Musings on an Ezee

[Benjahmin]

I've long suspected that my Ezee hub (now nearly 5 years old) is speed control rather than power.
The no load speed on max assist registers as 19mph. I suspect that this is magnetic saturation point as the motor never actually cuts out. If i rotate the pedals going downhill at, say 30mph, I can hear the motor. Obviously it doesn't drive, but it rotates. The only time it stops is when I stop pedalling or pull the brake.
Normally I ride in setting 2/5. This gives me a speed of 10-13mph on the flat (nothings really flat round here so it's hard to tell). Yesterday I did a 21 mile ride to the coast and back, two long steep climbs in each direction. Instead of using 2/5 I used setting 4. This was getting me 15-18mph on the flat but didn't seem to make much of a difference on the steeper hills.
From a starting measured voltage of 41.5 (this is what my meter measures both my chargers at - I suspect the meter is reading low), I returned with 37v when left to rest. Not really any different to what I normally get on this run.

So here's my conjecture. Because on the higher setting the motor is running closer to magnetic saturation, there is actually less current draw than in the lower setting.
Seems counter intuitive - as does the fact that my breathing and heart rate is slightly higher at this higher assist.

What do you think? Not really after the extra speed (it feels a bit frantic on the bumpier single track lanes) just trying to understand the system.

 

[Nealh]

It is the controller that is speed controlled and not the hub. A controller with P settings allows you to change between speed or current control.
Speed control gives the same current in each assist with each assist having a max speed setting, on inclines you won't feel the torque/current provided as you would with current control. With current control you actually feel the extra current esp on inclines as you up the PAS assist.

 

[vfr400]

The Ezee controller uses speed control algorithms.

Here's how to check whether you motor maxes out or is restricted by the controller. With a fully-charged battery, lift the wheel off the ground and measure its speed. Drain the battery somewhere past half-full. Repeat the speed measurement. If the speed is slower in the second test, the motor is not restricted by the controller.

All motors draw less current as they speed up. Its a ramp function, ramping down to zero current at the motor's max rpm, so yes, you use less battery the faster you go above a certain speed where the controller,s current limit is higher than the actual current. In other words, if you could pedal your bike everywhere at 30 mph, you would never flatten you battery, except that what's below applies.

You have no bike speed measurement in your control system. Any speed restriction is based on the motor's rpm, so the motor will always operate in a no-load condition when it's disengaged, i.e. when the bike is going faster than the motor, which is why you hear the motor when going fast down hills.

 

[Benjahmin]

My system just has an LED display, so no P settings, measuring speed via a Cateye.
I'm off on a ride today so I'll try what you say vfr.
Just put the bike on the stand and got these at full battery:
Throttle - 19.5
Pas1 - 9.2
2 - 14.5
3 - 18
4 - 19.6
5 - 19.6

 

[flecc]

As VFR says, the Ezee bikes are definitely speed control, both my models clearly indicating that. It was most obvious on the Quando, not just measured wheel off the ground, the road assist speed very noticeably linked to the battery state of charge/voltage.
.

 

[Benjahmin]

OK, I've put 28miles on it and got it down to 36.5 v at rest.
Speed readings are now:
Throttle: - 17.3
Pas1 - 7.6
2 - 12.3
3 - 15.6
4 - 17.3
5 - 17.3
Apart from level 5 being useless, what does this tell me?

 

[vfr400]

You have no speed limit in your controller, apart from when on levels 1 - 4.

 

[Benjahmin]

Eh?

 

[Benjahmin]

Just reread your last post vfr, think I've got it now.
So those very naughty people at Ezee, if they still use this control system, really have little idea about the road speed of their kits, as it depends what wheel size a particular wind code motor is built into.
Seems to me that , whilst they are not cheap, these are the kits for those who want a bit more speed. Pity they're not more readily available.

 

[flecc]

Just reread your last post vfr, think I've got it now.
So those very naughty people at Ezee, if they still use this control system, really have little idea about the road speed of their kits, as it depends what wheel size a particular wind code motor is built into.

That's exactly it. This started in 2004 with their Quando 20" wheel Quando model. That had the powerful rear wheel motor with their non limiting controller having no switched power levels, the bike merely running out of steam according to battery voltage. That meant hitting just over 17 mph assist when fully charged, dwindling to about 14 mph when almost empty.

Then in 2005 they had the idea of putting exactly the same complete electrical set into a 27" wheel sport bike called the Torq, but with the motor in the front wheel, the result being 22 mph assist but poor low speed torque due to the overgearing. The 22 mph was simply limited by the overgearing, with the wheel off the ground it would spin to over 26 mph and riding downhill with throttle open the motor would still be driving a little to that higher speed and above.

They've followed a similar pattern since in subsequent models, albeit with the 15.5 mph legal limiting, switched power levels and using their own motor in place of the Bafang they originally used.
.