This is an industrial designed exercise bike from Lithuania that can store 2KWh of electricity generated by your own exercise.
TLDR: It’s a great concept but it’s about 100× more exhausting than you imagine.
I absolutely love stuff like this, and I also love cycling.
However, there is a big caveat here: I’ve been cycling for years and know my own power output:
Output – Time Window – Heart Rate
- 1400 W* | 60 seconds | 208 bpm
- 385 W | 20 minutes | 162 bpm
- 148 W | 6 hours | 110 bpm
*(yes, I know. My thighs are larger than some people’s torsos and it scares me too)
That means that on average, around 13 and ½ hours of pedalling to charge this thing. (2 KWh is also worth $0.68¢ where I live at standard residential rates).
Humans are not great at converting their physical and thermal energy into kinetic or electrical (20-24% for most bodies).
Pedal power is amazing for things like charging phones or powering small devices and computers though, or for something completely meta: Charging up a eBike or electric scooter (120W), to then use without pedalling later.
Which then begs the question – if our “human/person power output” is like 150 watts constant … and the sun provides 1.4 kW/m² of energy – why not just lay down a 150W photovoltaic solar panel ($89) in the sun and sip on some unsweetened iced tea instead?
While what we can generate is negligible. If, for example you had these in all gyms, that’s generating something. Not a lot, but more than nothing. Also all houses should have batteries and being able to remove the cost of a phone charge from what you suck from the grid would be nice.
It’s a really good business idea that I’ve had more than once – a self sustaining “green gym”.
Members would leave their electronic devices in special hardened lockers, plug them in, and then go to work out, and the power from central battery bank would then charge everything that’s in the lockers.
I also had an idea for credit system where the more power you generated the cheaper your monthly bill/subscription would be for the gym (only a few bucks here and there), or some kind of perks, like a free t-shirt once a year if you generated over 1 MWh (1000 kWh) or whatever.
The power generated by such a place would probably be negligible but it would give people the same emotional high as other pro-social tasks.
I saw a report on a gym with the idea that the exercise equipment would power the gym. It wasn’t a good business model. They brought the reporter in and only turned on some of the lights - they had to be super stingy with electricity to get anywhere near net positive energy generation.
1400W for a minute is insane. You are either a pro track cyclist, or you should quit your job and become a pro track cyclist!
Haha, I wish – they call it the hour record for a reason!
I’ve got explosive short-term speed, but it doesn’t last, and I get dropped within 20 minutes, as my power output dips below the optimized pros who can do 400W constantly for entire Tour stages.
I appreciate the comment though!
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
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.
