#B150 Bike Diary (Testing)

                        W/O trailer             trailer full load     trailer no load

Ride length:       24.59 km                    24.48 km              24.6 km

Time:             52 min 29 sec             51min 19 sec     51 min 28 sec

Av. speed:         28.1 km/h                   28.6 km/h           28.6 km/h

Power usage:

                            6.85 Ah                       9.81 Ah              7.92 Ah

                        386.06 Wh                  501.27 Wh         414.39 Wh

                          15.7 Wh/km                20.6 Wh/km        16.7 Wh/km                          

Max speed:       45.0 km/h                    35.5 km/h           42.9 km/h

Start voltage      58.2                            58.2                    58.2

Finish voltage    53.0                            50.9                    52.0

Above is my Wike heavy duty flatbed trailer.

Weight 19 lbs.

Carrying capacity 125 lbs.

Tonight's test was to find the energy cost of the trailer's rolling resistance. The trailer was without any load and the aerodynamic profile was nearly zero because it is only a platform with no sides.

At an average speed of roughly 28 km/h the trailer adds about 1.0 Wh/km over the bike without `the trailer. Since the difference in energy consumption between Bike Alone and Bike With Trailer, this leaves the energy cost of the trailer's battery load at about 3.9 Wh/km. This represents the energy cost of the aerodynamic resistance and the added weight.

I will separate these two factors next time out by just loading the empty containers. The empty containers plus trailer weight are about 25%, or so, of the total load weight so, while the new figure will not completely separate out the weight from the aerodynamic resistance, it will still reveal good intel about the effect of weight on overall energy cost. 

Once the testing is complete I will have a very good idea of the percentages of energy consumption for rolling resistance, aerodynamic resistance, and inertial (weight) resistance.
 

#B147 Trailer Test For Parasidic Drag

Without trailer                         With trailer

Ride length: 24.59 km              24.48 km

Time: 52 min 29 sec                 51min 19 sec

Average speed: 28.1 km/h       28.6 km/h

Power usage:

6.85 Ah                                     9.81 Ah

386.06 Wh                                501.27 Wh

15.7 Wh/km                              20.6 Wh/km                            

Max speed: 45.0 km/h              35.5 km/h

Start voltage   58.2                    58.2

Finish voltage 53.0                    50.9

As you can see the two trips were nearly identical for length and average speed. The major difference was towing the 130 lb trailer with batteries, etc. 

The difference in energy consumption was entirely unexpected: it took an extra 4.9 Wh/km to tow the trailer. My original guess of an extra 1 Wh/km was so far off the mark that it is embarrassing.

Without even considering gravel impedance my range is reduced to 364 km and - using an additional factor of 1.5 Wh/km for gravel impedance - my range would be reduced to 340 km. This leaves me 65 km short of my destination. An even worse scenario is that my gravel impedance estimate might just as ridiculous as my trailer estimate.

This KOs the Dempster trip. Bummer.

Note: There is a plan "B" for the Yukon. I will write about it in the next couple of days.