Open source Bosch motors

[Cakey boy]

Anyone seen this ? Sounds very interesting!

 

[Rusty]

Don't know why anyone would want to screw up their kit by ramping it up to 500W. I can see changing the assist speed as no way in hell I could live with 15mph, but all boosting the power will do is destroy batteries and vastly reduce the service life of the motor.

 

[wepn]

Don't know why anyone would want to screw up their kit by ramping it up to 500W

Yeah absolutely right. I'd immediately double the voltage & go for 1000.

The batteries & motor can handle that...in my opinion. Obviously off-road only & no warranty to worry about since you've already hacked the hell out of the motor.

 

[Rusty]

@wepn - Not too sure about that. With double the power from the motor I would expect battery cycle life to suffer horrendously with lots of cell failures. There is some fudge factor in the specs of the battery circuit boards but not for double the output.
I would also expect motor life to reduce to about 1/3 of what it was designed for.

The above is based on discussions with a former electronics engineer and a guy involved in Formula-E.

 

[jerry]

The innards of the Bosch CX and the 300w (45Km/h) Pedelec-version are identical - it's all managed in software. So some beefing up should be possible without compromising reliability.

 

[wepn]

I think it depends on load. So a lightweight like me on flowing singletrack shouldn’t be too much. Not constant max rpm on off demand like Formula E. But yes expect shorter lifespan to eliminate disappointment when something fails.

 

[Zimmerframe]

Yeah absolutely right. I'd immediately double the voltage & go for 1000.

You might have problems with the cables too. I infrared scanned my last bike (hub motor - so easy to scan) after a hard climb and the cables were surprisingly warm ! Interestingly, the chain was pretty warm too and that was in below 0C temperatures.

 

[wepn]

You might have problems with the cables too. I infrared scanned my last bike (hub motor - so easy to scan) after a hard climb and the cables were surprisingly warm ! Interestingly, the chain was pretty warm too and that was in below 0C temperatures.

For sure. If I was going to actually overvolt a Bosch with this, I'd check everything...and then put a throttle on it. Of course heat is a result of increased current so serious overvolts - ok maybe not double - might be the sweet spot. Incidentally I saw a video that performancelinebearings.com did on Bosch motor servicing. They know what they're doing so will be very interesting.

 

[Rusty]

You might have problems with the cables too. I infrared scanned my last bike (hub motor - so easy to scan) after a hard climb and the cables were surprisingly warm ! Interestingly, the chain was pretty warm too and that was in below 0C temperatures.

That was one of the discussion topics. I understand the F-E guy had a commuter ebike that they over-rated and ended up melting a lot of wiring. The other thigs was the motor bindings also showed severe discolouring which is usually caused by overheating. Too many of those and they fail apparenty.

 

[Bearing Man]

Hang on guys! I posted the original post but it has been taken a little out of context here. The post was in relation to a previous post I wrote about the new Bosch software update that now has added anti tampering or "Improved manipulation detection" as they put it.
As this will possibly negate anyone using a dongle! We decided to see what is possible? So we have built a new circuit board to replace the Bosch board altogether. This is still at prototype stage and we will soon be testing to see exactly what does melt or break.
Although the motor maybe capable of 500W, It would not be currently possible to run it at this power level for all sorts of reasons. But, it will mean that you can run without 15mph restriction (private land) and if you wanted to have more (or less) than 75Nm of torque, you can.
We will obviously, set the upper limit to a safe level that wont melt your wiring or destroy your motor.
What it will mean, is you can decide what you want rather than bureaucracy deciding for you.
Obviously, this will come with all the usual caveats, private land, own risk, out of warranty etc.
As it's Bluetooth controlled and open source, people will soon take it further than I can, hopefully with new ideas, motor management maps, types of controllers etc.
This is a little way off yet but could lead to a total control system with some very handy features that are not currently possible.

 

[Dax]

This is awesome, nice to see the open source community hacking ebikes now.

 

[Rusty]

Me - I would not bother with an ebike if I was restricted to 15mph (25kph). I have enough frustration with the 20mph (31kph) limit as a lot of the trails I ride I am at a speed that has me on and off that limit, which is frustrating as anything. If they just cut assistance it would not be so much of a bother but witha 15mph restriction I find about 12-13mph it starts to feel like the anchors are on - same as with the 20mph - it seems at about 18mph things start to suck.
It is annoying that on many trails I am faster on my non ebike overall because the restriction and drag more than counters the benefit of the assist on the climbs.
I would like 25mph (40kph) as a more intelligent limit.