12V automotive relays are no match for a 150V DC, 150A load. The cheapest contactor that I found for those requirements on RS Online came to about 550 EUR...
And indeed a mistake can give you a nice explosion.
Of course an Arduino will have no problem controlling such a contactor, it's a simple 220V AC coil. That can be switched through a TRIAC or basic relay. There are Arduino boards with LoRa built in, that'd be a good starting point.