Dual batteries, or not?
I'm trying to figure out some things about the batteries in my '96 e350 7.3l powersrtoke ride bus conversion...there's a mouthful. For those who've delt with these vehicles: the manufacturar is Thor, the brand is Eldorado.
Due to a combination of bad circumstances, mental stress, and general incompetence, when my van wouldn't start and I couldn't jump it, I concluded my bats were underspec'd for cold weather, and rushed off to fix the problem with two new batteries; walmart everstart maxx's with 850CCA.
After more research, it looks like I have one to take back now. It seems my van has one regular looking battery -- BCI size 65 -- and one long, narrow battery -- BCI size 50. Both are only about two years old. It seem the smaller battery, which is on the front passenger side, is an auxillary battery. As far as I can tell, powestrokes should have two batteries with at least 750 CCA each; instead the main battery is 675 CCA, and the small battery only 600 CCA. For the larger battery I found the evertstart as a replacement, but for the smaller I can't find a higher CCA version. Initially I just thought the dissimilar batteries were a result of human error on the part of the previous owner; only later did I find I was incorrect. My questions are:
1. Can a powerstroke van be started with just one battery, or is the term 'auxillary battery' a bit of a misnomer in respect to whether or not it's used to help start the vehicle?
2. Can I get a BCI size 50 battery with more than 600 CCA, and if I can, do I need to?
3. There is a device between the two batteries that seems to be a simple heavy duty circuit breaker/relay. My guess is that this is for the wheelchair lift that came built in to the van, to keep it from overloading the battery if wheelchair lift stalls, jams, or overloads the system. As I am in the process of removing the lift anyway, I'm wondering if anyone who might have one of these vechiles can atest to whether I need this circuit breaker for any other purpose?