Electric Bikes - E-bike gauges

Hi from the wilds of China. I ride an e-bike out here, and it's always puzzled me what the gauges meant. Maybe on the export models, you get a real speedo, but on mine, it is labeled "km/h" but clearly does not measure speed. I'll be at top speed (30), bring the throttle to idle to coast, and the speedo immediately shows 20, which isn't correct at all. Do you guys get real speedometers on your ebikes? And does anyone have any idea what this gauge measures?

Likewise for the battery meter - on mine, it simply goes from 38 to 28, with 38 being fully charged, and 30 or so being in the red zone. I have no idea what the numbers mean.

It's not any better here in North America. Most people have the hub kits or inexpensive pedelec-type bikes, that only indicate with three LED lights the charge level of the battery.There are instruments available that you can use to get more accurate readings, but everything costs extra. I think the only kit that includes one is BionX.

As for speed, I use a wireless speedometer for a regular bike. It seems to work well. I have a top speed of about 30 km/hr also. I have observed that the sensor is a bit behind. When I pull to a stop it takes a few seconds before it reads '0'



Happy New Year!

It's not any better here in North America. Most people have the hub kits or inexpensive pedelec-type bikes, that only indicate with three LED lights the charge level of the battery.There are instruments available that you can use to get more accurate readings, but everything costs extra. I think the only kit that includes one is BionX.

As for speed, I use a wireless speedometer for a regular bike. It seems to work well. I have a top speed of about 30 km/hr also. I have observed that the sensor is a bit behind. When I pull to a stop it takes a few seconds before it reads '0'
Happy New Year!

Agh, yes, I've seen those bikes. Only the LED display, but that's only on the cheapest E-bikes. Fact remains, though - what does it measure? It measures *something*.

And I tried installing aftermarket accessories on my bike - a compass. It lasted about 2 days before someone tore it off my bike while it was parked. A pity, otherwise I would install the aftermarket speedo like you said.

It lasted about 2 days before someone tore it off my bike while it was parked. A pity, otherwise I would install the aftermarket speedo like you said.

Some people around here use an aftermarket speedometer and remove it from the bike every time they park. Personally, I don't feel the need to know how fast I'm going. I do like to know my approximate average speed, but I do that by checking a clock before and after the commute and using http://maps.google.com to figure out what the distance traveled is.

Agh, yes, I've seen those bikes. Only the LED display, but that's only on the cheapest E-bikes. Fact remains, though - what does it measure? It measures *something*.

And I tried installing aftermarket accessories on my bike - a compass. It lasted about 2 days before someone tore it off my bike while it was parked. A pity, otherwise I would install the aftermarket speedo like you said.


well if your have analog meters like i do, your speedo is hooked up to your controller it Measures voltage
your hubmotor makes when its in Motion. would explain why it doesn't drop to zero when you let off on the gas.

and the gas meter is hooked to you battery.

hope it helps

cheers

I would suggest getting a cyclometer, plain black or very uninteresting looking. Get a *wired* one and wrap the wire all the way down your brake cable or whatever you can use, down to your front fork.
Thus it doesn't look interesting and removing it is time and effort. Never had any problems that way personally.

On your battery meter, if you're using a 36v battery then that is likely simply a voltage readout, with 38 being a full charge, and 28 being your cutoff limit. The simple 3 light displays are pretty junk, as they don't give you any indication of how much run time remains, just when you're about to run out. Those also simply measure the voltage.

well if your have analog meters like i do, your speedo is hooked up to your controller it Measures voltage
your hubmotor makes when its in Motion. would explain why it doesn't drop to zero when you let off on the gas.

and the gas meter is hooked to you battery.

hope it helps

cheers

Wow, someone that knows what he's talking about...cool. What is the controller? The voltage the motor makes when it's in motion? I don't understand exactly.

And a 36V battery - I thought it maintained 36 volts throughout, otherwise the motor would not function. Isn't the amperage what gets drained, and thus determines the life of the battery?

Wow, someone that knows what he's talking about...cool. What is the controller? The voltage the motor makes when it's in motion? I don't understand exactly.

And a 36V battery - I thought it maintained 36 volts throughout, otherwise the motor would not function. Isn't the amperage what gets drained, and thus determines the life of the battery?

36v is the "average" voltage measure in your battery, but it actually fluctuates quite a bit. Your starting voltage will be higher, and your low/empty voltage will be quite lower. Your power output remains (relatively) smooth throughout, depending on the chemistry of the battery - an SLA powered e-bike will sag in power as it drains, NiMH and Lithium will remain near full performance until nearly completely drained.

OK! Well, that's one mystery solved! I'll go and check with some other friends who have 48V batteries and see if it's different on their e-bikes.

What does "SLA-powered" mean? And I still don't get "Measures voltage your hubmotor makes when its in Motion"...I'm not an electrical engineer, I just ride an e-bike...

the hubmotor works as a Alternator when your coasting :)

"SLA-powered" mean? -> led acid

here a small demo->http://www.youtube.com/watch?v=D93cIx7c9kc

and the little aluminum box is your controller it controls the voltage to the hubmotor ->http://www.youtube.com/watch?v=numr4QeujXY


cheers

OK - I see that the speedo jerks when you move the motor by hand. But what does it *measure*? When the speedo goes up to 30, what does that mean, and how is it different from when the speedo is showing 20, or 10?

well if your have analog meters like i do, your speedo is hooked up to your controller it Measures voltage
your hubmotor makes when its in Motion. would explain why it doesn't drop to zero when you let off on the gas.

and the gas meter is hooked to you battery.

hope it helps

cheers

WOW! Where'd you get analog meters?!?! Did you make them? Do you sell them? (I searched your site, and couldn't find any...) Very Cool!

no there from a old ebike. i upgraded to a pair of these.


https://www.kellycontroller.com/shop/