New to the Forum. I have looked for a thread but couldn't find one.

My wife has had a 2003 MX5 for about 15 years. Bought it with 60,000km and it now has 90,000km. Excellent car but it eats batteries. The problem is that it obviously sometimes sits in the garage for longish [2-3 days] periods between runs and if any longer the battery will run flat. Even after a good long charging run [by me] and a [newish] battery showing about 14v, if we leave it for two weeks while on a trip, the battery will be flat. As a result I disconnect the positive terminal before and after each day she uses it, and that way I feel confident she won't get stranded. Also I have had to replace the battery twice in the last 3 years. Once with Mazda and once with Canadian Tire equivalent. But my biggest problem is this slow drain of the battery when sitting in the garage. Is there a process, other than the dealer for tracking down a ground current leak? Pulling fuses one by one and checking voltage drop over a couple of days?