Split charger 2 batteries

hi all. I’m fitting a split charger. The vehicle has 2 12v batteries, 1 for the engine and one for a disabled lift i have removed. they are wired together so i thought to use the live feed off the second battery which was going to the lift for the split relay. Does it matter that there’s 2 batteries? does that make it 24v? please any help appreciated

Hi Peter,
I am in a similar situation with my repurposed paratransport van: trying to unravel the riddle of the house battery. Does your house battery feed back to the engine or is it a “one way flow”?

hi nancy. I don’t know if it feeds back to the engine. I assume its the same as any other car battery system which is one way flow. I think the best route for me is to removethe second battery and do it as normal

what van do you have? mines a 2004 ford transit

I have a 2006 Ford E350 high top.

So much to learn, used be that this was my go-to site to begin to explain the batteries, https://cheaprvliving.com/kb/ . It’s changed & it’s not as simple to find the answers as it was but there are answers there. Lot’s of answers on the cheaprvliving youtube channel too.

I did a search on “hooking batteries in series vs parallel”… if you hook the two batteries “parallel”, (+ to +), you are keeping the same voltage and doubling the capacity.
If you hook them in “series”, (+ to -), you are doubling the voltage and keeping the same capacity of amp hours.