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Twin Heads SRL Lightcharge



Simple, inexpensive USB charger for your dynamo-equipped bike

At every product is thoroughly tested for as long as it takes to get a proper insight into how well it works. Our reviewers are experienced cyclists that we trust to be objective. While we strive to ensure that opinions expressed are backed up by facts, reviews are by their nature an informed opinion, not a definitive verdict. We don't intentionally try to break anything (except locks) but we do try to look for weak points in any design. The overall score is not just an average of the other scores: it reflects both a product's function and value – with value determined by how a product compares with items of similar spec, quality, and price.

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The Lightcharge USB port is an inexpensive option for adding a charger for your devices to your bike if you run a dynamo of any kind. It works pretty well and has stood up to some weather too.

There are options for hub or bottle dynamos (and now a range of colours) but I tested the standard black unit, running it from a SP-PV8 hub dynamo. Fitting it is easy: simply wire in the Lightcharge with your existing light circuit, and the buttons on the front of the head unit allow you to choose between lighting and charging; you can't do both.

The wire from the hub to the unit ends in a micro-USB plug, so it can't be shortened. I found it over-long, so I zip-tied up a few coils to take up the slack. I initially thought the bar mounting mechanism, a simple elastic bungee, was a bit cheap but to its credit it's worked perfectly well. You could replace it with zipties if you wanted a permanent attachment; the Lightcharge is designed so it can be easily removed, although it's not the type of thing that's especially likely to get stolen.

It's simple to use: switch to charge mode, connect your phone/gps/etc via a standard USB port and ride off. Once you've got enough speed up your device will start charging. I used it mostly with an Xperia Z1 compact phone which is a little bit finnicky about what it'll charge from, but it was fine. I found that the 250mA charge wasn't quick, but it was enough to slowly increase the level of charge even when I was recording a track on the phone using Strava, and flicking the screen on from time to time. So in theory you should be self sufficient on longer rides, providing you don't have more than one device to do. Given that many larger devices charge at 1A, you'd be waiting a while to fill up an iPad or similar.

You can't charge stuff up at night, as you need the power to your lights and it's an either/or solution. And I'd be reluctant to use it in the pouring rain as there's no obvious sealing in the USB output. I've ridden with it on the bars with the input cable attached and the USB port cover sealed, and it's been fine in spite of some pretty filthy conditions. If you only needed one specific lead attached, you could glue the lead in with some epoxy resin, or seal it with Sugru. Then it'll probably be fine in all conditions.

The Lightcharge is one of the cheaper options for getting a charge port on your bike. It's not as elegant or quite as effective as something like the Tout Terrain Plug, and it does take up some space on the bars, but it does the job it needs to pretty well and it's simple to fit and use.


Simple, inexpensive USB charger for your dynamo-equipped bike

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Make and model: Twin Heads SRL Lightcharge

Size tested: Black

Tell us what the product is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?

Connect it to the dynamo of your bicycle, hang it to the bar and pushing a button, you can decide if you need the recharge mode or the light mode

Phones, smartphones, iPods ® and MP3 readers:' plug them to the USB, and you can recharge while riding!

lightcharge does not waste the energy: the electronic devices can be uploaded at a low speed with no effort.

People who does not have much physical strength can enjoy the lightcharge technology.

Connected to a common dynamo and starting from 13 Km/h, lightcharge can produce enough energy allows to charge most electronic devices.

To reduce the normal braking effect of dynamos, lightcharge can be connected to a rubber insert that enhances the head of the dynamo from 20 to 28 millimeters.

Now you can have a pleasant riding and your devices always uploaded!

Tell us some more about the technical aspects of the product?

Size: 45 x 43 x 31 mm

Weight: 23 gram

Input (A.C. or D.C.) from 3.5 to 18V and output direct current (D.C.): 5V and 250mA constant

Speed required for maximum production: 13 km/h

Rate the product for quality of construction:

Generally good. Lead a bit long, ports not well sealed when in use.

Rate the product for performance:

Fairly low charge level but enough to keep you topped up.

Rate the product for durability:

Not overbuilt but should be fine, it's not in a vulnerable position and you can remove it if you want.

Rate the product for weight, if applicable:

Nice and light.

Rate the product for value:

Good value, other options can be a lot dearer.

Tell us how the product performed overall when used for its designed purpose

It did the job, charge isn't fast but it's just about fast enough.

Tell us what you particularly liked about the product

Easy to fit.

Tell us what you particularly disliked about the product

Not especially well sealed.

Did you enjoy using the product? Yes.

Would you consider buying the product? Yes.

Would you recommend the product to a friend? Yes.

Overall rating: 7/10

About the tester

Age: 41  Height: 190cm  Weight: 102kg

I usually ride: whatever I'm testing...  My best bike is: Genesis Equilibrium 853

I've been riding for: 10-20 years  I ride: Every day  I would class myself as: Experienced

I regularly do the following types of riding: commuting, club rides, sportives, general fitness riding, fixed/singlespeed, mtb, Mountain Bike Bog Snorkelling, track


Dave is a founding father of, having previously worked on Cycling Plus and What Mountain Bike magazines back in the day. He also writes about e-bikes for our sister publication ebiketips. He's won three mountain bike bog snorkelling World Championships, and races at the back of the third cats.

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