Carries the camp
The enclosed trailer still transports shade, tools, bikes, kitchen equipment, an accessibility vehicle, and other camp infrastructure. Keeping useful cargo space is a core design requirement.
An open-source Regional prototype
The trailer that carries the camp can also help power it.
An open-source 7×16 cargo trailer that transports camp gear and an electric accessibility vehicle, then becomes a solar power system at the event.
Concept visualization · specifications are design targets, pending testing
- ~3.6 kW
- solar
- ~10 kWh
- storage
- 120 V
- camp power
- $6,000
- personally committed
01 / A REAL NEED
Why I’m building it.
I have multiple sclerosis and need an electric mobility vehicle for longer distances at large events. Bringing that vehicle creates two additional problems: transporting it and keeping it charged without also hauling a large generator and fuel.
At the same time, camps already bring trailers full of shade, tools, bikes, kitchen equipment and other infrastructure.
This project asks a simple question:
Can the trailer we already need also become part of the camp’s renewable-energy system?
Powers the camp
At the event, fixed roof solar and deployable side wings charge the battery system and supply suitable 120 V loads. The aim is less fuel to transport and store, and less generator runtime.
02 / THE SYSTEM
One trailer. Three operating modes.
A cargo trailer with solar built in.
A 7×16 enclosed tandem-axle trailer with four fixed roof panels and two panels on each side. The folding wings extend about 44 inches and use triangular support braces. Structure, clearances, and wind behavior still need review and testing.
Current prototype targets
- Trailer
- 7 ft × 16 ftEnclosed, tandem axle
- Solar array
- ~3.6 kW8 panels total
- Battery storage
- ~10 kWhLiFePO4
- Camp output
- 120 VSuitable loads and vehicle charging
- Roof
- 4 fixed panelsSeparate roof MPPT
- Side wings
- 2 panels per sideIndependent wing branches
- Wing extension
- ~44 inchesFrom each side when deployed
- Wing supports
- Triangular bracesFolding panels; retained cargo space
One MPPT for the roof. One for the wings.
Each side has two panels wired in series. The two side strings combine in parallel into a single wing MPPT charge controller. The roof array uses a separate MPPT.
Independent wing branches: either side can operate while the other remains stowed or disconnected. The roof array remains usable with both wings folded.
MODE 01 · BOTH SIDES DEPLOYED
Both wings open
Roof panels and both side wings collect solar when space and weather permit. Triangular support braces hold the folding wings in their deployed position.
- Four roof panels and four side panels
- Independent wing branches: either side can operate while the other remains stowed or disconnected
- Both side strings share the wing MPPT
01Solar arraysroof + independent wing branches
→
02Charge controlroof MPPT + shared wing MPPT
→
03Battery bank~10 kWh LiFePO4 target
→
04120 V outputsuitable camp loads and charging
03 / PUT IT TO USE
Small loads. Useful possibilities.
What can ~10 kWh actually do?
The battery is large enough to do more than keep the lights on. The prototype is being sized around practical camp loads: mobility charging, e-bikes, lighting, communications, and other modest 120 V equipment.
Planning examples
These are calculated possibilities, not measured results or guaranteed runtimes. Actual performance depends on battery size and condition, weather, dust, and other loads. Field testing will verify what the trailer can deliver.
Light the camp all night
A basic LED lighting setup can stay surprisingly small.
- Illuminated sign
- ~20–40 W
- String / ambient LEDs
- ~30–60 W
- Pathway & safety lights
- ~10–30 W
Those example fixtures total approximately 60–130 W. A well-designed setup could budget around 100–150 W, allowing some headroom.
1.2 kWh
100 W of lighting × 12 hours
That is approximately 12% of a 10.24 kWh battery, before conversion losses and system overhead.
Permanent lighting may use a suitable DC supply so the main AC inverter does not need to stay awake just for LEDs. The lighting design is still to be confirmed.
Charge a lot of bikes
For e-bike batteries in the 500–750 Wh range, a little energy goes a long way. Battery sizes vary; these are examples.
Starting full, set aside approximately 8 kWh for bike charging while preserving at least a 20% battery reserve. Assuming 90% reaches the bike batteries:
- 500 Wh battery
- ~14 charges
- 600–700 Wh battery
- ~10–12 charges
- 750 Wh battery
- ~9 charges
Full-charge equivalents across a charging session, not a simultaneous-bike count. This example uses the available energy for bikes alone; other camp loads or greater losses reduce the total. The 90% efficiency is an assumption to test.
Energy is only half the story.
Ten chargers drawing an assumed 150 W each would total 1.5 kW. Whether ten or more can run together depends on their actual AC input, the final inverter, outlets, circuits, and other loads.
Keep mobility power in reserve
The project began with an accessibility need. Stored energy can be prioritized for:
- Electric accessibility-vehicle charging
- Essential camp lighting
- Phones and radios
- Networking / communications
- Refrigeration or other modest camp loads
The design will test how much energy the accessibility vehicle actually requires and reserve battery capacity for mobility before discretionary loads.
Mobility charging comes before party loads.
Illustrative · adjustable allocations
One possible overnight energy budget
10.24 kWhnominal battery capacity
- 01 20% battery reserve
- ~2.05 kWh
- 02 Overnight lighting
- ~1.50 kWh
- 03 Mobility / accessibility
- ~4.00 kWh
- 04 Community charging + small loads
- ~2.69 kWh
One starting point from a full battery, not fixed allocations. The 20% reserve stays untouched; the mobility budget is held for accessibility charging. These are battery-side budgets: conversion losses and system overhead must fit within them. Usable capacity may be lower than nominal, and the split will change with measured needs.
This shared overnight budget is a separate example from the bikes-only charge counts above.
See the assumptions & arithmetic
Lighting
100 W × 12 h ÷ 1,000 = 1.2 kWh at the lights. 1.2 ÷ 10.24 ≈ 12% of nominal battery capacity, before losses. At 150 W, the same 12 hours uses 1.8 kWh before losses, so the lighting allocation would need to increase.
E-bike charge counts
10.24 kWh × 80% = 8.192 kWh, rounded down to 8 kWh for this example. 8 × 90% assumed combined inverter / charging efficiency = 7.2 kWh delivered to bike batteries.
7,200 Wh ÷ 500 / 600 / 700 / 750 Wh = 14.4 / 12 / 10.3 / 9.6. Rounding down gives approximately 14 / 12 / 10 / 9 full-charge equivalents. No other loads or solar replenishment are included.
Simultaneous charging
10 chargers × 150 W assumed AC input = 1,500 W (1.5 kW). This illustrates power demand only; it does not establish the number of chargers the final system can support.
Overnight allocation
Reserve: 10.24 × 20% = 2.048 kWh. Add 1.50 kWh for lighting and 4.00 kWh for mobility, leaving 2.692 kWh for community charging and small loads. The graphic rounds these to two decimal places; the total is 10.24 kWh.
Battery-size reference: Bosch eBike battery manuals list examples in the 500–750 Wh range, as well as smaller and larger batteries. This is a size reference, not a component selection or endorsement.
And when the sun is out? When solar generation exceeds current demand, the array can serve loads and replenish the battery. Actual harvest varies with sun, dust, temperature, orientation, and whether zero, one, or both side arrays can be deployed.
- How many kWh does the trailer actually generate?
- How much does dust reduce output?
- What happens during cloudy or windy days?
- How much energy does the accessibility vehicle actually need?
- How many bikes can we charge without compromising the overnight reserve?
- How well does roof-only operation work?
- How much does deploying one side improve daily production?
The prototype has to work outside the brochure. We’ll publish the answers — including the disappointing ones.
04 / DESERT REALITY
Conditions we need to test
The prototype has to work outside the brochure.
Dust and wind
Test dust intrusion, cleaning needs, and the effort needed to stow the wings. The high-wind plan is to fold both side wings down and continue from roof solar. Operating limits still need to be established.
Cloudy stretches
Measure how poor solar conditions affect generation, battery use, and the loads we can serve. Record backup charging when it is needed, along with its energy source.
Partial deployment
Test roof-only operation and each complete side separately. Measure the energy available with one side stowed, and check whether camp access and cargo loading remain practical.
Desert heat
Log equipment-bay temperatures, charging behavior, and any reduced output or shutdowns. Test whether the ventilation works in practice and document changes it needs.
05 / FIELD TEST
A proposal, with results still to come
Proposed field test: BEquinox 2027
BEquinox 2027 is the proposed first Regional demonstration, subject to organizer approval and confirmation of event dates. Participation and a host partnership are not confirmed.
What we’ll test
- Roof-only operation, one-side deployment, and both sides deployed
- Solar production, including poor solar conditions
- Accessibility vehicle charging and selected camp loads
- Dust, heat, and the wing-stowing procedure
- Setup effort and cargo capacity
- Participant feedback and accessibility in everyday use
What we’ll record
- Solar kWh generated and energy delivered to loads
- Battery use and accessibility charging energy
- Backup charging, its source, and the loads served
- Setup and teardown time, including help required
- Cargo space retained with the power system installed
- Practical failures, limitations, and changes needed
The aim is to test where solar can realistically replace fuel-powered generation. We’ll record generator runtime and fuel use where they can be measured. Any estimated fuel or emissions savings will state the baseline and assumptions, including backup charging.
06 / OPEN DESIGN
A build other camps can adapt
Build one. Document everything. Make the next one easier.
I’ll document the build and release the plans, actual costs, and test results as an open-source package. Other camps should be able to see what was built, what it took to operate, and what they would need to change.
Publishing what does not work is as important as publishing what does.
The v06 priced planning BOM is complete and now follows the Victron DC architecture: a MultiPlus-II inverter/charger, a roof MPPT, and one shared wing MPPT. It includes component references, quantities, published prices, explicit estimates, and the remaining funding gap. PG-04 now identifies an unpriced DC/PV ground-fault arrangement; the current total has not been revised for that selection. Used-equipment purchases and final engineering are still pending.
Download the v06 BOM (.xlsx) Read the electrical architectures- 01Priced bill of materialsv06 Victron revision, 17 September 2026. Prices, estimates, sources, funding allocations, and funding gap; procurement and engineering pending.COMPLETE
- 02DC, AC + grounding architecturesDC-02, AC-03 and PG-04 published for design review, with diagrams and document downloads. Final device selection, wiring, and bonding remain pending. DC/PV ground-fault hardware is still unselected and unpriced.DRAFTS PUBLISHED
- 03Mechanical drawingsTrailer layout, folding-wing drawings, triangular support braces, latches, and cargo clearancesPLANNED
- 04Operating and maintenance guideSetup and teardown procedure, stowing, inspections, cleaning, and maintenance informationPLANNED
- 05Field data and accessibility observationsEnergy, loads, weather, cargo use, setup effort, charging, and participant feedbackPLANNED
- 06Build log and revisionsFailures, modifications, limitations, and lessons learnedPLANNED
07 / ROADMAP
From planning to measured results
The next steps are practical ones.
-
01
DESIGN + FUNDING
Priced BOM complete; funding next
The v06 Victron planning estimate is $17,528.10, including tax, delivery, review, and contingency. I’m contributing $6,000 of personal savings plus donated labor and existing tools. A proposed $10,000 grant would leave $1,528.10 still to fund. Used trailer and panel prices remain sourcing targets; grants, donations, and sponsorships are not secured. -
02
REVIEW + BUILD
Keep the cargo space useful
Review wiring, wing supports, payload, restraints, and vehicle access before construction. Install and commission the power system, then record the layout, parts, costs, and changes. -
03
SHAKEDOWN
Measure what actually happens
Check roof-only and partial deployment, accessibility charging, selected loads, setup effort, heat, and poor solar conditions. Record backup charging and failures as well as successful operation. -
04
PROPOSED DEMO
BEquinox 2027
Seek organizer approval and confirm dates before planning attendance. If approved, run the field-test plan and collect feedback on camp utility and accessibility. -
05
RELEASE
Share the build and its limits
Publish the open-source plans, real prices, operating instructions, test data, failures, and revisions so another camp can copy or adapt the design.
What the prototype needs to prove
Success looks like
Success is not just making electricity. It means the trailer:
- Still works as useful cargo space
- Safely charges the accessibility vehicle
- Meaningfully reduces generator use for suitable loads
- Works with roof-only and partial deployment
- Handles real dust, heat, and wind within documented operating limits
- Produces documentation detailed enough for another camp to copy or adapt