SG2100 as Solar Panel Tracker

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New Member
Aug 4, 2013
So Cal
I'm looking for a drive motor with limit switches to move a 30-50 watt Solar panel to track the sun 1 axis.

The control system I'm considering is the TinyTracker. It just needs to operate the drive motor through relays, and it handles the rest.

It does depend on mechanical limit switches to set the east position and prevent west over run.

Rather than go the linear actuator route, I thought something like a SG2100 would do the trick.

My problem is interfacing the motor control relays to the SG2100.

I know the SG2100 is controlled digitally through the coax, so I would have to bypass the control circuit and operate the motor directly while still maintaining the limit switch controls.

So I'm wondering...

What would be the easiest way to control the motor?

I noticed a circuit board on the back of the motor, so I'm assuming it's a brushless or stepping motor.
Can I bypass the large circuit board entirely and supply voltage and control to the motor board directly?
Are there some voltage regulation issues if I do?

I guess I could supply logic voltage through the coax and cut the circuit board traces to the on board relays and control the motor through external relays.

Anyway, you get the idea... am I on the right path here?

Any schematics or wiring diagrams available?


FaT Air

HOA Free Zone
Feb 27, 2010
97W 48N
Ya beat me to it.
?Just a note: don't think it would work with a stepping motor, but don't think the motor is one. Just 2 'motor' terminals = PM magnet electric. 3 or more= stepping. They may have a pulse output to keep track of the position. Investigating the board wiring should indicate this. But AFAIK, its a standard PM magnet motor.
I built, although slightly modified*, a redrock 2 LED tracker controller. Connected to a modded GI 2000 mover PS(from BITD). The BUD was spot on the sun all day. Instead of the LED's mounted 90 degrees to one another, I just put a vertical plate (shade) between the LED's.
Problem with a prime focus, as a 'generator', you need dual axis. Or manually adjust the elevations thru the seasons. So that was the end of that. BUD returned to satellite signal hunting. Flat plate array isn't so 'fussy'.


Senior Member
Pub Member / Supporter
Feb 27, 2010
Traverse City, Michigan
So I'm wondering...

What would be the easiest way to control the motor?


The easiest way without any soldering or building complex circuts would be to pick up any old FTA receiver that can output diseqc commands. Program in a "fake" satellite every few degrees, and set up a "every day" recording for those sat positions with the time schedule coming from your solar position chart for your area. You will be dead on in the Spring and Fall, and a few degrees off other times, but with a flat panel array shouldn't matter much.


SatelliteGuys Master
Lifetime Supporter
Sep 3, 2004
Roseville, CA
To add to Pixl's post... Add a second linear actuator in place of the threaded elevation adjustment and a motor controller to change the elevation setting for tracking the seasons.


New Member
Aug 4, 2013
So Cal
Thank you guys for all the help.

Lots of different ways to accomplish this.

No matter which way I go, I'm convinced these motors are a great way to track up to a 100 watt panel.
Maybe larger, since solar panels can be easily counterbalanced.
Just wind load problems where I live, 90 mph gusts.

These motors have many attributes of a commercial tracking drive in a compact, neat, and inexpensive package.
Worm gear driven, so no coasting/drifting like a TV antenna rotor (not to mention the hassle of an ac motor), slow enough so simple controls can keep up with tracking, built in limit switches, much simpler and cleaner than a linear tracker, just not as heavy duty.

Just so you know, I'm using this to run some solar powered attic ventilation fans I'm installing along with a re-roof.
I'm located in Southern California near the desert. With the relentless sun, I'm really trying to cool the attic by upgrading the ventilation, and using white shingles on the roof section that's not visible from the street.

This makes the solar tracking easier, since it's for the summer months. One axis will do just fine, but I need most of the flow later in the day during peak attic temps. Thus, the tracking to aim the panels all the way to dusk.

My other option is to just use a larger panel in a fixed position and charge two 6v deep cycle batteries.
This would help in cloudy weather, and enable running past dusk and drawing in the cooler night air we usually have here.

Anyway, I have a couple bids on Ebay for some used/damaged motors.
Once I get my hands on one I'll know more, but a permanent magnet motor would make this really simple.

The roof fans arrived in good working order, and the roofers start tomorrow morning.

I'll keep you posted after I get past the re-roof drama.

Again, thank you all for the quick replies and great ideas.


SatelliteGuys Pro
For that project --- I would add 3 or 4 solar panels, each pointed at a different quadrant or maybe one 230 Watt panel and a decent 12 V deep cycle battery. A 230 watt panel with a voltage cutoff switch set at about 40 % (11.9V) will charge up the battery and probably keep it running an hour after dusk, depending on the current draw of the fan. Some of those fans draw 1/2 amp. Being sold with a 30 watt panel, I would guess about 1 + amp. The costs and problems involved with trackers - plus the current draw (seeking) on the motors will negate most of the gains. Your elevation will not be anywhere near as important as azimuth.
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