A year and a half or so back, I was looking for recharging options that I could have on the go. Given the recent trend in USB output adapters that hook on to the dynamo and the advancement in Solar panels, I was not sure what would be the best way to go about. I had a Dynamo hub and had tried a product called Pedal Power+ which was really disappointing. It was at this time, I came across SunUp Eco. I cannot figure out how I found them, but was really impressed with their pretty neat design of a retrofit dynamo powered charging system.

I wrote to the company, based in taiwan, and got a quick response back. I told them of my journey and my desire to be able to charge devices on the go (a long list including cameras, iPad mini, GPS, kindle etc. And after listening to my needs, they offered to send me their higher end model the MaxiDyn 8W dynamo kit. In return, I offered to use the product and write an honest review on real world use as a Touring cyclist. And here it is.

SunUp Eco shipped me the product pretty quickly and I had it sent to a friend’s place in Santa Barbara. It took me a month or so before I got to see the product. The package contained the dynamo system and the USB kit. The instructions were pretty clear and I managed to get it mounted on my rear wheel pretty much without any fuss. I should say a little bit of skills with tools is expected, but I’d expect a touring cyclist to have no trouble figuring things out. The mounting was cleanly thought out and I eventually mounted the rubber holder on my rear stays and it was a convenient place. Once could mount it on the horizontal stays too I suppose.

I ride a 58 cm Surly Long Haul Trucker, which is a big bike and the cables were long enough to reach from the dynamo, mounted on the rear hub all the way to the stem rider. Neat. The USB cable also had output leads for lighting system. I thought that was neat too. Given it is a 8W dynamo, I could run my lights and get USB output at the same time. It’s something not possible with USB systems that rely on hub dynamos (at least the standard Shimano and SON ones). Also running the cable was simple, just a few zip ties on its route and viola!

It would seem that the SunUp Eco MaxiDyn is a DC dynamo and that means that the Lights being powered by this dynamo must also be compatible with DC. I didn’t know that at first and had hooked up my LED lighting system to this dynamo. The lights worked fine, but after a few weeks the lights failed, may be the electronics burned out. Bummer. I decided to run my lights from my Front Shimano Dynamo hub and use the MaxiDyn for USB charging alone.

The MaxiDyn weighs a bit and I can notice it while lifting the bike up. With Touring load on, the additional weight of the MaxiDyn seems pretty tiny. But if you are into ultra light touring, then this is a concern. I thought given that the load was on one side of the rear wheel and that meant a bit of extra stress on those spokes and maybe the tires would wear out faster on that side too. But after a year of usage, I do not see any issues with spoke breakage (will report if there is any) and I suppose my rear panniers are loaded in a way to balance the load and I the tires have been wearing evenly. So it seems things are fine in that end.

The dynamo has been exposed to a lot of rain, dust, sun and particularly loads of mud over the course of the year and though I thought I might have additional issues with mud getting into the movable bits, it has held out pretty well. The bearings have a little play (they had a bit of play on day 1), but it has held up without complaints. The UBS Cable however is starting to rust a bit and I had to clean them off with a emery sheet when it did. I’d prefer if the connection ends were made of corrosion resistant material. I think it’s important that the connectors work over the long term. In my case it’s still working, but when rust enters the picture, its just a matter of time.

I installed the USB plug on the steering column with the leads facing down so as to prevent rain entering. But the conditions of Bike touring means that the constant exposure tends to easily get to the metal bits. It would be nice if they supplied a silicone or rubber cover for the USB to keep the elements out and prolong the life of the USB cable. SunUp Eco got back to me and mentioned that a new product line called Super Power would ship with Rain proof USB connections. Sweet indeed…

SunUp Eco recommends the use of a buffer battery pack and I would highly recommend it too. Directly charging devices works, but with constantly changing speeds (especially on a touring bike), the output can be inconsistent and the charging might not be efficient. Battery packs, can be plugged in and one can forget about it thro the day and after a good day’s ride, it’s possible to charge a 5000 mAh battery pack fully.

This is an area where the maxiDyn shines compared to other Hub Dynamo based USB chargers. This being a 8W dynamo, there seems to be a higher power output at lower speeds. For instance, while just using USB (and not lights), I seem to get consistet charge from the MaxiDyn while riding at 10 Km/h (much better then needing to get up to 15 Km/h on Hub dynamo based systems. That means that there is more time for charging thro the day. On a normal day, I ride 80 Km in about 6 hrs on the saddle and can easily charge a 5000 mAh battery pack fully. That’s enough to change my GPS batteries an have come charge left over to charge my iPad or kindle or my camera battery as I need them. Further, I like the idea of plugging in the battery pack and forget about it till the evening. Pretty sweet.

The design of the MaxiDyn means that when I do get that occasional flat, there are a couple more things to be aware of. Disconnect the cable and unscrew the dynamo from the mount. It’s not rocket science, but even after 15 months on the road, I occasionally forget to undo them. When I get the bike into any shop, I have to give special instructions to the mechanics on how to remove the rear wheel. It’s not a bother, but I’ve had times when the mechanics ended up undoing a lot of other bits while I wasn’t paying attention.

Apart from the minor quirk, the system is pretty much out of the way. I don’t pay it much attention and it just does it’s work of providing charge when I plug the cables in. I think the system is pretty well designed and a nice take on the dynamo design. The whole system works great and the best part is that the wheels need not be rebuilt. The team working at SunUp Eco seem to be a really friendly and are great to communicate with. They seemingly appreciate the lifestyle of power hungry Bicycle Tourists and have designed a high quality product that works well when put thro the rigours of touring.


  • Relatively easy Installation, with enough cables to route along a large bike.
  • Make sure lights being used are designed for DC (Update from SunUp Eco: They recommend HERRMANS H-FLOW & H-TRACE as their light options).
  • The version I have fits only on the rear wheel with rim brakes. New models compatible with disc brakes and ones to fit on the front wheel are supposedly in the cards.
  • A bit heavy and loaded to one side. However, it does not seem to be a big issue for me.
  • Dynamo is super durable.
  • The USB cable is rust prone. Would like the USB socket to be made of corrosion resistant stuff. (Update from SunUp Eco: There is a new model in the pipeline called “Super Power” which will ship with a rain proof USB port!)
  • A rubber or silicone cover for the USB housing will be useful.
  • A couple of additional steps while fixing flats on the rear.
  • Consistent output above 10 Km/h (better than other Hub Dynamo based systems where I need to be at 15 Km/h)
  • No need to rebuild wheels if you do not have a hub dynamo.
  • Able to easily charge a 5000 mAh battery in a day’s ride.

Track Notes