ZJEGO Dynamo Bicycle Rechargeable Battery USB Generator Charger Kit, Portable and Waterproof - No Tools Required (Silver)

I got the silver version because I needed a 12V dynamo rather than the normal 6V models. The build quality of the dynamo is not the greatest, but sufficient for most needs. The bracket is maybe a little weak for such a large dynamo, but again, they do work and are no more ugly than any other 'bottle' dynamo bracket available. A strip of old inner-tube and careful tightening (use the grub screw in the centre of the bracket to prevent it from slipping round the tube!) ensures that the bracket stays where I have set it.You need to make sure the dynamo (any version) is aligned properly with the back wheel - google search for how to do this, it's really easy. Dynamos are intended to be driven with the bracket facing away from the rotation direction of the tyre in order to prevent the dynamo becoming jammed between the wheel and frame should the bracket slip for any reason. And that is NOT the mounting position seen in the provided images. Anyone who has had this issue and has bent the bracket, has installed the dynamo incorrectly. However, if you make as much effort as possible to ensure the bracket cannot slip, then you will probably be OK with mounting the dynamo facing the direction of rotation, and this could actually help reduce slippage in wet conditions.The Dynamo is provided with a rubber cap to help reduce slippage against the tyre, and this will also allow you to run the dynamo against the metal wheel rim rather than the tyre (useful for knobbly tyre mountain bikes). A spare is included in the box. If for any reason you require a new set, these are actually standard rubber feet for metal leg chairs, and are available cheaply elsewhere on Amazon. Search for 'round rubber chair ferrule' or 'rubber chair feet' and you will find the exact match with a little looking, and even a few alternative styles that may be useful in different situations. I think it's a 14mm diameter required, but measure the metal cap of the dynamo to make sure it's a good tight fit.The provided instructions in the silver version are in Chinese only, though they are not really needed. If you are unsure about how to fit it, you can use the Google Translate app with your mobile phone camera to see a translation (just hold the instructions in front of the phone camera and you see a live translation on your screen). It should not matter which way round you connect the wires to the dynamo, as they are all alternating current (AC) output devices anyway, and the battery pack uses a diode pack to rectify this into the correct polarity DC for the charging circuit.The quality is fine for the price, the charging system for the battery would cost about the same if you were to build it yourself from the same parts. I'm using this as a charging system for a 12V lighting system, be aware that if you intend to run a dynamo lamp with the silver version that it has an output of 12V and nearly all available dynamo bike lights require 6V - you will quickly blow your bulbs unless you modify it to use the higher voltage (hint: LED conversion bulb, but you will need a diode to make DC current as all dynamos are AC output, and the LED's driver circuit will not like AC!).The battery pack uses a standard powerbank charging circuit, thus you should be able to charge the battery pack using the micro USB socket via a standard USB supply / charger. So really no need to ride for five hours to recharge the battery... ;) Using the battery pack to power your phone while it has a full battery will reduce your actual phone battery usage when using GPS and data on the move (usually this means Google maps). This will be more effective than trying to recharge a fully dead battery.As the battery pack is NOT waterproof and can't be left installed on the bike, I'm not really sure why they used a waterproof connector lead between the battery and dynamo, seems a little pointless as the connector will remain exposed when you disconnect the battery and take it with you, and you cant't use it in the rain anyway...Overall this is a fairly decent bit of kit, and is significantly cheaper than other 'brand name' products available. Worth the money in my opinion.

At first I wasn't sure if the rechargeable battery was working so I plugged it into the mains; after this, the dynamo does appear to be charging the battery and thereafter, my phone.Would have been 5 star but after two months I have gone through one of the two dynamo rubbers (trying to find somewhere to buy more as in a couple of months time, I will have nothing left).