3,442 Calories (14,388 kJ) is required to generate 2 kWh at a (generous) overall storage-work-storage efficiency of 50%.
For comparison, that is roughly:
- one pound of body fat
- a marathon
- a full day of cycling
this post was submitted on 12 May 2024
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Rule of thumb efficiency of humans is about 25%, which is about the kJ to Calorie conversion, too
so 14kJ of energy output burns ~14,000 Calories.
True, I only included kJ equivalent because some countries use kJ on nutritional panels instead of Calories. Actual conversion rate of human energy stores to usable power is, at a guess, more like
Calories * 0.25 * 0.6 * 0.8 - dt
where t is time, d is the self-discharge rate of the battery, 0.6 is the efficiency of the generator, and 0.8 is the efficiency of the battery.
So, user better eat their wheaties.
Love things like this, but at 3.500€, that's a massive ask. Hopefully the concept catches on.
2kwH is worth about $0.18 here. I'd have to charge it ~19,500 times to offset the cost in electricity.
A fun toy. But a normal exercise bike already converts the energy to heat. This heat then warms up the apartment.
Of course, with electricity, a heat pump for heating or cooling could be used, which is more efficient. But it's not like the energy remains unused with a normal exercise bike, as long as it is cold outdoors.
But sometimes it's hot outside 😓
I've been wanting this for years. But maybe not at that price.
As it seems to double as a balcony solar inverter if you add some PV pannels the price seems to be not so bad. A 2KWh LiPO4 battery, charge-controller and inverter alone will cost you at least half of the asking price.
Maybe making a bike for half the price that can just plug into an existing inverter / battery would be more versatile then.
That definitely changed things a bit there.
They need to put these in all of the gyms in the cardio equipment. Just think of the power they could store.