Best options for rechargeable LED lighting

[billymac]

I am working on some rechargeable lights that can be controlled as a group.
The controlling part is not an issue but I am having some trouble deciding the best parts to use for charging and powering the LED

I have it working using the following (parts list below) but there are a few issues .

reg.png (37.39 KiB) Viewed 5822 times

(the PWM controller is basically just some MosFets)

The first issue is my design may be overly complicated.
Although the charging module is cheap, it is pretty big to fit in my project with all the other parts.
I was thinking of simply using one of the tiny modules from inside a Duracel phone charger (1 x 18650) but it might not be able to handle 2 X 18650
Looking at my diagram, there is a power switch to disconnect power to the ESP and the LED circuit but there would still be some current drain through the charge module.
I have already ruined some cells when they over-discharged.
I may need to have the ESP monitor the battery voltage and auto- shutoff somehow.
Ideas? maybe using MOSFET?
I could do it with a small relay but would draw more current.
I also thought of scrapping the charge module and power the ESP directly from the batts since the ESP has its own regulator.
I may still need the buck converter to ensure my 3W leds get 2.9 v
The red is 2.9 but the green and glue are a bit higher so I am not sure how I should get the proper voltage to each of the LEDs
DC Forward Voltage(VF):Red:2.2-2.8V, Green:3.2-3.6V, Blue:3.2-3.6V
What would be the standard way of doing that?
Could I maybe run them at 3.7v and put a diode in series with the red to drop the voltage a bit? (to 3v?)
Resistors would be a waste of power
Or could I just scrap the buck module and drive the leds from the battery directly (3.7v).
Normally that would not be an option but since I am using PWM to control the brightness, maybe if I limit the duty cycle a bit, it will be ok?
I realise during the on times, they would be getting more voltage than they were designed for but if I liimit the duty cycle to maybe 90% I will be OK?
I guess I could try it...

https://www.banggood.com/3W-RGB-Color-6 ... ds=myorder

Any tips appreciated

Parts used:

- Constant Current and Voltage Buck module from Banggood
https://www.banggood.com/LED-Driver-Ch ... 39196.html
Output voltage set to 4.2 V
- 2 X 18650 in parallel
- ESP8266 Node MCU Devkit flashed with ESPEasy latest dev version
-XL4005 Step Down (Buck) module from BangGood
https://www.banggood.com/3Pcs-5A-XL4005 ... 31856.html

Heres the possibly oversimplified ver 2.0 design:

reg2.png (24.33 KiB) Viewed 5820 times

[bobbybeans]

I like the idea but I don't really find it that practical
just with the esp alone on a 18650 without any other step up/down and resistors the battery won't last long. maybe a day or 2 max. then you add lights on top of that you battery is gone in a matter of hours
you could put the esp into deep sleep which would make the batteries last longer but then you'd have to wake it up every couple a sec or more to listen for commands you sent. and the charger and step up would make it inefficient. I would say if you continue with this. buy 18650 batteries with protection built in OR buy a standard protection circuit of ebay for cheap

[Domosapiens]

I have already ruined some cells when they over-discharged.
I may need to have the ESP monitor the battery voltage and auto- shutoff somehow.

You could take a look at LiFePO4 Batteries

https://nl.aliexpress.com/item/4pcs-145 ... Title=true

They have a discharge graph like this


Fits very well to the ESP power needs and comes close to your LED power needs,
but you will need a few in parallel

[billymac]

I'll check into those cells but I wonder if there are as many fakes as with 18650s
I see they are 3.5 v so I assume I would need to use 2 in series to increase v and then regulate it down to 3.5 otherwise the esp would only get 3,5 for a short time when freshly charged

[Domosapiens]

Voltage for ESP8266 must be within the range of 1.7-3.6V
I think the fun with LiFePO4 Batteries is that you can do without regulator.
No regulator - No loss!

[Ton_vN]

Perhaps a battery-shield as solution?
The capacity of this small setup probably is not sufficient to drive LEDs&PWM for an extended period, but only to overcome dips in the primary power supply.
If your really desire a battery power supply with 'muscles', then you might look in this direction.