The DJI bikes still have the weight advantage a little bit. The 800Wh DJI bikes are coming in at a similar weight to the 600Wh Bosch bikes from what I've seen.
Their 600Wh battery is 2.87Kg to Bosch's 3.0Kg, and their 800Wh is 3.74Kg to Bosch's 3.90Kg. Not a huge difference, but it's something. Pair that with the range extender weighing 1.58Kg with the hardware and you end up having the 850Wh Bosch extended battery being .68Kg heavier overall than the 800Wh DJI battery setup. Their motor itself is also lighter by .32Kg and you end up with an exactly 1Kg difference in weight in the motor/battery setup in a Bosch 600Wh w/extender vs a DJI 800Wh. Yes, you're getting 50 additional Wh in capacity, but at the cost of a full kilo (2.2lbs) which is definitely "something".
Sure would be nice to see Bosch come out with a 700-720Wh battery that is the same width as the 600Wh but just a bit longer next year to allow some of the existing frames built around the 600Wh possibly take advantage of it. Unlikely, I know, but it would be nice to have a more reasonable capacity where most people aren't worried about adding an RE anymore and still be able to fit it into a respectable looking downtube.
Thanks for the math. But I guess my point is that if the Bosch with a 600-watt travels just as far as the DJI 800 watt, it's effectively a lighter package. Exactly .42 kgs, or basically one pound lighter actually using your numbers.
I finally watched that entire range comparison posted above. There was one climb where the extra DJI power offered additional assistance, and he only utilized it for a moment at the very top.
The DJI also got quite the 'range' boost because at the end, the rider had to ride the DJI with no assistance whereas the Bosch rider still had full assistance. In that time period the Bosch dropped another 7%.
In the end the Bosch had 20% battery juice and the DJI showed 4%. Assuming that the Bosch also provides no assistance at 5% like the DJI did, the Bosch used 26.6 watts per mile where-as the DJI used 31.9 watts per mile (really it was less miles as it was ridden without assistance).
Assuming same conditions, same riders, 95% battery usage, etc. that equates to the following:
1) Bosch 600 watt goes 21.4 miles.
2) Bosch 600 watt with 250 RE goes 30.4 miles.
3) Bosch 800 watt goes 28.6 miles.
4) Bosch 800 watt with RE goes 37.5 miles.
5) DJI 600 watt goes 17.9 miles
6) DJI 800 watt goes 23.8 miles.
Like I indicated above, the difference was probably more pronounced and even more in favor of Bosch efficiency if they would have recorded the mileage when the DJI went in to limp mode, then did the same for the Bosch.
Of course, there are a few other small faults in the above test. Tire pressure, the Amflow is super lightweight, the 600 Bosch would technically get a bit better as it would be lighter, etc.
I'm pretty convinced that running the 600 watt Bosch for most rides which is very close to the miles that an 800 watt DJI would do. Then you can add the RE for your big days and blow way past the DJI 800. Also, there are 800 watt Bosch's out there, namely the Norco VLT.
I'm really interested in the E-druid, but the HP will absolutely eat up a bit more range as well.
I ran the same efficiency comparisons on the mid power motors before I bought my Relay and noticed that the per mile of climbing of the Fazua, was more efficient. I think those German engineers have really worked on the efficiency of their motors and it shows.
