Dynohub Free charger.

[Tombo 707]

There is a batterry charger for the Dynohub, people out there that want to harness there power and use it to charge u.s.b gadgets. Its been a long time coming. The Biological Free charger by Dahon who make folding bikes. On the market March 2010. Iuse a solar freeloader at the moment but I think with a Dynohub and being able to charge stuff on the move this ones a winner.

 

[Joe24]

Or just make up a USB charger thing like this?
http://geektechnique.org/projectlab/511
Could easily add on a different connection instead to use to charge up whatever you have.

 

[Tombo 707]

Too many wires. Looks to much Tallybannish to me.

 

[Joe24]

Too many wires. Looks to much Tallybannish to me.

Well, it would be pretty simple to make it look neat wouldn't it? And wouldn't cost as much as a stupid Freeloader, they were just under £30 at work when we had them in, this new one will probably be about the same, or maybe more.

 

[Tombo 707]

I wish I had the skills to make one. I was just saying there is a big interest in taking power from your dynohub. There should have been something on the market by now. Regards Tom

 

[andrew_s]

Like buses...
there's the Dahon, and
http://www.bumm.de/index-e.html?docu/361e.htm
http://www.pedalpower.com.au/index.htm

 

[Davidc]

One wire, 2 diodes, a car 12v socket, 10 NiMH batteries, a box to mount them in and with things own car charger leads you can recharge anything!

If anyone's interested I'll draw and scan the circuit.

Only drawback - both the positive and negative connections are live to the bike frame.

Edit: Total cost about £5

 

[just jim]

I wish I had the skills to make one. I was just saying there is a big interest in taking power from your dynohub. There should have been something on the market by now. Regards Tom

There will be.

 

[yello]

http://www.bumm.de/index-e.html?docu/361e.htm

The E-Werk was at the Eurobike show and will be available next month. It looks like a top bit of kit but at €139, I think I'll be assessing other options!

 

[Joe24]

I should have a dynamo come sometime soon, weds/thurs, and i think im gonna have a play with that, and try and make up a charger with it, if i can, and hopefully have it so i can plug something into something on the dynamo, so its not on when i dont need it, if you get me.
Will have to see how it goes though, doesnt look too hard ....................

 

[andym]

These guys look like a good option. :

http://www.pedalpower.com.au/

They offer either a hub dynamo or a bottle dynamo (if you already have a hub dynamo then the B&M looks like the one to go for). When I contacted them earlier this year they said they could ship to the UK for $39 (US).

Good luck Joe. I must admit I'd like to have a quid for every post I've seen from people saying how easy it would be to make a gizmo to convert the output from a dynamo.

 

[oxford_guy]

Like buses...
there's the Dahon, and
http://www.bumm.de/index-e.html?docu/361e.htm
http://www.pedalpower.com.au/index.htm

I'm really interested in a dynohub charging solution to recharge my GPS etc. on long tours. One solution that wasn't mentioned was is the ZZing, which is cheaper than the B&M solution (which I wasn't aware of), though doesn't look as sophisticated. I'd be very interested to see how much the Dahon device will be and whether its a serious competitor to the other products mentioned.

I have a Schmidt SON 28 dynamo, which should be up to the job of providing power...

 

[bike_the_planet]

One wire, 2 diodes, a car 12v socket, 10 NiMH batteries, a box to mount them in and with things own car charger leads you can recharge anything!

If anyone's interested I'll draw and scan the circuit.

Only drawback - both the positive and negative connections are live to the bike frame.

Edit: Total cost about £5

Sorry - you'll need more than that. For a start, NiMh batteries have trickle and peak charge current limits. If you exceed those then you risk gassing the cells rendering them unuseable. At the very least you'll need a couple of resistors to limit that current.

However, a simple resistor plus diode is not very efficient, because at low wheel speeds you'll reduce the charging current and therefore the energy you're putting into the cells. You really need a regulator that maintains the max trickle current (normally C/20 for NiMh) regardless of dynamo output voltage to maximise the energy transfer to the batteries.

Also, to make a comprehensive charger you really need multiple output voltages: 5vdc for USB devices; 12 v for phones and cameras.

Cheers,

Tony

 

[Davidc]

Sorry - you'll need more than that. For a start, NiMh batteries have trickle and peak charge current limits. If you exceed those then you risk gassing the cells rendering them unuseable. At the very least you'll need a couple of resistors to limit that current.

However, a simple resistor plus diode is not very efficient, because at low wheel speeds you'll reduce the charging current and therefore the energy you're putting into the cells. You really need a regulator that maintains the max trickle current (normally C/20 for NiMh) regardless of dynamo output voltage to maximise the energy transfer to the batteries.

Also, to make a comprehensive charger you really need multiple output voltages: 5vdc for USB devices; 12 v for phones and cameras.

Cheers,

Tony

The circuit I used is 2 1/2 wave rectifiers charging a positive and separate negative set of NiMH cells. The mean current from the dynamo when running is 1/2 amp, 1/4 amp on each polarity cell set, and a bike dynamo is close to a constant current source.

The NiMH batteries used were RC spec, manufacturers figures were 3500 mAH capacity at 3.5A discharge, max continuous charge 400mA mean, 24A max peak current charge or discharge. (Roughly the size of C cells)

There is no need for any resistor in series. A hub dynamo can't produce an output exceeding these limits. Output being taken while charging needs to be deducted, and until the cells are fully charged they'll put up with almost anything (<24A)

I had silicon 'self resetting fuses' in series with the charging lead and both poles of the 12v output. NiMH batteries can discharge at very high currents, and both + and - of the 12v are live to the bike frame!

It's crude, but worked well for two 2 week tours, charging all of the party's mobile phones using a Nokia car charger (gives the 3.5v supply from a SMPS in the plug), and running several other bits of kit at the camp sites, keeping us self sufficient for power. In practice its unlikely that the batteries were ever fully charged, but we never ran out either.

(I still have the charger, somewhere in with the camping kit in the loft, and the batteries were last seen powering a boat.)

 

[andym]

I've just received the pedalpower universal cable plus bits and pieces. First impressions are that it looks like a polished and professional product. The electronics are in a full-sealed plastic case that's about 75mm long and 15mm square at its widest point. I also bought a charger and a set of accessory tips: although the tips seem to be compatible with the interchangeable tips used by the powerchimp and some other travel charger products.

Only downside was the delivery charge of 49 Australian dollars - but that was for delivery by UPS who were fast - but expensive.

I'll post again wen I've had a chance to give it a good test - not sure when that will be.