outdoorprowash
Member
A great idea, I assume you have long heavy gauge cables tying it all together. One battery with two charging systems. I don't see how doing that could be a problem, but I wonder if the current running into your vehicle charging system from hot water machine could cause a problem. You will figure it out. I can help with some testing procedures if you want to eliminate the possibilities. I worked for Autozone 4 years in the 90's and we got many parts returned which mgmt always blamed on the customer. Bad parts are a common occurrence with many parts suppliers. You could put a diode between the battery and vehicle alternator which will only let current travel in one direction. It would however, add to the many things that could go wrong later. Disconnect it from the hot water machine and take it to parts house for free testing. I do hope you put fuses in between those long cables for protection.