Bmach

Looking for a Micro USB external battery pack to charge my Wahoo Roam while riding? Anyone have any successful ideas?

Thanks
Brian

atwl77

Any external power bank should be fine. Typically something along the lines of 5,000mAh is small enough to carry in a top tube bag or similar. 10,000mAh if you plan on charging more than just the cycling computer. 20,000mAh might be overkill unless for a multi-day trip while charging lights and smartphone as well. If you have a modern smartphone with USB-C fast-charging, you might also want to consider a power bank with two charging ports - one for regular devices and the other with Power Delivery for your phone.

Tourist in MSN

Buy two small ones, keep at least one charged for immediate use.

adamrice 

You don't need any particular connector on the battery pack, you just need the right cable, and you can get cables with many permutations of connectors.

In fact, you can't charge your Wahoo from a micro-USB port on a power bank. Here's why: There are USB A connectors, B connectors, and C connectors. The A connector is the familiar wide rectangle, which you probably see on your computer. The B connector is more square in shape, and is very seldom used. There are a few variations on the B port: mini-B (uncommon), micro-B (very common), and micro-B for USB 3 (looks like micro-B but wider). There's also the newer C connector, which is oval, and is the only one that you can insert upside-down. The Wahoo has a micro-B connector. But if you have a B connector at one end, you can't have a B connector at the other end. Originally it had to be an A connector—I think this was to make sure you always connected your devices the right way around. These days you can also have a C connector. But A connectors are "host" connectors, and B connectors are "peripheral" connectors. C connectors can go either way.

If you see a power bank with a micro-B connector on it, that's for recharging the power bank (when it's acting as a peripheral), not for charging from the power bank (when it's acting as a host). C connectors can often be used to recharge the power bank more quickly, although that gets complicated.

fooferdoggie 

this has been a great battery not too large and can charge a iphone pretty close to max speed. I have had several for several years.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

znomit

I used to carry a small battery pack but recently switched to a handlebar mounted magicshine light with a USB-C port. Have charged my GPS and tail lights on the go.

https://www.magicshine.us/product/ma...e-light-front/

adamrice 

This guy has done an exhaustive analysis of power banks (I'm linking to the archive.org version because the whole site seems to be password-protected now), looking at weight, charging speed, capacity per unit weight, etc.

njkayaker

Buy a good one that is the size you need (no need to spend lots either).

People tend to buy big ones, which are often overkill and not something you want to carry while riding.

Bmach

Thanks guys I bought the Anker 10000. Works great.

fooferdoggie 

its been reliable for several years. I don't use it hard but it still holds up. got a large one for a bike LEDS on our tandem.

rlmalisz

Some time back, I picked up 5 "lipstick" banks that hold a (not included) single flat top 18650. Picked up a set of four of those rated at 3500mAH. The lipstick is bascially a case with enough electronics in it to charge a 3.7V battery off USB, and deliver USB power from same. 71g with battery. I got them for extending the uptime for GoTenna Mesh units in relay mode. Have used one to charge an Apple Watch 2-3 times on one lipstick charge. Could probably rubber-band one to a seat post, handlebars, whatever. Easily small enough to throw in a jersey pocket.

fooferdoggie 

I used to have one of those. kinda wimpy though no clue what happened to it I think it croaked.

Tourist in MSN

I had some of those that I bought on Ebay, shipped from Asia. Some worked better than others, and some were suddenly dead. After a few years, all were dead.

Some of them I could use in pass through mode on my dynohub powered USB charger (Sinewave), and then charge GPS or other devices, but some did not work in pass through mode.

They did not have a series of four (or some other number) of LEDs to give a rough guestimate on state of charge, all I knew was that if it would charge something it was not yet empty. I think that some mechanism to provide a state of charge estimate is a must for any powerbank used on a bike, you do not want to bring it along and find that after 10 minutes, its empty.

In my previous post above, I suggested:

There are so many brands out there, some are good, that I did not want to suggest a specific brand. But I have a few Goal Zero Flip 10 chargers like that one you have, except the Flip 10 is square instead of round. The Flip 10 includes a series of four LEDs to provide a state of charge estimate.

I bought several of these bundles of two batteries and charger at REI and gave as Christmas presents, REI no longer sells the bundles, I do not know if they are still sold or not.
https://www.rei.com/product/112965/g...charger-bundle

veloz

We’ve toured with Anker 10k ones for 3-4 years. Carry 2 of them for our phones, wahoos and Garmin wearables. We can go 3-4 days without plugging in. They charge quick and have been dependable. Very helpful to have when off power grid.

CliffordK

Thanks for the summary.

The large "B" connectors, somewhat "D" shaped, are used on many printers, at least they used to be.

I highly dislike the "Micro B" which was common on the old Android phones. Inevitably the cables wear out in a few months and the device connectors start having significant wear within a year or so. It is too early to know if Micro C will have the same failures.

I have a flashlight that has a double ended cable with two large male A connectors. A unique design where it uses the double-A for charging, and allows an A/B for supplying power.

Before investing too much in on the road charging, make sure the device allows that. You may be able to simulate on the road charging by simply plugging it into the PC and moving it around the house. Or plug it into a cigarette lighter socket in car and going for a drive.

I'm not sure charging on the road is good, and could risk damage to your device.

Tourist in MSN

My GPS (Garmin 64, not a cycling specific model) uses the mini, not micro cable.

For bike touring I have a couple Y cables that plug into my powerbank that have both mini and micro plugs.