I have a 2022 Coleman 400 utv. I have added a heater with a 3 speed fan. I notice that while running with nothing on, the battery voltage gets to about 13,7 volts when funning at speed. If I turn on the lights, the voltage drops to about 12.3,if I turn on the heater fan with the lights on, the battery light will come on. I have replaced the battery with a higher capacity one and have replaced the regulator/rectifier, both have made no difference. I have measured the ac voltage at 22 vac at idle across all 3 phases, so the stator is charging. I have never had any issues with not starting or running poorly due to low voltage. Just wondering if there is anything I can do to increase the voltage from the regulator or is this just a underachieving system?