I’ve gone round in circles for a while on this reading every post I can find but to no avail.
I have a 30a Orion non isolated connected to the positive input from the battery terminal of my vehicle battery. A 2015 Ford transit, which specifically has a customer connection point on the side of the drivers seat which delivers a fused power output. At the Orion the negative goes to a chassis earth and the positive output goes to my positive bus bar. From the bus bar is my multiplus, mppt, etc… the bus bar is connected to my 300ah lithium battery bank.
The issue I’m having is that the voltage at my vehicle battery (as shown by the Orion input voltage on the app) fluctuates depending on the load I put on my lithium bank. For example when my water heater turns on the vehicle battery voltage drops by about 0.2V, and if I use the inverter with approximately 80a load, it drops by 0.5-0.7V. When the lithium is charged my vehicle battery is sitting at 13.4+V which is surely doing it no good to be sat that high all the time. Also when my engine is running the input voltage shown on the app doesn’t increase or decrease. I can hear the alternator kick in (smart alternator) as the fan speed picks up in the cab.
I used to have an 18a isolated dc-dc until I upgraded to the 30a non isolated and I never noticed this issue with the 18a. I have a solid earth to the chassis and everything else in the system has worked perfectly for a few years now.
Effectively I’m left with no DC-DC charging capability and I think my vehicle battery is kept at too high of a voltage. I’m quite bamboozled by this one and if anyone has any pointers as to where to look I’d be massively appreciative.
