Hi all
I have a camper van, at it has to batteries - one for the car itself, and one for axial stuff, such as light, fridge etc for the living area.
By design there is a relay that kicks in when there are enough RPMs to also charge the axial battery. To put it simple - when starting the car, the cars battery get charged immediately, the axial battery only when I start moving. It simple puts the batteries in parallel. The relay is on the + side. There is no way to move it to the - side.
For some reason this relay tends to fall out, and using better relays did not solve the problem. It happens app every 4 days.
My idea is to use an electronic switch, or kind of an SSD relay to charge the axial battery.
My idea is to use a N-channel MOSFET, it has a low resistance. I can use e.g. a 7660 IC to drive the MOSFET. Now the problem is the parasite diode, meaning power can go from axial to main battery, how can I avoid that? I could use a schottky diode to avoid that current.
What idea do people in here have?