I am building a small (~200 mm high) rotating LED light assembly using approx 30 RGB LEDs. I would like to make it as portable as possible so would like to power it with something like a rechargeable 3.7 V Li-po battery, and use a boost converter to step up the voltage to 5 V.
As even a 2000 mAh Li-po battery will be drained within a few hours, I will build the circuit to allow the connection of a 5 V power supply. While powering the circuit, I would also like the power supply to recharge the battery - so everything stays working but the battery also recharges.
I have seen some threads which say to use two diodes on both the power supply and the battery supply voltage when you wish to have power options from both a battery and mains, but I couldn't find anything on recharging the battery when the DC power supply is connected. What other components do I require to achieve this? (e.g. battery charging PCB?)
As well as this, I am interested in anyone's thoughts on the best method of controlling power consumption of the LEDs with something like a 5 V dimmer switch, so the LEDs can be turned on with low brightness. Is a dimmer switch the best option here for controlling the power consumption and lengthening the battery life at times when this is required?