new converter

Your new converter shouldn't usually generate any more heat than the old one. The amount of current you use is a product of your lifestyle. If you never pulled over 50 amps, with your old converter, you will probably never pull over 50 amps, with the new one, even if it has a higher rated output. The rating is maximum output. Just because your old unit was rated at 55 amps, doesn't mean that you ever pulled that. It's like a car rated at 300 hp. The amount of time actually spent at the 300 hp red line is infintesimal. So, a replacement engine rated at 325 hp would make very little difference under normal operating conditions.