The question

The most asked question is always: "How far can you go with the battery?".
And the answer is: "It depends!".

The challenge

The highest point that the Tour de France has ever passed is the Col de la Bonette at 2802 m (9192 ft). 

The distance from Nice/France is 120 km thus back and forth is 240 km (150 miles). The challenge is to go up and back in one day with only one battery pack.

The tour

The start is in the early morning hours at the famous Promenade des Anglais in Nice.

Under clear blue skies it goes along the Var river towards the mountains. In the morning there is always a bit of head wind due to typical offshore winds close to the sea.

It is a very interesting landscape along the route which changes multiple times. A section in the middle is covered with red limestone.

89 km after the start the real ascent begins.

The peak in the background is the Col de la Bonette. Still 14km to go and 1000m of altitude to gain. It looked damn far away - and it was!

Last stop to refill the water supply

The difficult part starts roughly at 2500m - the thin air begins to effect the legs, every meter forward becomes a major effort. There is 40% less oxygen available than on sea level taking away your forces...

In the picture below is the "Camps des fourches", an old military village - and a veeery welcome stop to take some pictures.

And finally the summit - mission accomplished! 

Well almost, but the way back is all downhill ;)

Let's do some calculations

The battery on my bike is a medium sized battery with 48V and 11.6Ah giving roughly 550Wh of energy. Let's assume an average efficiency of the motor of 70% that gives us 385Wh of mechanical energy.

Let's assume the average speed is 24km/h (15mph) then we would need 10 hours for the trip.

The calculator on kreuzotter.de says we need 112W for 24km/h in the flat, thus in 10 hours we need 1.12 KWh for covering the distance.

For getting up to the top we need E = mgh -> 100kg * 9.81 * 2800m = 2746800Ws = 763Wh. Together this is a need of ~1.9KWh of energy, therefore the battery has supplied about 20% of the energy.

Conclusion: obviously eBikes keep you fit!

The maps

Ascent

http://cyclehikemap.eu/mymaps/view.php?id=73
http://cyclehikemap.eu/mymaps/view.php?id=72
http://cyclehikemap.eu/mymaps/view.php?id=71

Retour

http://cyclehikemap.eu/mymaps/view.php?id=70

Food

5 bananas
2 baguettes with mountain cheese, ham, tomatoes and olive oil
plenty of water

Fun

Priceless!