After my Wahoo TRACKR RADAR post/video a few weeks ago, where I noted that Garmin’s RTL-515 is the very last micro-USB device in my house, a bunch of you jested: “What about SRAM AXS batteries?!?!”.
That’s because, indeed, SRAM does still distribute a micro-USB charger with all AXS-equipped bikes. That’s the same battery type as eTAP, they are fully interchangeable. While I will continue to give SRAM a hard time for still distributing a micro-USB charger with $15,000 bikes, I will give them credit in that the eTAP/AXS batteries haven’t changed in like a decade. Seriously, what other company has kept the same proprietary battery for that long? Even most legacy camera companies slowly shift/tweak their batteries over time. So, kudos there.
Still, it’s ridiculous to have micro-USB for the charger in 2025.
Thankfully, there are some 3rd party USB-C options for charging that are great. I’ve been using one of them for a few years now, this dual-battery USB-C charger:
Simply slot in two batteries, plug a USB-C cable in the back, and come back whenever, and it’s charged. Donezo.
On the unit there are three status lights: Green, Yellow, and Red. As you might guess from your extensive experience with such primary colors, red means something’s bad-bad, yellow means charging, and green means go. Complex, this is not.
On the back, it notes this is a 5V-2A charger. While charging a single battery, it seems to float between 1-1.5W, and while charging 2 batteries, it floats around 2.5-3W (according to my Anker PowerBank I bought a year ago, also a favorite cause it can charge everything from my laptop, to drone batteries on a multi-day hike…all at 100w):
(At left, the USB-C variant. At right, the official SRAM micro-USB charger.)
Officially, the manufacturer claims it charges the batteries via USB-C some 30% faster, though practically it’s really hard for me to validate that, since I virtually never get my AXS batteries down to dead-dead status (let alone two of them to test side-by-side). And even if I did, I have no idea which ones are 3-5 years old, and which ones are 3-5 months old.
Wattage-wise, I’d see the USB-C version pulling about 4.0w for one battery, whereas the micro-USB one was pulling about 3.0w. But that’s, of course, only a piece of the amp/watts/volts story, and both units fluctuated a bit.
Either way, charging speed has never really mattered to me here…cause…uhh…below. If my math is right, I think I currently have five SRAM AXS battery-equipped bikes active in our fleet, between my wife’s bikes and mine. Additionally, we have three Shimano Di2-equipped bikes.
Now, while there are 3rd party batteries for SRAM AXS, I don’t use them. In general, my jam is that I try to use company-specific batteries as much as possible, to reduce any unexpected problems. Especially when that might result in me being gazillions of miles away from a solution (such as in the mountains on a multi-day trip). So I keep to the official SRAM AXS batteries, but use the third-party chargers. Likewise, I used to use third-party GoPro batteries, but eventually the GoPro ones became reasonable enough, price-wise with certain bundles/discounts, that I didn’t bother with third-party ones. However, for my main mirrorless cameras, I do use a third-party battery because those have USB-C charging ports directly in them (making it so I don’t have to carry any extra chargers):
At this point, we’ve totally gotten sidetracked on this review. But frankly, there isn’t much more to say. It just works, and I don’t think about it. As for the older micro-USB charging blocks? I actually stick them in my bike case in one of the secret compartments, just in case I somehow forgot the real USB-C charger, I’ve at least got something (and someone can always find an older micro-USB cable in a hotel from a desk drawer somewhere).
Now, I will leave you with this: You can also buy an 8-port AXS battery charger. While the inner-charging-geek in me could easily find a justification for this (at least, to justify it to my wife), it’s pretty hard for me to realistically justify it:
Still…I want it.
With that, thanks for reading!
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Sticking to its battery (connector, the chemistry changed):
Lupine is building premium bike lights since the 90s and the batteries are fully compatible. Yes, the old ones don’t deliver enough umph for all lights to shine at highest setting, but the other way around will work.
Ray,
This appears to be a first world or should I say five bike problem. I ONLY have one SRAM AXS Red XPLR bike, so only one battery. It lasts, according to SRAM, somewhere between 25 and 60 hours. Even at 25 hours at an almost leisurely 15 mph gravel ride that’s 375 miles. I carry a spare aftermarket battery in my seatbag that costs about $15 off of Amazon. I’ve never had to use it. I top off my battery before any rides longer than 100 miles with the standard charger. I’ve never urn out of power nor ever seen anyone in a race run out of power on an SRAM battery. So, the SRAM being micro usb is hardly an issue. Garmin, however, with their varia devices and slightly older computers that have to be charged, in my case twice a week, that gets annoying.
Ports lament. My Assioma Duo pedals use micro-USB cables that plug into the adapters. Don’t yours? My Polar Verity Sense HRM cradle plugs directly into a USB A charger port!!! My new Sigeyi spider PM uses a propriety cable that plugs into a USB A charger port. My Samsung laptop uses a small coaxial power plug, not USB at all. I’ve still have mini and micro USB bike lights. Wife’s Edge is micro-USB. My car’s active USB port is A. It does have B charging though. Dashcam is micro. And it goes on. I’ve got way more non C devices than C devices.
Hey Ray,
SRAM has manufactured a four slot USB-C charger for several years now. Need us to send you one?
Best,
-Troy
I’d be curious to hear about others experiences (and specifically data geeks) with 3rd party batteries.
I generally love all things SRAM, but the price of their batteries and USB-C charger, leave a lot to be desired.
There appears to be a massive mark-up on these.
And like Garmin’s taillights, it’s pretty obnoxious to ship premium devices with micro-USB these days.
I have two non-SRAM batteries that I have in rotation with 2 SRAM branded batteries. I can not tell any difference in use nor in hours per charge.
Hey one more thing about that dual port charger… I have a battery that was totally bad bad red dead, the official SRAM charger just would not charge it. Tried putting it in and out like 50 times as they say to do.
This charger charged it right away. This thing can bring back dead batteries that the official Saran one can’t.