Even the most expensive one has the bare copper plate which gets discolored because of arcing. I provided these pics and videos because Davenn wanted to see the dismantled solenoid otherwise,
wasn't me
I am concerned about the winding of the solenoid which draws about 3A and get burned after sometime.
will only happen if the current is applied for too longer bursts
Therefore, I was looking for some solid state replacement of the solenoid relay.
I gave one good suggestion good for around 200 - 250 A .... It may or may not be enough depending on the load on the starter motor
as suggested throughout the thread, I think you are going to struggle to find FET's that can handle 150+ Amps
A starter motor from a normal 2 Litre petrol car draws between 60 and 200 Amps when turning over the engine when the oil is warm and thin.
Under winter conditions, this current can easily double when the oil is thick.
Diesel engines have a very high compression ratio e.g. 22:1 and require more powerful starter motors. On average they draw between 300 and 500 Amps for average sized car engines 2 to 3 litre while on truck engines the current could easily reach 1000 Amps at initial turn over.
The real problem you need to take into account is, initially there will be a very high current spike before it settles down to the average cranking current
I saw a test on a Hyundai 4 cyl car, around 2 litre, where the initial spike was around 200 Amps then it settled down to 100A as it continued to operate for 10 sec
So if your FET cannot handle that initial big spike, it will die every time
Dave