1. WHY TWO-X
Q: What the heck *is* Two-X?
A: Two-X is a set of three battery packs, which form a single massive battery array once they are connected together. They come pre-wired to install into a Onewheel skateboard and connect to it in place of its original battery. We provide a detailed installation video that can be followed step by step to put it in.
The battery cells used are unique to the Two-X system, and out-perform every other known brand of the same chemistry in key metrics critical to the Onewheel. They make full use of the board's built-in automatic cell balancing circuitry and charge using the stock charger, same as the original.
A Onewheel with a Two-X installed will exhibit a profoundly improved performance, for example: Noticeably greater torque, faster acceleration, unprecedented hill climbing ability, reduced tendency to nosedive, and at least 13-17 mile range.
Q: Who can benefit the most from buying a Two-X, considering everything available today?
A: Here are the most compatible customers of Two-X:
- Anyone who prioritizes nosedive prevention over all else. You can't beat the Two-X on this front.
- People who are considering replacing their out-of-warranty OW+ battery. This is a no-brainer.
- People with a OW+ who want better range for reasonable cost.
- People who upgraded to XR, but kept their Plus, and want to make it keep up with their XR for a friend to ride.
- People who found a deal on a used Plus with dead batteries. Wheel and deal yourself a dope ride for cheap.
- People who don't like the ride dynamics of the XR. This is common, it pushes back weird and isn't as natural feeling as the Plus. Two-X preserves your Plus' awesome Plus-like feel.
- Anyone with a OW or OW+ that wants it to stay relevant. Bring it back to life on steroids.
- Handy people looking to pimp their ride, and not afraid to hack their board.
That's who we expect would be most interested in the Two-X, and for whom it presents the most obvious immediate value.
Q: How does a Two-X upgraded Onewheel+ compare to a Onewheel XR?
A: the Two-X is gonna be less prone to nosediving than XR. Slightly less range than XR when new, but this should more than reverse as they age. Two-X should last much longer than XR before degrading and needing replacement.
XR has smaller protrusions underneath footpads but neither of them truly gets in the way during actual riding. Two-X won't explode when you fold it around an oncoming truck axle - don't try that with XR. (This actually happened to me)
XR includes the much-discussed world-class FM customer service, and Two-X includes support from Two-X's smart little dedicated team.
The Two-X is a significant upgrade for owners of the Plus or V1. Seriously, they all should get Two-Xs. People buying a new board, probably easier to get an XR, unless you are insisting on the absolute best in nosedive prevention.
Of course, you're gonna need to have a bit of skillz and attitude to put in a Two-X. Anyone can unwrap an XR.
Q: I prefer the ride feel of the Plus over the XR. Does Two-X make a Plus *feel* like an XR?
A: No. We totally know what you mean, and no, it does not.
Although a Two-X does rival an XR in most measurable ways, it still has the basic smooth reliable feel of a Plus.
Q: How does an original Onewheel compare to a Onewheel+ or XR when upgraded with Two-X?
A: An original OW with Two-X will have torque similar to an OW+. It rides with a lot more confidence and is less choppy.
Range-wise, the Two-X upgrade gives an original OW range similar to an XR.
The closet is no longer the right place to keep your old Onewheel. Bring it out and make it awesome again.
Q: Isn't there some kind of easy way to visualize all these comparisons?
Note for above graphic: The Nosedive Safety values only account for undervoltage-related nosedives (thus the footpad-nosedive improvements in the later models vs. the V1 are not reflected). Nosedive risk is integrated across entire discharge curve for each model.
2. STORE-RELATED, CUSTOMER RESOURCES
Q: What is the status of Two-X availability?
A: Some units are now in stock and will sell until they run out. Orders will ship within 3 days while stock remains. After they run out, we'll order more sets from the factory and that will take three weeks.
Q: How can I keep tabs on this progress once my order is placed?
A: We will regularly post updates on the status of in-progress production runs in our facebook forum. Anyone remotely interested in Two-X for any reason should join and follow our forum.
Q: I'm having issues with the paypal system not letting me pay. What should I do?
A: If the paypal system built in to the shopping cart is giving you problems, email us at firstname.lastname@example.org and we can manually create an order and invoice you manually through paypal. Or even, arrange another way to pay if that doesn't work.
Q: What about shipping costs? International orders?
A: We can ship directly to the US and most places internationally. For international orders, send us an email at email@example.com with your exact address, and we can quote the shipping details for you.
For domestic orders, the cart will add an amount for shipping which is fairly determined based on shipping rates for already-shipped orders. We're not trying to gouge you guys on shipping.
Q: Isn't the price kind of expensive?
A: Not compared to a Onewheel.
We are offering a quality product that really works, and with top-notch support - so the price you see is where we ended up. And of course, there are a buttload of batteries in the Two-X kit. It has two Onewheels worth of new batteries, that's the big chunk of money we can't do much about.
Q: Hey, last time I was in here the price was different. What gives?
A: As we sort through the orders and quotes in our manufacturing process, often the numbers turn out different than forecasted. This could mean our costs will change, and most of that change will carry forward to affect the price.
Obviously, the price listed is locked in at the time of purchase.
3. MECHANICAL DESIGN
Q: Will it be possible for me to remove the Two-X upgrade and go back to normal?
A: Yes. The Two-X was designed thoughtfully such that no original functional parts must be permanently modified. This means you can reverse the upgrade process to revert your board back to its stock configuration. If you ever want to for whatever reason.
Q: Why are the additional batteries located under the footpads?
A: Once we decided we wanted a physically larger battery, the question became, where would we put it? We considered the fender ... but decided against it, for two reasons:
Some feel the fender tames a little bit of the passionate rawness of the onewheel experience. A wall that censors the simple thrill of balancing on a rolling wheel. This is a little weird, but does kinda make sense. We should avoid requiring people to add a fender.
So we experimented with a few other ideas, including under the footpads.
We were very skeptical about putting them under the board, because, obviously, we didn't see them lasting 8 minutes under there unless they're built like a tank. We taped some batteries under the footpads for a test, and got to work researching how we would create steel armored housings that were light and cheap enough.
But the batteries *did* last 8 minutes. Before we knew it the 8 minutes had become 8 days. And then, 8 months. Not only did the batteries survive just fine with only a few scratches on them, but after all these months of riding this way, we noticed with the batteries down there the feel of the ride was improved (see next question).
In summary, if your first impression of our housing location is, "that thing wouldn't last 8 minutes under there", we totally understand, and recommend riding one around for 8 months.
I've met countless folks who are completely unwilling to concede this misconception, and I'm sure this means less sales for us. But we're not willing to go for an inferior location just for easier marketing.
Q: How will the additional weight affect my ride?
A: When adding weight to a vehicle, where's the best place to put it? The answer, is: low down.
Two-X, exclusively, will lower your board's center of gravity.
The stock onewheel's center of gravity is around a couple inches behind and slightly above the center of the wheel. Two-X ends up moving it less than an inch forward toward the center, and drops it such that it is beneath the axle center. Our understanding of weight in vehicles tells us this should improve the ride, stability, control, and indeed, the safety of the board.
The Two-X feels more stable and in-control to ride, and this is part of the reason why.
Q: Are the skid housings weather resistant? What if I ride thru a puddle?
A: Yes, they are sealed, so your puddle won't affect them. It is necessary every few months to inspect the seals, and maintain them. The more critical concern is to make sure never to get water into your battery box. The results from this are catastrophic. All Onewheelers, with Two-X or not, should check their battery box seal.
Go read the "Notes on Weatherproofing" section on the Installation page. You do *not* want any water to get into your battery box.
Never tempt your board's ability to withstand water. Wheel splash from riding on wet roads should be OK, but anything more than that, and ... Let's just say you might as well be shooting yourself in the foot.
Q: How does the Two-X handle curb drops, curb hops, and other such trickery?
A: First, let's talk about curb drops.
We have done the math and physics analysis of riding off a curb with a Two-X, and, it turns out with a normal tire diameter and pressure, for a square curb to miss the Two-X and hit the board tail behind it, you'd have to ride off it at over 19 mph. So, you'll probably land on your rear Two-X housing.
This is OK, the housing can take it, but it will wear out eventually if you do it repeatedly.
Curb-droppers are advised to adjust their technique, to drastically reduce the damage to the Two-X housings from curb dropping. As you approach the edge, jump slightly, just enough to take your weight off the board during the moment the Two-X hits the curb. Then it'll just have the weight of the board smacking it into the cement, which is *way* easier on it.
As for climbing curbs, you can use the Two-X housing as a step to get up there even easier. The normal way won't work as usual, but once you develop and practice a new technique, you'll be better off than before.
If you're into more destructive stuff like sliding the rails along curbs, or bombing down long flights of stairs, then Two-X is not for you I think.
See the later question about what to do about it if you trash your housings.
Q: OK, let's say I'm *not* trying to grind rails or do skateboard tricks. But I do ride hard, on and off road on all kinds of terrain. How will those Two-X housings, being physically under my board, affect my ride?
A: They won't. Their presence will not limit you in any way whatsoever.
I mean, you are gonna love all the new power and range, etc. But will it keep you from clearing things? Or get in your way? No.
While it is possible, during just the right turning maneuver, over just the right ground surface irregularity, for ground features to occasionally contact the Two-X housings, it doesn't make any difference to anything. You'd probably have to be really concentrating to even notice it.
Go nuts. The under-footpad housing location is only a problem in the imaginations of those who have not tried it.
The most likely way for someone to actually shatter a Two-X housing is to bail off at high speed, and have the bad luck to have their Two-X slam directly into a concrete curb at full speed. Avoid this.
Q: I managed to crack open, or otherwise trash my housings. What can I do?
A: Contact our support. We will swap your f'd up housings for new ones for a reasonable fee that's just enough to cover our time, cost of new housings, and shipping.
Q: Are the batteries in the Two-X safe?
A: The Two-X uses Lithium Iron Phosphate (LiFePO) batteries, same chemistry as those that came in the original.
LiFePO cells are unique among lithium batteries in that they will not spontaneously start on fire when punctured or smashed. And in case they do end up in a fire somehow, unlike other types of Lithium they won't tend to begin producing their own oxygen, making the fire near impossible to extinguish.
LiFePO is widely recognized as the safest Lithium chemistry for electric vehicles.
Q: My original battery doesn’t last like it did when it was new. Will the Two-X upgrade still perform as well?
A: Yes. The Two-X upgrade completely replaces the original pack with brand new batteries. It doesn't matter what condition the original pack is in. You can send your old battery pack to your grandmother for Christmas.
Q: What's so special about the Two-X cells in particular?
A: We scoured the world for LiFePO cell manufacturers and tested samples from dozens of factories. Compared to an original Onewheel cell, a Two-X cell has measurably improved voltage stability when subjected to the conditions known to increase chances of nosediving.
Combine this with the fact that in the Two-X pack you have two of them working together for every one you used to have, and the resulting voltage stability improvement is significant.
These cells also have measured about 4% higher charge capacity than the Onewheel cells, (just a tiny bit more). But considering there are twice as many of them, the total increase in your range with Two-X, compared to a new Onewheel, will be 2.08x. More than double.
So that's 2.08x more than a *new* Onewheel. If your battery is used and/or old then it will have degraded in performance, and your results will be proportionally even better. For example, when I replaced my 1-yr and 1000-mile old battery for Two-X, I measured the improvement to be 3.14 times better.
That's right, my range had gone up by exactly a factor of pi.
And sure enough, whereas before I could barely make it straight across town from one end of town to the other, now I can ride a whole complete circle around my town on one charge.
Way to go, math.
Q: How does Two-X improve battery calendar life?
A: The Two-X should provide a vastly improved service life compared any other onewheel yet. This isn't mentioned on our front page because it isn't easy to test this. But here's why we're certain it will last longer:
Q: How does Two-X compare to other aftermarket battery extension solutions?
A: Other systems use separately-charged packs which connect to the board's charger port and pose as the charger. You can carry the battery pack on your person with a wire strung up your leg, or alternately attach it to the fender. The external packs are intended to be charged separately with additional equipment.
These differ from Two-X, which fully integrates in place of your old battery, and thus it is more of an install-and forget solution. You don't have to have a fender covered with hardware, or risk smashing up your charging port against a curb. But it needs to be installed, and costs more.
The cool thing is, it's fine if you want to use them both. For example, you can install Two-X for better baseline range for everyday running around or commuting, and then plug in your CnR pack when you need even more range for those longer weekend journeys.
Basically, Two-X is more of a permanent, fully integrated upgrade, if you can afford it and can deal with installing it. But again, it's OK to go ahead and use both.
Q: Can I connect my original battery to my charging port and get even more range than Two-X alone?
A: Actually, yes. You will need to create a long EC3 Female (w/ Male pins) to XLR Female cable, and you're good to go. You'll also need a short EC3 (same configuration) to Male XLR adapter, so you can recharge the external battery later.
Try to connect the external battery when both are at similar charge levels. You can find out more details on this via the links in our Community page or ask about it in the forum.
Q: What other general battery advice can you give me?
A: The battery cells suffer degradation when they are stored with a full charge for extended periods. This is a minor effect but can add up significantly over time.
By being smart you can mitigate this effect by running it down to 80% or less before putting it away, whenever you know you’re not going to use it for a while. If you're using the board often, this is not worth worrying about.
Also, don't be in the habit of always plugging your board in to charge whenever you can. If there's a bunch of charge left, leave it unplugged instead. Remember every charge cycle slightly ages and degrades the battery cells. This was not plausible with the Plus due to its really short range, but with Two-X you won't need to always be charging.
Q: What is nosediving?
A: This refers to an unpleasant Onewheel phenomenon where a fast-moving board tilts forward suddenly such that the front bumper slams into the ground.
Nosedives can be the result of general user fails, but here we are going to focus on ones that are the result of the board losing power independent of the user and stalling without warning. As dangerous as that may sound, this is nonetheless a present design flaw known to affect all Onewheel models: the V1, Plus, and XR.
A Onewheel stall is is not a casual event like it would be with practically any other type of vehicle ... The front of the board violently slams into the ground and the rider is then thrown forward in accordance with the Law. The Law of Conservation of Momentum.
(As a matter of definition, when the board cuts power at very low speed, there are other explanations for this. You have to be going at least running-speed for a stall to count as a "nosedive".)
Inconveniently, nosedives tend to happen specifically when the board is being pushed the hardest, such as, when the rider is cruising along at top speed. They also happen more when the batteries are getting low or old and degraded.
As you can imagine, this sort of thing can lead to you eating sh!t. You can read all about people’s experiences with nosedives in the major online forums.
In our opinion, the tendency of the Onewheel to nosedive is its most heinous flaw. Our goal isn't to whine about it, we still regard the Onewheel as an amazing triumph of an invention. We just want to fix this issue and keep on riding :)
Q: What causes nosedives?
A: There are different types of nosedives. Most types occur very rarely to experienced riders, and so are less of a concern. Included in this category are nosedives resulting from:
- Open foot sensor
- Wiring or software failure
- Temperature extremes
Two-X doesn't attempt to help with these. But they're either too rare to care, or an experienced rider can learn how to avoid them.
Which brings me to the killer. There is another type of nosedive, which strikes without warning, even to many seasoned riders. This is the one the Onewheel community lives in fear of. It's unpredictable enough that data on it is scattered, contributing to its mystery. This is the one the Two-X endeavors to prevent. We started our effort to understand it by analyzing what information we did have ...
From our own experience, and from subjective accounts of other riders, we noticed some trends: Sudden unexplained nosedives are known to happen more often when the board has old or low batteries, and particularly when the rider is sustaining a very high speed, accelerating especially hard, or scaling a slope - but never when going downhill. Reports suggest they affect heavier riders more than light ones, and occur more frequently with lower tire pressure or in extreme temperatures.
We recognized these conditions as the same as those which make batteries struggle to maintain voltage. So ...
Here's where we dare to diagnose the cause of this most elusive and troublesome type of nosedive:
- Battery undervoltage
We followed up on this hunch by conducting experiments which confirmed this theory to our satisfaction. Then we engineered a way to help prevent it. Welcome to Two-X.
Q. How does Two-X help prevent nosedives?
A: Two-X replaces each original cell with two fresh, matched cells working together, each of which is better than the original. Thus, it has a lot more ability to dump out current.
Here are data logged by a Two-X customer, showing the current (in red) and voltage (in yellow) of their Two-X as they rode from full to dead:
This guy was riding super hard, as you can tell by the wild current spikes. But just look how stable the voltage stays. Well out of range of nosedive territory.
That's what we are offering here.
Q: Explain what testing you did exactly? And what are the limitations of the Two-X? Do you even know what you're talking about?
A: Our lab tests confirmed that we can drop the voltage through loading the motor, and the result appears to be a sudden cutoff below a specific threshold.
First, we friction-loaded a full-speed running onewheel, causing it to suddenly stall (would-be nosedive), while measuring its voltage. You shoulda seen this test setup, it was kinda hilarious.
Then, we watched the current draw while going on rides, pushing the board hard and measuring the max load that put on the battery. (Onewheeling while monitoring an oscilloscope? Fricken nerdy.)
Back in the lab, we took a stock battery within operational state of charge, and applied that measured max load, and saw the voltage drop below our measured nosedive threshold. We had electrically characterized the nosedive.
So, we made our Two-X prototype pack, put it in the same state of charge, and applied the same current, and saw the voltage drop much less, indeed, enough less that it remained above the nosedive threshold.
Keep in mind, just because we haven't been able to nosedive a Two-X doesn't mean it'd be impossible.. Higher-still loading (than we could produce in our nerdy tests) could do it, and many things add to the loading, including: Accelerating hard, going uphill, being heavy, rough terrain, low tire pressure, larger tire, air resistance, temperature extremes, or any mechanical friction (worn bearings/motor, etc.). You might be able to nosedive a Two-X by increasing any combination of these things by enough (especially when the batteries are low, or getting old).
The Two-X has over twice the current-sourcing capability of the original. It thus effortlessly exhibits unprecedented voltage stability even in demanding conditions. And it works. The only known Two-X nosedive was a customer who was pushing the board to the max while the tire was nearly flat.
But we're not daring you to try. The real goal is for everyone to not break ribs wrists and collarbones. And we're doing it! Please be intelligent about that stuff when you ride. We wish you all the safest riding.
Q: Please explain footpad-related nosedives?
A: This is not the jurisdiction of Two-X, but we are including it anyway for riders who may not yet be aware. Because our M.O. is to stop nosediving.
Foot-sensor nosediving is a very real thing that affects riders who haven't yet been through the process of learning how the foot sensors work. So, go through that process! It turns out, that's usually all it takes to effectively eliminate these nosedives for good.
So, what's the connection between footpads and nosediving?: Basically, the board needs to have a way of detecting when you have bailed, otherwise nothing would stop it from sailing away down the street when you jump off. So, the Plus has two pressure sensors, one on each side of the front foot pad. The V1 has only one sensor. The sensors are pretty damn flaky, actually, kinda unreliable, which is why the Plus has two of them, for redundancy. Try turning on your board, then just touch various spots on the front footpad and watch the headlight, you can get a feeling for where they work and where they don't.
While at speed, if ever the left and the right front foot pad sensors both stay un-triggered continuously for a half second, then the board decides that you bailed. And to avoid shooting off down the road by itself, it cuts power. If in fact you are still on the board, riding, but just have your foot or weight off the sensors somehow ... then you're gonna nosedive.
Conclusion: Pay attention when you place your feet when getting on your board. Back foot? Doesn't matter at all, you can do yoga with it for all I care. Front foot? Just make damn sure that front foot is planted centered sideways across both sensors.
6. COMPATIBILITY WITH OTHER PRODUCTS
Q: What about my bomb-ass hoosier tire? Will it interfere?
A: The housings have more clearance than the stock footpads, from the tire. By a little bit.
Q: Can the Two-X be installed on a Onewheel XR?
A: No, the Two-X is specifically for the original Onewheel or Onewheel+, and can not be made to work on an XR.
Q: Is it true the girl who coded this website and the inventor of the Two-X are totally falling in love?
A: > Maybe.
Aw, that is so cute! It is true you totally ran my onewheel into a disabled homeless crackhead last night ;).
Q: Will I be able to use other Onewheel add-ons along with the Two-X?
A: That depends on whether they interfere with each other. For example, you can use Flight Fins, because they attach up top in an area Two-X doesn't require, but you can't use Float Plates, because they attach underneath the footpads.
Basically, Two-X wants the area underneath the footpads, and probably is incompatible with other products which attach there. Products that attach to the outside of the rails are probably OK, just get a good look at the attachment points and the space used to judge whether there are interferences.
Products that use the charging port should be fine, the Two-X doesn't need that. Charge-N-Ride setups should work seamlessly with Two-X. Though you probably won't need to use it as often, just for seriously long trips.
Q: Will Two-X work with my extra macho Beast Rails?
A: The Two-X beta units were hit and miss, as to whether they might fit on Beast Rails. But any Two-X unit manufactured after September 2018 will definitely fit.
Q: Will my board fit in my stand, with Two-X installed?
A: Depends on the stand. Usually not though.
Fortunately, most stand designs can be easily modified to work perfectly with the Two-X. Search through the forum, this is a common subject of discussion in there.
Q: How do I charge the Two-X battery?
A: The Two-X battery integrates seamlessly with the Onewheel; continue to use it the same as you do now. Charge it with the same charger in the same port, etc. You get the idea.
The only difference will be, it will take about twice as long to charge ;) Unless you get a Charge-X cable, which allows you charge in the same time as the original board, using two stock chargers.
Q: How can I know if the battery is fully charged?
A:The LED on the stock charger should still work as normal.
Red light means it's fast-charging. Once it turns green your Two-X is full and you're good to go, or if you leave it then it'll balance the cells.
Q: Wait a minute, what the heck is a Charge-X cable?
A: You get two Onewheel chargers, splice them together with our special cable, and charge your board with twice the current as before. So now, even though you have twice the capacity to charge, you can do it in the same time as you used to.
Charge-X effectively doubles the charge rate per mile.
Even though Charge-X will work with an original Onewheel, it is not recommended to use it regularly, as this amount of current is enough to cause some degradation of the cells, and will decrease their life span.
With Two-X installed, each pair of cells splits that current evenly, so it's not a problem.
Charge-X is not released quite yet, we have a lot of testing to do first.
8. MOBILE APP
Q: Does the Two-X properly report its status in the app (temperature, odometer, voltage, cell voltages, range, gauge)?
A: Yes, yes, yes, yes*, sort of, and no :) Read on ...
Temperature: Is a determined value based on readings from sensors on the main pack as well as both satellite packs.
Odometer: Functions normally. Trip lengths will come out correct.
Voltage: Also correct.
Cell voltages: These are also accurate, though each of the readings now applies to two cells instead of one. * Except, FM took the cell voltage reporting out of their app, but some third-party apps will still show them tho).
Gauge: Unfortunately the stock fuel gauge doesn't seem to be able to adjust its concept of your battery capacity. Which means it can't adjust to a change in capacity like the Two-X brings.
When you charge up to full, the app will accurately show 100% remaining. But as you use it up, the percent will drop twice as fast as it should. So at some point it will hit bottom, or 1%, when you really have at least another 50% left. Beyond that it just stays there at 1%, being quite uninformative.
See question below about reading your voltage. Once you get good at this you can get by just fine.
Range: Similar issues to the gauge. The app thinks you have a much less gutsy battery than you have now. So it predicts you have half the remaining range than you really do. You simply will have to mentally multiply this number. What will you multiply it by? (Hint: Two-X)
Q: Will there be a Two-X app?
A: We are working with the developers of an existing third-party onewheel app to provide an option to accurately show the range with a Two-X installed.
In the meantime, remaining battery life may be estimated by monitoring the overall pack voltage as it discharges. The voltage number must be linearized to give an accurate percentage. More on this later.
Q: How can I use my battery voltage as a fuel gauge?
A: Get good at this, and you can know how much battery you have left even when the fuel gauge isn't accurate.
Become familiar with the following graph. Use the red line to estimate charge remaining based on your battery voltage.
The blue line is what the voltage really looks like during a ride. Not as clean.
But you can see that most of the curve is basically a straight shallow slope. Which means for a reading to be useful it has to be fairly accurate.
The battery voltage jumps around all over the place in response to how much current it is putting out. So to get a reading you can use it's good to minimize that effect. Try slowing to a constant 3MPH or so for 5 seconds before taking each reading.
Note the stark non-linearities at the very start and the last quarter of the scale. In particular, as the batteries approach dead, notice how the voltage drops at an ever-increasing rate. This makes it pretty easy to tell how close you are to the end by taking regular readings and noticing how fast it's dropping.
A rule of thumb is, once the level drops below 50V during a ride, then you're going to be on that final descent and it's time to think about where you're going to plug in. After some practice this method serves well to know your battery remaining.
Q: What's next for Two-X?
A: Once Two-X Upgrade Kit is fully launched, we will make the Charge-X cable available (see more info elsewhere in here).
And we have a handful more clever and awesome upgrades to bring you, if this goes well enough :)
Q: How do I take my Two-X upgraded Onewheel on a plane?
A: The rules on this are not super clear, so you should research this first. A bunch of people have had luck following this approach, somebody posted somewhere:
This guy removed the battery enclosure from the board. With Two-X you would remove the two skid housings which are connected to it, along with it. Then reassemble the board and check it without any batteries. Then he cleaned up everything and put it neatly into an appropriate-sized Lithium battery pouch available on Amazon. It's all going to depend on what the TSA agents think of it, so it should be clear this is a commercial product, packed in a safe, commercially sanctioned way. So the more logos the better, the less dirt the better. Then he packed the pouch in a suitcase with his other stuff and carried it on, and some tools to reassemble it of course.
Honestly, just as important is your appearance and how you carry yourself. Always be put together, clean, well-spoken and calm in the security area.
This is not without risk, just one method people have been successful with. There is always a risk the agent will deny you, so leave yourself enough time at the airport to arrange to store it, ship it to yourself, or have someone come pick it up. And let us know how it went.