reading of your experiences; but what we learnt, mostly, was that a design-for-purpose hub motor was vastly superior to a hacked together re-purposing of auto-components.
It is a valuable lesson, but one that doesn't need to be repeated.
Probably true.
It depends on the resources of those reading, I suppose. You should look around at the threads for Numberonebikeslover (Naeem) here on ES--now THAT man can really build useful stuff from junk! (his resources were probably a lot less than mine)
For most people, going with a kit is "cheaper" because of time...and lack of DIY skills. Basic DIY skills can make individual parts (controller, motor, prebuilt battery pack, etc, all from different suppliers or even the same one but not sold as a kit) cheaper.
