Re: "I wonder about those load testers. Doing that once a week, seems like that would shorten life?"
The modern "Load Tester" does not pull any significant amount of current from a vehicles battery when it test it, and is insignificant to a battery.
The old carbon pile resistor loads do draw what ever CCA you select when they are used to test a battery.
But the new testers only place a light load on a battery and find out the change in voltage caused by the small current the tester causes to flow by the load it applies to the battery, and then knowing the voltage drop and the current, it calculates the internal resistance, and from that it calculates the load the battery can handle that will cause its output voltage to drop to where it is at maximum CCA. In other words it figures out the slope of the fall off of voltage of the battery and determines from that the CCA.
Bottom line, while I have not actually measured the amount of current that any of these testers place on the battery, it is not much, maybe less than an Amp, and certainly not more than a few Amps. The size of the wire for the test leads of these would have to be much thicker if it drew a lot of current. So testing with one of these modern ones does no more damage than placing the load of a car light bulb on the battery.
