I would like to buy 10 of the rechargeable power kits however $200 seems a little pricy for what’s just a few batteries motors and circuit boards. I noticed on Aliexpress you can find most of the makers supply kits but after about 30 min of searching I still could not find a rechargeable kit. Are there any cheaper alternatives to it?
Can you share a link to the Bambu version you’re doing the comparison to?
My bad, It’s this one: Rechargeable Power Kit | Bambu Lab USA Store
This looks like a convivence factor. One can obviously assemble kits from Amazon and get a much better price.
Here’s the charger board that I use for my Li-ion batteries. They come in other stiles as well. Their about $0.75 each when you buy them by the dozen on Amazon.
The batteries is where they get you. I wouldn’t trust too many vendors out there who are selling bulk Li-ion batteries, but these are readily available on Amazon and if you want more power, you can easily swap out a larger mAh.
https://www.amazon.com/s?k=500mah+lion+battery&i=electronics
Then there is the reduction motor which again is kind of pricing at $3-$5 each.
https://www.amazon.com/s?k=N20+Reduction+Gear+Motor+500rpm&i=electronics
All in all, you could assembly your own kit for a fraction of the price as you saw on Ali Express, TEMU and even I saw some on eBay but the prices weren’t any more competitive than on Amazon.
https://www.temu.com/search_result.html?search_key=N20%20Reduction%20Gear%20Motor%20500rpm
I did see this on Ali express which is likely a variant of what you saw. At $0.99 I guess one could really make a dent in the BOM costs but then one has to ask if its worth it. If you’re mass producing something then it’s a no brainer but the key there is that if you buy it anywhere, including Bambu, like all Chinese products, what are the odds of a sustainable supply chain?
https://www.aliexpress.us/w/wholesale-N20-Reduction-Gear-Motor-500rpm.html
1 Like
Thank you very much, these parts do look promising. Is there any charger board that uses the same output connector as the motor instead of USB-A? Or how do you connect the motor to the USB-A output? I will definitely purchase some of these parts, Thank you.
Hobbyking has great prices on all sorts of batteries. For future reference
2 Likes
are there makerworld models for their things
If you look at the purchase link
The model includes the STL and STEP files for the lipo, board and motor
1 Like
I am not aware of one specifically but it wouldn’t surprise me if somewhere in Ali Express land there was such a device. It should be noted that these USB charger boards are made from the same reference design and don’t really change that much. What one needs to be careful of is how they are jumpered and what resistors are soldered in place. This can as an example change whether the device is wired solely for USB or can accept some kind of Power Delivery(PD) input other than the standard USB 5VDC. These include 3.5, 9, 12 and 20 VDC.
If you have taken apart a power cell, you will find these boards inside, that’s when I discovered the Chinese secret sauce and started building my own 3D Printed powerbanks. Who needs MakerWorld when you have CAD? 
Here are the parts that I reverse engineered but in fairness, I bought mine off of eBay. https://www.aliexpress.us/item/3256802493043717.html
Click to zoom
It should be noted that there are plenty of YouTube videos that will walk you through the hidden features on these little charger boards. Since they all use the same chips, the work similarly. BigClive.com on YouTube really pulls the shroud of mystery off of many of these AliExpress products. I watch his channel all the time because he’s an electrical engineer that explains stuff for the rest of us non electrical engineers. He was the guy who inspired me that I could do this on my own and make a powerbank of any shape and size with my 3D printer and a little bit of CAD.
1 Like
This should probably be in Maker's Supply to keep things more organized
1 Like
As a Radio Control modeler, who uses an awful lot of Lithium Polymer batteries in all different sizes and capacities, I would offer a word of caution… LiPo batteries are a fire hazard. They can and do burst in to flames if mistreated (sometimes, even if not mistreated). The cylindrical cells (example: 18650) can explode. RC hobbyists who have been sloppy with their batteries have burned down their homes.
Putting together something like this is pretty easy and relatively straightforward. But there are still opportunities for mistakes. Someone who doesn’t have the electronics and battery background could easily make a mistake that leads to disaster.
So if you don’t know what you’re doing, and don’t know someone who does, I think you’re better off buying the kit even at its higher price. Think of the added cost as “fire insurance”.
Note: if you do want to do this, use a “Button Top” 18650 battery. This type has a built-in “Battery Management System” that will disconnect the internal battery if it is over-charged or over-discharged (the two most common causes of battery fires). The cylindrical cells are also stronger, the type that comes in a flat envelope can be damaged by bending/crushing/puncturing much more easily. And physically damaged cells are the next most common cause of a battery fire. 
3 Likes