This tiny, 3D-printed USB-C charger for Di2 rear derailleurs is a fantastic idea, but I wish Shimano made one.
Having spotted it on the excellent Instagram account @bettershifting (which is run by the same person behind bettershifting.com – an excellent resource for all things Shimano Di2), my interest was immediately piqued and I rushed to AliExpress to buy one for myself.
Perhaps unsurprisingly – given it’s essentially a bit of cheap plastic tech made by a brand I’d never heard of (ALLTOO), from an online marketplace renowned for low-priced stuff – the build quality and functionality of the unit I received leave a lot to be desired.
It works, kind of… but it’s nowhere near the level of a genuine Shimano EW-EC300 Di2 charging cable.
Nevertheless, let’s examine why I think this is such a great concept, despite its obvious flaws.
The problem with Shimano’s Di2 charging cable
Like many things made by Shimano, the standard EW-EC300 Di2 charging cable is a solid piece of kit.
It’s nothing fancy, but it’s built well, durable and ‘just works’ (which it should, considering it costs £45). Unfortunately, though, it is quite big.
That’s not a problem most of the time – 99.99 per cent of riders likely keep theirs at home in a drawer or toolbox, only pulling it out to charge their drivetrain every now and then.
If you’ve ever considered carrying a changing cable with you to guard against running out of juice a long way from home, though, it’s less practical.
It wouldn't be impossible, of course – it should fit in most saddle bags and only weighs 70g. However, it would be taking up valuable space you'll likely want to reserve for things such as mini tools and spare inner tubes.
The outdated USB-A interface also limits you to only using devices with that interface to charge from, unless you’re also willing to carry adaptors. Again, though, that's more to carry and leaves less space for other things.
In contrast, this ALLTOO USB-C adaptor is tiny – it measures 21x16x10.5mm and weighs only 2.6g, according to my espresso scales. Even the most devout weight weenies should be able to tolerate that.
You’ll need to carry a USB-C cable to connect it to whatever you want to be able to charge from, but this universal interface opens up some exciting possibilities.
Many smartphones and bike lights now support reverse charging (meaning they can charge other devices using power from their batteries), for example. With this little adaptor and a short cable, then, you’d be ready to top up a Di2 battery in a pinch.
Of course, given Di2 batteries tend to last for around 1,000 to 1,500km, it’s rare you’ll ever run out of battery power mid-ride if you remember to charge it every now and then.
In a way, though, because they last so long, Di2 batteries can be relatively easy to forget about.
It’s never happened to me, of course, because I’m perfect. However, it has happened to a friend, and me carrying this little device plus a cable just might help get them out of a future pickle.
The problem with the AliExpress Di2 USB-C adaptor
So far, so good then, but there’s one major problem with the AliExpress / ALLTOO Di2 USB-C adaptor – it’s naff.
Unfortunately, its build quality is pretty woeful and it barely works.
Unlike the official Shimano cable, there’s no reassuring click as it snaps onto the rear derailleur charging port, and while I was eventually able to get it working (and a Di2 drivetrain charging) after some fussing and wiggling, it’s far from ideal.
A closer look at the connector pins also shows they’re not identically sized – perhaps this doesn’t matter, but it’s another example of where the AliExpress item diverges from the genuine article.
At a total cost of £15.26, including postage, I’m in two minds as to whether I’d recommend it.
On the one hand, it’s poorly made and doesn’t really work. There may be better-made versions out there on AliExpress or elsewhere, but the chances of your money being wasted feel quite high.
On the other hand, now that I’ve got one, it will in all likelihood find its way into my saddle bag – you never know when it might come in handy after all.
What I’d really love to see, though, is Shimano – or anyone else, for that matter – making a good-quality version of this little adaptor. Doubtless, a ‘good’ version would cost more, but I think many riders would be willing to cough up their cash for it.
Come on Shimano, this is simply too good an idea to ignore.
