28 November, 2010

It's a long road – Day 11

Odo 364

Well I took it for a long ride today. Long for an electric bike anyway. I thought I'd see just how far I could get. Hypermiling. I think that's what it's called. I rode at about the same rate I did on a bicycle back when I was 20 years old and shaved my legs... I managed 72 km (45 miles). I may have been able to go further but the low battery warning was trilling away and the display only showed two flashing bars out of 11. I'm sure it would have gone further to dead flat, but I wasn't going to flatten my pack trying. I think really 72 km is the absolute limit that I would attempt on one charge.

I was really hoping for better than that. Riding at a third of the maximum speed I should have got 9 times further. I've already done 10 km flat out on a half full pack, so I really did expect to easily go over 100 km at that sort of speed on a full pack. The return journey was into a very stiff headwind. 40 km/h headwind, but still. I don't know what drained the pack that quickly. The fan may have been running, but it was impossible to tell. The noise from the cars was deafening.

I will do the same trip again, there were half a dozen opportunities to recharge but I didn't bother because I was testing range. Next time I'll be topping up as I go.

I've also bought a power meter so I can see what it draws when recharging. Seems to pull between 1000 and 1100 watts. The power factor seems close to 100% so the mains are seeing a purely resistive load.  The photo below shows 1020 watts, power factor of 98% and it's been charging for 1 hour and 55 minutes.

It's been charging for 3 hours now, the charger is warm but not hot and the pack is completely cool. I'm sure the 15 dollar desk fan is a winner.

Update, it's now 3 hours and 20 minutes and the consumption has dropped to 350 watts.  I assume it's now in a constant voltage phase of the charge. It looks like if you were on a trip you'd only let it charge to this point before heading off on the next leg.

Update of update, there's actually a light on the bike that indicates the bulk phase is finished and the absorbtion phase is running.  Its symbol is a battery that's nearly full (makes sense I suppose).  When the amber light by that symbol is lit it's in absorbtion.  So if you can see 3 amber lights it's time to roll again on the next leg of the journey.  


  1. My Brammo does a similar thing when it's charging. Really pulls the juice, then, when it's basically filled, it goes into a "cell balancing" mode. If you know the proper key combination, you can actually see how the individual cells are loading.

    So cool that you went 45 miles on a charge. I've managed about 40, but was really nursing it along. If you don't mind me asking, how tall are you and how much do you weigh? At the Brammo forum, we notice that the "rider profile" makes a big difference in your range.

  2. Brammofan, Hi there, I checked out your blog and it's Brammo-Fan-tastic. My milllions/thousands/dozens/both my readers (hey, guess where I stole that from) should go check out Brammofan's blog. Anyway, I was really nursing it along too. I weigh 220 lb or 100 kg, I'm 5 9 or 176 cm and I was wearing a bulky flappy jacket. I'm sure I can go further in still air (see today's blog entry)