solar tracker

conntaxmanconntaxman Solar Expert Posts: 125 ✭✭✭✭✭
I was just wondering how much difference their would be. If i was going to use 4 - 70 watt panels and a pwm controller and 4 - 115AH battery to supply ,I forgot how many ah it was for all the computers. ha ha .But put in a AH, useage.
But now we changed , Still 4- 70 watt panels but now with a mppt controller, AND a solar tracker. There would have to be a BIG difference. I think the load is about 4 ah per hour,x 8 hr would be 32 am hours per day.


  • abrockcaabrockca Solar Expert Posts: 72 ✭✭✭✭
    Re: solar tracker

    I don't have the numbers, but trackers make a big difference. We have one set of panels on a fixed array, and another set on a tracker that moves on both axis. (i.e. it swivels from east to west but also can lie flat on its back). It gets sun earlier and later than the fixed array and will orient itself vertically to get the maximum sun. The fixed array only gets maximum sun at certain times of year, when its angle matches the sun. We did our best with the fixed to position it where we get the majority of the sun, but the sun's angle changes...

    So if you can get a tracker, it's worth it.

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: solar tracker

    How much difference a tracker makes depends on the particular install. In some cases it is the only way to get increased Watt hours due to panel space restrictions. Sometimes there is a need to start recharging as early as possible and maintain output for as long as possible. In these instances trackers make sense. For most installs, however, the cost of the tracker can provide extra panel instead, which is simpler to add and less potential for mechanical trouble. In other words trackers usually do not make economic sense even though they do improve the over-all efficiency of the system.

    The Macslab angle calculator includes a graph which shows the increase in solar output for adjusting panel angle through the year. One of the lines indicates the improvement to be had from two axis tracking. The increase is greatest in Summer, of course.

    Dave Sparks is an advocate of tracker and I respect his position. But in practical terms you usually get more over-all output from spending the money on additional panel, if possible. Every case is different.
  • XRingerXRinger Solar Expert Posts: 529 ✭✭✭
    Re: solar tracker

    "depends on the particular install" is exactly right..

    My tracker needs to be about 15 feet south to get out of the morning shade.
    It's almost 11:00AM and it's still partly in the shade.
    Whereas the fixed mount has got full sun (but at an off-angle).


    I just got me a new chain saw!! :grr Yeah, it's going to be less green around here.
  • abrockcaabrockca Solar Expert Posts: 72 ✭✭✭✭
    Re: solar tracker

    know what you mean... we keep eyeing some trees up the hill that block some of the early sun ... thinking maybe we'll just trim some of the lower branches rather than taking them down though....

    I love watching the tracker lie flat on its back on a cloudy day, still absorbing some sun!


    ps - looks like the tracker can move... can you edge it south?
  • XRingerXRinger Solar Expert Posts: 529 ✭✭✭
    Re: solar tracker

    I've got some limbs and some large to medium tree trunks to cut.
    Should end up with a load of firewood. (I don't use it much anymore).

    Being so far reclined means they catch more tree & bird debris.

    Sitting under tree limbs, both the arrays collect a large amount of tree gunk.
    I cleaned them this AM and some of that stuff was stuck like glue..
    One species of bird seems to be on a diet of white epoxy paint.
    Hitting it with a water hose stream does nothing at all. Needs a scrub brush!

    On the cloudy days (like yesterday), I'm finding those Canadian panels
    on the fixed mount, do a pretty good job. More power than expected.

    If I had the tracker out in the middle of the yard, it would work much better,
    until the fall, then the house would shade it. Too heavy to be moving around.
    It's possible, but not fun..

    If I had my choice, I would dump the tracker and have all my PV on the roofs.
    I think the only maintenance problem would be snow removal..
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