Reverse battery protection - 2x Pmos in paralell - circuit check?

[Cvijo]

Hi all,

I just wanted to check if this circuit is OK for reverse battery protection.
My battery source can be 12V or 24V that's why that zener diode 16V is to protect the gate, and i used 2 mosfets in parallel because it will be high current (40+A) to i think that would be a good idea.

Thank you all for your suggestions and help.

[Peabody]

It looks good to me, but only for the battery discharging into the load.  If there's a charger in the circuit, things are more complicated since current can flow in the opposite direction.

[Cvijo]

It looks good to me, but only for the battery discharging into the load.  If there's a charger in the circuit, things are more complicated since current can flow in the opposite direction.

Thank you Peabody,

well, there will be a charger in the circuit, the alternator will charge the battery, and solar panels will charge too. Can you point me in some direction on what to search for on the web in that case or how to fix that?

[Peabody]

If there's a charger, then you have to protect both the load circuit and the charger circuit.  But the problem is that current can flow in either direction even when polarity is correct.  The solution is above my pay grade, but I seem to remember that this was all addressed in a thread here a while back.  I just can't find it.

One place to start would be this Great Scott video:



He ends up with a circuit that might work.  Or maybe someone else will remember that older thread, which I think had a number of different circuits proposed.  Edit:  It may have been this thread:

https://www.eevblog.com/forum/projects/how-do-i-add-reverse-battery-protection-to-a-battery-charger-with-common-ground/