I have seen a few questions on here as to how to do this.
Here is how I did it with a USB charger from an old BLU e cig kit.
First of all, the USB charger only outputs @ 100mA so this is not nearly enough to directly power the ecig as it takes over 1A or 1000mA.
So while charging, the battery needs to be disconnected from the load (in this case our atty).
There is an easy way to do this with just 1 part. A relay!
The relay you must use though is a 5v dc relay with a Normally Open side and a Normally Closed Side.
When the relay gets 5v across it's coil, the Normally open side closes, and the normally closed side opens.
So....re-read that if you didn't understand. The relay has a coil and two switches inside of it. One switch normally closed, one normally open.
So if you put your battery on the normally closed side and the 5v dc on the normally open side, and then use the 5v dc on the coil.....when 5v dc is present, the coil is energized which disconnects the battery and connects the 5v dc to your load.
Now you will put the battery charger directly from your 5v dc to the battery in parallel with the relay.
So now when 5v dc is present (needs to be 5v dc @ at least 1.5 amps) the charger turns on and charges the battery and turns the relay on with disconnects the battery from load.
The load is going to be your switch and atty.
Here is how I did it with a USB charger from an old BLU e cig kit.
First of all, the USB charger only outputs @ 100mA so this is not nearly enough to directly power the ecig as it takes over 1A or 1000mA.
So while charging, the battery needs to be disconnected from the load (in this case our atty).
There is an easy way to do this with just 1 part. A relay!
The relay you must use though is a 5v dc relay with a Normally Open side and a Normally Closed Side.
When the relay gets 5v across it's coil, the Normally open side closes, and the normally closed side opens.
So....re-read that if you didn't understand. The relay has a coil and two switches inside of it. One switch normally closed, one normally open.
So if you put your battery on the normally closed side and the 5v dc on the normally open side, and then use the 5v dc on the coil.....when 5v dc is present, the coil is energized which disconnects the battery and connects the 5v dc to your load.
Now you will put the battery charger directly from your 5v dc to the battery in parallel with the relay.
So now when 5v dc is present (needs to be 5v dc @ at least 1.5 amps) the charger turns on and charges the battery and turns the relay on with disconnects the battery from load.
The load is going to be your switch and atty.
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