18650 LiOn batteries - Parallel Connection

Thread Starter

nikolakisant03

Joined Oct 21, 2012
11
Hi everyone, I am designing a PCB that is going to be powered up by 2 x 18650 LiOn Batteries connected in parallel. The batteries will be placed into a battery holder, so the user will be capable to take them off in order to charge them. I want to integrate a reverse polarity protection mechanism on the PCB to prevent any damage from reverse polarity (that will short out the batteries). I am thinking to place two n-channel MOSFETs on the positive side of each battery like the circuit below. What is your opinion? Do you have to suggest another solution?

 

Thread Starter

nikolakisant03

Joined Oct 21, 2012
11
Thank you for your answer. I think that the p channels Mosfets will conduct when the batteries are connected as shown in the circuit while in case of reverse polarity they wont conduct. Do I miss something? I am sorry but I am a beginnner in this field :rolleyes:
 

ericgibbs

Joined Jan 29, 2010
8,851
hi 03,
Redraw and post a circuit showing the connections with the correct MOSFET's and batteries.

Showing the possible current flow directions, in the normal state and the reversed error state of the batteries.
We can then go thru it.
E
 
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