E-S Stealth Electric Bike Owners

Rix said:
Beutiful Fighter Kepler,

Don't know if its just the the video, but other geared hub motors Ive seen sound noisier than that. Is your BPM any noisier than a gearless hub motor? It sure doesn't sound like it is. Once again, super nice build. Spoke with Darrin last night, he says my bomber may be here next week. Can't wait!! Been a long 6 weeks. I thought for sure that I would get bumped back a little when Darrin and John suggested I switch my order to the bomber. Apparently not. Great Guys and a great company. So.... When you gonna do a comparo between your fighter and a stock fighter. I am curiouse if there will be any accelleration differences. Your fighter at 2KW and a stock fighter at 3KW would suggest that the stock fighter would be faster. However, factor in your fighter's much lighter rolling weight and the geared hub, I wouldn't be suprised if it could beat stock fighter. Thanks for showing your build details and posting the video. Rubberside down, or, at least one wheel. Rix
Click to expand...

Thanks Rix,

Noise wise the BPM is certainly no louder then a HS35 as used in a stock Fighter. The 54XX motors in the Bomber are definitely quieter though. In fact the 54XX motors are the quietest and smoothest hub motors I have come across so far.
 
Had a very interesting commuter type ride with my friend on his Fighter and me on my Fighter this morning.Total distance was just over 12km. As a re-cap, his Fighter has the stock HS35 motor but is running 18S 75V LiPo. We have the current limit set on his bike to 55A so it has over 4000W available. Mine is set to 30A. He weighs about 80kg and is a bit lighter then me.

We road wheel to wheel or side by side for the full ride and both just peddled lightly. I nearly fell off my bike when I saw the difference in economy.

By the figures below, my bike managed a whopping 40% better efficiency. :shock: This was at a moderate average speed of 33kph

IMG_1214.JPG

View attachment 3


We also had a bit of drag race from about 30kph until I ran out of legs. He was slightly quicker then me but not by much. I only lost one bike length to him over the distance. You can see from the numbers below, both bikes peaked a little higher then the set amp limit but this isn't unusual to see.

View attachment 2

IMG_1218.JPG

I could see one of the big advantages I had was that my bike seemed to glide for much longer when not under power. Although when coasting down a hill, both bikes seem to maintain the same speed. This surprised me as I thought my ability to fully free wheel would have seen me pull away under coast. However, this wasn't the case.

Finally, noise wise, although they had a different sound, the actual noise level between the two bikes were very similar.
 
Kepler said:
Had a very interesting commuter type ride with my friend on his Fighter and me on my Fighter this morning.Total distance was just over 12km. As a re-cap, his Fighter has the stock HS35 motor but is running 18S 75V LiPo. We have the current limit set on his bike to 55A so it has over 4000W available. Mine is set to 30A. He weighs about 80kg and is a bit lighter then me.

We road wheel to wheel or side by side for the full ride and both just peddled lightly. I nearly fell off my bike when I saw the difference in economy.

By the figures below, my bike managed a whopping 40% better efficiency. :shock: This was at a moderate average speed of 33kph



View attachment 3


We also had a bit of drag race from about 30kph until I ran out of legs. He was slightly quicker then me but not by much. I only lost one bike length to him over the distance. You can see from the numbers below, both bikes peaked a little higher the set amp limit but this not unusual to see.

View attachment 2

View attachment 1

I could see one of the big advantages I had was that my bike seemed to glide for much longer when not under power. Although when coasting down a hill, both bikes seem to maintain the same speed. This surprised me as I thought my ability to fully free wheel would have seen me pull away under coast. However, this wasn't the case.

Finally, noise wise, although they had a different sound, the actual noise level between the two bikes were very similar.
Click to expand...

impressive, for sure.

I'd love to see a drag race from a standing start... and at what speed did the Hx fighter start pulling away?
 
Interesting comparison. With some of the high power & speed setups out there, I'd be interested to see someone with a set daily ride gradually limit current with the CA and see at what point their overall ride time changed significantly. I suspect many people could run at lower current limits than they might have thought. Of course a max current 'turbo' button is nice to have if you need it :)

Peak current available can make a big difference to efficiency unless you're real gentle rolling on the throttle.

Also at 33 kph, riding wheel to wheel, whoever's at the back will need vastly less power to maintain the speed of the lead rider.

Having a motor that can freewheel is especially nice if you run out of power :D But as long as power is available, only a few watts are needed to overcome direct drive hubmotor cogging.

Overall, I'd guess the difference in motor weight would have the smallest contribution to any efficiency differences as a few kg difference between 100+kg bike&rider combo isn't much.
 
Some good points there voicecoils. I think perhaps a fairer comparison in relation to economy would be to set the HS equipped Fighter for the same current limit as my Fighter. In relation to drafting, its worth noting that what I meant by "wheel to wheel", was that we rode close to each other but there was certainly no drafting.
 
sn0wchyld said:
I'd love to see a drag race from a standing start... and at what speed did the Hx fighter start pulling away?
Click to expand...

The pull away was fairly linear from the time we nailed it to about 60kph where my Fighter ran out of legs. The Hx Fighter had another 10kph in it.

More comparison data to come. :)
 
voicecoils said:
Having a motor that can freewheel is especially nice if you run out of power :D But as long as power is available, only a few watts are needed to overcome direct drive hubmotor cogging.
Click to expand...

This is something I am trying to get my head around.At this stage I cant agree with the above.Using a 5304 hub for comparison to my freewheeling geared hub I would have to say it feels like a lot more than a few watts of resistance when trying to peddle a large cogging hub motor .

I can ride the 4kg geared hub like a normal bike and not really notice any difference. The 5304 is like riding a bike through deep sand and every time you let off the throttle its like you are going up a incline and your coasting speed quickly declines due to cogging. Also getting a heavy hub motor up to speed from a dead stop is like trying to spin up a large flywheel every time.

it just from experience and I guess some hubs cog more than others.

it would be interesting to do the same ride ,with the ca limiting wattage to say 2000w and no peddling at all just motor, ride side by side or even better get the same rider on both bikes.

Kurt
 
Kurt said:
voicecoils said:
Having a motor that can freewheel is especially nice if you run out of power :D But as long as power is available, only a few watts are needed to overcome direct drive hubmotor cogging.
Click to expand...

This is something I am trying to get my head around.At this stage I cant agree with the above.Using a 5304 hub for comparison to my freewheeling geared hub I would have to say it feels like a lot more than a few watts of resistance when trying to peddle a large cogging hub motor .

I can ride the 4kg geared hub like a normal bike and not really notice any difference. The 5304 is like riding a bike through deep sand and every time you let off the throttle its like you are going up a incline and your coasting speed quickly declines due to cogging. Also getting a heavy hub motor up to speed from a dead stop is like trying to spin up a large flywheel every time.

it just from experience and I guess some hubs cog more than others.

it would be interesting to do the same ride ,with the ca limiting wattage to say 2000w and no peddling at all just motor, ride side by side or even better get the same rider on both bikes.

Kurt
Click to expand...

I think what he means is it only requires an amp or so from the battery to overcome this cogging and make it 'free-wheel'. even after hitting LVC batteries will still seep out that much power, particularly if you have a conservative one on your CA to begin with. Once I finally get my ass in gear and change my CA to be a current based throttle I'll try and make a button bypass whereby pressing it tells the ca to deliver ~1A to the motor, which should be perfect for coasting + normal pedalling.
 
Ok so say its 1A that would be 75w on a 18s bike and that is acting as a 75w brake all the time !

I was thinking about a experiment using one of my bikes that has 26' wheel laced with a DD hub motor 5304 clamp the bike upside down then drive the wheel (friction drive) using the wheel my another ebike (tread to tread) . Set the CA of the driving bike for speed limiting at say 5kmh - 10kmh - 20kmh and then 30kmh typical peddle speeds and take not of the power consumed to drive the hub motor wheel. Then compare that to the driving bikes wheel spinning under power at the same speeds on its own and deduct the difference. This would give me the a reasonably accurate way to know the true wattage wasted overcoming clogging on the DD hub motor . It's a bit like a cheap nasty dyno.

I remember a long time ago some one did this test it and had some numbers.

Like you have said set CA at 1A but trying to modulate your accelerate just enough to overcome cogging and not give any extra power is very hard.

kurt
 
Kepler wrote:
Had a very interesting commuter type ride with my friend on his Fighter and me on my Fighter this morning.Total distance was just over 12km. As a re-cap, his Fighter has the stock HS35 motor but is running 18S 75V LiPo. We have the current limit set on his bike to 55A so it has over 4000W available. Mine is set to 30A. He weighs about 80kg and is a bit lighter then me.
We road wheel to wheel or side by side for the full ride and both just peddled lightly. I nearly fell off my bike when I saw the difference in economy.
By the figures below, my bike managed a whopping 40% better efficiency. This was at a moderate average speed of 33kph

Hey Kepler,
Do you have theory why your bike was 40% more efficient and you being the heavier pilot? It appears that you are getting more performance with less current with the geared hub motor running minimal current imput over a gearless hub motor. You mentioned coasting down hill there wasn't any more percievable scavaging drag on the HS, but flat there is less drag on the bpm. Anyway I find that your set up using 40% less current with 90+% of the performance to be impressive.
 
I am re doing the experiment this morning again but this time with my friend's bike current limited to 35A just to see how much of an impact that will have. I think the figures will be much closer however, I am sure I will have a definite acceleration advantage.

I think its important not loose site of why a stock Fighter has a Hx motor and a massive 18FET controller though. The stock offering is all about a proven balance between performance and reliability. The Stock Fighter will hit dirt tracks hard and you know you are going to get it home. My setup, well we dont really know how it will survive in the wild. As an Urban weapon though, its looking very solid 8)
 
Kepler said:
I am re doing the experiment this morning again but this time with my friend's bike current limited to 35A just to see how much of an impact that will have. I think the figures will be much closer however, I am sure I will have a definite acceleration advantage.

I think its important not loose site of why a stock Fighter has a Hx motor and a massive 18FET controller though. The stock offering is all about a proven balance between performance and reliability. The Stock Fighter will hit dirt tracks hard and you know you are going to get it home. My setup, well we dont really know how it will survive in the wild. As an Urban weapon though, its looking very solid 8)
Click to expand...


a 18fet is somehow safe do to your daily commute in a cromo, but thats depending on the size of your wheel and voltage... .

on the other hand I think my 24fet lyen (unused) ll do 150a main with active cooling and no other mod(and the 24fet has alot of room mods)
 
Nice work on the lightweight variant Kepler, frame looks clean with the controller mounted internally, lends itself well to steeper technical climbing rides like the ones I like to play on...

The weight reduction and preservation of torque for climbing gets me wondering about how it'd go with some targeted trials arena play, similar to what I put mine through (briefly) whilst demonstrating at Royal Easter Show earlier this month. The rider, Jack Field, might just be a distant relative of Al's, seems to have the same inclination for front wheel lofting. Did a writeup of the show at http://store.quietrush.com.au/1/post/2012/04/2012-royal-easter-show-with-aeva.html

Let me know if you're ever Canberra bound, would love to throw it at some local rock slabs..
 
dave.a said:
Anyone with a bomber, could you tell me Amps drawn unloaded. Mine is 3.9A. Seems a little high?
Cheers Dave
Click to expand...

Does seem a bit high. I presume you have checked for any drag from brakes, freewheel etc. Worth zeroing the amps on the CA in the advanced menu just incase the calibration has drifted a bit.
 
QuietRush said:
Nice work on the lightweight variant Kepler, frame looks clean with the controller mounted internally, lends itself well to steeper technical climbing rides like the ones I like to play on...

The weight reduction and preservation of torque for climbing gets me wondering about how it'd go with some targeted trials arena play, similar to what I put mine through (briefly) whilst demonstrating at Royal Easter Show earlier this month. The rider, Jack Field, might just be a distant relative of Al's, seems to have the same inclination for front wheel lofting. Did a writeup of the show at http://store.quietrush.com.au/1/post/2012/04/2012-royal-easter-show-with-aeva.html

Let me know if you're ever Canberra bound, would love to throw it at some local rock slabs..
Click to expand...

Thanks QuietRush. It actually climbs really well so it might go OK on the stuff you ride. It will be the long steep stuff that will kill it. The trials arena would be interesting for this bike too. With the suspension setup for this type of riding, I think it would be quite handy. If I was going to setup bike for that type of riding, I would fit the higher torque code 12 motor to the bike and run a 48V 12S 8ah setup to make the bike even lighter. Then have a second pack to hotswap out. I dont think a slow moving trials bike would be particularly Ahr hungry.
 
Hi All

Just inquiring what type of bike racks for your car you guys are using to transport your stealth bike around. Waiting to get a fighter, ordered through Quite Rush. He was nice enough to let me test ride his fighter. Very impressed, can't wait for delivery.
 
sethgl said:
Hi All

Just inquiring what type of bike racks for your car you guys are using to transport your stealth bike around. Waiting to get a fighter, ordered through Quite Rush. He was nice enough to let me test ride his fighter. Very impressed, can't wait for delivery.
Click to expand...

I've used the Stealth rack to transport the Bomber about 10,000 km to date. I think Stealth have them in stock.
 
Can't recall exactly but it was very reasonably priced...maybe $200?. In any case, much less than some other ones I've seen that probably wouldn't hold the Fighter let alone the Bomber.
 
sethgl said:
Hi All

Just inquiring what type of bike racks for your car you guys are using to transport your stealth bike around. Waiting to get a fighter, ordered through Quite Rush. He was nice enough to let me test ride his fighter. Very impressed, can't wait for delivery.
Click to expand...

I added a trailer hitch to my car and use this MC type rack. No way I could lift a Bomber up to put on a bike rack nor would I trust it.

http://www.amazon.com/gp/product/B003E2WQE4/ref=s9_simh_gw_p263_d0_i1?pf_rd_m=ATVPDKIKX0DER&pf_rd_s=center-2&pf_rd_r=09VH64MFMVYQAV3KVNZ2&pf_rd_t=101&pf_rd_p=470938631&pf_rd_i=507846
 
I am perplexed and intrigued. I just got my Fighter motor back from Stealth after an axle & bearing replacement. I put it back together yesterday & went for a quick spin. Felt great but there was one thing, it felt quicker. Put it down to my imagination. Today I went for a proper ride and it IS quicker. A lot quicker according to the CA.

81.7 kph - 50.7 mph on flat ground after the repairs...66 kph - 41.5 mph before. I can't explain it...some may say my herbal tea is too strong but the CA doesn't lie...or does it? Any explanations that anyone can think of?

On further thought it sounds suspiciously like my no load speed or some kind of spike in the CA...probably the placebo effect.

81.7 kph.jpg
 
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