MX60 goes to Carrs

One of the nice places in my region is Carrs lookout, and its a place I like to take the motorbike up to now and then (especially in summer when its bloody hot). I wanted to see if the new scooter would make it there and back, so this morning with a full battery I headed up to find out.

Its pretty steep mountain road and a more or less continuous climb there and a more or less continuous down hill back home. GPS on the phone reports the return trip is about 38km

So basically because there is some up and down the total climb up that the scooter had to do is 1,317 meters (or 4,317 feet for those people still using feet, inches, fingers and when insufficient toes too).

The basic data shows that for a good portion of the time the scooter was doing just over 24kmh, but because of some long downhills gravity assist brought the average speeds up :-)

Its interesting to note also that the cruising speed (gear mode 2) changed from 27 on the way out (with a fresh battery) to noticeably slower on the way back (on basically flat ground with no significant winds).

Which is in keeping with the knowledge that power is Volts x Amps and as Volts sag you loose power or you have to pump in more amps (which I'm willing to bet the cruise contrller does not do) which will flatten the battery even faster. Recall the discharge curve at constant amps:

In the graph above I've chosen to compare an LG S3  2.2Ah cell with what I believe are the batteries in my Widewheel (and thus likely too those in the MX60) which shows that at first the cells in my MX60 give me over 3.8V per cell but at 3.5V you're getting steady loss of power that then falls off a cliff at either 3.3 or 3.1V

Because the MX60 is an 16S configuration thats 62.4V, 56V and 52.8V respectively

My MX60 left the building with 67.2V showing on the battery and 57V (or about 3.5V per cell) while on the road still under power in Gear Mode 2. Combined with the battery reporting a State of Charge of 43 ~ 42% with a short rest.

So assuming those curves are what indeed my battery was following (which seems a reasonable first order approximation) I would expect it didn't have many more kilometers up its sleeve. Perhaps 9 or 10km more on a flat less if there were hills. 38 + 10 = 48 which means that I'd feel comfortable doing 50km on this using gear mode 2 most of the time in "typical gentle urban terrain" without significant apprehension that you'd be doing the "Dead Battery Walking" routine...

For the interested, here's some video notes from the trip.

HTH