.... Gear hub efficiency Question ...
- Thread starter Papa
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If any of the ones youre looking at are also in the ebikes.ca motor simulator, you can compare the simulator results with the manufacturer claims; the ebikes.ca info is modelled from actual results / testing they've done (which is why there are so few listed). If they match then you'll know the manufacturer is including the entire efficiency of the unit, as that's what ebikes.ca is doing.
The ones with "overheat in" info available when a sim is run also have thermal testing data in their model.
The ones with "overheat in" info available when a sim is run also have thermal testing data in their model.
Typically they do.
80% efficiency is very low, consider a motor with higher efficiency like the Shengyi SX2 which can peak in the 86% range. Geared motors are at a huge heat shedding disadvantage VS DDs, so turning 6% less battery power into heat is great.
86%... that's the same figure stated in Ebike.ca's sim. I did run several hubs (trying to draw a comparison) - using the same conditions. I started with 48V 16.5Ah, Baserunner, and 4% grade. Efficiency # were all over the map, most in mid to lower 80's.
Why the mxus? Because I have one collecting dust. And after a little research finding images of its guts, I discovered it has one necessary feature that renders it suitable for the mods intended. Not so easy with the Shengyi.
What's the speculation Re OEM internal gearing loses? 2% maybe?.... 5%?... or more?
Edit:
I just ran the Grin V2 (All Axle, DD?) in the sim - same conditions - 79%
Grin V2 (fast wind), 76.9%
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4% grade will lower motor RPM and therefore dock you down into a lower part of the efficiency curve on any motor.
500w motors are not very powerful hill climbers, so they'll be running at lower RPM than a motor capable of more power, reducing efficiency more.
Most important is what happens on the flats because that's the normal case a motor will be operating in tho
My best bet about the efficiency difference is that the MXUS has 0.5mm laminations. A lot of newer motors have 0.35mm laminations which produce a significant efficiency boost.
500w motors are not very powerful hill climbers, so they'll be running at lower RPM than a motor capable of more power, reducing efficiency more.
Most important is what happens on the flats because that's the normal case a motor will be operating in tho
My best bet about the efficiency difference is that the MXUS has 0.5mm laminations. A lot of newer motors have 0.35mm laminations which produce a significant efficiency boost.
My primary conditions mandate 1800ft elevation gain for 12.5mi. (my commute home). The Mxus (still undecided) will be paired with a second, front hub motor (trike config). I have a V6 Baserunner (currently in transit) and an estimated 40Ah capacity. I'll purchase a second BR if the first proves sufficient.Most important is what happens on the flats because that's the normal case a motor will be operating in tho
My best bet about the efficiency difference is that the MXUS has 0.5mm laminations. A lot of newer motors have 0.35mm laminations which produce a significant efficiency boost.
A member here dissected a XF15 Mxus and stated .35 lams. So I 'assume' it does. Somewhere buried
in this thread:
mxus xf15 gear hub motor teardown
Sorry my friend ,i was talking about the kit (witch has the same controller)reviews that are 14 and has 27 orders! https://www.aliexpress.com/item/4000258829938.html?spm=2114.12010612.8148356.12.621176ddcs8rp1
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Hmmm, that's exceptionally low efficiency for a motor with 0.35mm lams then.
IDK, MXUS in general is not a great brand and they have a lot of so/so motor designs
Are you crossing the mountain from Beaverton to Portland, BTW?
IDK, MXUS in general is not a great brand and they have a lot of so/so motor designs
Are you crossing the mountain from Beaverton to Portland, BTW?
Nope. I'm on the western slope of Clearwater
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I'm no motor engineer so you may, in fact, be spot-on. This is why I'd like to try and estimate where the 'biggest' internal loses are in this hubmotor. QC?... dunno yet,.. but soon to find out just how well it's glued together. (I'm being intentionally vague here Re the technical damage I'm about to inflect on this XF15 freebe. So please bare with me
)
IIRC the faster the motor spins, the greater the effect of lamination thickness?
If so,because the gearing lets the geared motor spin at least several times faster, then to get equivalent efficiency from a geared hubmotor vs a DD at the same wheel speed, you'd need laminations thinner by X amount (but I don't know by how much).
If so,because the gearing lets the geared motor spin at least several times faster, then to get equivalent efficiency from a geared hubmotor vs a DD at the same wheel speed, you'd need laminations thinner by X amount (but I don't know by how much).
All I was really interested in was...
1.) Do manufactures' include internal gearing loses in geared hub efficiency claims?
2.) If so,... wild, but reasonably intelligent guesses on how much those gear loses cause? 2%?.. 5%?... more?
Extra points for manufactures' data docs.
1.) Do manufactures' include internal gearing loses in geared hub efficiency claims?
2.) If so,... wild, but reasonably intelligent guesses on how much those gear loses cause? 2%?.. 5%?... more?
Extra points for manufactures' data docs.
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Ya know.... I did look... twice even, and failed to unearth said vid. I did breeze through the "Watts" vid, but it contained few details regarding efficiency.
Since geared hubs almsot always use straightcut planetary gearsets, it's apparently reasonably well documented / tested for their efficiencies, according to a very quick search. This page was the second hit, and while my eyes glazed instantly at the math, there's a chart that might be more useful, but near the very end it says a basic planetary set is around 96.7% efficient.
I copied the likely useful chart below
What the actual efficiency of a specific motor's gearset is, I don't know.
I copied the likely useful chart below
What the actual efficiency of a specific motor's gearset is, I don't know.
Thankyou AW
It also states...
"If a geartrain is composed of more than one pair, the efficiencies of both pairs are multiplied to obtain the overall efficiency."
I probably missed a lot of things in it, as I skimmed it lightly (too much math for me to follow) 
nicobie
100 MW
Big Moose used to say to not just take into consideration a single component of a system but the whole system in it's entirety. In my experience A gear motor can't handle heat. I have smoked 4 gear motors compared with only 2 hub motors when climbing the same hill at the same speeds.
While the statement embraces at least some degree of merit.
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The lecture hall series does not look to be on the channel any more
I must've watched them more then twice each.
I will watch this one titled "School of Watts Part 1: The Power to Propel Bicycles"
Oops I did one last thing, a yt search and it popped right up.
another good video
I'll grab some popcorn and watch them.
I must've watched them more then twice each.
I will watch this one titled "School of Watts Part 1: The Power to Propel Bicycles"
Oops I did one last thing, a yt search and it popped right up.
gracias amigoThe lecture hall series does not look to be on the channel any more
I must've watched them more then twice each.
I will watch this one titled "School of Watts Part 1: The Power to Propel Bicycles"
Oops I did one last thing, a yt search and it popped right up.
another good videoI'll grab some popcorn and watch them.
nicobie
100 MW
Yes, that is what I said only with more words. Of course individual components affect how the whole system operates. But it still is a whole system that needs to be evaluated.I 'evaluated' my whole system well over 20 years ago... It's been pieced-mealed (periodically) ever since.
