Hi,
Sometime back, we had a very simple and wonderful LED product in the market. It was a small LED lamp which had a small Lithium battery in it. When the lamp was on, it would automatically switched between AC source and battery when the power went off (which happens very often in India).
This was an excellent product for the rural market due to power problems there. Unfortunately, the company stopped that product for some reason.
I am trying build something similar for some of my friends in the villages, but want to make it as simple as it could get. I decided to use a TP4056 based CC CV battery charger board.
A review of the TP4056 is here:
http://lygte-info.dk/review/Review Charger TP4056 UK.html
It seems to be fairly reliable and offer upto 850mA of current. I know this board is for battery charging, but the size and features made me decide on this one.
So on the board I have:
1. Input (5V from any USB charger)
2. Output (4.2v i think?)
3. Red LED indicating "charging"
4. Green LED indicating "charged" (almost)
5. Battery (external) connected to the output of the board
I could use input/output to power few 0.5W LEDs (eliminates use of heatsinks that are needed foe high power LEDs) depending on whether AC power is available or not.
Of what I could think of, i could use two methods:
1. Make a small transistor/mosfet based switch to switch between input/output for powering the LEDs based. I cant seem to find a simple circuit to achieve this. I land up using multiple discrete elements, which i am trying to avoid.
2. Possibly connect the LEDs directly to the output in parallel with the battery and let the 4056 board do the rest. Possibly use the voltage acros the RED/GREEN indicator LEDs to switch between input/output source?
If you gurus could help me build something relatively simplistic, some simple people will surely send some blessings in return
Regards,
Deepak
Sometime back, we had a very simple and wonderful LED product in the market. It was a small LED lamp which had a small Lithium battery in it. When the lamp was on, it would automatically switched between AC source and battery when the power went off (which happens very often in India).
This was an excellent product for the rural market due to power problems there. Unfortunately, the company stopped that product for some reason.
I am trying build something similar for some of my friends in the villages, but want to make it as simple as it could get. I decided to use a TP4056 based CC CV battery charger board.
A review of the TP4056 is here:
http://lygte-info.dk/review/Review Charger TP4056 UK.html
It seems to be fairly reliable and offer upto 850mA of current. I know this board is for battery charging, but the size and features made me decide on this one.
So on the board I have:
1. Input (5V from any USB charger)
2. Output (4.2v i think?)
3. Red LED indicating "charging"
4. Green LED indicating "charged" (almost)
5. Battery (external) connected to the output of the board
I could use input/output to power few 0.5W LEDs (eliminates use of heatsinks that are needed foe high power LEDs) depending on whether AC power is available or not.
Of what I could think of, i could use two methods:
1. Make a small transistor/mosfet based switch to switch between input/output for powering the LEDs based. I cant seem to find a simple circuit to achieve this. I land up using multiple discrete elements, which i am trying to avoid.
2. Possibly connect the LEDs directly to the output in parallel with the battery and let the 4056 board do the rest. Possibly use the voltage acros the RED/GREEN indicator LEDs to switch between input/output source?
If you gurus could help me build something relatively simplistic, some simple people will surely send some blessings in return
Regards,
Deepak