Getting a charge: An exercise bike that turns your pedaling into power

I enjoy getting my exercise, but hate doing it indoors. I'd much rather get some fresh air and watch the world drift past me as I cycle or hike somewhere than watch a screen while sweating away on something stationary.

To get a bit more of what I like, I've invested in a variety of gear that has extended my cycling season deeper into the winter. But even with that, there are various conditions—near-freezing temperatures, heavy rains, Canada catching fire—that have kept me off the roads. So, a backup exercise plan has always been on my to-do list.

The company LifeSpan offers exercise equipment that fits well into a home office and gave me the chance to try its Ampera model. It's a stationary bike that tucks nicely under a standing desk and has a distinct twist: You can pedal to power the laptop you're working on. Overall, the hardware is well-designed, but some glitches, software issues, and design decisions keep it from living up to its potential.

Solid hardware

Many aspects of the Ampera are pretty well designed. Its hefty weight keeps it stable even when someone my size (~90 kg/200 lbs) is pedaling away on it. If it starts tilting, there's a metal ring around the base that should keep it from falling over, although I've been fortunate enough not to test this. Despite its size, it's still easy to move around since it tilts forward onto some wheels and rolls around easily.

That tilting is best managed by using a handle that attaches to the underside of the seat. That's more of a mixed bag, as it limits how far back on the seat you can sit. It should be possible to install it upside-down so the handle tilts under the seat if this is a problem, though. The height of the seat is easily adjustable. It telescopes out of the base on a metal pole; pull up on a lever under the seat, and it will slide up or down to wherever you find comfortable.

Even with my relatively long legs, I had no problem finding a comfortable setting. However, to keep working while pedaling, I needed to set a standing desk at its maximum height. This is not something that you can expect to use while sitting at a more traditional desk.

As for the seat itself, it's wide and cushy, so quite unlike a typical bike saddle. There are a few things about this that I'm not convinced by. To start with, the padding will eventually wear down if it's heavily used, and the use of a non-cycling attachment—it bolts onto a flat metal plate—means it's going to be harder to replace. The fabric might also be a problem if, as I do, you tend to sweat a lot while exercising. (More expensive stationary bikes, like Pelotons, can fit standard bicycle seats.)

Enlarge / The seat of the Ampera isn't typical cycling hardware, and incorporates a handled to move the base around.

John Timmer

The pedals are fine. The texture of the polymer mostly kept my feet where I wanted them. The occasional slip was likely because I'm unused to thinking about how to keep my feet in place—the product of using clipless pedals on both my road and mountain bikes.

The two other notable features of the hardware are a ring of colored LEDs around the cranks, a USB-C port at the front of the base, and a Qi wireless charging pad in the center of the pedestal. There aren't any controls on the hardware; everything is controlled via software.

Under control?

The software pairs with the Ampera via Bluetooth. The pedestal does not have batteries or capacitors; instead, the onboard electronics are only powered when you turn the cranks. That means that the software can't really do anything until after you've started cycling. That's not a problem, per se, but it does shape the experience in significant ways, like having to keep the cranks turning throughout the entire setup process.

The controls let you select the color of the LEDs, with more than a dozen different options, from tasteful and understated to garish. You can also choose from several levels of resistance, from the equivalent of coasting on flats to pushing up a moderate hill. (Thanks to a glitch I experienced, I discovered that there's also a "pushing up a really tough hill" level of resistance that's not a user-selectable option.)

Enlarge / The wireless charger sits in a recessed area at the center of the Ampera's base.

John Timmer

The software displays all the expected numbers: how long you've been pedaling, what your output would mean in terms of cycling speed, etc., and it uses your height and weight to estimate things like calories burned. The numbers it produced were quite similar to the ones I got when I tracked the same workout on my Apple Watch. At the end of a session, it'll store all the stats for long-term tracking, but only if you tell it to do so in the few seconds between when you stop pedaling and when the system shuts down because it lacks power after you stop pedaling.

The software was probably the weakest link in the package. I used the iOS version, which doesn't use native controls. Beyond looking out of place, some of the dialogs I came across ran offscreen, leaving me to guess what it was asking for. And when it asks for your date of birth, it uses a calendar-style date picker to select it, meaning you have to navigate through every month between the present and the year of your birth to enter it. That's more than a bit of an annoyance if, like me, said year predates 1970. I ended up letting it think it was being pedaled by a 3-month-old.

While it mostly got the job done, the software felt like a step down from the stylish hardware.

Functional but glitchy

The device is stylish but not without its own set of issues. To begin with, there's a fundamental design disconnect in the Ampera. If you want to do anything resembling a workout—say a warmup, intervals of high and low resistance, and then a cooldown—you've got to be regularly using your phone to control the hardware. But if you're using your phone, it can't be sitting on the wireless charging pad, which is down near the pedals. At the seat height I was using, you had to step off the pedals to pick up the phone. If you didn't get back on the pedals quickly, then the power cut from the lack of pedaling would shut the Ampera down, leaving me to start again by powering it up and pairing it with the phone all over again.

Enlarge / No matter how hard I pedaled, the wide ring kept the base steady.

John Timmer

You can still charge your phone using the included USB-C adaptor, but it's unclear why the charging pad was included in that case. The only way I tested the wireless charging was by resuscitating my previous model phone and installing the software on that, using it to control the bike while my current phone charged.

All of this led me to uncover some truly odd behavior. I've done my best to experiment with various configurations to understand where the issues are. I have no access to the Ampere's internals, so everything that follows is only an inference.

The first thing I noticed is that not all of the data the app gathers is accurate if you aren't using the wireless charging. When charging my phone via the USB-C port, I was shocked to find that, after an hour-long session where the display told me I was never producing less than about 70 watts, the software told me I had generated less than a single watt-hour. In contrast, when I charged the same phone on the wireless pad (using my older phone as the controller), I got a reasonable value for the watt-hours generated.

To nail things down, I looked up my laptop's original battery capacity, asked the operating system how much of that I had left after three years, and then went to work filling it through the USB-C port. After half an hour of pedaling, the battery received over 25 watt-hours of juice from the Ampera, a figure that does not count all the power used by working on the laptop while exercising. Yet the app suggested I had only generated 0.23 watt-hours.

This revealed something else unexpected about the power system. Obviously, the laptop could draw much more power than a phone. The Ampera appears to lack anything to regulate this draw, meaning it got directly transferred to the generating hardware and then to the pedals. Resistance shot through the roof, making it much harder to turn the pedals than even the highest resistance setting available in the app. But, for reasons I can't identify, the Ampera started looping through settings ranging from no charging/low resistance, through charging at intermediate resistances, and up to nearly impossible to pedal, before starting the cycle over. Unplugging the laptop quickly returned things to the expected behavior.

Enlarge / Even with the seat fully extended, the Ampera can be tucked out of the way under a standing desk.

John Timmer

Adding all those issues up, I suspect the Ampera can only register the power sent to devices if it goes via the wireless port and that the fraction of a watt-hour I saw when using the USB-C port alone is simply lost to the wireless charger. It's also clear that there's nothing that regulates the amount of power drawn through the USB-C port.

I don't have internal wiring diagrams, so I can't confirm any of this, and there are still one or two tests I hope to do to confirm some suspicions. But even in the absence of confirmation, it's clear that you can get some weird behavior if you're doing anything that falls outside of Lifespan's expectations.

Setting expectations

The numbers I got out of my experiments should tell us a few things about the remarkable amount of energy you can cram into modern batteries and the remarkable efficiency with which a decent bicycle can convert energy into mileage. And those should set expectations for what you can accomplish using the Ampera. If you're a regular user, you can probably keep your phone working without plugging it into an outlet. If you're an aggressive user and manage a laptop's energy carefully, you can potentially do the same (although at the cost of experiencing random changes in resistance during your workouts).

But your legs are not going to turn into one of your apartment's primary sources of energy.

For some people, the charging can potentially be used as motivation. If you're the sort of person who can stop themselves from plugging their phone into the wall, then you're guaranteed to get some exercise if you want it to work. It will also be motivating for people who like to gamify their workout stats. Beyond that, it's a bit of a fun extra—it's one thing to have software take your age and weight and estimate how many calories you're burning. It's quite another to watch the battery meter on your laptop climb upward.

Regardless of your motivation, it works in one regard. I'm starting the spring cycling season ready for much longer rides than I have been in the last few years. But whether it will work for you depends on whether device charging is a key feature and whether the hardware you expect to charge will play nicely with the Ampera's quirks and limitations.

As for the hardware, it's pretty nice. Price-wise, at $800, it falls somewhere in between budget options (like the hybrid desk/pedals hardware we looked at a few years back) and dedicated workout machines like the Peloton. What you get is a somewhat less bike-like experience but solidly built hardware that feels like it's likely to hold up to some heavy use.

LifeSpan's mobile software is central to the experience, though, and that also needs a bit of work. Most of its problems could probably be sorted out by spending some time with someone as they use it, though, so there's no reason it needs to remain the product's weak point.