Electric Jam

[JennyB]

Last week I did a 120 mile ride on my ebike, which included about 700 metres of climbing. It took around 11 hours: 8 hours on the bike at 15 mph average, 2 hours in cafes recharging myself and the battery, and one hour for camera stops and general faffing. I wasn't riding particularly hard (I'm not fit enough), and used a bit less than 9 watt hours per mile.  I'm estimating my own contribution was about 4 watt hours per mile and so the electric system is around 60% efficient - 3 watt hours at the wheel take five watt hours from the battery.

At that level of effort I feel as if I could go on forever, though of course I want to increase my fitness and be able to do the same trip with less assistance. Even four watt hours per mile or less is nice to have, to push you over the points that would otherwise slow you down and force you to accelerate yet again at the end of a long day.

But for now I'm just curious - just how much does my battery eat?  My typical cafe stop puts about 300 watt hours into the battery, or 258 kcal.  Given the difference in conversion efficiency (4 kcal of food energy to 1 kcal of output) each watt hour is "worth" just over 2 kcal. 

So 300 wh is equivalent to [roots through larder - quick calculation]  just over half a pot of raspberry jam? 

[mattc]

Fascinating. Keep it up 

[The unit "Watt hour per mile" will turn some brains here into jam  ]

I might work "Peak faffing hours per mile" into future ride reports.

[clarion]

You're absolutely right.  It should be foot pounds per furlong, no?

[JennyB]

You're absolutely right.  It should be foot pounds per furlong, no?

Well then, just multiply by 332! 

[Cudzoziemiec]

Miles per jam jar is a fascinating measure, though I think km per flapjack has more currency among cyclists. 

As it happens I did a 120-mile ride a couple of weekends ago, my longest ever so far. It took me more like 13 hours including eating, looking at things, sitting in the sun, checking the map and so on. No idea how much climbing but I very much doubt it was 700m as they were about the easiest 120 miles you could find in the country - up the A38 and down the Sharpness Canal, pretty much. No jam was eaten but electricity was used (in lights).

But for now I'm just curious - just how much does my battery eat?  My typical cafe stop puts about 300 watt hours into the battery, or 258 kcal.

Or how much do you eat and how many kcal/watt hours/jam jars do you put in?   

Given the difference in conversion efficiency (4 kcal of food energy to 1 kcal of output) each watt hour is "worth" just over 2 kcal.

Isn't the human body inefficient?  Still, I guess if all the food input was converted to power output, that would negate the whole point of riding as you wouldn't be... alive!

I might work "Peak faffing hours per mile" into future ride reports.

I look forward to it, but I bet yours don't match up to mine! (Oh no, those aren't faffing hours, those are hours spent in subsidiary activities!)

You're absolutely right.  It should be foot pounds per furlong, no?

I suggest flapjack-furlongs per faff.