This exercise bike generates power while I pedal — and I used it to see how fast it charges the OnePlus 12

Lifestyle image of LifeSpan Ampera Office Bike.
(Image credit: LifeSpan)

I’ve reviewed my fair share of smart exercise equipment over the last few years. From the best exercise bikes that simulate the ride outdoors to the personal trainer experience of smart fitness mirrors like the Lululemon Studio, there has been a big push for so-called "smart" home gym equipment the last few years. Yet, the biggest issue I have with all of them is that they function mainly with a paid subscription.

That’s why I’ve been using the LifeSpan Ampera Office Bike, which is unlike any other exercise bike I’ve used before. Not only can I ride it without the need of a subscription, but the Ampera Office Bike has one unique feature that sets it apart — the ability to charge my gadgets, all while I pedal. If I’m going to be exerting energy into a workout, I might as well transfer it into charging my phone. Am I right?

After injuring my foot a couple weeks back, derailing me from doing my weekly 5K runs, I’ve been riding the LifeSpan Ampera Office Bike as an alternative for my cardio fix. In order to definitely say how good it is at charging, I took one of the all-time fast charging phones Tom’s Guide has tested, the OnePlus 12, to see how fast my pedaling could charge up a drained device. 

Here’s what happened.

LifeSpan Ampera Office Bike: was $998 now $799 @ AmazonPrice check: $799 @ LifeSpan | $321 @ Walmart

LifeSpan Ampera Office Bike: <a href="https://target.georiot.com/Proxy.ashx?tsid=45724&GR_URL=https%3A%2F%2Famazon.com%2FFitness-Generating-Eco-Friendly-Sustainable-Materials%2Fdp%2FB0CKY5LK4B%2F%3Ftag%3Dhawk-future-20%26ascsubtag%3Dhawk-custom-tracking-20" data-link-merchant="Amazon US"" target="_blank" rel="nofollow">was $998 now $799 @ Amazon
Put your pedaling to good use with the LifeSpan Ampera Office Bike, which lets you pedal to charge your devices with either a UBS-C port or integrated Qi wireless charging pad. It's a good way to stay active, all while using your pedaling power to charge stuff.
Price check: <a href="https://go.redirectingat.com/?id=92X1584493&xcust=hawk-custom-tracking&xs=1&url=https%3A%2F%2Fwww.lifespanfitness.com%2Fproducts%2Fampera-under-desk-bike&sref" data-link-merchant="SkimLinks - lifespanfitness.com"" data-link-merchant="Amazon US"" target="_blank">$799 @ LifeSpan | <a href="https://goto.walmart.com/c/1943169/565706/9383?subId1=hawk-custom-tracking&sharedId=hawk&u=https%3A%2F%2Fwww.walmart.com%2Fip%2FSony-WH-1000XM5-The-Best-Wireless-Noise-Canceling-Headphones-Black%2F386006068" data-link-merchant="goto.walmart.com"" data-link-merchant="SkimLinks - lifespanfitness.com"" data-link-merchant="Amazon US"" target="_blank">$321 @ Walmart

Wired or wireless: you have the choice

Lifestyle image of LifeSpan Ampera Office Bike.

(Image credit: Future)

The LifeSpan Ampera Office Bike is designed differently from other exercise bikes you’ve probably used. Missing are the handles and resting arms, so it’s best to pair it with a tabletop or adjustable standing desk. I paired the bike with a Tresanti adjustable standing desk, allowing me to work on my laptop as I was biking.

In keeping with the LifeSpan Ampera Office Bike's more modern look, there’s a built-in 15W wireless charging pad situated in between the pedals. It’s even wide enough to accommodate larger-sized phones like the Galaxy S24 Ultra. Even though it’s more convenient to use the wireless charger, you’ll get faster charging speeds from the USB-C port hidden near the base of the bike. It tops out at 65W, which is faster than what most smartphones offer via wired charging.

For the OnePlus 12, I opted for USB-C charging to get the most out of my sweaty exercising. In Tom’s Guide’s benchmark testing, the OnePlus 12 broke records for being one of the fastest charging phones to date — reaching a 60% charge in 15 minutes with the included charger, subsequently hitting 100% in 30 minutes flat. It helps that the OnePlus 12 supports 80W charging speeds to fill up its 5,400 mAh battery.

More resistance, more power

Lifestyle image of LifeSpan Ampera Office Bike.

(Image credit: Future)

There’s a companion app with the LifeSpan Ampera Office Bike that lets me track my exercises by detailing my current power output, calories burned, cadence, and distance. During my first two rides, I found pedaling to be relatively effortless — averaging about 50 watts of power. Switching over to the next level (2), I noticed more resistance as I pedaled. I felt my quads burning a bit more while the power output reaching 75 watts on average.

At resistance level 4, however, I found my pedaling unbearable after 10 minutes — almost a turtle’s pace — making it feel like I was going uphill all the time. That’s why I kept things at level 1 for this OnePlus 12 charging test to see how much power I could produce in an hour. Since there are no handlebars to rest my arms on, I would recommend trying to straighten your back as much as possible while biking for the best posture.

Once the hour was finished, not only did I have a decent sweat going and an elevated 148-BPM heart rate level, but the OnePlus 12 got to a 71% charge. That puts it at a rate of 1.18% charge per minute. What’s really impressive about all of this is that I wasn’t putting a ton of effort into my pedaling, which was leaning more casual than anything else.

The promise of limitless power

Lifestyle image of LifeSpan Ampera Office Bike.

(Image credit: Future)

The fascinating part of all this is how the bike is able to do this. There’s actually a flywheel that contains the bike’s resistance mechanism, which then feeds the generator and eventually the USB-C port or Qi wireless charger. And you know what? You don’t have to plug the bike into an outlet. Just start pedaling and it’ll just start producing the power needed to charge your device.

This basically follows the fundamental laws of energy transfer, which brings me to my final point about why I love this bike — the sustainability premise behind it. I love gadgets that have the promise of limitless power behind them, like my Ring Wall Light Solar that I’ve yet to recharge after a year of using it or my solar powered GoSun Portable Electric Cooler. The LifeSpan Ampera Office Bike falls into the same category.

Much like those gadgets, the LifeSpan Ampera Office Bike comes at a cost. At $799, you might think it’s overpriced when compared to standard exercise bikes, but it’s still much cheaper than the $1,445 you’d fork over for a Peloton Bike — and that doesn’t factor in the subscription that’s needed to get the most out of the bike.

Any excuse for me to be more active is an incentive, so when I factor how the LifeSpan Ampera Office Bike serves double duty as a charger, it only increases its value in my eyes. Even if I bike on it twice a week for an hour (which I intend to do), I’m doing so willingly with a secondary purpose. And it saves me time because of the extra productivity I’m able to get out of using it. Why just exercise when I can be working on my laptop at the same time?

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John Velasco
Senior Channel Editor for Phones

John’s a senior editor covering phones for Tom’s Guide. He’s no stranger in this area having covered mobile phones and gadgets since 2008 when he started his career. On top of his editor duties, he’s a seasoned videographer being in front and behind the camera producing YouTube videos. Previously, he held editor roles with PhoneArena, Android Authority, Digital Trends, and SPY. Outside of tech, he enjoys producing mini documentaries and fun social clips for small businesses, enjoying the beach life at the Jersey Shore, and recently becoming a first time homeowner.