Electric motor blocks wireless signal?

[veloman]

Being a road cyclist, I was tempted to put my Powertap wheel on the ebike and see what ACTUAL power was being transmitted to the back wheel. The rear hub of the wheel transmits the data to the receiver on the rear seatstay, only 4 inches away. But as soon as I use the motor, my CPU shows no data. Pedal with no motor and I get power data. (Oh btw, my motor drives my front chainrings.)

Is there anyway to get around this? I'd love to get actual real power data and see how efficient / inefficient my bike is. On my road bike, when I create 200watts, I get about 20-21mph in good flat conditions. I'm really curious see what power it takes to cruise on the ebike.

On a side note, based on my charge time with my 36v 1.6ah charger, I'm pretty sure I've drawn 300 watt hours out of my 22lb 36v 12ah battery pack I put together. That pack has a theoretical 432 watt hours, and at the end of that said ride, I had no drop in performance. (Isn't it said that SLA's only give about 50-60% of 20 hour ah rating?)

I get the feeling I'm really lucky.... Especially considering how I mentioned on this site that 3 12v 12ah SLA batteries 'should' weigh more than 22lbs. Should be 27lbs.

 

[Drunkskunk]

No easy solution. you'll need shielded cable sheaths, and a fairaday shield around the motor, controller, and battery. putting the battery and controller in a metal box, using an RF shielding sheath around all the wires exiting it, and tieing it into a common ground with the motor's case should solve much of the trouble.

 

[TylerDurden]

It's prolly the controller... They can throw off heaps of RFI.

 

[wrobinson0413]

.

 

[Russell]

It's prolly the controller... They can throw off heaps of RFI.

Yes the controller is a big source of electrical noise. When I had my controller mounted on the handlebars it would interfere with the wireless computer. The only place the computer worked 100% was when I mounted it down on the front fork just above the transmitter.

For your application try to get the transmiter and receiver even closer if possible or use trial and error and simply move the receiving unit around to see if another location works better.

(I eventually purchased a cheap wired computer so I could mount it where I wanted it.)

-R

 

[Mark_A_W]

I tried to listen to an AM radio on my ebike :?


It didn't go well...


EMC sheilded, they are not.

 

[icecube57]

Listening to my bluetooth headphones on my bike doesnt work to well either. My phone can be a foot away in my front pocket and i cant hear squat. It drops in and out every 5-10 seconds. At home i can be outside cutting grass with the phone inside the house and hear it fine.

 

[grindz145]

Shorten up all the wires as much as possible as well, then add excessive amounts of aluminum tape (like for heating/cooling). I would bet that with enough of the tape you could get it to work but they are nasty...

 

[jateureka]

Hmm, lucky I stumbled on this thread - was going to buy a wireless cycle computer for my e-bike but guess I will get a wired one now. I should have realised sooner that it would be a problem - my Polar computer heart rate monitor drops in and out on the eliptical trainer...

I'd be interested to know - has anyone had any luck running a wireless cycle computer???

 

[Hillhater]

I'd be interested to know - has anyone has had any luck running a wireless cycle computer???

NO , mine is useless on my Aprilla Enjoy ...and that is a fully legal European built Ebike ......( but with a few mods :wink: )

 

[DAND214]

My Bluetooth headphones work fine on my ebike. Controller behind the seat under the rack with my phones on my belt. Batteries are in the panniers. Works great, I listen to my tunes or talk on the phone any time without a problem. I also have a CA with the wires going under the seat to the front. I would guess all situations are differant. This is on more than one bike but they all have the controller under the rack.
Dan

 

[John in CR]

Just a few weeks ago experts were telling me due to the AL case no noise was coming from our controllers, so there was no issue mounting it directly under my seat so close to the family jewels. Where is the problem then? Do the wires need shielding?

 

[rhitee05]

A wireless cycle computer is especially vulnerable to interference since they usually operate at around 150-200 kHz, which is well within the range of harmonics that would be put out by a PWM controller. I'm sure they also use a very simple receiver that doesn't have much immunity to interference. Something like Bluetooth or a cell phone operates at a much, much higher frequency that should be well above any noise put out by the controller.

John, there's a HUGE difference in the EM field strength that's considered dangerous and the levels that could potentially interfere with other radio devices. Several orders of magnitude.

 

[chvidgov.bc.ca]

I use the ebikes.ca Veloamp stereo amplifier with waterproof marine speakers on my recumbent and a Sansa Fuze Mp3 player, and I have never noticed any interference from the controller. It sounds great!