Utility-scale solar is booming, but most projects are built in places where grid power, fiber and physical patrols are expensive or simply unavailable. Trenching for power or data routinely lands in the 30 to 60 USD per linear foot range, and a single 24/7 guard post can burn 25,000 to 40,000 USD per month. Those two numbers alone explain why many EPCs and O&M teams are turning to solar powered surveillance trailers to protect panels, copper, inverters and laydown yards from day one, long before COD.
This post is written for readers who want a vendor neutral look at what these solar surveillance trailers are, how to size them, when they beat fixed poles or guards, and what to demand in your RFP so you do not inherit a fleet of dead batteries and dark cameras every cloudy week in January.
What a Solar Surveillance Trailer Actually is?
Think of it as a mobile, off grid security stack in a towable chassis. A PV array charges a LiFePO4 battery bank that is sized to give you multiple days of autonomy. A telescopic mast carries PTZ and fixed cameras, sometimes thermal. An edge computer on board runs AI analytics so you only transmit events, not every pixel. Backhaul is usually LTE or 5G, but Starlink or microwave is common on very remote sites. The whole unit can be dropped, leveled, configured and live in hours, then redeployed to the next project when you energize and move on.
Why Trailers Solve Real PV Problems?
Construction sites are power poor and risk rich. You need eyes on high value inventory the second it arrives. Permanent poles and fiber often arrive late in the schedule, and the economics of trenching kilometers of conduit just to power a few cameras rarely clears the bar. Even after COD, large solar farms have access roads, buffer zones and BESS pads that are expensive to cover with fixed infrastructure. Trailers let you close those gaps quickly and cleanly, without diesel generators that clash with your ESG posture.
The four subsystems you must understand
Power
Most modern units use LiFePO4 because of cycle life and temperature tolerance. Sizing is everything. You calculate average daily watt hours across cameras, computers and radios, add duty cycle spikes for PTZ movement and IR, then multiply by the number of autonomy days you want. Three to five days is common for winter or storm planning. PV is then sized so that in your worst irradiance month you can recharge in one to two days after depletion. Use a conservative system efficiency factor in the 0.7 to 0.8 range.
Imaging and analytics
A good mix is PTZ for reach, 4K fixed for detail and optionally thermal for night or wildfire risk. Run person and vehicle detection, intrusion zones, line crossing and loitering on the edge so you are not shipping raw video. LPR is useful on contractor gates. PPE detection is increasingly requested on large construction sites. Radar or PIR sensors can wake the higher power stack only when needed, saving energy.
Connectivity
LTE or 5G works well when coverage is there. Use dual SIM and automatic failover. For deep rural assets, Starlink is fast to deploy but draws more power and needs sky view. Microwave or private LTE is worth it when you have many clustered assets or strict data sovereignty rules. Event first, video later is the pattern that keeps bandwidth and storage sane.
Management, integration and cyber
Demand a fleet dashboard that shows battery state of charge, solar harvest, camera uptime, storage remaining and link quality. Make sure the platform exposes ONVIF, RTSP, webhooks or a documented REST API so you can feed your VMS, PSIM, SOC or even SCADA. Enforce MFA, role based access, encrypted storage and signed firmware like you would on any other OT edge node.
When a Trailer wins and when it does not?
Trailers shine on greenfield builds, seasonal hotspots, after a theft cluster or around remote BESS and substations. They are also ideal as a stopgap while you wait for permanent poles and fiber. They are less compelling when you already have dense permanent infrastructure, or where the trailer physically cannot enter. Indoors or dense urban perimeters still belong to fixed systems.
Cost and deployment reality check
If you pencil in 30 to 60 USD per foot for trenching and compare it to a trailer that deploys in a day, the math usually favors mobile units during construction. Guard hours stack up even faster. Long term, fixed poles still win where coverage is permanent and dense. The sweet spot is often a hybrid model: permanent poles in hot zones, trailers for the edges and for temporary risk.
How to size autonomy without guessing
Start with power budgets on the datasheets. Sum continuous loads, then estimate duty cycle loads realistically. Pick your autonomy days for the worst weather window in your latitude. Compute usable battery capacity with your chosen depth of discharge. Now size the PV array with your worst month peak sun hours and a conservative efficiency factor. Ask vendors to show their math and to model your latitude and temperature range. Then require them to guarantee runtime in that worst month.
What you should put in an RFP
Write it so you do not have to reverse engineer anything later.
- Required autonomy days at your site latitude in the worst irradiance month
- Camera mix and minimum specs for resolution, IR range, thermal sensitivity if used
- Exact analytics that must run on the edge, not the cloud
- Connectivity options, failover logic and bandwidth budgeting
- Operating temperature, IP rating, wind rating for the mast
- Fleet health dashboard requirements and alerting channels
- ONVIF, RTSP, API, webhook requirements and version numbers
- Cyber requirements: MFA, RBAC, encrypted storage, signed firmware, patch cadence
- Data ownership, retention, export and deletion clauses
- SLA for hardware swap, firmware updates and support response
If you want to see how a vendor positions this class of product, Coram has a public spec page for its solar surveillance trailers. Use it as a reference point, not as an endorsement, and force every bidder to map their answers against your checklist.
Alternatives to keep on the table
Fixed solar powered poles are great when the location is permanent. Thermal plus radar rings can give you very low power, wide area detection with few false negatives. Drones on demand can verify alarms quickly, but require strict privacy controls and airspace compliance. Manned guards still matter for response and investigations. The question is how many hours you can safely replace with automation.
FAQ
Will a trailer survive a week of clouds in winter
Only if you sized it for that week. Put the autonomy guarantee in the contract and make vendors prove it with your latitude and historic irradiance.
Do I still need guards
Usually yes for response. Trailers reduce routine patrols and close blind spots, they do not replace handcuffs.
Can I integrate with my existing VMS or PSIM
You can if the vendor truly supports ONVIF or provides a documented API. Ask for version numbers and a live demo against your stack.
What about privacy and compliance
Define retention periods, user roles, audit trails and a process for regulator or law enforcement requests before you roll a single unit onto a site.
Conclusion
If you take nothing else from this post, remember two numbers. First, trenching and permanent infrastructure routinely cost 30 to 60 USD per linear foot, which is why a trailer that deploys in hours often wins during construction.
Second, design for three to five days of autonomy, use a conservative 0.7 to 0.8 system efficiency factor in your PV maths and insist on a worst month irradiance guarantee in your RFP. Do that, and you will avoid most of the “the trailer died in the storm” tickets that keep asset managers up at night.
Want a spreadsheet that turns your latitude, peak sun hours and load table into an autonomy and PV size you can paste into your RFP? Tell me the site location, desired autonomy days and your camera and radio stack, and I will send you one.
