where to install ammeter in solar system

The placement of th ampmeter depends on what you want to know, and what kind of regulation you're using. On my small system, all I want to know is how much current is being produced by the panels, so I place the ampmeter in the positive lead coming from the panels (negative lead would also work). I also have a voltmeter across the battery to see if I'm maintaining the proper float voltage after full charge. In the case of my MPPT converter, I monitor the amperage from the panels, the amperage to the batteries, and the float voltage. I use two 250 watt panels in series that produce a total of 60 volts at full production (500 watts. As the current demand deminishes, the current from the panel goes down, and the voltage creeps up to about 80 volts. I preferred the higher voltage configuration to permit the use of #10 AWG wire without significant voltage drop from the panels. The current can go as high as 45 amps to the battery so I use #6 AWG on a short run from the converter to the battery.