Ocean Spray did a long term study some years back. They could find no evidence to support the theory that cranberry juice aided in urinary tract health. This is why they do not promote their product as having such health benefits
I deal with goofy electrical problems all the time on the job. Old school basic mechanical logic is often the answer with basic tools. Start eliminating variables. Load test the battery, not just a voltage test. If you are 100% sure the battery is good move on to the next option. I would...