Hub Dynamo recommendations

[d1verjim]

Hi all,

First post for me, though I've been hanging around browsing for a while now

I am about to buy one of these: PP+ V4 Charger

to allow me to charge my phone/gps while cycling to & from work everyday (about 8.5 miles each way).

However, the company is out of stock of it's own hub dynamos, so I'm just going to get a standard one from somewhere else (I'm in the UK - have to get the charger from Australia so makes sense anyway to get a dynamo somewhere locally)

Not knowing anything much about dynamos, I'm looking at getting a Shimano DH-3N71, which has the same output as the PP+ one.

Any alternative recommendations, or advice on the Shimano one would be most appreciated.

Many thanks,
James.

 

[frenchyge]

I'm a racer, but I bought a 3N71 in January and had it built into a Mavic Open wheel to use as a science project (ie, geek toy). The hub seems solid, doesn't add much unnecessary resistance, etc. I had intended to build an LED light setup to go with it, but haven't gotten that far yet. I still commute on that wheel even though I don't have a light yet (summer).

Most hub dynos are AC, so you would need the AC Universal cable. It looks like it would work, although I'm discouraged that it takes 2.5 hrs of pedalling to charge a cell phone. You said you only have a 8.5 mile commute, right?

Note that you will have a speed requirement in order to get the hub up to the rated 6w output. According to the testing this guy did, that would require about 24 kph+. At slower speeds, it should still work (to a point) although the charging will be slower.

That same guy has some other interesting information and ideas on his site, and was kind enough to answer some of my questions, so take a look if you're interested.

 

[d1verjim]

Cheers Frenchyge,

The main aim is to keep the phone charged while running GPS, which currently drains the battery 50% over 40 mins.

Even if it only extends it rather than charging it fully, it'll do the job, and 24kph is probably about my average speed.

Thanks for the link - interesting reading.

 

[steve]

Cheers Frenchyge,

The main aim is to keep the phone charged while running GPS, which currently drains the battery 50% over 40 mins.

Even if it only extends it rather than charging it fully, it'll do the job, and 24kph is probably about my average speed.

Thanks for the link - interesting reading.

What phone are you using?

 

[d1verjim]

A HTC Tytn ii (or Kaiser if you prefer).

Will probably be switching to a Palm pre early next year, and hopefully that will still work...

 

[steve]

A HTC Tytn ii (or Kaiser if you prefer).

Will probably be switching to a Palm pre early next year, and hopefully that will still work...

Cool, I have a palm treo pro, battery life if pretty good.

 

[frenchyge]

My reading on that PP+ V4 is that is has an internal storage which charges up, then can be used to discharge into the end device. You might inquire with the manufacturer to verify it is capable of charging/discharging simultaneously during use.

It's also possible to build your own charger using some of the projects here: Instructables - Make, How To, and DIY if you have such an inclination. I searched on bike phone charger and found several projects that seemed promising.