Common 12v Negative

Hi This is my first post on here so here go’s
I plan to use my AC200 Max both in my off grid home and in my Camper van (RV)
When in the RV I want to charge off the alternator circuit via VSR etc … That bit I am ok with.
My question is will it cause an issue using the AC max to feed my 12v lights, fridge etc as some of the circuits , lighting for instance uses the vehicle chassis as the 12v negative return. In other words the vehicle battery and the liesure battery currently use a common negative. If I use the AC max would having the negative of the 12v input and the negative of the 12v output connected together ie common chassis return cause any problems.

1 Like

@FannyCamper Welcome to the forum Dennis and Tina!!

What I have done in my camper is that I have installed a selector switch that allows me to run my 12v fuse panel directly from the 12v/30a dc output of the bluetti OR the campers’ “house” battery and/or on-board converter line. I dont think you would have any “issues” per say with your current setup as the bluetti has protections builtin that would prevent any backfeeding or something from happening, BUT personally I like to have everything isolated individually. Having a selector switch also will allow you to easily move your bluetti from your house to your RV with ease.

Thanks Mike
My intention is to use the AC max as the house battery but want to be able to charge from the vehicle 12v battery / alternator ( maybe via a Voltage Sesative Relay ie split charge relay ) but as I said this would involve using the vehicle chassis as a common negative thus in effect connnecting the AC max 12v input negative to the AC max 12v RV output negative.
The positives are totally seperate systems so no feedback issues just the question of will the AC max be OK with the 12v input & the 12v output negatives being connected together.

@FannyCamper Ahhh! I gotcha. Well I will let the experts over at @BLUETTI and @BLUETTI_CARE answer this one as I dont want to give any false information. Keep us posted on what they say and we all look forward to seeing some pics of your setup! Cheers!

Sorry for late reply.
The input and output are two separate circuits with different positive and negative terminals. Connecting the positive and negative terminals of the input and output is not allowed and will cause a short circuit.
A common ground may result in a short circuit of the sampling resistor and abnormal functionality.