A lithium cell shield/charger with a USB charger and a switch that allows high discharge Amp ?

[gotchock]

Hello !

I'm (noob) trying to build a power supply with the following characteristics, but i struggle to find what i want so i'm not sure i'm doing it the right way:

• 1 single 18650 lithium cell (needs to be very compact and light: hand held application for LED)
• 1 USB plug to recharge it with protection against overcharge: not requiring an external battery charger
• 1 switch to ON/OFF power drain (else the LED controller that can't be turned off will always drain the battery)
• Protection against over-discharge (safety)
• Ability to draw 5V @2.5-3A max (ideally), 3.7V @2.0-2.2A is working too but less ideal.

I found several solutions, but none of them is "all in one" which makes compacity/assembly a challenge and i have some questions:

Examples:

• Shield V3: great all in one solution (just need to put it into a heat-shrink sleeve to hide it), but:
  • the 5V output handles 2A max and can't be switched ON/OFF
  • the USB output can be switched ON/OFF but it seems it handles even less than 2A.
• Boost charging board with USB: nice and compact. I can put an additionnal switch but 2A is too low...
• Boost charging board without USB or Battery protection board: these seems exactly what i want, but i don't know:
  • How to connect the battery and a USB charging plug to this ?
  • If i want to add a switch and a USB charging plug but i don't want it lying around (that's why i like the shield V3, it's all assembled), how do you recommend to fix it ? I don't have any skill in 3D printing, and i can't find a case that would allow me to put that together

I understand i might be asking something impossible because i don't know how it's usually done. If you have any advice i'm all ears !

Thank you !

 

[rjenkinsgb]

This one looks to be a good fit to your requirements?

https://www.aliexpress.com/item/1005004995781158.html

Just add a suitably rated switch between the USB A connection and your lamp circuit.

 

[gotchock]

Wow you're absolutely right. I can't believe I looked for this for hours without finding it. There's really something to improve with Ali express search tool...

How would you recommend to assemble this and a switch with the battery in a compact and "pretty" way considering its going to be handheld...
I was thinking about heatshrink tube and hot glue, but doesn't sound like the nicest way...

Thank you again for the link!

 

[rjenkinsgb]

I'd not glue anything, it may run warm and need some airflow around it.

Other than that I don't know what to suggest as I'm not sure what form the device you want to make should be?

 

[gotchock]

Apologies, i have not given much details.
It's similar to a handheld festival totem:

• A stick made of plastic (2cm large, flat surface) with a handle at the bottom (like on a square profile cane)
• Art piece at the top of the pole including several LED strips
• I want to stick on the pole (as close as the handle as possible for gravity center reasons):
  • 1 lithium cell 18650 (only one for weight reasons).
  • the circuit we discussed above (1 switch and the boost/USB chargin board)
  • 1 LED controller (USB or not)

I can stick all of this to the pole (with epoxy glue or velcro), but it's not very nice to see the electronics exposed, and easy to damage (running cables between the components).
So far my ideas are:

1. Heat shrink tube with some holes for the USB plug and switch, attached with plastic straps or velcro (heat dissipation might be a concern you're right)
2. 3D printing case to contain everything (but i have no idea how to design it, and no 3D printer on hand)
3. Plastic tube and everything stuck in it with hot glue (heat dissipations issues + no maintenance possible)
4. This kind of thing and stick things in place inside (makes maintenance difficult if needed): the problem is that i'd rather avoid anything larger than 2.5cm, so i need to find a "long" case to put components in a line... https://www.aliexpress.com/item/1005002656654805.html?spm=a2g0o.productlist.main.1.27e64X2K4X2Kvv&algo_pvid=ee6c0f50-b3b8-424c-9921-91871cc0df83&algo_exp_id=ee6c0f50-b3b8-424c-9921-91871cc0df83-0&pdp_ext_f={"sku_id":"12000021581873513"}&pdp_npi=2@dis!THB!13.14!13.14!!!!!@0b0a558a16754156753711329d06a6!12000021581873513!sea&curPageLogUid=F0TeI4serIHt

 

[rjenkinsgb]

How about using a length of eg. 25mm plastic conduit or similar plastic waterpipe etc. for the device handle?
And that also doubling as it's battery & USB module housing?

You can get various fittings & endcaps etc. to suit it, so eg. possibly the USB socket could be in the endcap and a thin plastic strip attached to that and the battery, so the assembly could be threaded into the handle?

Or put the USB module with the charge socket where the light strip attaches & the battery etc. further down?

 

[gotchock]

Thank you for the advice, i will look into this !