keybrickone

Keybrick One / Rechargeable battery pack for Powered Up

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Hello everyone,

first of all, I'd like to thank @Jim for giving his blessing for me to write about our new project / Kickstarter campaign.

So, when speaking about "us" I really mean Till and myself (Yannic) who spent the better part of the last 10 months working on Keybrick One.

It's a rechargeable battery pack for the Powered Up Hub 88009 we started working on as the battery waste (and fiddly replacement process for said batteries) really bothered us a lot.After a first round of prototypes which looked like that:

powaaabrick-2-1024x768.jpg

 

 

powaaabrick-first-case-1024x768.jpg

first-PCB-1024x768.jpg

powaabrick-v2.jpg

 

Over the course of a few months we evolved the design quite a bit for keybrick to become a replacement of the full lower shell of the Hub.

powaabrick-v1.2-rendering-1024x519.png

powaabrick-polyjet-3d-print-edited.jpg

first-rainbow-1.jpg


It's become quite good in our opinion with being both more powerful than using alkaline cells (like drift-mode more powerful :)) and having a way longer play time than when using rechargeables in the hub (actually comparable to alkalines).

keybrick-proto-full-1-1024x852.jpg

Now we're launching Keybrick as a Kickstarter project because we think its a great addition to what TLC did with the Powered Up series, which really lack that rechargeable option in our opinion.

The Campaign is here: Keybrick One on Kickstarter

We'd like to use this to open the discussion with everyone intereste in the Powered Up series and are really eager to see what questions you all will come up with.

All the best,
- Yannic

 

 

 

Edited by keybrickone
fixed link to kickstarter

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This is interesting to me for sure! What kind of performance are we talking? mAh and voltage? I would assume you are running a 2S pack to get ~7.4V average to avoid damage to the LEGO components. 

 

As a side note, you will need to hotlink your pics from places like Flickr, BrickSafe, or your own website because the space here is only for your avatar and signature. 

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Thanks for the info about hotlinking. Will edit my post accordingly!

The output voltage is selectable between ~6.3V (lower would make the hub think the batteries are depleted) and ~9.25V (which is an arbitrary upper limit we determined will not cause the hub to heat up too much under load, the motors are pretty happy with more).
The reason Keybrick generates a lot more torque is that we're using an regulated DC/DC (step up) converter in there which regulates the voltage to whatever was set for pretty much every load situation the hub will present (we have got a comfortable head room). This means the voltage isn't dropping under load as with the AAA cells.

The battery pack is a 1S2P pack with 1200mAh nominal. As these are designed to deliver very high current (specced at over 30A) they do deliver quite a bit more in our case, with our testing showing consistently arround 1400mAh when discharged at 5A constant current to the discharge end voltage of Keybrick (2.9V, again with a comfortable margin the the specified 2.5V that would be acceptable from the cell manufacturers side). We have three cells undergoing invervall cycle test since august now, with each cumulating over 50 cycles now showing little to no wear in terms of net capacity (nominally down 20mAh average, still well above the specced 1200mAh).

We did the DC/DC conversion to avoid having a voltage drop over the discharge curve as the regulator keeps that "invisible" to the hub. Step up was more practical for a multitude of reasons.

 

Just now, Roadmonkeytj said:

I'm intrigued ... 

About...? :classic:

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Yeah, we went into this adventure because we were really sick of buying new batteries (actually Till, I didn't have any Powered Up stuff back then). Plus they managed to make changing the cell really annoying IMO. The screws might be a good idea, but the clips of the base are away too weak, at least on my two hubs the contact springs always hold the battery carriage so tight that I have to take it out in a second step...

Any other performance figure of interest? Playtime is close to alkalines as I said. We have a loop test video in prep where we put the Keybrick up agains high quality (and thus expensive) alkalines as well as NiMH rechargeables and we got following results:

- Keybrick in normal mode: 2h34
- Alkalines: 3h:36 (with the last 40minutes being a crawl to death where Till's son would start complaining)
- NiMH: 2h02 (with no power from the start and the last 20minutes being the same annoying crawl to a stop...)

We tested this on a relatively small oval at equal start speeds. As Keybrick doesn't slow down the pure time based comparison is a bit against up, because the hub will use available power.

Running the same test using the "eco" mode (6.3V) we managed over 4h in the same test. Got no footage of that though.

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I know you have the replacement base but would you also consider offering the earlier style of just the replacement battery cell? I have been integrating Powered Up in to my MOCs by making the top portion of the hub lift off and never using the screws. This allows me to have the base built into the build and then have the top section lift off (with some parts attached) saving me having to rebuild my model to get to the battery. I know you have "solved" this by making the charging port accessible but then there is the issue of how to clear enough space in some very small locomotives to make the charging port accessible. I also cant bury the hub in the frame of a locomotive to save me some vertical space for details. 

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Just now, Q3671 said:

succes, i support Keybrick on Kickstarter .

Thank you for the trust and support :cry_happy:

Just now, supertruper1988 said:

I know you have the replacement base but would you also consider offering the earlier style of just the replacement battery cell? I have been integrating Powered Up in to my MOCs by making the top portion of the hub lift off and never using the screws. This allows me to have the base built into the build and then have the top section lift off (with some parts attached) saving me having to rebuild my model to get to the battery. I know you have "solved" this by making the charging port accessible but then there is the issue of how to clear enough space in some very small locomotives to make the charging port accessible. I also cant bury the hub in the frame of a locomotive to save me some vertical space for details. 

That design had some pretty big downsides concerning manufacturability, which was really one of the top priorities for the current version. But we actually may have a solution on hands that could fit your needs (it's on our laundry list of possible stretch goals / addons): we have some very low profile 90° flat flex cable USB connector options  such as this one:

FPV-Micro-USB-2-0-Type-A-90-degree-Adapt

 

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Clearly from the Hub design Lego had envisioned a rechargeable battery alternative for the PUP Hub that would replace the AAA stack. Given the fact that the LiPo PF batteries disappeared over night, I wouldn't be surprised if the official PUP version never comes to light.

So it is good to see someone else pursuing this avenue... and it looks like doing a better job in the process.

After reading the introduction I was echoing the following

19 hours ago, supertruper1988 said:

I have been integrating Powered Up in to my MOCs by making the top portion of the hub lift off and never using the screws. This allows me to have the base built into the build and then have the top section lift off (with some parts attached) saving me having to rebuild my model to get to the battery.

My first thought when seeing the announcement in this thread was, oh no, I would have to pull the battery out to charge it, and now I can't even leave the base in for structural support. I went with the lego PF LiPo because it was easy and convenient to build the battery into MOCs and leave a small opening to get  the power in. My biggest dislike of PUP is the fact that you have to leave so much space to pull the battery cover. That point was cleared up on the KS page though.

Your solution,

19 hours ago, keybrickone said:

we have some very low profile 90° flat flex cable USB connector options  such as this one:

seems like a "must do" to me. Probably as an optional add on that can be bought from your store when purchasing a Keybrick but in my mind it should be easily available. This could open up new options to simply thread the power cable out to the bottom of a MOC or some other convenient location to bring in power (though one still needs to access the power button on the battery).

 

Oh, one more thing, given the fact that shipping LiPo batteries has gotten more difficult, will this be able to ship internationally?

 

Anyway, looks like a great addition to PUP

 

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Hello everyone,

here is Till, the second creator of Keybrick.One 

I am so happy to see you being as excited as we are about the possibility of a rechargeable PUP.

Feel free to ask any questions, especially about possible placements in MOCs and daily use (my son is a very demanding tester)  I am happy to answer.

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Thank you for the kind word zephy1934 :sweet:

the flex cable is definitely on the list of things we *are* looking into, it's just difficult to find a reliable supplier for them. The three we tested up now had all their very own set of quirks...

Regarding the international shipping: it's generally not a problem to ship the batteries as long as they are built into equipment (which the cells technically are in Keybrick), it's just relatively expensive because we can't use classic international mail but are forced to express services. For the US we will probably resort to Fedex and/or UPS depending on the location. I've been shipping batteries etc. for the last three years so this isn't anything new for me (I'm running an hobby electronics shop [hhtronik] and am selling another consumer electronics device [called Luccia Light]).

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22 hours ago, keybrickone said:

the flex cable is definitely on the list of things we *are* looking into, it's just difficult to find a reliable supplier for them. The three we tested up now had all their very own set of quirks...

Ah, yes, and if a reliable source of cables cannot be found, what about short "normal plug" cables? I would imagine that leaving a 2x3 or 2x4 spot for a shorty cable would be feasible in many builds.

If the housing will be 3D printed into the foreseeable future, another idea would be future variants offering different locations of the plug. If I could pick only one spot for the charging plug it would be right where you put it (given the fact that the top is not an option). But I could see advantages to having the plug on the opposite side of the battery so that you can put that end one stud in from the end of a locomotive and just leave a small hole for the socket. Or having the plug in the bottom. Obviously this would not work if you are injection molding the housings.

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It would be possible to manufacture the ends ourselves, but I'd rather try sourcing something good "off the shelf".

 

Regarding the location of the USB port, the issue is not only having the variants in the case (3d printed or not) but the power/charger section of PCB would need to be redesigned too, as the USB port has to be physically close to it. A verstical mount option is pretty much impossible (if we want stay with a standard plug, because of the limited verdical space (3.2mm from pcb to case plus 1.1mm wall thickness, and the shortest vertical mount port I know of is about 4.9mm long). So that would stick out and make the mating surface unusable in that spot...

I guess we could resort to building the cables ourselves in the worst case 🙈

 

Thanks for the input 🙂

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What about the idea of having a (relatively short) cable extension of the current port? Perhaps you can put it in a 1x2 brick? That way a builder can embed the box anywhere in the train and either charge directly on the box (if the port is accessible from outside or if the box can be lifted out of the model) or plug in the extension, put the 1x2 brick somewhere in the outside wall of the train and use that to plug in the charger. Of course, then there will be the request to get that brick into as many colors as possible, but perhaps just printing it as black or LBG would be sufficient.

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11 minutes ago, Phil B said:

What about the idea of having a (relatively short) cable extension of the current port? Perhaps you can put it in a 1x2 brick? That way a builder can embed the box anywhere in the train and either charge directly on the box (if the port is accessible from outside or if the box can be lifted out of the model) or plug in the extension, put the 1x2 brick somewhere in the outside wall of the train and use that to plug in the charger. Of course, then there will be the request to get that brick into as many colors as possible, but perhaps just printing it as black or LBG would be sufficient.

That's something we can definitely investigate, great idea! The point with the flat flex usb cable was mainly about having a very small space taken up by the actual connector. The 90° connector in the picture above would actually just need a mere 1x3 studs. We could probably even build it a bit differently (in a custom design) to have it flush with the side of the hub...

I'll make a few drawings tomorrow of what should be possible 😉

Edited by keybrickone
typos

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52 minutes ago, keybrickone said:

That's something we can definitely investigate, great idea! The point with the flat flex usb cable was mainly about having a very small space taken up by the actual connector. The 90° connector in the picture above would actually just need a mere 1x3 studs. We could probably even build it a bit differently (in a custom design) to have it flush with the side of the hub...

I'll make a few drawings tomorrow of what should be possible 😉

If it helps, here is a crude illustration of how my proposal would look like. Imagine a port in the 1x2 brick ...

50405582907_7e6bb97e48_b.jpg

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Wireless charging would be amazing. Whether it could fit in the key brick or if a small charging Pad could plug into it.

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Great idea. Can you please provide some safety information?

I really do not want to burn down my layout. That is why I avoided battery modifications and custom lipo batteries until now.

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6 hours ago, Tomacco88 said:

Wireless charging would be amazing. Whether it could fit in the key brick or if a small charging Pad could plug into it.

 

3 hours ago, mattmarsden said:

I would be all over this if you could include wireless charging.

Wireless charging may be something we could look into indeed. It's a bit tricky to implement because of geometrical reasons at least if the charge pad should be placed beneath the train / "in" the rails. At least the rail spacing are a problem if one wanted to use off-the shelf standards as Qi (which requires ~55mm coil diameter to transmit a reasonable amount of energy). If something on the side or atop the train would be an acceptable solution then this might actually be both simple and reasonably cheap to implement.

3 hours ago, TuffTuffTuff said:

Great idea. Can you please provide some safety information?

I really do not want to burn down my layout. That is why I avoided battery modifications and custom lipo batteries until now.

What exactly are you interested in?

  • The cells are high quality pouch cells designed specifically for high-drain applications (its a 1S2P pack, and the cells are rated at 20C repeated discharge rate 30C peak, meanining the pack would sustain 1200mA * 20 = 24A discharge rate. We tested up to 14A - we don't have lab equipment that would allow us to do more and the cells were just fine after over 30 cycles of rapid discharge and charging at 1A. As they are not going to see more than 7.5A peak load inside Keybrick the battery is going to have a pretty relaxed life, which will be great for both safety and longevity)
  • We are using a switching mode charger IC which we set to 800mA constant current rate and 4.2V charge end voltage (which is below the specified normal charge rate of 1200mA for this pack and the manufacturer technically allows for up to 4.25V charge voltage)
  • The microcontroller in Keybrick continually monitors the output current and cell voltage. It starts indicating "empty" batteries at 3.1V (which is 30% state of charge) and cuts the output at 2.75V (which is 17% SoC).
  • Even if this cutout was to fail for some reason there is an in-built pack protection IC which will deal with error conditions such as short-circuit, over-current, over-charge, over-discharge.
  • The output is over-load protected by a PTC fuse (self resetting) which will cut output supply after a few seconds in case of serious overload (~2.2A for more than 15s) as when someone was to short the output terminals
  • The switch mode converters have built-in over temperature protection, but that should never come to action unless something shorts out internally (see PTC)
  • We tested the design a LOT. Even sustained continuous maximum load (1.6A@9V in boost mode) doesn't harm the electronics taking them at ~77°C in the enclosure with ambient at 30°C. And that's is a pretty unlikely scenario as the Hub will cut supply if it detects such load condition from the motor side. The maximum sustained load we were able to create was about 1.1A which was with two motors attached to the hub running short of their stalling point.

I think I said it all, but you're welcome to ask more details :)

Edited by keybrickone

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2 hours ago, keybrickone said:

If something on the side or atop the train would be an acceptable solution

Something on the side of a powered car or car that connects to the powered portion of the train by cabling which will "dock" next to a trackside emitter and receive power to charge the battery would be a real game-changer for Lego trains, I think. It's the logical evolution for trains, since it would eliminate the need to break stuff apart to get to the battery box and/or charging port, as well as potentially allowing a train with a battery-powered emitter to charge another train, then return to the stationary, mains-powered emitter to charge itself. Assuming that the car containing the emitter can be made to look like a guard's van, caboose, freight boxcar, or the rear "driving" car of a passenger locomotive, this would totally transform the way that people build and power Lego trains. Assuming that the rechargable unit has an expiry date of around 2-3 years from the first charge (similar to mobile phones), I can see this ultimately being adopted by most Lego train builders.

 

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1 hour ago, rday1982 said:

Something on the side of a powered car or car that connects to the powered portion of the train by cabling which will "dock" next to a trackside emitter and receive power to charge the battery would be a real game-changer for Lego trains, I think. It's the logical evolution for trains, since it would eliminate the need to break stuff apart to get to the battery box and/or charging port, as well as potentially allowing a train with a battery-powered emitter to charge another train, then return to the stationary, mains-powered emitter to charge itself. Assuming that the car containing the emitter can be made to look like a guard's van, caboose, freight boxcar, or the rear "driving" car of a passenger locomotive, this would totally transform the way that people build and power Lego trains. Assuming that the rechargable unit has an expiry date of around 2-3 years from the first charge (similar to mobile phones), I can see this ultimately being adopted by most Lego train builders.

 

I'll look into options. The main challenges will probably be getting the coil alignment approximately right, and the distance between the emitter and receiver sides as small as possible. I guess the hardest thing will be to get it to look pretty in the end 😅

 

 

48 minutes ago, zephyr1934 said:

At the price point for the base battery, wireless charging should be an add on rather than a stock option.

Yes. Plus making it usable for other 3rd party solutions would be the best solution for the community too.

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Can wireless charging cause issues for some types of implanted heart pace makers?   Any legal risks or liabilities to a LUG running public train show events that has wireless charging points on their layout?

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