New for 2023! We now offer financing on our largest units via our partnership with First Citizen’s Bank of Portsmouth, NH. Call or email for more information and/or application form.

The Model ST 4000-60 TSW

Sun Tracking Portable Solar Power System…. Powerful, Portable, Fully Automatic and Affordable.

As of December 1st, 2019, we now offer Lithium Valley lithium-iron phosphate batteries as an option on our Models 5000, 6000, and all the ST Series.

Little Brother to our flagship ST 6000-100!

For those who don’t have the need or room for the ST-6000 and it’s capabilities. Features 1260 watts of built-in solar panels that can be raised and adjusted at the push of a button! This is currently the smaller of our ST Series, but shares many features of it’s larger relative, including an identical command-and-control system, which is made right here in Maine in our own electronics shop! All these larger units come standard with 240 volt AC output to run many deep-well pumps (or most anything else)!

Time-lapse video of the unit in action, from sunrise to sunset.


Sun Tracking Portable Solar Power System

Sun Tracking System Stowed for travel

Sun Tracking system control panel

Check it out!

Download the ST Series Diagnostic Manual here.

Download the latest firmware here.




Assembled Dimensions: 96” Long, including tongue, with the rear stabilizers retracted.


72“ Long, not including tongue 60” Wide by 55” High, with panels in transport position.

Assembled Weight: approx. 1,900 lbs.

Solar panels: 3, 480 watt panels; 1440 watts total capacity.


Battery Bank:

Standard: 10, 110 amp/hr 12 Volt Deep-cycle AGM batteries

Optional: 12, 50 amp/hr 24V Lithium-iron phosphate batteries1

Battery capacity: 600 amp/hrs @ 24 volts; 14,400 watt/hrs with the lithium batteries, 550 amp/hrs & 13,200 watt/hrs. with AGM batteries.

Inverter: 24 volt AIMS 4000 watt continuous duty rating, True sine-wave; 12,000 watts surge for 20 seconds to start tough loads

Inverter Output: 120/240 VAC, True sine-wave; +/- 5% THD max.

AC Charger: PowerMax 50 amp dedicated charger.

Solar charge controller: 60 amp MPPT; can handle up to 1440 watts of solar panels.

Mounted on a 4′ x 6′ trailer for full mobility.


Base price w/ AGM Batteries:


Base price w/ Lithium batteries1:


**Shipping by truck freight only; freight cost not included. Please email us at with your address for a shipping quote.

Due to the large size, and customizable nature, we do not stock these units. Please email us at for more information.



1Since LiFePO4 batteries can be safely drawn down more than 95% vs. 50% for lead/acid batteries, the lithium battery option almost doubles the usable power from the battery bank vs. the stock lead/acid AGM batteries. Combine that with the lithium batteries lifespan of 3000 to 5000 deep-discharge cycles vs. 300 to 500 for even the best lead-acid batteries, and the slight added cost for the lithium batteries makes a lot of sense.

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