I can't say I'm entirely content with the Heinzmann motor though. Again there's no problem on the build quality, but having seen brushes give out at two years of personal use, I'd prefer a technically more up to date design, a Hall effect motor with the German build quality which would have less maintenance requirements, better economy, and could have a more useful flatter torque curve for the commercial load application.
It's just sad that such a thing doesn't exist yet.
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...Exactly, which is why we have to go with the best of what does exist now.
With the current E-bike technology, we couldn't go with a 'hall effect' motor even if we wanted to, simply because of the type of work that a 'heavy utility and commercial use' E-bike in a majority of cases, would be required to do. That is, lots of slow speed work that would necessitate the use of a throttle control for smooth progressive power delivery.
As far as I am aware, the control units on the current crop of 'hall effect motored bikes', are not sophisticated enough to do this. Instead, the throttle on these machines, simply acts like a giant 'On and Off' switch - wherein you just get a surge of power with no reasonable way of regulating what you get.
Further more, as far as I am aware, there isn't a 'hall effect' motor yet that can match the torque you can get out of a brush motor - the version we are currently using, has 58Nm for 200watts, ( it's the same motor as used on the Deutsch post mail bikes ).
In addition to all this, the Heinzmann design may be old but it is proven, tested and very reliable. The simpler design making for easier and quicker diagnosis and fixing of problems should they occur, keeping 'down-time' for a working machine to a minimum. Of equal importance, is the easy predictability of when/if things are likely to go wrong with it, due to a long and well documented history of use.
Also, the way in which the Heinzmann controller (Ebike and pedelec versions) operates, is ideal for workbike usage. For example, it has a 2 second ramp up ( delay) and instantaneous ramp down, many others don't. The pedelec version has a 'start/walk assist' function, wherein the motor will power the bike up to 4mph, after that, YOU pedal - this being ideal if you have to dismount and walk a heavily loaded bike through a pedestrianised area or up a hill.
The MonVal Electra, although a new design, is powered by a proven and tested technology, simply because 'questionable reliability', is not an option.
... Back to the 'original posters' statement - 'when 15mph is not enough.' In the case of electric bikes especially workbikes, or rather Commercial use E-bikes like mine, IMHO it most definately is!!
... WHY? ... because although the E-bicycle has advanced, the braking technology hasn't and generally speaking, as most E-bikes are alot heavier than unpowered ones, they need a lot more force to slow them down. And one of the things that I have noticed that is regularly complained about on this forum, regardless of manufacturer, is the poor braking of many of these machines.
