2muchwhine2littlewine
New Member
I have built out a Ram Promaster van and have a house battery setup using a 200AH LiFePO4 PowerUrus battery, 12v fuse box for lights, fridge, fan, USB chargers, 2*200W rich solar panels in series, and a MPP solar inverter (1000w 12v 110vac MPP Solar off grid Inverter 40A MPPT solar charger 1012LV MS). I installed the battery, MPP solar inverter, fuse blocks and all my 12V appliances a few months ago with no issues. After connecting up my solar panels I now get a high pitch whine coming from the mpp solar inverter only when I am at driving at a certain speed. It starts pretty quietly around 40MPH gets louder and then reduces in volume until it goes away at ~48mph. If I drive at 45 it stays on loudly at a constant volume. Accelerating and decelerating, bumpy vs smooth road, windy verses calm, driving in the sun verses no sun has no effect on the noise. It has been like this for a few weeks now and I have checked all my connections are tight. I also have disabled the alarm beep on the unit though it still beeps when the sun turns it on and off and this noise sounds just like the alarm though the beeps though the beeps always start and stop and don't gradually fade in and out. Also, the unit still is charging my battery while this sound is going on and I don't have any USB device plugged into the coms port. Anyone have any ideas on what I could try to get rid of this noise?