Mercane Wide Wheel range testing (bumpy country roads)

I decided to take an afternoon toddle today on the Mercane (after already doing a few km around the town which is actually hilly too). I wanted to test 3 things:

1. what range it would do on a battery that's had a little load (IE not straight off the charge)
2. see how hilly areas would effect the range (and using the lower power setting)
3. how effective google is at estimating ride times when I'm on a scooter and not on a bicycle

I picked a route which heads out of town (the same one I took last weekend on my sunday ride with a mate on an MTB, but to go that bit further. Now because photographs just don't seem to show how steep something is, I thought I'd put it into Google Maps to get the data. This is the ride:

You can see that Google things it'll take 15min and that over the 4.1km the elevation goes up by 50meters.

I didn't check the elevation with my GPS, but I did check the distance and I actually went a bit further than that point, I went around that bend just almost off the bottom of the picture. This has actually quite a steep hill as it curves. Its hard to get a sense of scale from a wide angle picture, but you can see that it rises to about the same height as the gum tree over there (red), and the town is back down on the other side of that ridge (blue).

I had to kick a few times going up the slope (not enough to work up a sweat mind you, just long swinging kicks to just give it that few extra Watts).

Results:

• My GPS said that it was 4.5Km there.
• It took 13 and a half minutes to get there but
• 14 and a half minutes to get back
• when I left battery was @ 50V (rested state, key on and go)
• when I got back my battery was down to 45V (after the last leg on the slight uphill that's my street

Obviously on the balance of things its an uphil journey, however the reality is that there are uphills and down hills of different grades on the trip (looking at the graph even suggests this). So even though "going back" is going downhill) there are some steep uphills there too. This is important because a steep uphill will suck more out of the battery than you regain from a longer down hill (where the battery can re-gather some energy by not being loaded up as gravity does the propulsion).

Anyone with a voltage meter on their scooter (few it seems) will know that the harder you load the battery the more the voltage drops (and so too your power), and while the battery voltage recovers when at rest as the chemistry moves around and depleted areas can recover charge from other areas of the cell (complex chemistry but google it if you're keen).

Right now (some hours later) the battery is at 48.1V:

 ...but I anticipate that on tomorrows ride that it will sag pretty quickly on the first steep hill.

So in terms of commuting unless you live in a hilly area (and most cities are built on river plains or costal areas) that you'll get less battery hit for doing essentially 9km (plus probably 2km earlier in the day).

As always, the rest of my posts on the Mercane Wide Wheel can be had by clicking this link or using the topic list on the left.

None the less it was a lovely afternoon ride and I had fun doing that for this "testing"

Sometimes science pays off :-)

PS: I thought I'd add in the next mornings ride to this, where I went up my "torture test hill" behind my place. It started out with the battery at a neat 48V in the morning (so dropped 0.1V overnight, perhaps due to it being cold). So in the few hundred meters of climbing this hill from my place it got to the top a bit depleted.

This is the google maps which shows the hill a little

So you can see that its steep. Here's a quick video.

Because I'm no professional voice over guy (and had no script) and tend to mumble let meadd this here.
[PS: and I've subsequently measured it and its 9°]

So battery now sagging in voltage to 41.2V under load going up there, and I had to (well, chose to) give it a few kicks on the steepest part just before the crest. That's dropping to about 3.1V per cell, which is under load. As soon as you stop it springs back up to 47V which is still in the nice 3.7V per cell range so clearly there's a little more in them (recalling the voltage curve of Lithium)...

and so indeed it made it to the top of the hill described in that video. So if you can tolerate my unscripted mumbling and wind noise here are my thoughts when I got to the top...

As I mentioned back EMF (which I doubt many will know much about, here is a little about that in motors (which I mentioned in my ramble): https://studyelectrical.com/2015/02/back-emf-and-significance-in-dc-motor.html). Basically what it does is to increase resistance (impedance actually) which means that the battery is not having such a high demand placed on it (think of how a short circuit provides a HUGE load on the battery vs a small LED). So when going slow (because of load on the motor, not throttle) the battery gets hammered.

:-)