Ultimate 18650 Power Bank with Infinitely Expandable Capacity

by Mrkplayer May 29, 2019
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I posted a make. Surprised that there isn't more. There are quite a bit of things that needs to be noted and corrected on the youtube video. I posted a long list of them along with timestamps in the comments under my name.

Many of the parts and components used were different than the recommended components. This was mostly on error but I had to make them work. Unfortunately, this meant that I had to redesign many of the existing files. Thankfully all the cad files were provided and easily modified with Fusion 360.

I got a 10 watt fast wireless charger instead of the recommended 5 watt. This will charge wireless devices twice as fast but it was larger than the recommended. The charger actually needs 9 volts instead of 5 volts to use it's full potential. I used a mini step down to drop the voltage from the battery down to 9 volts and soldered the power cables to the wireless charger. This way, I don't need to turn on the usb switch to turn on the wireless charger. I also got RGBW instead of RGB and the light switch was larger. These upgrades required the top compartment, and outer shell to require modification. The inset for the wireless charger circuitry had to be pushed more toward the center of the device and some of the dividers needed to be removed in the top compartment cover. The outer shell was changed too. I pushed the target circle for the charging back to it's new location, holes were relocated to match the new outputs of the lights and RGBW controller hole was changed to be more clean. I made a new switch cover and completely closed the hole that is usually on the top.

I had to modify the IO plate a decent amount. All the test had to be enlarged and they had to be put in a bit deeper. I also had to enlarge the hole and add some cutouts for my outlet plug as my plug had side tabs, which meant that I needed no glue. I also had to lower the led hole for the inverter my 4 mm. I literally printed about 11 or so IO face plates till it got it correct. The usb 3.0 charger I got was much smaller than the one recommended so I made a adaptor tray with a thermostat slot for the new circuitry to sit on. The CC/CV buck converter was also different and had no screw holes so I used some high power 3M double sticky tape to hold it down.

I had a spot welder so no copper strips were needed. I had some nickel strips which I used. Fortunately my inverter already had heatsinks.

I used some pretty good cells that tested out to be great on my iCharger 1010b+. On my first test, the capacity came out to be 17,226 mAh @ 11.1 Volts or 191.2086 Watt hours. Does it seem low? 191.21 Watt hours is about 52,000 mAh at 3.7 volts if I were to show the capacity like most scumbag sellers do.

I feel like a moron for not noticing that you included the IO plate file in non stl both here and Off of your google drive folder. Thanks for your great work. I am still awaiting the parts from China to USA but I 3d printed all the parts already. I had trouble with the IO Plate but noticed that you used .15 instead of .2. I spent hours editing the STL file as those are difficult. If I saw the file, it would have taken minutes. I had to cut some out of the plug port and lower the LED by 4 mm and fill in the hole.

Thanks again.

Thanks for sharing great work!!

Is there any reason not using ABS for all parts??

I printed everything out of ABS, except the flexible parts and the outer shell and it seems to make no difference.

Personally, I can get nicer prints with PLA so I decided to print the visible parts in PLA. ABS-Printing can be tricky if you don't have the right settings, a heated build-surface and a chamber around your printer because your parts can warp (which makes them often unprecise for such a tight assembly).
But if you can print ABS successfully witout warping, you can just go for it.

It ok to modify for me to use VRUZEND caps?

I think you would have to modify it yourself. Above and under the batteries you have very little room for modification (+- 2mm above/under). I think that you would need to enlarge the whole battery pack.

But if someone manages to modify the design, it would certainly be great for people who are worried about soldering batteries!

For those who want to start this project, check out my remix. It makes the process of ordering and building easier, as I'm adding as much information about it along the way as I build the powerbank.
I'm doing this because it is a project that I find very interesting, and because I struggled myself in the beginning to find all the needed informations.
Thank you Mrkplayer for sharing this with everybody!

I started putting this together tonight and immediately ran into issues. The battery "cap" did not sit flush with the top of the batteries once I slid the BMS in place. The only way I could get the top of the battery holder to sit flush with the batteries was if I cut the BMS holder tabs, and even then it is slightly larger than the battery pack itself dimensionally. I purchased the listed BMS and listed batteries, any idea what is going on or is this normal?

I had no issues fitting the BMS. Maybe they are selling a slightly larger one now. Mine is 56mm long and 45mm wide. I don't think that you need the holder tabs, as the BMS is held in place once you solder the copper strips. You can even cut a small groove in the XT60 connector holder, as there will be nothing there.
I remember seeing BMS boards that were slightly longer, but the end could be cut off in my opinion. If you send me a picture of yours I can check it out.

Thanks for your response, this is exactly what it was! The end of the board has a part that almost looks like it is meant to be broken off? Broke off easily with pliers and fit perfectly in front of the battery pack in the slots. Thank you!

Thanks for your response, this is exactly what it was! The end of the board has a part that almost looks like it is meant to be broken off? Broke off easily with pliers and fit perfectly in front of the battery pack in the slots. Thank you!

I placed an order for most of the parts last night, I am excited for the build but the youtube video is misleading. No way you're spending under $60 for the parts. Not only that, but many parts are missing from the youtube description that I had find myself. I'm about $130 in right now, after plastic and other misc items that I'm sure will come up the total will most likely be around $150. This is not including other things that I already have on hand like wire, solder, soldering iron, printer, electricity for the 70-100 hour print time, etcetc. I would just appreciate a bit more honesty. Great design nonetheless, thank you.

There are quite a few parts missing from the youtube description. I managed to find most on aliexpress or eBay, but I am a bit confused on which "Copper Strip" and "hinge" you used. Could you please provide a direct link to these?

If you can't find the hinge, I remixed the model and it includes a Pull Tab that can be printed in flexible material. I could not find a hinge myself, so this replaces it.

I got both of them at Home Depot. 0.5mm thick copper foil, the hinge measures 0.5x0.75in. You can also use 0.3mmx8mm nickel strips.

What are the numbers for besides the files? I thought maybe for the number of parts of that kind but then it wouldn't make sense to have two outer shells.

I don't know what they are supposed to mean, but I remixed the model with a reworked naming scheme that is much clearer. There is just one part that you have to print two times.

can you do a 2 part outer shell stl files? Most people cannot print this height.

I remixed the model with oriented parts and the outer shell cut. Go check it out

for people who have dual color printers, could you possibly include stls to print all the text parts without a color swap mid print?

Brilliant work Kennedy

Assembly file has a full of unresolved and wrongly pointed files in the tree. You should use Solidworks pack-and-go feature for sharing.

The post is now updated with Pack and go Zip file. There should be little to no error in the assembly now.

Super, I think very hard that I wil build this very soon. But just change the frontface to an Euro-plug ;)

Do you also have a solution to mount the 230V inverter ? How can I mount the EU plug instead of the US outlet plug ?

Sadly, due to size constraints, you might need us to eu adapter.

Where can I buy the parts to build this?

Go to the YouTube video description, all the part links and schematics are there.