Don's Blog

New bike needs new winter tires. And today they arrived. Dillinger 5 studded. 26 x 4.65. Rolling Resistance? Why, yes! But hopefully also slipping resistance.

Now why the tan-sidewall you ask? Blackwalls, whitewalls, those are you traditional walls. (side note: if you are now humming Wonderwall by Oasis, you are welcome). Well, its a case of beggars XOR choosers. You take what you get when you order half way through the season of Covid.

Am I excited to install winter tires again in the same season? No. Also, the new bike, the tires on it are *@#$ tight, I managed to break the bead but the tube seems to be bonded to the tire somehow and I can’t break it free of the tape. So, I’m going to declare defeat and see if the bike shop can finish the last bit.

As for the flame thrower anti-theft device, we are still working on that. Perhaps I will just hire a junkyard dog.

Here you go Wonderwall fans…

Yesterday I completed the power pack for the handle grips. Today I gave it a bit of a bench test. One of my assertions in the design was that I did not need the 12V buck converter, that the ~11V – ~15.5V output of the 4S battery post BMS was sufficiently close to the 12V Lead Acid + Alternator these were designed for (which would normally have a charging voltage of about 13.8V).

Lets see, let them run for half hour, whip out the FLIR. Hmm. 140C. That’s normal for your hands, right?

Now, the handlegrips have a 3-position switch (OFF/LOW/HIGH). I suspect that the High puts 2 coils in parallel, and Low puts them in series. But I’m not sure, it might be just 1 coil versus 2 coils.

The multi-meter suggests that HIGH is 5.9 Ohms, and LOW is 7.1 Ohms. Hmm. So its not as simple as that.

Unloaded, full charge, the output from my pack is 16.3V. Measured at the load (so post drop in wire) we see 16.0V on LO, and 15.9V on HIGH.

Doing a little math, on the LO (7.1Ohm) setting, we are drawing 36W. On the HI setting we are drawing 43W.

OK, so its more or less inline with what I was thinking. Once these are installed on steel handlebars there is a lot of heat sinking, that loss plus the colder outdoor plus the wind will probably drop these to 60C or so, and, with my gloves on, no burning. Or so I predict.

What do you think?

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Earlier I wrote about the 3rd gen heated handlegrips. I used a “12V” battery box which as 3S2P 18650-based. Sadly it turned out to not really have a BMS inside, and, well, the batteries died permanently. Undaunted I installed a backup set and… the bike was stolen. So, gen 4. Let’s go.

For gen 4 we are taking a bit of a different approach to the energy source. I’ve got a 7000mAH 4S LiPo pouch battery.. Its meant for some remote controlled vehicle. At full voltage it is 16.8V, at nominal it is 14.8. I am going to couple this with a proper 4S BMS with balance leads.

Now, I considered a 12V constant-current/constant-voltage output buckl converter on the output. This would provide the handle bar grips a 12V supply until the battery got near empty, then dropping to 11.2V. Instead, on observing the BMS has about 1 diode drop in normal use, so the output of the BMS is more like 15V at fullish charge, and 11-14V in normal operation. This is sufficiently close to the alternator output of the vehicle these handlegrips were designed for. They have no active electronics, just nichrome wire, so they’ll run warmer when the battery is full, and cooler as it gets close to empty. So I’ll drop the CC/CV buck converter.

This means the wiring is simple: 16.8V charge in to BMS. Battery to BMS. Output from BMS to handle grips.

OK, case time. The 12V battery box had quite a nice robust case, relatively weather proof, velcro-strap to bolt to the bike. I’m going to go with a 3D printed case.

OK, printed. On to the soldering. First we hookup the BMS, have to splice the balance leads, add a deans-t power connector. Boom, measuring @ P1/P2 we have 14.6V for 15.5V out of the battery, so we should be good enough. We’ll lose a bit of voltage in the wires and under load, i should be ok. No fires or shorts! (ps, you have to be super careful with these LiPo, this one can output over 800A (120C @ 7AH). I’ve put a 30A BMS on, the hand grips draw about 4A. In hindsight I should have put a polyfuse in here, let me go rummage for one.

I was considering a trigger to avoid leaving them on by accident and having cold hands on the way home. I might still add this. There is a USB plug on the display on the bike which is switched. I could use its 5V line to drive a mosfet to enable the power. To be continued there I guess.

Add a 12V (ish) lighted switch so we can turn it off easily plus know if its on (since the on/off switch of the handlegrips are inside the bear-paws).

Do a quick dry fit of the front-panel, looks good. Time to solder up the wires inside.

OK let’s buckle it up and test. Perfect. We have an output which varies from 11V to 15V, should be ok for the resistive load in these hand warmers. Gen 4 is ready to install!

After many years of trying to make the web a proprietary thing, and some modest success, Adobe Flash eventually gave up faced with an overwhelming set of security flaws, lack of accessibility, multi-platform woes, etc. It outlived the Java Applet Dancing Duke, and its main contribution was fancy loading bars on websites of the late 90’s.

It then entered a long zombie stage of life where you could stort of install it if you worked around a set of of challenges. Why you would? I dunno, maybe you had a geocities site cached?

Well, today is the last day of flash’s life. So sayeth the Adobe Flash Player EOL General Information Page. I don’t know why I bothered linking it, I know you have the URL memorised and have been checking it daily.

So, security experts cheer, people who care about the free and open web rejoice, nostalgia freaks shed a modest tear.

Download quick and fire up that last favourite game, for today is the last day of Flash.

OK, bike #1 was the folding bike. I liked that one a lot. So did the thief. RIP.

Bike #2 was purchased for $5 online, just to get to the office. It has been passed forward and is still in action.

Bike #3 was purchased to replace Bike #1. It was a Voltbike Yukon. I liked that one a lot too, as did the 2nd thief. Thief identified and warrant out for arrest. I’m not hopeful.

So, enter Bike #4. They are pretty scarce these days, Covid made everyone take up biking. But, I found one to my spec in Saskatoon, and, it arrived today. After some assembly, the photo above.

This is the Biktrix Ultra Beast. It has 2 batteries (each 48V @ 15AH), and a mid-drive M620 Ultra Max motor.

Now I’m awaiting some locking mechanisms….