Prolonging the life of an eSkateboard battery pack

Small electric mobility devices usually use lower grade LiIo batteries and “passive balancing battery management systems” – if they use any balancing system whatsoever at all. So does my “premium” Evolve Hadean skateboard; it appears the BMS doesn’t do any balancing at all; read on and you will understand…

Those battery cells slowly have their charge level (state-of-charge, SoC) get out of sync because the charger charges all cells with the same amount of power until the first cell reports “full”. Likewise the whole system says “empty” when the first cell reports so. As a result, my board recently just shut off even though a second earlier it still said “30% battery left”. Yes, 30% in all cells but one. Almost threw me off. Good thing for the blog that the remote shows the SoC of all cells – combines 12 pictures of a multimeter reading into one frame. Here’s what mine looked like after fully charging it:

The charger correctly stopped when the first (and other) cells were at 4.11V. But one really bad cell (#5) only got to 3.78V. Thats the culprit which earlier reported “empty” first… Before replacing this cell (yes, it’s actually 4 cells each, but that’s an irrelevant detail here) and maybe #9, I thought to give it a try and bring those cells back into sync; there’s usually not one really bad cell in 4 but just a small difference in capacity of consumer cells, accumulating the difference of SoC over many charges of the whole pack, so they might just need an occasional support to catch up with the rest. So off to opening the pack, soldering wires to the culprit (group of-) cell(s) and fully charging it while the others were charged earlier to 100% in the board:

On another side note I actually cycled the cell a couple of times to check capacity. All good there. I also tended to cell #9 before putting the pack back. After reassembly the result looked very promising (yes, #12 looks a bit, well, maybe I should’ve attended to it as well):

So I dared to take it out for some rides. Actually 4 full cycles of depleting it to about 10%, recharging to 100% and repeating. Without any surprise shutdowns. It now shows this at around 60% charge:

Concluding, I admit that I have no idea how long this “fix” will really fix things but knowing how a passive cell balancing BMS works I’m not too surprised that the occasional “manual cell balancing” does prolong cheapish packs for quite some time. Go Google “battery cell balancing” – it just slowly directs charging energy to cells that are not fully charged yet; simple enough, for a passive system. active systems also work on the discharge cycle where they draw more power from the cells that still hold more energy… Anyway, my manual intervention appears to emulate passive balancing; I’m ready to replace defective or if need-be all cells to higher quality ones but for now things seem fine.

Also, as an afterthought, the pack doesn’t need to be removed from the board (which puts mechanical strain on the tiny connectors). Down the road when #12 will give me grief I’ll get it in synch with the pack in the board – just 2 handfuls of bolts to be removed, wires soldered and made sure not to turn the board on while charging the cells.

As a disclaimer, please do understand what you’re doing with regards to LiIo batteries. Short-circuiting, charging with wrong parameters or mechanically impacting the pack can have disastrous results.

GAAARRRMIIINNN!!!

Garmin is essentially defining the GPX standard nowadays. Bear with me. Enter the Garmin Zumo XT:
The Zumo XT can accept routes – one kind of GPX files which allow the device to do routing, turn-by-turn navigation guidance and whatnot. Those GPX files containing routes can be sent to the device by just connecting a USB cable and copying them over or by Garmin’s own, neat system called ‘Garmin Explore”.

Now. The Garmin Zumo XT (and probably many other newer Garmin devices) can only cope with such files if they contain the “<extensions><trp:ShapingPoint></extensions>”-Extension (never mind, geek details there). If this magic extension is there, the Zumo XT happily digests the route. If it’s not there, your beautiful plan in the form of a route never gets accepted by the Zumo XT. So far, so what?

If you happen to use Garmin Explore – Garmin’s suggested way of transferring your routes to the Zumo XT, guess what. Garmin Explore doesn’t appear to like the above Extension and just strips it. Yeah, thank you for nothing; another excellent example of a company with multiple different departments, handling different products and not talking to each other…

Wind management on a Yamaha Tenere 700

For the taller ones amongst you, you may be in a situation where your helmet is right in the turbulence area that the Yamaha Tenere 700 creates with the stock wind shield. Great to keep your visor rain-free, not so great on longer rides though. Plenty (expensive) aftermarket remedies are out there but here’s a DIY option I picked up from a Youtube video (and modded slightly, skipping zip ties). It involves height-adjustable sliders which can be picked up for cheap from Taobao, Aliexpress and probably eBay/Amazon; this is one part where brand name really doesn’t matter; it’s a simple piece of elox’d alu…

Get an old visor. Remove the stock wind shield of the T7, push the visor quite hard against the wind shield mount and, with a sharpie, mark the position of 4 holes to drill plus lines where to cut the visor. Drill, cut (I used metal scissors) and sand the edges of the visor. Install the visor to check fit:

Visor installed temporarily to test fit.

Then install said sliders to height-adjust the OEM wind shield to comfort. Note the min. Height of the visor so that there’ll be an overlap to the wind shield even in the highest position:

Without the visor, a raised wind shield allows a lot of air to come in at the bottom, passing the instrument cluster and heading directly towards the rider.

With the visor installed there is still some wind coming in but it’s directed along the rear surface of the wind shield upwards, helping to move the turbulences even higher above the rider.

DIY SilNylon seam sealant

That SilNylon (and SilPoly) material is a lovely, lightweight and very waterproof material for tents, tarps and such. Perfect. Until you need to seal seams: normal sealant and tape doesn’t adhere to the silicone surface. That leaves you with buying expensive sealant that comes in tiny tubes or, of course, make your own for cheap:

Get a tube of transparent silicone from your hardware store. Yes, the stuff that seals gaps in your bathroom, kitchen or outdoors. Mix it with enough white spirit or better yet Toluene if you can get hold of that until you get a liquid consistency that can be easily brushed onto the seams. It’ll take a while to properly dilute the silicone without having any lumps left but you’ll get there; patience!

Brush it on and it should be dry to the touch after about 6 hours. To fully cure I’d allow some 24 hours. Store remains in an airtight container.

Taiwan – where people are very friendly and considerate

Taiwan – where drivers, on a daily level, beat each other up with baseball clubs over some minor road rage

Taiwan – where toilet paper is sold out for weeks everywhere after a 5% price hike was anmouncedk since people only consider themselves and stock up for years

Taiwan – where after a virus outbreak across the straight people stock up on masks and hand sanitizer for decades to come and no, you hence can’t buy them anywhere.

Taiwan – where people, when you tell them in a supermarket to please not touch every single item on the shelf when they are sick, respond with “so what, don’t buy it then!”

Friendly and considerate Taiwanese, yeah…

DIY 3-in-1 Poncho

When I recently wrote the Felled seams guide,I didn’t do so only for the fun of creating seams, obviously. I was rather in the progress of scouting the basics for a DIY 3-in-1 poncho. 3 as in poncho, tarp and shelter. Basically all you need to survive in wet conditions, conditions that are prevalent where I live…

I spent quite some time to incorporate extra features to make the system as flexible as possible. With those I believe can stand up against many if not most commercial offers out there. Here’s the highlights:

Poncho Mode

• Velcro-closures at neck line opens wide for maximum airflow in hot climates and closes completely, covering up to your chin for cold and stormy days
• Extra deep hood drops down to eye level or exposes your forehead to even “high” hairlines for light drizzles — adjustable by a velcro at the back
• 3D cut of hood avoids material sticking to your cheeks
• Velcro runs all the way down at sides of poncho for full enclosure during those days of horizontal rain.
• Inverted Velcro pieces at bottom corners allow both front and rear flap to be rolled up and fixed in any position for light drizzle or vertical rain days when maximum ventilation is demanded
• Opposing Velcro on right and left of front panel allow Poncho front to be wrapped around your body and closed for a very tight fit during stormy days.
• Same opposing Velcro on rear panel, allowing two layers of full wrap around your body for maximum heat retention
• Full felled seams throughout for maximum waterproofing. This seam is waterproof by itself, yet all seams are sealed at the interior. This makes seam tapes which tend to break with time obsolete. Just apply a new layer of seam sealant where necessary.
• Webbing strap at rear to attach a bicycle tail light – walking on a road in a thunderstorm at night, wearing a camouflage poncho might not be the safest of ideas without some sort of illumination.
• Optional: Snap fasteners at panels to fold panels up by a predetermined size
• Optional: Pocket at inside or outside of front panel

Tarp/Tent Mode

• 8 heavily reinforced grommets around perimeter to securely tie the sheet down
• Optional: 2 grommets on reinforcing webbing along center-line of sheet to build an A-frame shelter without poles
• Optional: 2nd drawstring closure around neckline for 100% sealing of the opening (Velcros around neckline make for a tight seal already)

Others

• Made intentionally from non-breathable Nylon ripstop — All “breathable” material has waterproofing which degrades over time; usually when you need it most. On the other hand, a poncho breathes due to its design, so I felt waterproofing requirements outweigh “breathing” fabrics. More field testing will tell shortly.
• Stuff sack consists of 2 compartments. Main compartment for poncho and 2nd, internal, compartment for ridge line, guy lines, stakes.

Want one? You can’t buy it, but you can download my dimensions and sew it yourself. If you build one and are not aware yet, you may also consider how to sew felled seams.

If you have questions, let me know! And in any case, ideas for improvements are highly appreciated, MK2 is already beginning to take shape in my head.

Felled seams for synthetic fabric aka ultralight backpacking ripstop

Very wet winter here, encouraging me to spend quality time with the sewing machine. Since it appears to rain in my subtropical vicinity for some 380 days a year, I decided to dig deeper into waterproof gear. Ponchos, tarps, tents, roll-top bags and the like. Which quickly leads to waterproof seams and the massive confusion there’s out there on the net about how a proper, waterproof, “felled seam” is supposed to be constructed. Most advice, out there, is not really a full felled seam and will leak given enough exposure to the elements.

So out testing it was, putting down the results mostly for my own old, fading memory. Here is how I construct waterproof seams that won’t need those ugly seam tapes that fall off after one short use. Those seams hold by themselves but running a liquid seam sealant on their inside from time to time never hurts, ey?

It’s weekend. It’s raining. So a new stove it is. Ultralight.

When it came to ultralight stoves, I was sold to (alcohol-burning) penny stoves for quite a while. Well, not going ultralight is always the preferred choice, but then… Recently I revisited the concept of an ultralight stove with integrated pot stand (mind the chill factor of the pot on the stove though!) and I think I’m finally sold! No fiddly pot stand. No penny that doesn’t seal well. No troublesome refill. Just “pour-n-boil” (TM?). So here it is:

 

the instructions on how to build a can stove with integrated pot stand.

Personal data protection – Asian style

LINE user here. LINE – the Japanese pendant to WhatsApp, KakaoTalk, WeChat or whatever you use to chat these days. On a related note, consider switching to Signal, Telegram or something similar; but read on: LINE is also the app of choice in Taiwan, so it’s an obvious choice if you live there.

Recently, on starting the app, it asked me to accept its new personal data protection terms. With this screen (notice the second bullet at the bottom):

Agreeing to LINE sharing my personal info for marketing purposes (to third parties, aka spammers)? Maybe not. Nope. They have at least my phone number and email address, probably some more personal data about me. Not happening… Fortunately, one can tap on the green check-mark and uncheck it. Easy, one thinks. But then, when you want to proceed:

Haha, thank you for offering to uncheck an item (all 3 are checked by default, btw). But going back to the first screen and actually reading the text, one finds a link that explains how to opt out of direct marketing. OK, choose that link and you are presented with this:

Easy, huh? This must be among the worst behavior regarding customer data privacy any large-scale Internet company has ever shown. My LINE account is deleted (which I could only perform after agreeing to their terms!).

Please go ahead and share this, IMHO a company having such standards should not have the right to stay in business…

A new hobby

A picture tells more than a thousand words. Well, make it 2 pictures… The old hobby we indulged in for years in the tropics. This time sans all the heavy and expensive gear. In exchange a bit of daily training to get more than 10 secs a run out of it: