Sunup-Eco external bicycle dynamo power generator with no drag and high efficiency

First, there was the roller generator that put a small rubber cylinder on the tire or rim to turn a dynamo. My grandmother had one on her tricycle to power the lights and turn signals. Yes, my Nani had all that, and I rode the heck outta it as a kid.

Then came hub dynamos, which do an admirable job of turning your power into watts and volts. But they require a new wheel (or rebuild), can be heavy, and have a good bit of drag. Their efficiency ratings top out under 80%, too.

Now, Sunup Eco has what they think is the next generation of bicycle dynamos. With a few usage exceptions, the DS1-R dynamo solves all of the inherent weaknesses of the others: It’s lightweight, bolts onto your existing bike and wheels, and boasts 84% efficiency…

Sunup-Eco external bicycle dynamo power generator with no drag and high efficiency

They units are anodized alloy, but the colors look better than the gold and silver ones, which oddly end up looking rather like plastic.

Sunup-Eco external bicycle dynamo power generator with no drag and high efficiency

They fit over the non-drive side of your rear hub and mount to the spokes (below). An arm, like on a coaster brake hub, attaches to the frame, in this case to the seatstay.

Sunup-Eco external bicycle dynamo power generator with no drag and high efficiency

The “flywheel” bolts to back plates, capturing the spokes to drive it. The only real downside is the current inability to work with disc brake wheels. It’s a problem they’re well aware of and are working on (we’re thinking it could bolt to the rotor bolts). The temporary solution they mentioned is that it can also be mounted to the driveside of the front wheel since the direction of rotation is irrelevant.

The dynamo motor is housed below and behind the flywheel.

From there, it runs to an extension wire with open +/- wire ends that can be wired to any lights or other directly powered accessories. Good quality lights generally have small capacitors in them to store a small amount of power to keep them illuminated while stopped in traffic or whatever.

Further down the wire, they offer a Power Bank (silver) with USB output to charge your phone, GPS, MP3 player or any other device so equipped. Just wire it in to the system with the regulator (black) in between it and the generator and you’re good to go. It’ll store enough juice to bring an iPhone back from dead to fully charged. The Power Bank itself takes about three hours to charge while riding about 20-22km/h.

The system has been tested to 100,000km in all types of weather. It’ll work up to 120km/h and generate power at speeds as slow as 8km/h. Besides being more efficient, it’s amazingly smooth. Hub dynamos all have quite a bit of friction. You may not notice it so much while riding, but it’s there. The DS1-R spins freely, virtually devoid of any noticeable friction.

On top of all that, retail is just $120 – considerably less than a good quality hub model. The Power Bank should retail for around $40 – $60 (our best guess based on NTD currency prices mentioned during our visit).


  1. What is the weight? It seems irresponsible to list lightweight as an attribute and not give the weight of the unit. Lightweight is also relative since this is an add on part to the bike rather than an alternative or replacement part such as a generator hub. With generator hubs easily found in the 400g range and most (relatively) inexpensive front hubs in the 125g+ range, this cannot weigh more than 275g for it to be considered a weight savings.

  2. wont this stretch out the rear triangle? will it need a special skewer? it doesn’t look like it will fit in a standard wheel width….

  3. @blake: most people who would use this are touring cyclists and commuters, so a bit more heft wouldn’t be a hard sell for a low cost, reliable and (nearly) universal generator. The inclusion of a USB charging port is also a fairly unique feature than not many dynamos have.

  4. Yes it will power your lights and smartphone together or any appliance using a USB socket. If you are riding and don’t want to power anything you can charge a pocket powerbank to charge your cel phone later.

  5. Independent test in Bicycle Quarterly this month showed this to be the worst by far of all dynamos on the market, with only about 20% efficiency. Compare that to about 80% efficiency for a good hub dynamo. The reason for the “low drag” is that it doesn’t generate much electricity… about 1W at 20km/h and 2w at 50km/h. Compare those numbers to 3W and 5W for most hub dynamos. Also, the weight is about a pound more than a good hub dynamo.

    The only advantage of this is the cost. You might save a hundred dollars or so.

  6. Points for effort, cancelled out by low efficiency, bulk and incompatibility with disc brakes which any good wet weather commuter will have. Come to that I don’t think it will play well with fender stays either. I was interested until I saw it wouldn’t work with discs and hen the 20% efficiency was the final nail.

  7. Funny how cyclist (including me) tend to be judge and jury without actually trying something or seeing it in person. Maybe this will develop into something better, and I congratulate them for thinking outside the dynamo box. For the low end OEM market this might be a good thing! Lights that require no batteries for inexpensive commuter bikes. Years ago I had a German Lightspin bottle dynamo. I got mixed reviews, but I loved that thing. Ran it until the bearings wore out, and it never let me down. Quite efficient for a bottle dynamo as well.

  8. Go Chad!! Hey great voices – Just wanted to say – If you were thinking about having a front hub dynamo and another power source then this could be a good option – Would be great to have a rear hub dynamo too -does anyone know why there isnt one or is there one? cheers

  9. About 1996ish, I bought the German Speichendynamo in Germany. Compared to all others, it was great. A lot of light for commuting in and around Toronto, Canada. But the bushings wore out within a year.
    I also tried the bottle types of several makes. The ancient Miller from England and the NordLicht from Switzerland. The Nordlicht has the best efficiency and lifespan for the bottle types, given its ball bearings, instead of the bushings in others.
    But it is time to move on to the hub types. So when I tried the first generation Shimano, it was nothing but a frustration. The drag/friction was so high, it was unbelievable. And when I tried to open the hub to replace the bearings, it was impossible.
    So my search continues and am hoping to get the SP-8 and hope to use it on my touring bikes.

  10. Also, the Sunup website says output is 3 watts. Not even enough to charge an iPhone. Literally every decent hub dynamo on the market is 5-6 watts.

  11. “Hub dynamos all have quite a bit of friction. You may not notice it so much while riding, but it’s there. The DS1-R spins freely, virtually devoid of any noticeable friction.” BS. Hub dynamos have no more friction than ordinary hubs, though they do have a bit of electrical drag due to hysteresis even when no load is connected. Unless the generator disconnects when not in use, this device will have more friction than a hub dynamo, because it has a more complicated mechanism — gear or belt drive.

COMMENT HERE: (For best results, log in through Wordpress or your social media account. Anonymous/fake email comments may be unapproved or deleted. ALL first-time commenter's posts are held for moderation. Check our Comment Policy for full details.)

This site uses Akismet to reduce spam. Learn how your comment data is processed.