I finally took my ebike for a test ride.

[6zfshdb]

You could add a third motor with a front wheel hub drive.

I considered using a front wheel hub as a second motor on my rear hub bike. It would act as a spare, but I'd do it mostly for something to cobble on.

 

[Gionnirocket]

You could mount the front hub motor so that it spins in the opposite direction... Now that'll give you some braking!

 

[PCeBiker]

The answer is automotive split-sleeve loom or corrugated tubing as a full chain guard.

There's plenty of things to use as a chain guard, including an actual chain guard like @RunForTheHills posted,..


The issue for me is installing it.

Do you have any experience installing a chain guard on a BBS02B and a full suspension frame?

How the hell am I supposed to mount sleeve loom or corrugated tubing?

 

[PCeBiker]

I have a Sr. friend with a huge eTrike. We put in Tanus in his 4.5" 26 rim front tire. He was thinking that it keeps losing air. Really what is happening is that the Tanus is compressing. It starts at about an inch thick but will eventually compress to the thickness of a dime.

I know all about that.
I've got Numerous posts and complaints about Tannus.


There's no Tannus on my new ebike.

I will say one good thing about Tannus.
My first ebike (26"X4") has Tannus inserts, Mr Tuffy tire liners, and Flat-Out.

Apparently the tire liners will eventually wear through the innertube at the end of the overlap.
The edge should be chamfered so the liner doesn't dig into the innertube, eventually causing a flat.

I installed the tire liners between the tire and the Tannus, so my tube was protected and my Tannus got chewed up instead.

I've got 5-6 thousand km on those wheels with No flats.

I rode on broken glass, needles and nails on purpose to see if I'd get a flat. (close to home so I could push it home if I had to.)

 

[PCeBiker]

I bought some stuff today,..







I took some measurements of the hex bolts that came with my motor kit and bought grade 12.9 hardened steel 5 mm hex bolts, 16 mm long to mount my two chainrings on top of each other.

I thought it would be smart to buy washers and lock washers for the bolts as well.

 

[PCeBiker]

HOLY SHịT !!!

I had my display unplugged and my programming cable plugged in, getting ready to check my settings.

I realized that I hadn't checked to see if my 46t chain would work for first gear with my 52t chainring.

It was in 7th gear, so I leaned the bike over on the kickstand to get the wheel off the ground and started cranking the pedal to work the derailleur into low gear.
I can go up one gear at a time by pushing the shifter button then cranking the pedal.
(I can go in to high gear all at once with repeated presses)


As I was changing from 5th to to 4th gear, the Damn Mid-Drive Powered Up !!??
WTF !!???

The Fricken Display wasn't plugged in, and neither was my smartphone.


So to make sure that I'd remember the incident, I did it a few more times and stopped at 3rd gear, and unplugged both batteries.
Then I cranked the pedals again to make sure it was dead.

 

[PCeBiker]

I realized that I hadn't checked to see if my 46t chain would work for first gear with my 52t chainring.

So my original 46t chain is not long enough to go into 1st gear,..

Second gear is fine though,..

So now I need to reinstall my 44t deep dish Bling to see if my original 46t chain is too long for 7th gear.

I'm gunna wait for my new bolts and washers to arrive, before I take it apart and break something again.

 

[Gionnirocket]

You're dangerous on the dance floor!

 

[PCeBiker]

https://velo-orange.com/products/vo...eQ66OAiiiKUYtmoTu_wMdQ8C-Bpow_pl-3eVDdqW9HyuM

I took another look at my e-bike and it looks like that fender might fit my e-bike?

It looks like it mounts around the bottom bracket like a Big washer?
I might have enough clearance with my swingarm?

The bracket on the other end of the fender would need to be mounted creatively with a spring or something, because my swingarm moves.

Meanwhile, the plastic chain guard is working, but it's a little warped now.

 

[PCeBiker]

Yeah, it's up to me to mesh the motors gently.

My biggest problem will probably be trying not to Slam the pawls in my freewheel

I was noticing a "clack" every time I touched the throttle, and the display was showing 2-3 amps in every PAS mode even with everything turned Way down.


So I messed with my settings and realized I needed to turn down my "start current" (which I think overrides the PAS and throttle settings?), and I had to turn down my initial maximum PAS speeds.

I came up with this for settings,..

Now the motor powers up Real slow with no freewheel "clack", then I should be able lock the throttle and rattle through the 9 PAS modes to increase my speed and power.


I wanted to try to make sure PAS doesn't kick in on me, so I chose a 12 pulse PAS sensor with 20 pulses before the power engages, so one and a half crank rotations.
I also chose 1 amp for PAS mode 0 so my throttle is active but hopefully PAS is turned off?


And I chose stop decay 0ms incase my pant leg gets caught in the chain.
I want the power to cut the instant I stop pedaling so I don't cut my foot clean off.

And my general settings,..

@Gionnirocket

My "80%" power setting seems to apply to the maximum power of the motor. (25 amps)
I set my power to 18 amps, so I think that's what the "80%" is referring to?

I still don't really know what the RPM of the motor is?

I think that I might have to do some gear tooth, inch foot, torque, RPM calculations to figure out what the actual motor RPM is?

I should be able to reach the maximum RPM of the motor with the gearing I've got, so that should allow me to calculate maximum RPMS?

@6zfshdb @harryS @Gionnirocket @PedalUma @RunForTheHills @anybody


Is there any way to "hook up a Tachometer" to my ebike?

I can't see any option for it?
I don't care about my cadence, it's my motors cadence that I'm interested in.
I'd like to keep it at it's most efficient 80% operating RPMs.

 

[6zfshdb]

Is there any way to "hook up a Tachometer" to my ebike?

I can't see any option for it?
I don't care about my cadence, it's my motors cadence that I'm interested in.
I'd like to keep it at it's most efficient 80% operating RPMs.

If you can access the motor phase wiring, usually blue, green & yellow on a Bafang motor, you could use a digital pulse tachometer such as this one:

https://www.ebay.com/itm/364494740622

Tap one of the phase wires, connect it to the "signal in" lead and ground the "signal" lead.
This should generate a pulse for each motor revolution.

Keep in mind, this is an off the cuff idea that is loaded with possible problems. Voltage compatibility is one, and buck converters might be necessary.
Connecting the gauge to a phase wire might also alter it's effect on the motor circuit depending on the characteristics of the internal gauge impedance.
There isn't much info available for this particular gauge, but there are many others available.

An interesting idea though.

 

[Gionnirocket]

Though it would be an interesting cobble, personally I wouldn't bother complicating things with a tach. With an electric motor it's more important to monitor current... at least in this application. For reference, the published guesstimate of max RPM is 140
Yes your % of current set on the Levels page is of your setting of the Current Limit on the General Page. So that's a % of the 18a you now set. You can safely keep your Current Limit set to 20 or even 22 and temper with the PAS settings. My experience tells me most things are very dependable when used around at 80% of their max rating.

 

[PCeBiker]

If you can access the motor phase wiring, usually blue, green & yellow on a Bafang motor, you could use a digital pulse tachometer such as this one:

I was sorta thinking about that, but it would require me to open up my motor, and I don't wanna get that carried away.

I figure that I shouldn't need to tap the wire directly.
I should be able to simply put a tiny coil around one of the phase wires to induce a pulse for every revolution of the motor, but that too involves opening up my motor.

Though it would be an interesting cobble, personally I wouldn't bother complicating things with a tach.

Yeah, I'm not gunna bother.
I just want to get an idea of what my motors RPMs are.

With an electric motor it's more important to monitor current... at least in this application.

Yeah, that's my main interest.
I actually switched from power (watts) to current (amps) on all my displays, because I don't really care about the power or voltage.
It's always the amps that heat up a motor, and drain my batteries.

I found out that my Voltbike Outback does actually have a 32 kph maximum speed based on RPMs per Volt.

My maximum speed starts to drop below 32 kph just before my battery shuts down at ~40 Volts.

So, my Voltbike will go ~43 kph with a fully charged battery, then slow down to 32 kph just before the battery dies.

I'm assuming that's because of the "maximum rpms per volt" thing?
It is a hub motor, so there's no gearing to consider.

For reference, the published guesstimate of max RPM is 140

OK, that's good to know .

Yes your % of current set on the Levels page is of your setting of the Current Limit on the General Page. So that's a % of the 18a you now set.

That's what I was figuring, but I can't seem to find a way to translate that into motor rpms?

You can safely keep your Current Limit set to 20 or even 22 and temper with the PAS settings.

I'm just gunna keep it at 18 amps.
It's kinda the Canadian limit (500 Watts continuous, 750 Watts instantaneous), and I have no need for more.

If I do, I should be able to pull over and crank it up if I'm off-roading and climbing hills or trees or doing wheelies or burnouts or something?

I'm not sure yet if I can crank it up using my display, or if I have to use the programming cable?

My experience tells me most things are very dependable when used around at 80% of their max rating.

That's pretty much what I'm aiming for, but I still suffer from lingering range anxiety that I just can't seem to shake.

I'm aiming for the most efficient motor, not the most powerful.

So even though I'm neutering my motor to 18 amps, I also want to conserve Every Single Electron that I can, and operate my motor at a consistent 80% rpm regardless of the power draw.

The only time I've actually used 18 amps continuous on my hub motor was when I was plowing into a 20 mph headwind.

So now I can add another 18 amps continuous into my mid-drive, that's geared for going 32 kph so I should be able to go chase the next 🌪when it blows through town.

 

[Gionnirocket]

You can't convert amps to rpm.
The load varies greatly, thus current is ever changing. Even knowing no load RPM for each PAS will be useless information.
More important than high spinning which the motor appreciates... Is bogging it down with high current/load at a low RPM

 

[PCeBiker]

So,..
Thinking about it some more,..
(Yes there is a faint hint of Vado smoke in the air. )

Me limiting my maximum Amps shouldn't limit the motors maximum rpms.

So, I should be able to simply remove my chain and fire up my motor to max.

Then I'll put a mark on my chainwheel and record my chainwheel spinning for 60 seconds.

Then, I can review the video and count the revolutions of the chainwheel.

I can do it with a fully charged battery and a near dead battery to see if the rpms are different.
(Which they should be if maximum revolutions per volt are met for both battery tests.)

For reference, the published guesstimate of max RPM is 140

So, I'm gunna assume that that is for a 52 Volt battery (58.8 V fully charged) and my batteries are 54.6 volts fully charged,
So 140 ÷ 58.8 × 54.6 = 130

So my motor should probably have a maximum RPM of 130 with my batteries.

And
140 ÷ 58.8 × 40.0 = ~95 RPMs
For a near dead battery.

130 × 80% = ~104 RPMs

However the efficiency is probably best at 80% of 140 RPMs, so,..
140 × 80% = ~112 RPMs

So I should see just under two revolutions of the chain wheel per second to be around 80% RPMs?


So I can do a no-load test to establish maximum rpm of the chainwheel then throw the chain back on and take it for a spin with my tiny chainwheel in low gear.

I should easily be able to reach maximum RPMs per volt without going anywhere near my 18 amp maximum power with my 44t chain wheel, and my 34t granny gear?
Then I can note the speed in every gear, and just go at 80% of that speed to be most efficient in each gear.


I can use the speedometer from my hub-drive display to check what my maximum speed is when I'm in different gears, and assume that the maximum revolutions per volt are the same for every gear if the current draw stays below 18 amps.


I just made all that up.

I think it's actually an empirically correct application of the proper Scientific Method?
Instead of just my anecdotal Vado based nonsense.



My mid-drive works fine without the speed sensor hooked up.
I would only need it to know my speed, but I've got my hub motor to see my speed.

I should just stick the magnet (or better yet, five or six of them?) to my chain wheel and connect the speed sensor to one of @6zfshdb 's pulse counters?

The chain wheels RPM is directly proportional to the motors RPM, regardless of what size chain wheel is installed.

 

[Gionnirocket]

Not at all how it works...
And why you're concerned about rpm has me baffled.
Maybe it's a Vado thàng?

You want efficiency... Stay in the lowest gear possible.

 

[PCeBiker]

Not at all how it works...

I think it is, and I shall try to prove it with some empirical data.

And why you're concerned about rpm has me baffled.

It all stems from my motorcycle days.
I remember a kid on an RM 80 that didn't know the motorcycle had more than one gear (or how to shift for that matter)

He just hammered the gas, dumped the clutch, and revved the Living Snot out of it, leaving a Huge blue cloud of two-stroke smoke behind him.

My dirtbike didn't have a tach but I knew how to shift gears and to not bog the engine.

My street bike 🏍 did have a tach and I really did need it.
I couldn't tell for listening when I was near redline.
I would rev it out just listening for what I thought was red line (10,000 rpms) and check my tach and I was barely over 5,000 rpms.

The damn thing was just Fricken Screaming at 10,000 rpms but I knew it was safe because I had a tachometer.
(I used to get it up over 80 kph in second gear, then tap it all the way into 6th gear in one shift)

My car was the same.
I Always looked at my tach.

I drove it very conservatively and rarely went over 3,500 rpms.

Ever month or so, I'd get it fully warmed up, then run it up to redline (6,500 rpm) in first and second gear to blow out the cats and give it a good cardiovascular workout.

I Hated hearing it scream.
I had to stare at my tach and trust it.
It sure sounded like it was gunna Fricken Blow up !!



I suppose a gutless electric ebike motor is different, but I don't know why the motors rpm appears to be proprietary information?

You want efficiency... Stay in the lowest gear possible.

I guess that's easy enough.

It's not like I can over-rev it and blow it up ?
It is voltage limited.

But who know?
I'm sure I can blow it up if I put my mind to it.

 

[PCeBiker]

A guy had a motor that was shuddering and had almost no power. I told him he needs a new motor. I installed it today. A Bafang hub. The final step was turning off the battery and connecting the motor. It wouldn't connect. I checked the new pins. Perfect. Nadda. What it was, was that a pin had broken inside the female side. Which reminds me of a joke. That connector arrives tomorrow and I will solder it in.
Here is the joke: A leper visited a street walker. When he was done he said. Keep the tip.

So did you sell him a new motor when the problem was a broken pin making intermittent contact?

Here's a tip,..

Keep the old motor.
It's probably fine.
Just needs a new cable.

 

[Gionnirocket]

You can not over rev' an electric motor in this application... But you can bog it down.
The latter should be your only concern

 

[PCeBiker]

You can not over rev' an electric motor in this application... But you can bog it down.
The latter should be your only concern

OK, I'm done exploring that 🕳


I won't be bogging my motor.
I have lots of gears to choose from, and with a 20 mph speed limit, I should be able to stay off my 11t sprocket, especially with my 52t chain wheel.

In a way, I will be bogging my motor starting from a stop with 1 amp, but it's only an amp, and I'm sure the motor will shut me down if it is putting out power but the motor isn't rotating.

My hub motor monitors the speed magnets in the motor housing to make sure the motor rotates.
I get about 3 seconds of power before the motor shuts down due to lack of rotation.

I'm sure the BBS02B has a similar function inside the motor.


I still want to check my chain wheel RPMs with a fully charged battery and a discharged battery for curiosities sake.

Easy enough to do the test.