Is there a way to charge my USB lights on the move?

[onyerbike531]

Hello forum people

I've been directed here by the helpful people at Retrobike who have told me you're more in the know about dynamo lighting.

I need a bit of advice on the possibilities of charging up lights on the move. I have use a Cateye volt 800 USB rechargeable front and a Exposure TraceR back also USB charged. I wanted to know if it would be possible to charge these up on the move using a sidewall (bottle) dynamo connected to something like a Kemo M172N Bicycle USB charger or do I need to get specific dynamo compatible lights? I'm on a tight budget and I don't want to spend more on lighting than the bike cost me, (it's a beaten up old racer/tourer from the mid eighties), I have seen there's a Shimano dynamo hub; a Capreo DH-F703 6v 3.0w that's in my price range and I have a spare Rigida rim I could get rebuilt with this hub providing the spacing's right and swap the wheels around when I'm using the lighting during the winter months, would this be compatible?

Any advice would be very appreciated, as you might have gathered I'm not very knowledgeable with matters such as electronics, I would just like to know if it would be possible to charge my existing lights on the move after I had an issue with my front light running out of juice midway through a 40 mile ride a couple of nights ago.

Many thanks in advance.

[gaz]

Welcome to the forum.

A little light reading to get you started here whilst you wait for more informed replies.

[onyerbike531]

Hello and thank you, I will take a look at that now.

[meic]

One thing to check first is whether or not you can have your particular light turned on while it is charging.
If not then you are still restricted to the battery lifespan while night riding and can be left stranded in the dark again.

[the snail]

Seems like an odd way to go about it - for similar cost to a charging gizmo you could buy a good quality dyno light, and avoid the inefficiency of the charging circuit and battery.

[Norman H]

It's certainly doable, providing your existing lights are capable of working whilst accepting a charge, but it's not the most efficient use of dynamo power and I can't really see the point. Cheap usb chargers are best avoided and the better ones aren't cheap. You would be better off spending the money on some dynamo lighting. A 30 Lux front light is certainly good enough for urban commuting and can be bought quite cheaply. Axa make some good lights in the 30 - 50 Lux range, it's also worth looking at the B&M line up.

German on line retailers tend to be the cheapest for all things dynamo but postage will be more expensive.

[Mick F]

I raised this very point on another thread, that the dynamo could be used to charge battery lights. Seems eminently sensible to me.

Battery lighting is cheap and plentiful, so all you need is the dynamo with a USB output. You could pick whatever rechargeable lights you wanted.

I bought a Spanninga front light and a B+M rear light for my hub dynamo. I have a plethora of battery lights and a few of them are USB rechargeables. Instead of laying out for the dynamo lighting, I could have bought a USB thingy for the existing lights instead that could not only charge the lights, but be used to power my Garmin and my phone.

Much better system IMHO.

[meic]

I raised this very point on another thread, that the dynamo could be used to charge battery lights. Seems eminently sensible to me.

Seems even more sensible to me to use it directly to power the lights, at first glance at least.

I use a more dated B&M light 'n charge which allows me to charge AA batteries in my Ixon light.
Or to run the light directly from the dynamo (though it will wreck the light if the batteries are not correctly in place)
It can charge the batteries in about 4 hours of riding on the flat (lights off), which is the same order of magnitude as the batteries last powering the light on high. Or the batteries will charge from flat with the light on, overnight. So the losses through charging and then using this to power the lights is mostly just a burden in having to pedal a (undetectable) bit harder.
On the other hand the ride 'n charge, switches, auxiliary wires and Ixon IQ are a lot more faff, bulk and weight than a Cyo headlight, only worth it to charge batteries for other toys.

[Heltor Chasca]

I use a Thrunite ‘lipstick charger’for my gps, phone, mini iPad, torch etc. Unlike most of the chargers out there you can replace the 18650 battery inside it. You can therefore carry multiple batteries on tour if there is no other way of recharging your charger (mains, solar or dynamo) And of course when the battery degrades, you don’t have to chuck the whole thing out, you jus5 change the battery. I found the batteries ‘vapers’ use to have the best mAh and value.

I wouldn’t know if they charge while you are using your lights.

[onyerbike531]

Thanks for all your replies, you've given me a lot to consider. The reason I asked about the charging method is because I have existing lights that are USB charged and they cost me quite a lot of money in the first place and didn't really want to have to fork out on more lights. I'd try charging them up during the my day riding with the method I'd mentioned or if I got caught out on a long ride at night again I'll be using a back up light whilst I pedalled some charge back into my powerful Cateye ones. I will be making sure my lights are fully charged up before making any long trips in the dark again and will always carry a back up light from now on.

Thanks

[nez]

I always have two sets of lights - one dynamo, one USB charged. For a very long ride I suppose I might want something different, but the truth is I can do 50k with the battery ones and I'm not sure I want any more than that in the dark in the winter. I have a thing about this in the winter - two spare inner tubes, even two pairs of gloves if I think it's going to rain good and proper! Pulling on dry gloves after getting a soaking is such an indulgence!

[Samuel D]

First of all, the Capreo DH-F703 hub you mention is designed for small wheels (folding bicycles and the like). It would therefore be a poor choice for charging batteries on a bicycle with full-size wheels that rotate more slowly.

But dynamo hubs are wonderful things for lighting and will also allow USB charging. I would spend money on the charger: many cheap ones do not seem to work reliably. Reliable options include the Busch & Müller USB-Werk and Igaro D1.

Running lamps directly would be slightly more efficient and allow access to the wonderful German lamps with shaped beams. All of this does cost money, but not necessarily a fortune.