You may have seen plenty of these simple lights all over the place (instructables/youtube), This is nothing different really but just sharing what I made. This project uses very few materials and is very simple to make.

My soldering and design skills are quite mediocre, I just began electronics as a hobby so bare with me.

I had a few old phone batteries lying around and they are still capable of holding about 65% charge so its good enough for this project, the lithium ion battery in this project can also be replaced by a suitable AA or AAA or even a 9V battery, you only need to change the resistors accordingly. If you were having my exact thoughts at this moment you would have realised that as voltage of the batteries reduces the brightness of the light also decreases gradually (like i mentioned earlier crappy design), I could probably add a constant current / constant voltage design later.

I used 10 ohm resistors as that is what i had, the led's that I have used are 5730 normal white which are rated at 3V and 150ma(max), the resistors in this design are not the most suitable for these LED but for my need it was not required to be on max current and also at max currents these led's last much shorter, so at max battery voltage of about 4.1V I get 110ma and at about 3.7V I still get about 70ma per LED which is half its brightness. Please calculate using

V - Vled = IR (Vled is the voltage to drop at LED which is 3V). If you require higher brightness you can reduce the resistor value.

Supplies

Components I used are :

3cm x 7cm perf board X 2
Old Lithium battery OR AA
5730 white LED
Spacers
10ohm resistors X 10
cable ties
2 pin PH connector
Self locking Switch X 2
silver coated copper wire
Glue

Step 1: Connections

Very basic connections here , connected alternate led's together as I wanted to limit the brightness depending on what am using it for.

My desk area is quite dim and the ceiling lights being behind me it's just so difficult to work on things like soldering so i wanted to hook this up to my bendable mobile phone holder stand so that I could position it exactly where needed. But I also use this as an emergency lamp in my house, gives decent output when all 10 led's turned on.

I've used self locking switches here so that it can be easily operated with one hand, each switch turns on/off set of 5 led's. On the bottom perf board I added a 2 pin PH connector to make it easy to charge my battery using an external TP4056 charging module which has a male PH connector (not shown in here)

As you noticed i left some space between the perf boards deliberately so as to facilitate adequate ventilation for the battery during charging and for the led's which generate a bit of heat.

As an improvement I will add a case and a constant current /constant voltage led driver .

This is my first Instructable , I hope you liked it . Suggestions / compliments and criticism is well appreciated.