Using USB-C to charge a Mavic Air?

Somewhere I got the crazy idea that it would be fun to bring a camera drone on my bike tours. Every bit of weight counts, of course, so I got a portable one called a Mavic Air.

It’s great, but it uses a custom battery that can only be charged with a large power adapter, and the adapter weighs half a pound. I’m already packing a 5-port USB charger that has one USB-C output suitable for charging a MacBook. That should put out more than enough voltage to charge the Mavic battery. Why can’t I use that?

Well, it turns out I can.

This is a little widget called a PD Buddy Sink. You can plug it into a USBC charger like so:

Then you can program it to ask for any voltage that a USBC power source can supply, and make it available. For example, 15 volts at 2 amps, which is enough to feed into this Mavic Air charger designed to plug into a vehicle’s accessory port:

I removed part of the casing to expose the wires, then linked them up to the PD Buddy Sink, like so:

Then I decided to get arts-and-craftsy. I formed a gross looking extension to the car adapter case, using some two-part epoxy and silicone glue. Now it looks like the adapter is digesting the PD Buddy. Mmm! Delicious!

Using my MacBook, I then programmed the PD Buddy Sink to ask my power adapter for 12.5 to 15 volts at 3 amps, with 15 volts preferred:

And after writing the configuration to the PD Buddy, I plugged it in, and presto! It started charging.

On the left, I’m using the 5-port USB charger to charge my MacBook, with a digital USBC power meter attached. The MacBook has negotiated for 20 volts and is getting about 19 volts. On the right, I’ve plugged the same USB charger into my Frankensteined car adapter, and it’s negotiated for 15 volts. Success!

(If you look closely you can see the adapter is pulling only 0.005 amps. That’s because the Mavic Air battery is fully charged.)

So, was it worth it? Well, I weighed my new Frankensteined adapter, and it’s a little less than 1/4th of a pound. So I’ve saved 1/4th of a pound, but I’ve lost the ability to charge my laptop and my battery at the same time, and lost the two extra USB ports that the power brick provided. Nah, it wasn’t really worth it. But I had a good time!

Valoria II: Rear rack

Is the Bacchetta “universal rear rack” suitable for touring?
It is a relatively lightweight bolt together rack with a lot of adjustability. So not ideal for loaded touring but people have used it for that purpose. The weight rating is 25 kg.

It’s a pretty snazzy, minimalist-looking rack. (By the way, I found what looks like the generic version of it for about half as much money.) It took a very long time to assemble and position properly since I wanted it as high as possible off the ground. It also has some flex to it, which might not be a good thing. They say you want a rack to be as stiff as possible.

Could I really rely on this skinny little thing to carry 50 pounds over bumpy roads?

I went in search of other options. It was going to be an especially difficult search because of the weird positioning of the rack mount points on my 2016 Giro frame. They were sandwiched between the mounts for the seat struts and the disc brakes:

That is not much room to work with. The fact that I had to use spacers to fit Bacchetta’s own rack is an embarrassment. Would any other rack have struts narrow enough to fit without spacers? Is the distance between the rack arms going to be a problem?

Surly Rear Rack

(1260 grams, rated for 36kg)

  • Strong
  • Has a handle
  • Adjustable height
  • Thin struts at mount points
  • U.S.-style light mount
  • Very heavy

This was my go-to choice, except for the weight. I’ve always toured with an aluminum rack and found them plenty dependable. Heck, my frame is aluminum now. Moving to a steel rack seems kind of backwards.

Axiom Journey

(700 grams, rated for 70kg)

  • Suspiciously high load rating
  • Good fit angle
  • Crappy U.S.-style light mount
  • Handle is blocked

This was my second choice, except I would be giving up the handle. It’s hard to overstate how useful a rack handle is for moving the Giro around in tight spaces. Also, the light mount on this rack is a total afterthought, and their load rating seems really out of wack. Did they actually test that?

Topeak Uni Super Tourist DX

(875 grams, rated for 30kg)

  • Nice handle
  • Adjustable height
  • Good secondary bar placement
  • Not quite European-style light mount (RedLite only)
  • Stupid proprietary mounting strip along the top

This would have been perfect except for that mounting plate. I wish Topeak would sell a good rack without that plate, but they apparently want to compel you to use only their bags.

Topeak Uni Explorer

(782 grams, rated for 30kg)

  • Nice handle
  • Adjustable height
  • Not quite European-style light mount
  • Stupid mounting strip

A lighter option than the Super Tourist model with just as much capacity, but I’m still bothered by that mounting plate.

Topeak Explorer

(625 grams, rated for 30kg)

  • Nice handle
  • No-frills design
  • Best weight-to-capacity ratio of Topeak racks
  • Not quite European-style light mount
  • Stupid mounting strip

A even lighter rack, without the height-adjustment hardware. I would have gone with this except I stubbornly kept looking and found a better option.

Blackburn EX-1 Rack

(535 grams, rated for 18.2kg)

  • Has a handle
  • Minimalist design
  • No light mount
  • Low maximum load does not inspire confidence

I really liked the look of this one but the weight capacity was just too low.

Blackburn Outpost Fat Bike Rear Rack

(1105 grams, rated for 31kg)

  • Has a handle
  • Adjustable height
  • Secondary mount bars
  • U.S.-style light mount

This is Blackburn’s more upscale offering. I had an idea that the articulated mounting arms would fit inside that narrow gap around the mount points on the Giro … but when I got a closer look they were too thick. Mounting this rack would require spacers just like the rest.

Ortlieb Bike Rack R2

(640 grams, rated for 30kg)

  • Has a handle
  • European-style light mount. Finally!
  • Large amount of material around mount points

Interesting to see what Ortlieb wants to contribute to the rack market. Looks like they just want to make something that has their QL3 mounting system directly integrated. Good for them. Unfortunately the amount of reinforcement around the mount points makes them too big to fit on my frame without long spacers – long enough to widen the rack all the way beyond the top of the bolts that hold my seat struts in place. That’s an awful lot of extra strain on a rack.

When considering the Tubus racks I found this photo from The Touring Store very helpful:

Tubus Carry Titanium Rack

(470 grams, rated for 30kg)

  • VERY light
  • European-style light mount
  • Good lower rail placement
  • No handle
  • Top rails are not very long
  • Expensive as hell

The base weight of this fancy rack is astonishingly low, but once you add in the mounting hardware it moves up and becomes merely impressive. Tubus has discontinued this rack but you can still find it around. I think it’s mostly good for bragging rights. The weight difference between this and an aluminum rack with the same capacity is less than the weight of a good-sized sandwich.

Tubus Logo Titan Rear Rack

(390 grams, rated for 30kg)

  • VERY light
  • European-style light mount
  • Good lower rail placement
  • Handle is narrow and hard to reach
  • Expensive as hell

Even lighter than the Tubus Carry, this was the flagship Tubus rack for a while, and it’s easy to see why. Titanium is a very sexy material and the rack design is almost perfect. Sadly, Tubus discontinued it. I would track one of these down and use it except there is a slightly better, and more road-tested option…

Tubus Cargo Evo

(530 grams, rated for 40kg)

  • Has a good handle
  • European-style light mount
  • Good weight-to-capacity ratio
  • No secondary mounting rail

This is a newer revision of the same rack I have on my Bridgestone upright bike. It has two differences: A better shape for the mount points, and a carrying handle. 40 kilograms of load capacity (88 pounds) is plenty, and the frame design is very stiff. It’s also much lighter than the Surly, and doesn’t need an adapter to mount a European-style tail light.

The Tubus Cargo is my choice.

The space between the rack mounting holes on the Giro frame, including the thickness of the frame itself, is exactly 150mm. That happens to be in the middle of the width tolerance for the Tubus Cargo:

This means I can put spacers on either side – up to a centimeter each – without compromising the rack.

Also, notice the way the mount points project inward, like the ends of a clamp. That gives me plenty of clearance around the bolt heads that stick out on the seat struts.

This is important because the rack ends are pretty wide:

If I didn’t have that extra space, I’d run into those bolts for sure.

A picture is worth a thousand words, so here’s a gallery showing how it turned out:

It's quite sturdy and I can't detect any flex in it, unlike the standard rack which flexed alarmingly with bags on it.
It's close, but the rack manages to leave space for both the disc brake assembly and the various bolt heads around it.
These are actually the arms from the standard Bacchetta adjustable rack. I liked the fit a little better. The arms that come with the Tubus work fine though.
Closeup of the spacers I needed to fit the rack to the frame.

Aluminum spacerThe aluminum spacer I used – visible in the fourth photo – came from Amazon. I know I paid too much for them but it was just too convenient to throw them in with some household goods in another order.

It only took a few test rides to know that I was dealing with a much, much better rack than the standard Bacchetta one. After a few months, during which I loaded it up with a huge pile of gear and sailed around Oakland for hours at a time, I was convinced that I’d made the right choice. The handle was perfect, the weight was low, the capacity was high, and the brake light mounted easily.

In the meantime, the Tubus rack that I’d put on my upright bike nearly ten years ago continued to be a workhorse. Just last week I used it to transport a truck battery across town.

NZ Day 25: A last day of riding

Fun fact: New Zealand has more cute roadside ponds per capita than any place else in the southern hemisphere.

New Zealand is awash in cute roadside ponds!

(Note: Today’s Fun Fact has not been peer-reviewed.)

We slept in late, and checked out of the Plateau Lodge even later. The 12-mile mountain hike we did yesterday was probably slowing us down. What a surprise!

Nevertheless, we were in good spirits. It was all downhill to Taurmaranui and the weather was fantastic. Plus I was all stocked up on dark chocolate:

Roadside chocolate break!

In the photo you can see the New Zealand flag attached to the bike. It was part of my fabulous plan to boost our visibility to drivers, but in retrospect it was mostly a nuisance. If it was smaller I could have attached it to a pole like recumbent riders usually do. Oh well… Wisdom for the next trip.

Knowing how much we obsessed about weight, it’s odd that I didn’t just discard the flag somewhere along the way. But on the other hand, when you’re visiting a country, you shouldn’t throw their flag in the trash – that’s just rude!

There's the mountain we hiked near two days ago - Mt Ngauruhoe - free of clouds for the first time in a week.

During the chocolate break I looked back to the east and saw Mt Ngauruhoe – free of clouds for the first time in a week. The weather wasn’t that clear yesterday when we hiked it. It’s true what the locals say: The mountain makes its own weather system, and it’s only sometimes related to what goes on around it.

Looking to the north I saw what looked like a smaller, flatter version of Ngauruhoe.

I believe that plateau is called Mt Komokoriri. (That's based on a guess from looking at .)

In the evening I got obsessed and spent an entire hour on the laptop, browsing around topograpic maps trying to identify the plateau. My best guess was that it’s Mt Komokoriri?

Since it was the last day we would be riding cross-country, I decided to do what I did for the first day, and record some video. This time I attached the camera to the front of the recumbent instead of my helmet. “Now it’ll be nice and steady!” I declared. Nope. Every single tiny ridge on the pavement made the camera jitter like crazy. It looked like I was riding a bicycle with square wheels.


About halfway through the ride we stopped to chat with some outdoorsmen walking along the road.

Friends we met while cycling down from National Park, including Mark the photographer.

The guy on the right is Mark Watson, a nature photographer and fellow cycling enthusiast. I barraged him with questions about photography equipment and techniques, which he answered gracefully.

Stopping for photos of a mountain and seeing smoke in the air

Second video:

Checking in: I’d grown quite a beard.

Resting up after an easy day's riding!

I spent a non-trivial amount of vacation time like this, futzing with photos. Fun!

Odd sockets and switches:

This is how you know the hotel was built a while ago!

NZ Day 24: Tongariro Crossing Extra Photos

Sun pressing through the morning clouds, promising warmth later in the day. ... A promise that was thoroughly broken!
Clouds still clinging to the mountain in the early morning.
A broken signpost, contoured by the endless wind.
The most important part of this sign has been preserved, at least...
Snack time!
Looking back the way we came, we saw a curtain of fog sliding sideways along the peak.
Looking to the left along the trail, and some menacing clouds beyond.

NZ Day 24: Tongariro Crossing!

Up at the crack of dawn with our backpacks and snacks! The weather was looking ominous but the shuttle driver claimed it would clear up and get warmer later in the day, so we boarded the shuttle with a handful of other explorers.

When we unloaded at the base of the trail, we immediately met a park ranger. Her purpose was to quickly examine the people starting the hike, and stop the ones that looked like they weren’t prepared well enough, and sternly warn them to turn around and leave. She was not as optimistic about the weather as our shuttle driver had been, and her information was more up-to-date.

“With wind chill, the temperature up there will drop below freezing,” she said. “And the wind will be blowing all the time.”

A few people turned around. Plenty of other people hurried by, as if they were trying to sneak past the ranger without being noticed — as if they were sneaking past a bouncer to get into an exclusive club. I spotted a young couple dressed in shorts, the boy charging up the trail with selfish bravado carrying only a water bottle, and the girl trailing nervously behind him with a fanny pack. She threw a glance back at the ranger but clearly didn’t have the guts to stop her boyfriend from making them both miserable.

And they surely would be miserable. Hours later Kerry and I would pass by clusters of people hunched behind rocks, their exposed skin turned purple, trying to decide what to do now that they were miles from civilization and anything warm.

We didn’t want to interfere with the ranger’s work, so we chatted with her just long enough to get news about the weather. Then we stepped onto the causeway and began the hike!

The causeway zigzagged to the east over alpine tundra, across tiny slow-moving streams and clusters of fragile-looking succulents and grass.

What manner of plant is this??

Most of the rocks were rough and porous, and they quickly became boulders as we went along.

As the route got steeper, Kerry and I remembered all our conversations with the locals about roads and bicycling and hiking trails. We decided that New Zealanders were so used to going up and down hills that they eventually stopped noticing them, and only remembered that a given route involved climbing when it went straight up an actual mountain. A while back we asked one of them to describe the Tongariro Crossing and he actually used the words, “It’s flat all the way up.”

Flat all the way up. That’s some serious “ancient Greek philosopher” logic, there.

While pondering the terrain’s obvious non-flatness, we posed for a couple of dramatic photos with Mt Ngauruhoe – a.k.a. Mt Doom – in the background.

The trail continued towards the left-hand flank of the mountain, and soon the stairs began.

At first it was little sections of stairs, a dozen steps at a time, and then we reached a rest area with some pit toilets and beheld one extremely long staircase that went lurching up the shoulder of Mt Ngauruhoe towards an unseen plateau to the north. Small groups of people were standing around trying to reach consensus over whether to continue, or turn back. Other people were just hunkered down eating snacks.

It was interesting to see how people dealt with the extreme weather. By this point most of the people with inadequate gear had been filtered out. We spotted a trio of older ladies who looked like they were in their late 60’s, each carrying a heavy pack. They had thick clothing but it was too porous to block the intense wind, so they compensated by moving quickly. I was more the plodding, cautious type, and spent a lot of time standing aside so other people could pass by without breaking their pace. It was a constant reminder that I wasn’t nearly as in-shape as I imagined.

The trail split, offering a partial route up the side of Mt. Ngauruhoe for the especially brave, but Kerry and I skipped it. A while later we met up with a group who made the climb, and they expressed disappointment that the peak was drowned in mist when they reached the top.

We followed the trail straight ahead, across a wide, flat plateau. The wind was still bitterly cold. Ahead of us we could see a hillside scattered with the bright dots of people in hiking gear, zig-zagging up to the top of a ridge, then following the ridge to a peak way up on the left.

Here’s a line showing the route:

Once we got up on the ridge we took a few shots looking back:

We climbed, then rested for a while in the shelter of some boulders on the ridge. Anyone around us who wasn’t resting out of the wind was getting more tired instead of less, and we heard plenty of tense muttering around us as clusters of people tried to decide whether to turn back. It was safe to assume that almost every one of the hundreds of hikers around us was doing this hike for the first time – like us – and wasn’t completely sure how much rough terrain lay ahead. (In retrospect, we were about a third of the way along the crossing.)

The trail got narrower and more hazardous. Cables were attached to the rock wall in some places, and we used them gratefully.

When we followed the ridge all the way to the top, we could see the Emerald Lakes down the other side, to the north. The trail also split off to the west, and to the east we could look down into a steep crater — the remains of a huge volcanic explosion.

We were standing on the top of Mount Tongariro – or at least, the highest remaining peak of it, after the top was blasted off long ago. The Tongariro crossing is actually named after this mountain, and the volcanic complex surrounding it. Even the much taller Ngauruhoe (Mt Doom) behind us – is technically just a vent of the Tongariro complex.

Even before the view, the first thing we noticed was the wind. It was up to 40 miles per hour, and it blasted us continuously from the north. We had to be careful to lean in that direction no matter which way we were actually walking.

Whoooooooooooooooooooosssssh goes the wind!

In the distance we could see the shimmering, chilly surface of Blue Lake. What a view!

Some hikers were taking the more ambitious western trail, which continued along the top of the ridge and bent around to the south, eventually returning them to the brutal staircase and the shuttle station. We followed the majority, stomping and slipping our way down the loose rock towards the Emerald Lakes.

This descent was tricky. Kerry couldn’t go four steps without slipping, and some other people were slipping and falling constantly, dropping their butts and hands into the soil. It looked painful. I went down the way I would on the chalk hills near my childhood home: Turned sideways, planting my heels very heavily to dig in each step. I didn’t fall over but I got a huge pile of gravel in my shoes!

The lakes grew more enchanting as we approached them. Soon we could see their strange coloring and watch the mist percolating and oozing out from the hills around them.

We went right down to the shore, then sat around resting and drinking the water we brought with us. I gobbled a bunch of snacks from my backpack. Kerry discovered that there was exactly one boulder in the whole area large enough to provide cover to pee behind, and when she went around it she found wads of toilet paper everywhere. Eeeew.

A fellow hiker snapped this nice photo, just before we set out again:

Fortified by the rest, we made good time across the plateau to the north, and then climbed another hill to arrive at the edge of Blue Lake. It was gorgeous; the kind of rugged-looking primeval terrain that an artist might put on the cover of a fantasy novel to grab the reader’s eye.

We took the opportunity to make silly poses in front of it. Kerry’s fantasy novel is called “Space-Queen Of The Freezing Teapots.” Mine is called “I Can’t Believe How Silly Kerry Is.”

Kerry: "I'm a little teapot ... COLD and stout!"

Kerry was making a really ridiculous face just before she snapped this one!

I couldn’t help asking myself, why would this terrain be so inspiring? As I walked along I came up with a pretty good theory: It inspires dramatic tension because it’s exposed. Unlike a dense forest or the crowded streets of a city, this terrain is composed only of things that are gigantic – the lake, the ridge, the sky – and things that are tiny. Anything medium-sized that you construct in it, or send wandering through it, can only look fragile and insignificant by comparison. … Or it will be so far away that you won’t see it at all.

So either you’re lost, or you’re totally exposed and vulnerable. Quite a setting for drama! There isn’t even a single bush growing around the shore of the lake that you could hide behind. About the only way you could surprise someone would be to bury yourself in rocks and wait until they wander past you on the trail. (I bet some treacherous bandits in Mongolia have done just that!)

Eventually we passed around the side of a hill, losing sight of Blue Lake, and discovered one good hiding place:

… So we took another pee break and ate snacks there. The wind was not as bitterly cold as before, but still cold.

This is how we keep warm in 35mph winds!

Eventually we passed around to the north face of the Tongariro complex. From this point the trail only went downward. It felt like we were more than two thirds done with the crossing, but for the sheer distance we had to walk, it was closer to halfway.

We were treated to another lovely panorama, this one quite different from the last. We could see Lake Taupo in the far distance.

The track below looked easy enough to walk, and we thought we were right on schedule to make it to the shuttle stop at the end by 5:00pm. We didn’t reckon that most of the remaining path was hidden in the forest beyond.

We'll be walking every inch of that track to get down ... and then a bunch more that's hidden in the trees below.

Along the way we saw some more geothermal activity, and a sign sternly warning us to keep our distance.

After an eternity of foot-numbing descent, we arrived at the Ketetahi cabin, a structure that used to offer overnight stays and cooking equipment to hikers before it was damaged in the 2012 volcanic eruption.

In 2012 an explosion shot thousands of rocks high into the air, and one of them came down right through the roof of the cabin and smashed one of the bunk beds. Thankfully, it was not occupied at the time!

Now the cabin is only good for temporary shelter and bathroom breaks, while the forestry service decides what to do with it. The current proposition is fix up the cabin but seal off the damaged room – including a plastic plate over the hole – and turn it into an exhibit showing the power and unpredictability of the volcano.

We got a good look at the bas-relief map on the table and saw that yes, now we were more than 2/3 of the way. Sheesh!

We walked as fast as we could, very conscious of the time. The trail finally leveled out and the forest closed around us. Soon we passed this sign:

Okay; can anyone tell me what a lahar is? Ah. The USGS website has answered my question. It's an "Indonesian term that describes a hot or cold mixture of water and rock fragments flowing down the slopes of a volcano and (or) river valleys."

So what in the world is a “lahar”?

The USGS website has an answer: It’s an “Indonesian term that describes a hot or cold mixture of water and rock fragments flowing down the slopes of a volcano and (or) river valleys.”

Basically a flash-flood of cement that comes roaring down out of the mountains without warning and half-drowns, half-bulldozes everything in its way. Terrifying!

At this point we were almost jogging, trying to make the 5:00pm pickup. For the last half-hour we did jog, when our sore feet would allow us to. I still paused to snap a few pictures of the amazing foliage around us — I couldn’t help it!

Those leaves do not belong to the tree - they are actually yet another parasitic organism. New Zealand is crazy.

Whoah. I don't think I've ever seen such a huge specimen of this type of lichen anywhere before... ( )

The shuttle driver waited a few minutes after we arrived, since there was one more group behind us on the trail that hadn’t appeared yet. If we’d known that the driver would wait past pickup time, we wouldn’t have taxed ourselves so much on the last few miles. Oh well.

Back at the hotel we exploded our luggage and took the longest showers ever. Then we rode to the restaurant for a huge dinner:


The banners in a restaurant. We just did these! HAH!

We checked the weather for tomorrow, and the transportation out of National Park, and decided to do one last day of cross-country riding, all downhill to Taumurunui!