Reverse polarity proptection with P MOSFET

[anso-engineer]

Hello, I checked some reverse polarity protection and looks like it isn't totally protect.
Current still goes (probably through the body diode)

Is this schematic can be reliable at all?

[madires]

Please try again with drain and source swapped.

[golden_labels]

Madires gave the solution. Supplementing that with some explanation: you used MOSFET as a switch. While in this circuit it acts as an approximation of an ideal one-way valve.

[anso-engineer]

It works 
Could you explain, how Q1(S) point got 11.94V?

[ledtester]

It works 
Could you explain, how Q1(S) point got 11.94V?

See this video at 2:09...

How to protect circuits from reversed voltage polarity! -- Afrotechmods
https://youtu.be/IrB-FPcv1Dc?t=2m9s

[madires]

The voltage drop of the MOSFET is R_DS_on * I_load when fully turned on. Your simulation software assumes an R_DS_on of about 90 mOhms (I&R datasheet: 117 mOhms).

[golden_labels]

Watch the video linked by ledtester from 00:00, not 02:09. It explains what is the purpose of the MOSFET.

In short: there is still a diode to control direction. But if the polarity is correct, the MOSFET provides an additional path in parallel. That path is still no 0 Ω, though.

[anso-engineer]

Observed the video and extra ressources.
Main my misunderstading was that this body diode acts as regular diode. So diode is foraward biased, and we simly get the voltage on the side with "Source" pin.
I have observed some schematic, and looks like PMOS ususally conneted as high switch, where mosfet diode is reverse biased. This is the reason why I got confused.