Bka

I updated the circuit in the meantime. Changed the resistors to the right ones I hope. The batteries connected to each other the same way as on my first post. That’s because of balance charging your right. Diode would be an easy solution. I guess voltage loss would be significant as 0.6v loss per diode. Here, if you swap one shorted to it’s pair above or below. After the fuse blown there is only one way to go which is the transistor. Correct me if I’m wrong. I rather go with the easy solution. Here, the ssr relay (U2) is always on according to the datasheet. When it gets + to the pin 6, connects SB to drain.

Hi Harry Thank you for your suggestion. I spent 48 hours on google learn about these components, and i came up with this please see below. Do you think it is a viable setup? I know it is full of errors, however if the principal works it can be refined. Circuit to prevent damage if batteries polarity swapped. Any of the fuses blown turns on the transistor then the LED and the same line switches the SSR that turns off MOSFET so that break the whole circuit. The diode placed above the MOSFET is for charging. Load: 21v Average 5A-15A, Peak 20A BOM Fuse SMT PTC - VDC 6V max, Hold 7A, Trip 14A, Max to trip 35A MOSFET Max 30V 50A Battery 3.7V 3A Thanks for reading.

Hi Harry. The batteries use the same circuit for charging and discharging. Thinking about something between the main pcb and the batteries that prevents short circuit in case of swapped polarity and cuts out the main feed to the pcb. This way both would be protected. I need this connection because of balance charging. Thank you

Hello guys. We are working on a project and looking for someone who can draw/make us a circuit for this particular scenario. I like to know if it's even possible, if so send me a quote please. If it is not, i like to hear your solution. Can you build a circuit with reverse polarity protection on each cel in Series parallel connection using 18650 cells (5S3P ) ? Thank you in advance.