I have a laptop that uses a 5V 3A wall charger.
I have spliced some of that power to run an ESP-01/3V single channel relay... I'm estimating that takes about 300mA away from the 3A.
I tested everything against a bench top power supply and it works within the design of the charger eg. pulls 2.58 Amps at 5V.
I'm just wondering... if you alter this power supply, can it have a negative impact on the laptop's side other than charging slowly.
I will also note that I have a linear regulator LD33V inline to drop the 5V to 3.3V for the ESP-01.
This whole thing is just a manual method to start/stop charging between 20-80% battery (some code is ran on the laptop and it tells the relay to turn on/off based on battery). That feature is not built into this laptop. I just didn't want to have two plugs to plug into a wall. I considered using the laptop's USB out however that requires adding some extra code to get more than 100mA from the USB.
After separating the power supplies, it is cooler than before. This is a fanless laptop so I'll feel better just using it as it was.
122F/106F (wall adapter/laptop base)
It's starting to rise over time though the temp, adapter now at 111 F so maybe it's just normal. Laptop is a little cooler but still in 100F range
Laptop's at 103F now so maybe it's the same regardless... just takes longer to charge.
The temps are the same... 40-50% battery charge, so it seems like that's jut how the laptop/charger is.
It was a mistake to use the GPIO2 for the high-side trigger on the relay since when the ESP-01 boots GPIO2 is held high.
I swapped it for RX pin then I had to figure out to set it to low on boot, otherwise it was a floating pin/causing problems. Now it seems stable, using shared power supply.