Tracker vs. MPPT controller

Trackers generally give you more sun hours. The reflective quality of the solar panels substrate make them not want to absorb photons that hit it at high angles. So on a fixed panel installation you generally set it angles in the middle of the pathway between the winter sun and the summer sun. That covers one angle of the panel The other angle is that fixed panels just don't start working until the sun reaches a fairly high in the sky attitude. So you generally calculate 5 sun hours for a fixed panel as they produce power from 10 am to 3pm. You can get 7 to 8 sun hours with a tracker and that increases your yeild significantly if it weren't for one gotcha. Cloudiness is more prone to occur in morning and evening as the sun is better able to "break" up clouds with solar power during the time periods a fixed panel produces power. So cloudiness of your area has a large affect on whether a tracker is a good investment.

MPPT's take advantage of a peculiarity of solar panels current flows. Solar panels have to be built with alot of excess voltage to be able to function in less than ideal circumstances. That excess voltage is is simply wasted or thrown away power once it's connected to a battery system. If you take a 100 watt panel and it gives 100 watts at 18 volts and you attach it to a battery system at 12.5 volts you get 12.5/18x100 watts or 69.4 watts.The losses aren't always this extreme but there are situations where they can be even more extreme like if your battery system gets run down to 11.2 volts and it takes FOREVER for your array to finally bring it up to a voltage that allows it to efficiently fill up the rest.

Use of a MPPT solar controller is always firstmost and foremost the best way to gain more power from a panel as well as the easiest. If you are space constrained or want to minimize the panels to keep trees etc then adding a tracker can give you a decent boost to your panels but that boost will be magnofied many more times by having a MPPT controller in the first place.