Roadtrek CS Adventrous 12v Dips

[Alan19067]

Hello. Was wondering if any Roadtrek CS Adventrous owners have experienced and hopefully solved a 12v power dip/drop. I have a 2016 CS Adventrous XL E-Trek. Over the last 2 years have replaced the solar controller, Lithium power modules and inverter (this van has on 3000w inverter).

I have been experiencing a significant dip in 12v voltage when running 12v appliances. At first I suspected the fridge (Dometic 12/110 DE0061). Now I don’t think it is the fridge after using one of the 12v outlets with a portable compressor fridge I am also seeing a voltage dip. Smaller voltage dip even occur when just using the fantastic roof fan or water pump. I have two lithium power modules (300ah each) on when this happens and this also happens when driving. The 12v dip does not happen with the inverter is on (110 power). For example, on 12v I see 13.3v then turn the fridge on. The fridge will run normally but then I hear the fridge compressor slowing and the voltage progressively drops to 12.4 then the compressor turns off and voltage returns to 13.3. During these events if I switch on the inverter voltage jumps immediately back to 13.3. Even the fantastic fan will pull 13.1 down from 13.3 (or n this example). I have checked fuses and some connections but most wires are obviously hidden. Appreciate any thoughts on this.