This guide sets out how to choose and prepare a site for a mobile solar power trailer, from a quick walk-around to the questions about wind and ballast that deserve a proper answer. Always follow the manufacturer’s instructions for the specific model, which state the permitted wind speeds, the ground conditions and the stowing procedure.
Start with a walk-around survey
Before the trailer arrives, walk the site. Look at the ground, the surroundings, the sun path, access for the tow vehicle and the route for cables to the load. Check for overhead lines, underground services, drainage paths and hazards such as vehicle traffic.
Take photographs and note the compass bearing of the site. These simple records help the next team and speed up redeployment.
Ground conditions and levelling
The trailer needs a firm, level surface. Soft soil, wet clay and loose fill can allow stabiliser feet to sink, and slopes make levelling hard. Use load-spreading plates under stabilisers, and check the bearing capacity if the ground is uncertain.
After rain, recheck the levelling. A trailer that settles unevenly can twist the mast or the array and can create gaps between the ground and the stabilisers.
Wind loading: the critical risk
A solar array acts like a sail. Wind loads rise quickly with speed, and gusts matter more than averages. Trailers have a maximum operating wind speed and a maximum survival wind speed with the array stowed. These values are on the data sheet, and they determine whether the site is suitable.
Check local wind records or ask site staff about storms. Exposed sites, hill tops and open plains need extra care. In the storm season, plan to stow the array when forecasts warn of high winds.
Stowing procedure
Stowing means lowering or folding the array to its low-profile position. Practise it, so that crews can do it quickly. Make stowing part of the site procedure for storms and for moving, and put a laminated card on the trailer showing the steps.
If the stowing mechanism is manual, make sure two people can do it safely in strong wind. For motorised systems, test the backup procedure for loss of power.
Ballast and anchoring
Some trailers rely on their own weight and outriggers, while others add ballast, ground anchors or tie-downs. The correct method depends on the model and ground. Never improvise: use only the ballast and anchor types that the manufacturer specifies, and check that they are properly installed.
Anchors in soft ground need testing, and ballast blocks should be placed so that they do not create a trip hazard or block access.
Orientation, tilt and shading
In the northern hemisphere, arrays face south, and in the southern hemisphere, north. Even small shadows from trees, buildings or equipment can sharply cut output, especially on strings with series connections. Check shading at different times of day, including winter sun angles.
Our guide to solar trailer energy per day explains how site conditions change output, and how to estimate it before choosing a spot.
Cable routes, protection and electrical safety
Plan cable runs so that they are short, protected from vehicles and not in water paths. Use cable covers or conduits where people walk or drive. Check earthing, residual current protection and isolation points, and follow the electrical code for temporary installations.
Label all disconnects and keep them accessible. Use the commissioning steps in the solar trailer testing guide before connecting the load.
Security and public safety
Trailers carry valuable batteries and panels. Fence or place the unit where it can be seen, use wheel clamps or locks and consider tracking. Warn people with signs, particularly at construction sites and events where the public may be nearby.
Keep clear zones around the array for maintenance and for safe stowing.
A one-page siting checklist
Before arrival, confirm ground bearing and levelling, the manufacturer’s wind limits and stowing steps, the ballast or anchors required, the orientation and shading check, the cable route and protection, the security arrangement and the plan for relocation. Sign off each item and keep the sheet with the trailer.
A short checklist that is actually used beats a long manual that sits in the cab.
Seasonal and weather planning
Review the seasons at the site. Storm and monsoon seasons call for stowing procedures and possibly for relocating the unit. Dusty seasons call for more frequent cleaning, and winter low sun angles change shading patterns.
Assign a person to watch the forecast, with authority to order the array to be stowed. The decision should be quick and not require a committee.
Relocation notes for the next crew
At every site, leave a note for the next team: soil type, wind exposure, the best orientation, any shading from structures that will appear later and any problems with access. Keep the notes in the trailer’s logbook.
These small records make later deployments faster and avoid repeating mistakes.
Relocating and recording
When the job ends, stow the array, disconnect, clean and inspect the trailer before it moves. Record what worked and what did not at the site, so that the next deployment starts with better information.
Over time, these notes build a small library of lessons for different ground and weather conditions.
Who writes this
Choosing where to park a relocatable solar unit is a practical question for our hybrid power engineers. Drafted by the USP&E hybrid power team. USP&E is no broker. It carries EPC and O&M risk directly, citing 24+ years in the field, 25,000 MW contracted since 2002 and 150+ power projects in 45+ countries. See our hybrid power systems work for mining and industrial clients.
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Questions about solar trailer siting
How level does a solar trailer need to be?
Follow the manufacturer’s tolerance. Level the trailer on firm ground with load-spreading plates under stabilisers and recheck after rain.
What wind speed can a solar trailer survive?
It depends on the model. The data sheet gives an operating limit and a survival limit with the array stowed.
Do I need extra ballast?
Only if the manufacturer calls for it. Use the specified ballast or anchors for the ground conditions.
Why does shading matter so much?
A small shadow can cut the output of a whole string, so check shading through the day and the seasons.
Choosing a solar power solution for a site?
Send us the site type, load and location, and our engineers will help you decide whether a mobile solar trailer, a hybrid set or a different solution fits.
Send drawings, load data or questions via the project enquiry form; the switchboard is +27 10 822 2324 and the inbox is info@uspeglobal.com. Generators to pair with a trailer are listed in our diesel generator inventory.