Quest for "super stealth"

At the moment I have three e-bikes (who only has one?):
Bike 1. Cyclone 500W (6s 10,000mAh LiPo or 6s 17,000mAh LiPo) driving a rear derailleur and DualDrive.

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Bike 2. Astro 3210, 2-stage drive, (12s 10,000mAh LiPo) fixed gearing giving about 16mph.

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Bike 3. 250W MY1016 Unite Motor friction drive (6s 5,000mAh LiPo), top speed about 8mph.
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I live in an area with lots of hills/mountains, many 10% to 20% inclines, but, apart from hill climbing, my main priority is to not attract attention either audibly or visually - "super stealth".

Audible:
The Astro and Cyclone are too noisy (roughly the same level) - people hear them coming and some turnaround to look. It is possible to run Cyclone at low rpm when reduced noise is necessary, the Astro 3210 bike does not like running at low speeds.
The 250W friction drive is quiet and few people notice the noise.

Visual:
The 250W friction drive is not noticed because the bike looks like it should be on the scrapheap, an empty milk bottle covers the battery and a cardboard box the motor).
The Cyclone motor/gearbox is partially hidden by the BB so most casual observers do not see it (battery is in a backpack).
The Astro drive system is more visible and often noticed (admired by some).

Result:
I use 250W friction drive bike when there are no steep hills and I am not in a rush e.g. going to the pub.
The Cyclone bike is used for everything else - mountain paths (up to 15% incline, transporting wife etc).
The Astro bike lies unused - I could fit sprockets, layshafts, chains etc but this would only increase the drive system visibility - I am about to remove this drive system and put it in the "Items for Sale - Used" section - such is life!

Builds just started:
Bike 4. Two wheel drive
Two 350W geared hub motor kits have arrived from cellman.
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Plan to run on 12s 10,000mAh LiPo, guesstimating 44V x 17A x 2 or 1,500W.
Disc brake rotors should mask these small hub motors (larger diameter DD hub motors are too visible).
Will use a mule bike to try the system and eventually use a steel frame and forks, fatty tyres and maybe suspension seat post.
Battery, as usual, will be in a backpack.

Bike 5. Tricycle
Will use a 500W motor (48V 12A) and chain drive to axle (d
id think of 2 rear hub motors but wanted to do something different).

Motor will be hidden under a passenger seat or in a tool box.
Battery pack type and location as yet undecided, probaly use 12s 10,000mAh LiPo to test.

Soon as my Chopper gets built and the daughter get home with the digital Cam. I will show you my Stealth bike. The plan is to have a 4" rear tire the makes the the rear hub motor look like nothing more then a beefed up rim to hold the size. The hub motors put out a little less noise and I notice with a little traffic you don't even hear them yourself. I plan on hiding the LiFePo4s and controller in the fake gas tank. Even my beach cruiser I have now I just tell people the oversized hub is a drum brake. Why is Stealth so important some people ask me. Simple I break the law and go faster then 20MPH lol.

Hi Phil,

looking forward to seeing how you get on with the dual geared kits. Make sure you get a few pics up

Cheers
Paul

Though the gear motors will produce some sound when loaded up climbing a hill, they may be the best route for stealth.

Even on the front, 99% won't notice the motor, and the other 1% will say someting like, "nice drum brakes".

I've run 400 watt gearmotors, but never liked the climbing performance of one motor. Just bogs down on 8%. Two though, might just be real sweet. It's just a wattage thing. I'd love a big fat 14" diameter 1500 watt gearmotor I bet.

ChinaPhil said:

Bike 4. Two wheel drive Two 350W geared hub motor kits have arrived from cellman.

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Is that the Bafang BPM or something else?

There's a recent build on Pedelec.co.uk using a BPM Code 10 (315rpm, 20"?) in a 26" wheel with 48v9.2AHr of A123 battery with a 30A-80A controller. Reasonably stealthy and considerable top speed and hill climbing ability. Claimed top speed is 27mph. The BPM as a rear wheel is pretty much hidden by the disk and gear sprockets.

My own experience of the BPM (code 11, 26" wheel 36v Lion battery, 9A controller) is that it works well sensorless and is pretty quiet. Wind noise above 15 mph or so means I can't hear it. It will only do about 20mph on the flat, but will climb virtually any hill at 10mph.

In my experiance, there is nothing as quiet as a Clyte 40X series, or any of it's direct compeditors (Aetoma, early Golden motor). They're a small diameter DD, but bigger than a geared hub. On the rear of a bike, they disapear behind the gears and a disk brake. The noise level is about equivilent to a celing fan motor

ChinaPhil said:

I live in an area with lots of hills/mountains, many 10% to 20% inclines, but, apart from hill climbing, my main priority is to not attract attention either audibly or visually - "super stealth".

Builds just started:
Bike 4. Two wheel drive
Two 350W geared hub motor kits have arrived from cellman.

Click to expand...

I also think you are going the right route with hub motors. They are not inaudible, but visually not very noticable, so most people won't notice the motor and make the connection that it is an eBike.

Like drunkskunk says, some DD motors like the clyte 400 series are quieter. However quietness comes due to large mass (damps vibration) and crappy torque compared to a 9C. I have been thinking that the quietest high torque option would be a low rpm DD motor used in a left side drive with a 4:1 or even 2:1 down gearing. RPM will still be low so there should be no chain noise. Such a setup could be hidden on a recumbent, trike or longtail cargo bike using shields on the side of the motor.

For hiding the battery a triangle bag works great. I use it on 2 bikes

Stoke monkey sells such a system with a through the cranks drive. Someone who has driven a Stokemonkey can perhaps comment on sound level.

I agree, the quietest motors are definitely the 408, or similar aotema types. You can get a 4011 winding crystalyte for climbing the steep stuff.

But I also think, if you double motor the gear drives, neither one will load up so much, and both together will still be fairly quiet.

You could just put something noisy on the bike, like a chain lock that rattles a lot, or something like that.

Rear wheel now on the test bike, 7 gear cassette a straightforward fit, visual stealth good. Went for a ride using 12s 10,000mAh LiPo, a little rumble when starting from stop, quiet when rolling, more power than I expected. So audible stealth just about there. Will fit the front wheel tomorrow, I hope!

Nothing beats those little rear gearmotors for visual stealth. In front, nobody really sees a hub that small either.

Front wheel now fitted (cardboard box is full of controllers and connections - will tidy up later)!


View attachment 1


Tyre noise from the chunky tyres, especially the front one, masks any hub motor noise.
Iinitially I am using 2 throttles - both have a cruise control button!

On a short stretch of flattish road top speed, with either motor, is about 28km/h, with both about 32 km/h (GPS readings) - probably higher with a longer stretch of road and less wind - today was windy.

Initial thoughts - I prefer riding with the rear motor and then using the front when I need to accelerate hard or climb hills (not climbed a gradient greater than 10% yet).
Will try one throttle, connected to both controllers, as soon as I figure out how to do it!

It's barely noticeable that it's an ebike!

Was the 7 gear cassette from the original bike or bought separately?

Are these Bafang motors?

spence91
I used a new 7 gear cassette in order to keep the old wheel "as is" - this is a bike I use for evaluation and the old wheel will go back on, eventually.

Jbond
They are not Bafang hub motors - both are 350W geared hub motor kits from cell_man who is a member of ES. They are rated for 36V but seem to be OK at a nominal 44V (12s LiPo).

ChinaPhil said:

They are not Bafang hub motors - both are 350W geared hub motor kits from cell_man who is a member of ES. They are rated for 36V but seem to be OK at a nominal 44V (12s LiPo).

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Ah, ok. Dug around on cell_man's thread in for sale. They appear to be Cute QR-100 I was looking at Cute motors as they are very light but was put off by warnings of unreliability. I'm also a bit bothered that the axle doesn't go right through but is 2 piece. None of this may be a problem.

I'm still planning a stealth 700c hybrid. The approach I'm interested in is a rear sensorless Bafang QSWH motor. Using a 20" or 24" wind in a 700c rim to get the top speed, 36v and a Lyen or modified Infineon controller running 25A max or so to get the hillclimbing back. And a DPN 11t-30t freewheel with Shimano 48t front chainset to keep the cadence down at top speed. The catch in making it stealth is hiding the battery. I'd really like the battery in the triangle for weight distribution but it's pretty obvious there.

jbond said:

The catch in making it stealth is hiding the battery. I'd really like the battery in the triangle for weight distribution but it's pretty obvious there.

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It doesn't have to be obious. A frame bag looks perfectly normal there. Its a harder trick to hide the controller. But the thing that attracts attention is anything that looks hand made, or has wires sticking out of it.

jbond said:

ChinaPhil said:

They are not Bafang hub motors - both are 350W geared hub motor kits from cell_man who is a member of ES. They are rated for 36V but seem to be OK at a nominal 44V (12s LiPo).

Click to expand...

Ah, ok. Dug around on cell_man's thread in for sale. They appear to be Cute QR-100 I was looking at Cute motors as they are very light but was put off by warnings of unreliability. I'm also a bit bothered that the axle doesn't go right through but is 2 piece. None of this may be a problem.

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They are not Ananda/Cute motors.

I always carry batteries (4 off 6s 5,000mAh 25C) in a backpack, easy to hear the LV buzzers.

Just climbed some 15% inclines and the speed is higher than the 500W Cyclone bike with all of its gearing - guess 15km/h versus less than 10 km/h - the inclines are narrow so there is no time to look at speed readouts.

At this stage I am content with the visual stealth, audible stealth, hill climbing ability and top speed.

Hi Phil,

That sounds pretty good, those figures aren't bad at all. Who would believe it, a couple of hub motors can beat a non hub setup on an incline I recently supplied a dual Mac setup, both were low speed winds, about 200rpm loaded at 36V, so no faster than your setup. Difference is the rear is running a 500W Mac and the Front a 350W Mac, 12 fet (about 40A) infineon on the rear and a 9 Fet (30A) on the front. Should make for an interesting ride at 48V.

How did you get on with the throttle? Are you still using 1 throttle for each controller or have you tried the mod'd throttles I sent you to run both controllers simultaneously?

Cheers
Paul

Will try one throttle as soon as possible and maybe fit a switch to give one throttle or two. At the moment I have the front wheel throttle on the right and the rear on the left to match the braking.

Sorry Phil,

don't want to get personal but how heavy are you? The bike and battery pack is what, somewhere between 25 & 30kg? It's just good to have some figures in mind, unfortunately there are no hills around here to check the hill climbing ability.

Cheers
Paul

Paul,

it is a good job that we both live in the East where this sort of question is the norm. I am 95kg fully dressed, so a total of 125kg sounds about right. And, before you ask, I was born in the year of the rat.

Phil

cell_man said:

Hi Phil,

That sounds pretty good, those figures aren't bad at all. Who would believe it, a couple of hub motors can beat a non hub setup on an incline

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People are starting to see the the advantages of dual hubs. Set up right it's really hard to beat.

I'm liking the stealth you have going on there Phil, nice looking bike. I still plan on doing more to hide my controllers and wiring to try and achieve super stealth status. 8)

Gary

Just been out on a ride with one throttle driving both controllers. Now I can't decide which I prefer, one or two throttles. Suspect that for audio stealth two throttles are better as only one motor can be used but, for steep hill climbing, when I am just trying to hang on, one throttle is best. Tending to think that a switch to select 1 or 2 throttles is the way forward.

ChinaPhil said:

J...Tending to think that a switch to select 1 or 2 throttles is the way forward.

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Why not one throttle, with a switch to select 1 or 2 WD