Orion 12/12 30 TR Smart low charge amps

I’m suffering what I think is a common issue with this unit. I’m only getting about 5-10 amps charging from my car with the engine shutdown detection set to 12.8v. If I lower it to 11v etc, I can manage to get 15-20a but I’ve found no way to get 30a out of it. In the past I’ve had no issues pulling 30a with a redarc charger.

Is there a solution to this?