Charging battery using Dynamo Hub

[brianleach]

I am still trying to settle on a way to keep electronic gadgets charged whilst touring.

I have tried a number of portable chargers, solar etc, none of which are entirely satisfactory.

Next attempt was one of these

http://www.cyclewiz.co.uk/BikeCharge_A10I76.aspx

but it doesn't seem to want to fit in the forks of the Dawes Super Galaxy as there seems to be insufficient space and it doesn't fit parallel to the wheel but is slightly angled in towards the spokes.

So my current thought is this

http://www.evanscycles.com/products/m-w ... l-ec039316

but I wonder what other connections/equipment I would need to charge a battery such as this one

http://www.cyclewiz.co.uk/PowerPack_A12UIM.aspx

I don't want to charge the devices directly whilst on the move.

Any thoughts appreciated.

[Elizabethsdad]

I am not sure how you expect a dyno hub to charge your devices if you don't want to charge them on the move. B+M do a front light with a USB port for chrging/running mobile devices and the new dyno light from the exposure can do the same via a booster cable plugged into the SPT port. This booster cable will work with any SPT equipped exposure light and also their piggy back batteries. Otherwise check out the thread titled 'poratble power'.

[stewartpratt]

Lots of threads on this: have a rummage for Busch & Mueller's e-Werk, Tout Terrain's The Plug, Kemo's M172 and the Busch & Mueller Luxos U (and another lamp, but I forget its name).

I have the Kemo and it works fine, but only if you want to use 2 out of front light, rear light and USB charger. I also have the Luxos but haven't tested it yet.

The Luxos charges via an internal battery so you wouldn't need an additional one if you're concerned about protection. The e-Werk has the option of a dedicated cache battery, too.

I am not sure how you expect a dyno hub to charge your devices if you don't want to charge them on the move.

I think he means he doesn't want the charging circuitry plugged directly into the device, but to go via a battery as a protective measure.

[brianleach]

Thanks for the responses. I will look up the references given.

I am really coming from a position of keeping a smartphone and a Nexus 7 charged whilst camping.

The lights and the Garmin use batteries. Not very environmentally friendly but much easier as readily available to purchase overseas.

What I am trying to do is charge a battery, such as the one I indicated, during the day which can be used to charge the devices in the evening or overnight.

Am I being unrealistic here?

[stewartpratt]

It's perfectly realistic.

That battery won't go very far with a Nexus 7, though - you'll get around 50% of the Nexus's capacity - and it's not cheap. For less money you could have ~4x the capacity, plus 2A output (which matches the Nexus wall charger, though it'll still charge using most if not all 1A, and probably 500mA, chargers): http://www.amazon.co.uk/s/ref=nb_sb_nos ... ttery%202a

You lose the weatherproofing, of course, but that's easily solved by sticking it in a handlebar bag or similar.

[brianleach]

Thanks Stewart.

The waterproofing isn't an issue as I always ride with handlebar bag.

I'm being a bit dim here I know but what connections would I need to connect the dynamo to the battery?

[stewartpratt]

It's not just a connection, you need some electronics in there. So you'll need one of the above devices, or an equivalent.

Note that different battery packs use different connectors. I would recommend getting one that uses USB connections of some sort - generally either full size or micro - for both input and output. If you get one that uses a 3.5mm jack then you have to carry (and risk losing) more leads and connectors. Note that the Kemo charger has a mini USB output, which plugs straight into most, if not all, Garmin devices, but other devices these days (Nexus included) more commonly use micro.

[brianleach]

Many thanks for the information.

[andrew_s]

Bear in mind that when you charge a battery you only get out 80-90% of what you put in, so charging from an intermediate battery rather than direct from the dynamo will mean more time spent charging on the move. If you have something that uses a lot of power or if you ride somewhere hilly where your average speed is low, you may be struggling with charging time anyway without adding extra.

The best power source is a dynohub. The Shimano 3N20, 3N30 and 3D30 are all fairly old models and give more drag when not in use. Most others are pretty similar. Hubs and wheels are usually cheapest from Germany (eg Rose).

Some devices don't like it when the charger stops supplying power, and will either turn off or stop charging until the cable is unplugged and plugged back in (or both). To get round this it is common to put a small cache battery between the dynohub and the device. Normally this is fully charged and power goes straight through to the device, but if you stop at traffic lights or wherever it will keep everything going until you get going again, within limits.

The B+M Luxos U front light and the B+M usb-Werk (but not the e-Werk) have small built-in cache batteries.
There is a cache battery available as an extra for the e-Werk, at significant cost
If using a DIY cache battery, you need to take care. With some you can't supply power at the same time as charging the cache, which makes it a bit pointless.

The other lights with built in USB power supplies are the Axa Luxx 70 plus and the Axa Nano 50 plus

[stewartpratt]

With some you can't supply power at the same time as charging the cache, which makes it a bit pointless.

Personally I tend to agree, but it only really applies for devices you're using while on the move. If the OP's only aiming to charge a tablet, and to do so overnight, then it's not an issue for that.

[stephenjubb]

deleted

[brianleach]

Thanks for the help. I shall have to give it some more thought.

[CJ]

Bear in mind that when you charge a battery you only get out 80-90% of what you put in, so charging from an intermediate battery rather than direct from the dynamo will mean more time spent charging on the move.

From what I've read, I think even 80% is ambitous. I would expect to have to ride twice as far to charge something from a storage battery, compared to charging it directly.

[al_yrpal]

You could make one. You will need a circuit board some pins and these components from Maplin - cost a couple of quid:

AQ96E W02
UJ54J L78S05CV
VH52G PC Elect 1000uF 63V

Its just a diode bridge rectifier to get DC from the Dynamos AC, a capacitor and a voltage limiter, I think mine was built into the voltage limiter. Then you can buy a cheap phone charger and cut up the cable to get the connector to charge the battery. I used one of these : http://www.amazon.co.uk/gp/product/B000 ... UTF8&psc=1

Al

[brianleach]

Many thanks for this but I'm afraid it is a bit technical for a pen pusher like me. It might help a more competent person though so thanks for posting.