iphone as a bicycle computer – the ebike tests

The last week has been insanely busy, so I have not even had time for a quick 10 mile ride in the hills.  I did however take my ebike to get lunch and did a recording just for fun.

Now for those of you who do not ride electric bikes, (and I’m guessing that is almost all of you), there are three reason to have an ebike.

1) you want to bike to work but not all sweaty.  (the main reason I got it)

2) You are hawling stuff.

3) You cannot ride (or keep up) on a normal bike but still want to ride.

All good reasons to have one.  Now the ebike I have is 36v with a 500w motor.  Pretty strong. It’s top speed, however, is a joke at around 20mph, so I do not engage the electric motor and let it run… instead I use a pulse and peddle technique (kinda like pulse and glide to you hypermilers out there). Its simple enough. At around 15mph I punch it to 20mph.  Peddle till its back to 15 and then punch again.  You get way more life out of the battery this way.

Anyway, the jist of all this is you can keep a pretty stable speed even with a bit of a climb.  In these two charts from the iphone app TrackThing, we can see basically that.

Now the only problem with this, and an issue I’ve had with other tests, is the occational spike. According to one graph, at one point I was doing 48 mph! And, why are the altitudes different?  Went from home, to the market and back home.  Same path. Clearly erroneous spikes. So what is causing these spikes?

Most likely, its the accuacy of the GPS slipping in and out. A useful app for understanding this is InstaMapper GPS Tracker. When you first turn it on, it uses the cell antenna to locate you, then slowly brings the GPS in as the system finds satilites.  The more satilite it can fine, the more accurate the readings.  So the question is; how can we inprove the GPS during our bike rides?

Well.. we will find out soon enough, because I’m going to do a quick ride friday and try a few things.  Check back then kiddies. :)

About perivision

All you need to know you can get here or google. http://www.perivision.net