I have a Fluke77 multimeter. Perhaps one of the easiest things to test. I'm going to run this test to see what my IOD is. I keep a trickle charger on my battery during the winter and in even in the summer if my car is not being driven. I went about 3 or 4 weeks with starting my car here recently, in warm weather, and the battery was nearly dead. I bought my trickle charger from Harbor Freight for $20. Not a bad investment. It will not recharge a battery that is completely dead, but it will be keep your battery charged when not driving for longer periods of time. The charger will stop charging when the battery is fully charged. Can't wait to until Pb batteries are replaced by Li+ batteries.