Typical camp loads

A small exploration camp may have accommodation units with lighting and fans or air conditioning, a kitchen with refrigeration, an office with computers and satellite communications, a core shed with lighting and saws, and water pumps. Night loads are lower than daytime loads, but refrigeration and communications run continuously.

Estimate daily energy use in kilowatt-hours, not just peak power. Our guide to solar trailer energy per day shows how to build that estimate.

Core shed and laboratory

Core saws, lighting, dust extraction and small laboratory instruments add daytime load, sometimes in short, heavy bursts. Solar output is highest when this work happens, which suits solar well.

Sensitive instruments may need clean power from an inverter with good voltage regulation, or a small UPS.

Drill rig support

Most drill rigs carry their own diesel engines, so they are not usually powered from the camp system. However, drill sites may need power for lighting, pumps, compressors or monitoring equipment. A second, smaller solar trailer at the drill site can cover these loads and reduce idling of rig engines.

Plan drill site power separately from camp power, because drill sites move more often than camps.

Sizing panels and batteries

Panel capacity must cover daily energy use with margin for cloudy days and seasonal changes in sunlight. Battery capacity must carry the night load and some reserve. A trailer that is too small will run its batteries down and rely heavily on diesel; one that is too large adds cost and transport weight.

Use local solar data for the site and season. Exploration in tropical regions may face long rainy seasons with much lower output.

Diesel backup in a hybrid

Few camps run on solar alone. A diesel generator sized for peak loads and battery charging provides backup on cloudy days and covers high loads such as air conditioning in hot weather. The hybrid controller starts the generator only when batteries reach a set level.

This approach can cut generator running hours substantially, reducing fuel, maintenance and noise. Our comparison of solar and diesel mobile power explains the trade-offs.

Moving between targets

Solar trailers are designed to fold, secure and tow. When a camp moves, the trailer can be packed and relocated with the rest of the camp. Plan the move so panels are stowed carefully and batteries are protected from shocks and extreme temperatures in transit.

Check towing requirements and road conditions. Exploration access tracks can be rough, and trailers need suitable axles and tyres.

Wet and dry seasons

In regions with distinct seasons, solar output and camp loads can change significantly. Dry seasons may bring dust that reduces panel output, requiring regular cleaning. Wet seasons bring cloud and possibly flooding that limits access.

Adjust expectations for diesel use by season, and plan fuel deliveries accordingly.

Security and theft

Panels, batteries and cables are valuable. Camps should secure trailers with locks, fencing and lighting where possible. Remote monitoring of battery state and alarms helps detect tampering.

Mark equipment clearly and keep records of serial numbers to help recovery if theft occurs.

Fuel and logistics savings

Every litre of diesel not burned saves the cost of the fuel and the cost of moving it to site, which can be several times the fuel price for remote or fly-in camps. Fewer fuel deliveries also mean fewer vehicle movements, lower safety risk and less disturbance to the area.

Track fuel use before and after adding solar to measure the real saving.

Environmental and community benefits

Exploration companies increasingly report environmental performance to investors and regulators. Solar reduces emissions, noise and fuel spill risk at the camp. Quieter camps are also better neighbours to nearby communities and wildlife.

These benefits can support permitting and community relations as a project moves from exploration toward development.

Commissioning at a new camp

Each time a trailer arrives at a new camp, run a short commissioning routine. Orient and tilt the panels for the site latitude, check all cable connections after transport, confirm battery state of charge and temperature, and test the hybrid controller’s generator start and stop settings. Walk the camp with the site manager to confirm which loads are connected to the solar system and which stay on the generator.

Record the first week of energy production and generator hours. That baseline shows quickly whether the system is performing as expected at the new location, and whether loads need to be rearranged.

Scaling up as the project grows

If exploration succeeds and the project moves toward feasibility, power needs grow. Additional solar trailers can be added, or the experience can inform the design of a larger hybrid system for construction and operations. Our guide to off-grid solar trailers explains how systems can be combined.

Planning for growth early helps avoid replacing equipment that could have been expanded.

Typical loads along a pipeline

Cathodic protection rectifiers that protect buried steel from corrosion, remote terminal units and radios for SCADA, flow and pressure transmitters, gas detectors, valve actuators, lighting and cameras are the usual consumers. Most are small, a few hundred watts to a few kilowatts, but they run continuously.

Because the loads are small and steady, they suit solar with batteries well. The challenge is less the size of the load than the need for it never to stop, through cloudy spells and long nights.

Cathodic protection

Impressed current cathodic protection systems use a rectifier to drive a small DC current from anodes through the soil to the pipe. Where there is no grid, the rectifier needs an independent supply. A solar trailer can power the rectifier directly or through an inverter, depending on the equipment. Temporary protection during construction, before permanent power is available, is a common use.

Work with the corrosion engineer to confirm the rectifier’s power demand and any limits on supply interruptions, because protection must remain within its criteria.

SCADA, telemetry and metering

Remote terminal units, radios or satellite terminals and meters let operators watch and control the pipeline from a central room. Losing power at a remote valve site means losing visibility of that section. A solar trailer with enough battery autonomy keeps these systems online and can also report its own state of charge and alarms through the same link.

Plan for the extra power drawn by satellite terminals or heaters in cold weather, which can be larger than the instruments themselves.

Gas detection, valves and security

Gas detectors, actuated valves, lighting and cameras at compressor sites, metering stations and well pads add to the demand. Actuators draw high power for short periods, so the battery and inverter must handle those peaks. Cameras and lights add night-time load. Our article on solar trailers for security and surveillance covers that part in detail.

List each load with its operating pattern so the system is sized for real daily energy, not just peak power.

Keep the trailer out of the hazardous area

Oil and gas sites are divided into hazardous areas where flammable gas may be present. A standard solar trailer, with its inverter, charge controller and batteries, is not certified for use inside those zones. Place it outside the classified area and run cable to the loads, or use equipment specifically certified for the zone.

Ask the site’s area classification drawing and agree the trailer position with the operator’s safety team before arrival.

Sizing for continuous loads

Start from the daily energy, in kWh, that the loads use. Add losses in the inverter, cabling and battery, then size the panels for the worst month’s solar resource at the site. Our page on how many kWh a solar trailer delivers per day explains how to do this.

For constant loads, battery autonomy matters as much as panel size. Several days of autonomy protects against cloudy spells and dust storms that cut solar output.

Battery choice and temperature

Oilfields are often very hot or very cold. Battery life and capacity depend heavily on temperature. Lithium iron phosphate batteries are common on modern trailers; they need thermal management in extreme climates to stay within their limits. Our guide to solar trailer battery storage compares the options.

Shade the battery compartment, ventilate it in hot climates and provide heating where temperatures fall below the battery’s charging limit.

Dust, wind and security

Desert and plains oilfields bring dust that settles on panels and cuts output, and wind that loads the mast and panel frame. Plan regular cleaning, especially after dust storms, and follow the maker’s wind limits for raised panels. Lock the trailer, anchor it and monitor it, because remote unattended equipment can attract theft.

Choose trailers with ballast or ground anchors suited to the site’s wind exposure.

Hybrid backup

Where loads are critical and the solar resource is poor in some months, a small backup generator integrated with the trailer can start automatically when batteries run low. It runs only a few hours instead of continuously, cutting fuel use and visits.

Make sure the backup generator is also outside the hazardous area and meets the site’s rules for engines.

Moving with the work

During construction, testing and maintenance campaigns, power is needed at different points along the right of way. A trailer can be towed to the next location, set up quickly and left running. That mobility suits temporary cathodic protection, hydrotest monitoring and maintenance camps.

Plan moves alongside access permits and landowner agreements, and record each location for asset tracking.

List the security loads

Start with a list of every device the trailer will power: cameras, infrared illuminators, floodlights, a video recorder or edge storage, radio links, cellular or satellite modems, sensors, sirens and any access control equipment. Note each device’s average power, not just its peak rating, and how many hours per day it runs.

Cameras with built-in infrared often draw more at night than during the day. Floodlights switched by motion sensors use far less energy than lights left on all night. Small choices in equipment can halve the battery and solar capacity needed.

A 24-hour profile with a night peak

Most security loads run continuously, and lighting adds a night-time peak. That means a large share of daily energy is used when the solar panels produce nothing, so the battery must carry the whole night and the panels must recharge it the next day while also powering daytime loads.

Our page on daily solar trailer output explains how to estimate the energy a trailer produces at a given location, which is the other half of the calculation.

Battery autonomy for poor weather

Security systems cannot simply switch off on a cloudy day. Size the battery for several days of autonomy, so the system keeps running through a run of poor weather without recharging fully. The number of days depends on the climate and how critical the site is.

Battery chemistry, depth of discharge limits and temperature all affect usable capacity. Our article on solar trailer battery storage covers chemistry and sizing in more detail.

Seasonal sun and panel tilt

Solar output varies with season and latitude. Size the system for the worst month, not the annual average, or the cameras may go dark in winter. Panel tilt can be adjusted on many trailers to favour winter sun, at the cost of some summer output that the system does not need anyway.

Shading from buildings, trees or stockpiles reduces output sharply. Survey the location before placing the trailer and check how shadows move through the day and the year.

Communications options

Remote cameras need a way to send images or alarms to a control room. Cellular modems are simplest where coverage exists. Point-to-point radio links work well on large sites with line of sight. Satellite terminals reach anywhere but draw more power and need careful bandwidth management.

Include the communications equipment in the load list, and remember that some modems and radios draw more power when signal is weak. Local recording on the trailer provides a backup if the link fails.

Mast height and siting

Many surveillance trailers carry a telescopic mast that raises cameras and lights above fences and vehicles. Mast height affects the view, wind loading and stability. Follow the manufacturer’s limits for wind speed and outrigger use, and lower the mast in storms if required.

Our guide to ballast, wind loading and siting explains how to set a trailer up safely on different ground.

Protecting the equipment

A trailer that guards a site can itself become a target. Lockable battery and electronics compartments, tamper alarms, anti-theft fixings for panels and cameras that cover the trailer help deter interference.

We cover measures for the trailer itself in our article on solar trailer site security; the focus here is on keeping the surveillance equipment powered and online.

Monitoring and maintenance

Remote monitoring of battery state of charge, solar input and load lets operators spot problems before the cameras go down. Alerts for low battery, communications loss or tampering should reach the security control room as well as the maintenance team.

Routine maintenance is light: clean panels in dusty locations, check connections and fixings, inspect the mast mechanism and test the batteries. Plan visits around the dry season, when dust builds up fastest.

Choosing efficient security equipment

The energy budget of a surveillance trailer is set largely by the equipment chosen. Low-power cameras with efficient infrared, motion-triggered LED lighting, edge recording that sends only alarms or short clips, and modems that sleep between transmissions can greatly reduce daily energy use. Specify the security equipment and the power system together, rather than buying cameras first and then trying to power them.

When to add a generator

For sites with heavy lighting loads, very short winter days or extreme criticality, a small generator can be added as backup to charge the batteries when solar is not enough. It runs only occasionally, so fuel use and refuelling visits stay low.

Hybrid trailers combine solar, batteries and a generator in one unit with automatic control. They suit high-security sites that cannot accept any downtime and locations with long periods of poor weather.

Typical pumping jobs

Common applications include borehole pumps for livestock and irrigation, surface pumps moving water between ponds and tanks, dewatering of excavations and small pits on construction and mining sites, and water supply for remote camps. Each has a different pattern: some need water every day at a steady rate, others need large volumes for a few weeks.

Start by writing down how much water is needed per day, from what depth or height, and over how many weeks. That tells you whether a trailer suits the job and how big it must be.

Pump and drive choices

Many solar pumping systems use variable speed drives that let the pump run faster when the sun is strong and slower when it is weak, so the pump moves water all day instead of stopping when power drops. Solar pump controllers and drives designed for this purpose can run standard AC pumps from a solar array.

Choose the pump for the head and flow, then size the solar array and drive for the pump. Pumps with high starting currents may need soft starting or a battery buffer so the trailer can start them reliably.

Sizing from water volume

The energy needed depends on the volume of water and the total head, including friction losses in pipes. Calculate the daily energy, then compare it with the trailer’s expected daily output for the site and season. Our guide to daily kWh from a solar trailer explains how output varies with location and weather.

Size for the worst month in which the water is needed, not the annual average. Irrigation demand is often highest in hot, sunny months, which helps; dewatering demand may peak in the rainy season, when solar output is lower.

Store water or store energy

Where water can be pumped into a tank or reservoir during the day and used later, the tank acts as storage and the system may need little or no battery. Water storage is usually simpler and cheaper than batteries. For livestock or camp supply, a few days of tank storage covers cloudy spells.

Dewatering is different. Water keeps flowing into the excavation day and night, so the pump may have to run after dark. That calls for battery storage on the trailer or a backup generator. The battery storage guide covers the options.

Hybrid backup

For critical pumping, such as dewatering where flooding would stop work, combine the solar trailer with a small diesel or gas generator. The controller runs the pump on solar when available and starts the generator only when the sun and batteries cannot keep up. Fuel use falls sharply compared with a generator-only setup.

Make sure the controller manages the changeover automatically and that the generator is sized for the pump’s starting current.

Siting and moving the trailer

Place the trailer where the panels have clear sun for most of the day, as close as practical to the pump to keep cable runs short. On construction sites, check that the trailer does not block plant movement and is protected from vehicles.

Moving between boreholes or work areas is the point of a trailer, so plan the cable and pipe connections for quick disconnection. Secure the trailer against theft and vandalism; see site security for solar trailers for practical measures.

Controls and monitoring

Level switches in tanks and sumps start and stop the pump automatically, preventing dry running and overflow. Remote monitoring shows pump hours, water level and trailer output, so the operator knows whether the system is keeping up without visiting the site.

Protect pumps from dry running and over-temperature. A pump that runs dry in a remote borehole can be destroyed before anyone notices.

Water quality and pump protection

Sand and silt in borehole or dewatering water wear pump impellers and seals quickly. Use pumps suited to the water quality, fit screens or filters where practical, and check flow and current regularly for signs of wear. Dewatering pumps on construction sites often handle very dirty water and need robust designs and frequent inspection.

Record pump current along with flow. A rising current at the same flow often signals wear or blockage before the pump fails.

Maintenance

Solar trailers need little maintenance, but pumping sites are often dusty. Clean panels regularly, check cables and connectors after each move, and inspect batteries and controllers in hot weather. Pumps need their own maintenance according to the manufacturer’s schedule.

Keep a simple log of water pumped and energy produced. If water output falls while solar output stays steady, the pump or the borehole needs attention.

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.

Start with the energy demand

The most important number is daily energy use in kilowatt-hours, not just peak power. Lighting towers, cameras and small offices use modest amounts of energy; welding, pumps and site cabins with air conditioning use much more. A solar trailer can cover small and steady loads well, while large or peaky loads favour a diesel or hybrid unit.

Our guide to estimating kWh per day shows how to work out the figure.

Solar trailers with batteries

A solar trailer charges its batteries during the day and supplies the load day and night. It is silent, has no fuel cost and needs little maintenance. Output depends on the sun: cloudy seasons, shading and short winter days reduce the energy available.

Solar trailers work best where the load is predictable and the site has good sun for most of the year.

Diesel generator trailers

A diesel trailer delivers high power on demand regardless of weather, which suits heavy or variable loads. The trade-offs are fuel cost, refuelling logistics, noise, emissions and regular maintenance. Lightly loaded diesel sets also tend to wear faster, which is common on sites with small night loads.

Hybrid trailers

A hybrid combines solar panels, batteries and a small generator. Solar and batteries cover most of the energy, and the generator starts automatically when the batteries are low or the load is high. The generator runs fewer hours and at a better load, which saves fuel and service visits.

For many remote sites a hybrid gives the best balance of reliability and running cost. Our page on logging fuel savings shows how owners measure the result.

Noise, emissions and site rules

Urban sites, events and residential areas often limit noise and exhaust. Solar trailers and hybrids running mostly on batteries are much quieter than diesel units. Mining and construction clients increasingly track fuel use and emissions too, which favours solar and hybrid options.

Maintenance and lifecycle

Solar trailers need panel cleaning, battery health checks and occasional inspection of cables and connectors, especially after transport. Battery life depends on depth of discharge and temperature, so shading the battery compartment and avoiding very deep cycles extends it.

Diesel and hybrid trailers add engine servicing: oil, filters, coolant and fuel quality. In a hybrid, the generator runs fewer hours, so service intervals stretch further apart. When comparing options, look at the full cost over several years, including fuel, service visits and battery replacement, not only the purchase price.

Choosing the right trailer

Match the trailer to the energy demand, the solar resource, the runtime required and the site rules. Where loads are small and steady, solar alone works. Where they are large or the weather is poor, diesel or hybrid is safer. When in doubt, a hybrid gives margin while keeping fuel use down.

The formula

Daily energy (kWh) = array size (kWp) x peak sun hours x performance ratio.

Array size is the total rated power of the solar panels on the trailer, in kilowatts peak. Peak sun hours is the number of hours of full sun equivalent at the site, which varies by location and season. Performance ratio covers the losses between the panels and the load: heat, dust, wiring, inverter and battery losses.

Peak sun hours by site and season

Sunny regions often see five to six peak sun hours a day in good months, while cloudy or high-latitude sites may see two or three in winter. Public solar resource tools give monthly figures for any location. Always size for the worst month in which the trailer must carry the load, not the annual average.

Performance ratio: where energy goes

On a mobile trailer, performance ratio is often in the range of 0.65 to 0.8. Panels lose output when hot. Dust on the panels can cost several percent, more on mining and construction sites, which is why soiling and washing matters. Energy that passes through the battery loses a little more. Panels that cannot be tilted or turned towards the sun, or that are shaded by nearby structures, produce less again.

Worked example

If the load uses 30 kWh a day, this trailer covers it in the worst month with some margin. If the load uses 50 kWh, it does not, and the gap must come from a second trailer or a generator. These figures are illustrative; use the actual array size and your site’s solar data.

Batteries and night loads

Solar only produces in daylight, so any load at night runs from the battery. The usable battery capacity must cover the night load plus a margin, and the array must produce enough by day to run the daytime load and recharge the battery. If cloudy days are common, either more battery or a backup generator is needed. Our pages on solar trailer battery storage and night cover cover this in more depth.

Matching the trailer to the load

Start with a load profile: what runs, at what power, for how many hours, and when. Lighting towers, CCTV and telecom loads are small and steady and suit solar well. Pumps, workshops and site offices with air conditioning are larger and peakier and usually need a hybrid with a generator. See building a load profile for a simple template.

When a generator still belongs on site

A hybrid of solar, batteries and a small generator often gives the best result: solar does most of the work, the battery covers the night, and the generator runs only when the battery is low. Fuel use and engine hours fall sharply compared with a generator running all day, without risking an outage in a cloudy week.

Stage 1: Factory acceptance tests

Ask the supplier to test each trailer before it ships and to give you the results. Witness the tests yourself, or have someone witness them, on the first unit of a batch.

Standards help structure this: IEC 62446-1 covers testing and documentation for PV systems, and battery systems should come with evidence of compliance with the relevant safety standard for their chemistry. Ask which standards the supplier tests to.

Stage 2: Transport readiness

Before the trailer leaves, check that panels are stowed and locked, the battery is at a safe state of charge for transport, loose items are secured and the road gear (lights, brakes, tyres, coupling) is in order. Lithium batteries may carry transport rules depending on the route and mode. Our page on transport and tie-down covers the securing side.

Stage 3: Site acceptance tests

1. Visual inspection after delivery: damage to panels, frames, cables, enclosures and connectors.
2. Deployment: unfold or raise the array, level the trailer, set outriggers and check stow functions.
3. Earthing: connect to a site earth and measure; our grounding guide explains the arrangement.
4. Electrical re-test: string voltages and insulation resistance, compared with factory values.
5. Functional test: run the real site load through a full day, including a battery discharge into the evening and, if fitted, a generator auto-start.
6. Remote monitoring: confirm data arrives and alarms reach the right people.

Keep the readings. They become the baseline for every later check.

What the numbers should tell you

Compare string readings with each other and with the factory sheet. A string with lower current than its neighbours in the same light may have a damaged panel, a shaded cell or a bad connector. Falling insulation resistance after a move can point to cable damage or water ingress. A battery that delivers noticeably less energy than its rated capacity at the same discharge rate should be investigated under warranty.

Telemetry makes this easier over time. Our page on remote telemetry explains which values to track.

Re-test after every move

Each relocation repeats the risks of the first delivery. A short re-test (visual check, insulation resistance, string voltages, functional run) after every move catches damage early. On construction and mining sites, where trailers may move often, build the re-test into the move procedure so it is not skipped.

Writing acceptance into the purchase order

Testing only protects you if the purchase order says what happens when a test fails. State the tests required at the factory and on site, the standards they follow, the pass criteria and who witnesses them. Link a share of the payment to successful site acceptance, and set a deadline for fixing defects found.

• List the tests by system: PV, power conversion, battery, generator, earthing, mechanical, telemetry.
• Define tolerances, for example how far a string reading may differ from its neighbours.
• Require test sheets with serial numbers, instrument details and calibration dates.
• Agree warranty response times for failures found after acceptance.

This adds a page to the order and removes most of the arguments later. Suppliers who test properly as standard rarely object.

Where trailers fit in a bigger plan

Solar trailers suit temporary, remote and moving loads: construction sites, camps, telecom sites and events. When the load grows or becomes permanent, a fixed hybrid plant with solar, storage and engines or turbines usually costs less per kilowatt-hour. Our hybrid power systems page explains how we design those plants.

What Is Inside a Solar Generator Trailer

A typical unit carries folding or tilting solar panels, a battery bank, an inverter and charge controller, and often a small backup engine. The panels charge the batteries during the day. The inverter supplies your loads from the batteries, day and night. When the batteries run low after a long run of cloud, the backup engine starts automatically, charges them and stops again.

Some trailers also carry lighting masts, cameras or communications equipment, so the trailer becomes a complete self-powered station rather than just a power source.

Where Solar Trailers Fit Best

They suit loads that are modest and steady, such as site offices, lighting, security cameras, telecom equipment, signage and small tools. They work well where fuel deliveries are costly or noise is a problem, and where a site moves every few weeks or months.

They are not the right tool for heavy, continuous loads such as large pumps, crushers or welding bays. For those, a diesel or gas set, or a larger fixed hybrid plant, makes more sense. Our hybrid power page explains how bigger systems combine solar, batteries and engines.

How to Size One Properly

Start with your daily energy use, not just peak power. List each load, its power and the hours it runs, and add them up. That figure sets the battery size and the solar array you need. Then check your peak: the inverter must handle the largest load that runs at once, including starting surges.

Next, look at your sunlight through the year, not just in summer. Plan for the worst season and for several cloudy days in a row. That is where the backup engine earns its place.

Finally, think about security and handling. Trailers in remote spots need theft protection and remote monitoring, and the trailer must be legal and practical to tow on your routes.

When You Need More Power

As sites grow, many clients move to bridge or larger hybrid plants. Our rental and bridge power service and mining power team cover larger needs, and we also build natural gas engines/stations, supply used/new gas turbines and gas turbine generators, and offer a remanufactured GE Frame 6B.

For data centres we deliver hyperscale EPC/O&M with AI gas turbines, hyperscale generators, gas turbines for compute and New USP&E FX-45 45MW Modular Gas Turbine for the Hyperscale Data Center sector in the USA. See our full equipment inventory.

Why Storage Is the Heart of a Solar Trailer

A solar trailer collects energy only in daylight, but most of the sites it serves need power around the clock: a security camera mast, a telecoms repeater, a construction site office, a water pump or a remote monitoring station. The battery bridges the gap. Its size and condition decide whether the trailer runs through the night and the cloudy spells, or calls on a generator.

Storage is also usually the most expensive and the most perishable part of the trailer. Panels last for decades with little attention; batteries age with every cycle and with every hot afternoon. Choosing and running them well is where most of the value of a trailer is made or lost.

Sizing in Three Steps

A simple method gives a good first estimate. The detail can then be refined with local solar data and the trailer maker’s figures.

1. Work out the daily energy use. List each load, its power in watts and the hours it runs each day, then add them up to get watt-hours or kWh per day.
2. Decide the autonomy. How many hours, or days, must the trailer run without useful sun? A security mast in a sunny climate may need a single night; a telecom site in a rainy season may need two or three days.
3. Divide by the usable depth of discharge. A battery that should not be taken below a certain charge level must be larger than the energy it delivers.

Then check the array. The panels must replace the energy used overnight and still run the daytime load, in the shortest days of the year, with allowance for dust and heat. If they cannot, either the array grows, the load shrinks or a generator covers the shortfall. Our article on load profiles for solar trailers shows how to build the daily energy picture.

Battery Chemistry Choices

Three chemistries dominate trailer storage today, each with a different balance of cost, weight, life and temperature tolerance.

Lithium iron phosphate has become the default for new trailers because it handles daily deep cycling far better than lead-acid and weighs much less for the same usable energy. Lead-acid still appears on older or budget units, and in some cold-climate applications where charging lithium below freezing is a concern.

Heat, Cold and Battery Life

Temperature is the biggest single influence on battery life after cycling. High temperatures speed up the chemical ageing of every battery type; a trailer parked in full sun on a hot site can shorten its battery life dramatically. Ventilated or insulated battery compartments, light-coloured enclosures and, where needed, active cooling make a real difference.

Cold brings the opposite problem. Lithium batteries should not be charged below freezing without heating, and lead-acid loses much of its capacity in the cold. Battery management systems on good trailers block charging until the cells are warm enough. Our article on battery thermal management in trailers covers enclosure design for hot and cold sites.

Inverters, Charge Controllers and the BMS

Storage does not work on its own. A charge controller, or a hybrid inverter with built-in charging, manages the flow of energy from panels to battery. The inverter converts the battery’s direct current into alternating current for the load. The battery management system watches every cell, balances them and protects against over-charge, over-discharge and temperature extremes.

These parts must be matched. An inverter that draws more current than the battery can safely supply will trip; a charger that cannot accept the array’s full output wastes sun. Communication between the BMS and the inverter lets the system make smarter decisions, such as limiting load before the battery reaches a damaging level.

• Battery voltage and maximum continuous discharge current matched to inverter demand.
• Charge controller or hybrid inverter rated for the full array output.
• BMS communication with the inverter, not just a stand-alone cut-off.
• Remote monitoring of state of charge, temperatures and alarms.

When a Generator Steps In

No practical trailer can carry every load through every spell of bad weather on solar alone. Hybrid trailers add a small generator, either built in or alongside, that starts when the battery falls to a set level and stops once it has recharged. Run this way the generator works at efficient load for short periods rather than idling all night.

Sizing the battery and the generator together is the key design choice. A larger battery means fewer generator starts and lower fuel use; a smaller battery saves weight and cost but runs the generator more often. USP&E’s approach to hybrid power that blends solar, storage and generation applies the same logic at larger scale, and our page on battery trailers with genset firming looks at the trailer case.

Keeping Storage Healthy in the Field

A few habits extend battery life considerably. Avoid leaving batteries at very low charge for long periods, especially lead-acid. Keep compartments clean and ventilated. Check terminal torque and cable condition during routine visits, since vibration from towing loosens connections. Review state-of-charge history remotely to catch a failing array or a growing load before the battery suffers.

When batteries do reach the end of their life, replace them as a matched set and recycle the old ones through approved channels. Our guide to battery replacement on solar trailers covers timing and handling.

Safety and Transport of Trailer Batteries

Batteries store a lot of energy in a small space, so trailers must be designed and handled with care. Lithium batteries are classed as dangerous goods for transport, with rules on packaging, labelling and state of charge. A trailer moving between sites with its batteries installed must meet the road transport rules in each country it passes through.

Good trailers separate the battery compartment from the inverter and generator, provide ventilation and include fire detection, and sometimes suppression. Operators should be trained to recognise warning signs such as swelling, unusual heat or smell, and to isolate the battery safely. Clear labelling of isolation points helps emergency crews if a fault does occur.

Monitoring Battery Health Remotely

Most modern trailers report battery data over a cellular or satellite link. The most useful readings are state of charge through the day, the lowest charge reached each night, cell temperatures, and the spread of voltage between the highest and lowest cells. A widening spread is an early sign of a weak cell or a balancing problem.

Set alerts for low overnight charge, high temperature and communication loss, and review the trends monthly rather than only when an alarm fires. Our article on remote telemetry for solar trailers describes the dashboards fleet operators use to spot problems across many units.

Renting or Owning Trailers With Storage

Short projects often suit rental, where the provider maintains the batteries and swaps units if one fails. Long deployments or fleets of many trailers can favour ownership, provided someone takes responsibility for monitoring and maintenance. Mining camps, exploration sites and remote infrastructure often run mixed fleets. USP&E supports both routes through its rental and bridge power service and its work in the mining sector.