Solar Panel vs. Dynamo Hub (Efficiency Report)

Should you go with a solar panel or a dynamo hub to charge accessories or batteries for lights on your bike? There is a lot of debate about which is better, a solar panel vs. a dynamo hub.

One thing we noticed is that the answer to that question boils down to application. What? Yeah! So, let’s dive in and explore how or why one is better than the other.

We add a little spice in the form of a few bits of essential information too. 

In this blog, we discuss: 

  • The pros and cons of solar for biking
  • The pros and cons of dynamo hubs for biking
  • What dynamo hubs do 
Solar Panel and. Dynamo Hub

Solar panel vs. dynamo hub

Is a solar panel better than a dynamo hub for bicycles? Two differences set each apart. Those are:

  1. Solar Panels – have the advantage beyond bicycling. For example, a portable solar panel makes it possible to take solar power with you when a bicycle is not an option. 
  2. Dynamo Hub – have the advantage of producing a charge regardless of whether the sun is shining or not. 

Those two applications are what we mean about which is better and how that answer relates to your situation.

So, for example, a touring bike or racing bike may find that the dynamo hub is a better option since you would be pedaling long distances during the sunny daytime. 

That means once you hit camp, your sunlight is limited, and a solar panel may not produce much energy. 

If you are riding on short trips, say a few miles to the river, to enjoy a summer swim, a portable solar panel would be a better option since you would be pedaling less and stationary in a sunny spot for much longer.

In addition, you’d get more energy from the solar panel over the dynamo hub. 

Which is better – The solar panel or the dynamo hub? Again, the answer is very situational. The answer may be “both” if your lifestyle on your bike is both short and long-distance trips. 

Are dynamo hubs worth it?

Dynamo hubs are an excellent investment for anyone who rides their bike for more than an hour a day.

If you commute to work, enjoy longer day rides, tour, race, or enjoy endurance training, then a dynamo hub is an excellent investment.

On the other hand, if you ride your bike for shorter periods, do not right at night, and keep day trips to less than five miles from home, then a dynamo hub is likely not an excellent investment. 

The pros for dynamo hubs are that you produce electricity that can power your bike’s lighting system as you pedal.

That’s a big plus for everyone, regardless of how long your ride is. Of course, shorter rides produce less energy, but you can still light up a path to get home. 

See also: Solar Powered Vehicles: A Comprehensive Guide to the Future of Transportation

The cons of dynamo hubs are twofold: 

  1. They produce drag
  2. They add weight 

Drag and weight are not generally an issue for most riders. However, those who endurance train, ride exceptionally long distances, tour for multiple days, or race, drag, and weight can become an issue.

One last con that we need to bring up is the risk of using DC energy with AC devices. Dynamo hubs produce DC energy, and almost everything in the modern world uses AC energy.

Charging your phone with a dynamo hub could damage the phone unless there is an inverter somewhere between the dynamo hub and the phone.

For that reason, many cyclists use their dynamo hub to charge a battery bank from which they charge other devices. What that means is – more weight.

Are dynamo hubs slow?

In terms of overall time from point A to point B, dynamo hubs maybe add a few minutes to a 50-mile trip. For everyday bikers, that’s not even noticeable.

However, for racers who are trying to shave off small increments of time, that can mean the difference between finishing in the top three spots or not. 

Regarding charging a device, dynamo hubs can be slow and made even slower by poor technology matching the brand of dynamo hub and the item being charged, especially for cell phones.

A reasonable expectation is a dead bike like to be fully charged in about two hours – depending on how much riding you do and how fast you pedal.

The faster the front tire spins, the more energy your bike can create. 

What does a dynamo hub do?

Dynamo hubs produce electricity by creating an electromagnetic induction current. The process works as a series of magnets spin around a copper coil.

That process produces energy that can be used in a battery storage device or, with some adaptation, to charge smaller devices.

Is this a process you’d use at home? Not really. Electromagnetic induction from a bicycle is not that efficient. 

One reason why dynamo hub efficiency is poor is due to conflicts between hub software and device software. However, as technology and relationships continue to improve, the efficiency of dynamo hubs should increase.

One place to look for better software is open-source apps that may be coded to function better with charging software. 

Can a dynamo hub charge a phone?

A dynamo hub can charge many things, including a phone. How fast that occurs depends on the relationship between the brand of the hub and the cell phone brand.

The time it takes to charge your phone will also vary depending on fast you ride and how long you ride – x number of revolutions per minute of the front tire = Y amount of watts. 

As you can see, many variables go into figuring out how fast a dynamo hub can charge specific devices. One of the issues is a disconnect between the charging software and the devices’ software.

There are instances when the device will not recognize the dynamo hub or the controller views the incoming energy as a hazard and shuts it out, so charging does not occur. 

An excellent solution to situations where your device will not pair with the dynamo hub is to charge a battery bank rather than a phone or other device. You can use the battery bank to charge your other devices. 


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Elliot has 20+ years of experience in renewable technology, from conservation to efficient living. His passion is to help others achieve independent off-grid living.

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