Hi Branch,
Yes, 4.2 hours average insolation means exactly that. This may mean for your location you may only get 1 hour in winter but 8 hours in summer. The point being that if you want to stay off the grid during winter you would have to size your panels accordingly. To give you an idea, I have a 1.6kw array which in winter only gave me around 2kwh/day but at this time of year I'm getting around 7kwh/day.
Also note that the ambient temperature has a large effect on panel efficiency. Basically the hotter it is, the less efficient the panels are. Expect to lose about 50 percent on a 100F day, but alternatively you will x percent more than the rated panel power when it's freezing.
I haven't had the chance to run a Tesla Solar Tracker V through its paces yet, so I don't have any data to share however my TSTIII starts charging batteries before sunrise and after sundown, obviously not full power but at a guess I would get at least an extra 10 percent out of the panels.
nte makes a good point about panel orientation to the sun, obviously the more direct sun you can get on the panels the more energy you will harvest. Ideally you would have a sun follower to tilt the panels but the cost and energy associated with doing that may be prohibitive or impractical.
I'm still working towards an off-grid system that would lean on the grid for a backup, but the cost vs. ROI is the main issue.
John K.
Yes, 4.2 hours average insolation means exactly that. This may mean for your location you may only get 1 hour in winter but 8 hours in summer. The point being that if you want to stay off the grid during winter you would have to size your panels accordingly. To give you an idea, I have a 1.6kw array which in winter only gave me around 2kwh/day but at this time of year I'm getting around 7kwh/day.
Also note that the ambient temperature has a large effect on panel efficiency. Basically the hotter it is, the less efficient the panels are. Expect to lose about 50 percent on a 100F day, but alternatively you will x percent more than the rated panel power when it's freezing.
I haven't had the chance to run a Tesla Solar Tracker V through its paces yet, so I don't have any data to share however my TSTIII starts charging batteries before sunrise and after sundown, obviously not full power but at a guess I would get at least an extra 10 percent out of the panels.
nte makes a good point about panel orientation to the sun, obviously the more direct sun you can get on the panels the more energy you will harvest. Ideally you would have a sun follower to tilt the panels but the cost and energy associated with doing that may be prohibitive or impractical.
I'm still working towards an off-grid system that would lean on the grid for a backup, but the cost vs. ROI is the main issue.
John K.
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