Thank you for your message. It is holding up well, the only disadvantage so far is that I should really make sure to turn off the bike when charging the battery. For some reason the DC-DC converter in the motor driver cannot deal with what the charger does on the battery BUS, perhaps a high frequency problem, I'm not sure...
Congratulations on your Mercedes bike. Do you have the original battery case included? It might be possible to build 18650 cells in there, I am not sure about the dimensions of that casing. Be aware that Sachs also build bikes using the same hub and battery, which was sold as a newer version of the Sachs 'elo' (in case you need spares).
I will go through your options one by one:
1. This will probably work, indeed.
2. I think the transistors are rated 40V or 50V (cannot be absolutely sure), so be aware of that. I am not close to the 3M hub I have, so cannot check it quickly for you. You can still install a controller that uses a pedal sensor as input, rather than a throttle. This is what I use on the 1M, and works well.
3. This is indeed quite some work, but also most space-efficient. The 3M only uses a torque sensor read-out, no speed measurement, so that would make it a bit different from the 1M version.
I am sorry to say that I am just now thinking about giving up on the 3M hubs, because of a small mechanical issue I just don't seem to be able to fix. I can almost guarantee you that you will also get to deal with it at some point when using it long enough (I have three hubs, they all have this problem). I will write about it in more detail on my blog later, but the summary is that the motor axis, that drives a mechanical reductor using rollers, starts slipping and stuttering at some point. I have worked on making that motor axis thicker again, since I thought wear was the culprit, but this only helped for a while. I still have to diagnose what has happened with it now, I will let you know my conclusions when I've done that.
BTW: If you want to exchange the belt for a normal chain, be aware you need to make either the mount on the hub a bit smaller, or the new rear sprocket hole a bit larger. I don't know why they made this an almost-but-not-quite standard size.
Also be aware that I have spare parts for this hub, if you need anything let me know.
All the best,
- Turning the press-fit cylinder to size
- 20220103_131806.jpg (4.13 MiB) Viewed 124 times
- The press-fit cylinder installed
- 20220103_141617.jpg (3.24 MiB) Viewed 124 times