Hey we have this 38 ford , stock 6V pos ground and we had 5 batteries fail in almost 2 years . We checked for voltage drains , none found and the car is started about once week or so and drives great but after a few months the battery just won't stay charged up. These are just normal parts store batteries , not an optima or anything . I believe everything on the car is working normal . Just a short lifespan on batteries . Any ideas from the guys still running 6V systems ?