What do you recommend? Trunk Battery, like to put a inline fuse. what size?

You can't really fuse the main line. The only thing you would protect is the big fat cable. Fuse/ breaker/ fuse link the main alternator output sized appropriate to the alternator. Fuse / breaker the rest of the loads coming off the main feeding whatever they feed, fans, pumps etc, and keep those fuses as close to the main line as possible, because in this case it's not really possible to fuse the main line.


The other strategy is suggested by guys like Crackedback, which is to use a rear mount Ford type relay / solenoid to "key" the starter, so that the main line is only hot during starting, then using a smaller feed for the other loads. This line could be small enough to protect. It's size is going to depend on vehicle electrical loads and the alternator output. That feed might vary all the way from no6 to no4.

That in part is why this problem can get so complicated.......there are simply lots of variables. Or as crackedback has been known to say, "more than one way to skin that cat."