Without a gearbox it seems like there is always going to be the problem of not running a hub motor at the most efficient rpm , so for people who want to ride at the upper speeds
For those of us that ride on the road with big/heavy cars and trucks , the faster / larger diameter wheels , is a necessary trade off,
so ... is there not some cooling effect on the motor when air is passing over the surface of it , at faster speeds ?
to actually reduce some of the heat build up ?
the work around to that heat/bogging down problem, that I do now with my Mac powered bike , is to use less throttle, but keep pedaling , using many gears , so as to not have the motor bog down.
When I go up hills I presently use all of the 8 cogs available on the rear , and also at the same time only have the throttle about 1/2 or less , so as to over come the heat problem.
But is the Mac just better at not absorbing / holding on to heat than a motor like the Q100H ?
I would like to see a road test with the same motor, like a Q100H ... on the same road bike, with a 26 inch rear and a 700c rear , in both 201 and 328 winds, done with
the same battery , the same controller, display, etc. with some thermal readings, trying to do this with graphs just does not convince me, as I am running a fast wind 410 rpm , mac motor
with large diameter wheels at the present time , and I run it at 200-400 watts most of the time , it does just fine. So I really wonder about graphs, since someone is already using that motor on a 700c wheel, with good results.
By the Way, the 4s packs that were said to be a good deal , are no longer a good deal price wise. I was thinking about making them into a 16 s pack, but they have gone back up in price, so it looks like I am back to
looking into 52 volt pack when the price gets better, or just using a 48 volt pack that I already have now, it is rated at only 2c max continuous but it would work with the little low power Q100H .
So it looks like my speeds will not be all that much with a 700c wheel and 328 rpm wind , after all. ( I do want to start using 52 volt pack in the future )
Sunder said:
You can see efficiency peaks out at about 75% of the max RPM, at just over 80% efficient. I don't want to go into too much detail, but those curves can be deceptive. Let's just say if the Q100H can safely dissipate 200W of heat into the air, then going from 80% efficient @ 1kw (200w of waste heat generated), to 70% efficient (300w of waste heat generated), doesn't mean you've lost 10% efficiency. It means you've gone from absorbing 0w of heat to absorbing 100w of heat. That 100w could melt enamel coatings in a very very short time.
I rarely change between 12 and 16S, since I rarely travel >20km these days. But I have the other config saved and it's about 5 clicks in the programming software (Which you don't need the internet to use) to change over. If I had a BMS on my 16S pack (have ordered one), I could easily just set the LVC to 42V and the HVC to 68v, and both packs would be happy. But without a BMS, I don't want to get sloppy and over-drain the battery.
eBikes are definitely meant to be a money saver, so a controller that sets you back $300 is definitely a shock, especially when you can get other good Sinewave controllers at $40-50. I don't know why I love the Phaserunner so much. I think most of it is because it's silent. Totally silent, as compared to just the quiet of the S12SH. The ability to program things like throttle feel and start up currents is also useful, but also, all the other bits about field oriented control providing better efficiency than other types of commutation just appealed to the perfectionist in me, even though I will probably never notice the 1-2% gains. I know I shouldn't be pushing you towards any single solution, since your needs and financial situation could be very different from mine, but the first few rides I had with this controller really did live up to the "Grin Cyclery" namesake. After years of buzzing and having to feather my throttle to get a smooth take off, it was just such a natural, gentle feeling, like I was getting on a bike at the top of a hill, not riding an electric.
