I would like to power my Wemos d1 mini off of a 12v rail which is the main power line for a strip of led lights (Smd5050) . I read that it's wise to lower the voltage from 12v to 3,4v for example so the wemos' regulators don't have to dissipate as much heat and will therefore function for a longer period of time.
So the power consumption of the wemos is about 0,3 Amps at 3,3v. The lm2596 needs to step the voltage down from 12v to 3,3v. Does that mean I need to have a Lm2596 that is able to deal with (12-3,3=8, 7V so 8,7 *0,3=2,61 amps? Or am I calculating this in a wrong manner?
Does that mean I need to have a Lm2596 that is able to deal with (12-3,3=8, 7V so 8,7 *0,3=2,61 amps?
No, it has to supply 0.3 Amps.
8.7V x 0.3A = is 2.61 Watts. That would be the power/heat dissipation of a linear regulator.
But, the 2596 is a switching regulator which is much more efficient with energy stored in the inductor & capacitor, rather than being wasted as heat. And, you should be drawing less than 0.3A from the 12V power supply.
3.4volt is a bit on the low side for the 3.3volt regulator on the WeMos D1 mini.
Better to keep it between 3.5 and 5volt (~4volt is good) on the 5volt pin (pin1).
The D1 mini draws about 80mA on average (~300mA short peaks), and that would draw ~35mA from the 12volt supply if you use a buck converter. The 2596 is overkill. A much smaller one (higher efficiency) would do.
A 5volt cellphone charger with USB socket, and a micro-USB lead plugged into the WeMos, is a much easier/quicker solution.
Leo..
Wawa:
3.4volt is a bit on the low side for the 3.3volt regulator on the WeMos D1 mini.
Better to keep it between 3.5 and 5volt (~4volt is good) on the 5volt pin (pin1).
The D1 mini draws about 80mA on average (~300mA short peaks), and that would draw ~35mA from the 12volt supply if you use a buck converter. The 2596 is overkill. A much smaller one (higher efficiency) would do.
A 5volt cellphone charger with USB socket, and a micro-USB lead plugged into the WeMos, is a much easier/quicker solution.
Leo..
I'll set the voltage to around 4 volts then, will do.
I think I'm going to go for the lm2596 option for the wemos' power supply cause it is less of a hassle to fit them in since I already have a 12v+ line running which has unused amps that I can tap into. I've ordered a bunch of lm2596's from China so that is cheaper option for me.
