Just got my home nema 14-50 setup last night. Plugged in with only about 10% battery left and got 40/40 amps very quickly. Just plugged in now with about 60% battery and I'm getting 229V 30/40amps. Haven't seen it go above 30 yet at all. Is this normal or is there an issue. Car is cold, has been parked outside for 4 hours. Thanks!