web-log/container/site/content/posts/solar-generator/index.md

+++ categories = ["build"] tags = ["solar", "battery", "truck", "camping"] date = 2021-09-09T19:06:11Z description = "Building a truck-mounted wooden deck and 1,200-watt solar generator for camping, tailgating, refrigeration, lights, and cooking." draft = false slug = "solar-generator" title = "☀️ Mobile Deck & Solar Generator" author = "nicholas" +++

Sometime in 2021 I build a wood platform and solar generator to sit on top of the latter rack I installed on my truck. I use it for camping, fireworks shows, tailgating, etc. The solar generator allows me to silently power a portable fridge, lights, cooking equipment. Anything that draws less than 1200 watts. The deck was built as an all-purpose platform. It is large enough to sleep on or put chairs on, and for my sanity was totally and completely overengineered. It places me something like 9 feet off the ground, comfortably away from ground-dwelling bugs and critters.

Solar Generator Build

This is a mostly comprehensive list of components used to assemble the solar generator.

{{< image src="images/solar-generator-components-assembled.jpg" caption="Solar generator" >}} {{< image src="images/solar-generator-installed.jpg" caption="Solar generator installed" >}}

Main Electrical Components

• 100 Ah liFePo4 battery
• 100w solar panels (3)
• 40A solar charge controller
• Battery switch
• Inverter
• Fuse box
• Circuit breakers (2)
• Bus bar

Tools and Hardware

• MC4 crimp tool
• Wire strippers
• Wire cutters
• Hammer
• Screwdriver

Hardware Accessories

• Mc4 connectors, terminals
• Crimp ring terminals
• Screws
• Wire clamps
• Shrink tube (sized for wire)
• Copper lugs (sized for wire, terminal)
• 3/4" plywood
• Strut channel
• Fuses
• Strut channel mounting hardware
• 6AWG stranded copper wire
• 10 AWG stranded copper wire
• 12V female cigarette lighter outlet

Determining Requirements

Given the purpose of a solar generator is to generate power for use in various devices, I consider which devices will operate using the power from the solar generator. This document will assume requirements, but the reasoning and calculation used to determine components will be the same.

Load Type

Power Consumption (W)	Run Time/Day (h)	Average Daily Power Use (Wh)
Portable refrigerator	60	8
Laptop charger	40	4
Rice cooker	300	0.3
Phone charger	30	2
Fan	5	4
Totals	435	810

Components

Battery

Since the above chart indicates a daily average power use of 810 Wh, a battery with at least this much capacity should be used to be able to run them for a full day with no sun. Building the generator around this near-worst-case assumption provides a comfortable margin. (Again, battery sizing depends on many variables such as sunlight availability, budget, etc.)

Batteries are typically labeled in reference to their capacity, in amp-hours Ah. To calculate watt-hours Wh, multiply the nominal battery voltage 12.4 with the stated capacity 100.

12.4 V * 100 Ah = 1240 Wh ...This is good – 1240 > 810 – a fully charged battery will theoretically run the selected devices for at least 24 hours.

Solar Panels

One of my only requirements was that the solar panels be mountable in a way that will not make me nervous driving down the highway – anything that would accept metal bolts. I imagined this would be common, and the first local source seemed to support this notion. I sourced my panels from Harbor Freight Tools. The price and build quality of the solar panels they sold were unbeatable at the time (2021), and go pretty much unbeatable to this day (2024). They included unfilled bolt holes in the frame, they were cheap, and they were dimensioned to be compatible with the spacing of my channel struts. There were no further considerations.

Here are some photos of the electronics. It is a mostly-fully assembled board of all of the components necessary to collect and convert solar energy. They are mounted on a piece of plywood cut to fit flush with back wall of the orange jobsite box. Pictured from left to right: power switch, breaker, charge controller, bus bar, another breaker, fuse box, and inverter.

{{< image src="images/solar-generator-components.jpg" caption="Solar generator component layout" >}}

Roof Rack Deck Platform Build

In the of the photos below, it is possible to see how the deck is mounted. It is useful to think of the assembly in three parts:

• Channel struts that run the length of the ladder rack

  • Three ~8' steel channel struts are each mounted to the tubular steel ladder rack. The half-slot type channel strut is oriented channel-side-up, atop and flush with the tube. This allows a U-bolt to be slotted into the strut, around the tube, and fastened with a washer plate and a two bolts. Semi-permanent threadlocker is applied to each of the 2 threads on each of the 3 u-bolts to ensure that the vibration of the road does not loosen the fasteners.

• Joists (wooden 2x4)

  • Three ~8' wood 2x4 pieces of framing lumber are each mounted to the channel strut. At pre-determined points along the board – avoiding the spaces along the strut with U-bolt mounting hardware beneath – a 1/2" diameter hole is bored through the wood, with a countersink hole large enough to allow a bolt head to both sit flush with the wood once inserted, and wide enough to allow the bolt to be tightened with a socket wrench. The bolt is inserted into the hole, and a spring nut is waiting in the channel for the bolt thread to be inserted. As the bolt is rotated, it pulls or

{{< image src="images/truck-deck-complete-underside.jpg" caption="Deck underside" >}}

• Wooden deck
  • This component of the assembly is made up of 14 4' pieces of pressure treated, stained and sealed pieces of decking lumber screwed into the wooden joists.

{{< image src="images/truck-deck-lumber.jpg" caption="Deck Lumber" >}} {{< image src="images/truck-deck-lumber-stained.jpg" caption="Deck lumber stained" >}} {{< image src="images/truck-deck-assembly.jpg" caption="Deck assembly" >}}

Assembly

Hardware

• Decking lumber - 5/8" x ~4'
• 2 1/2" Deck screws
• Thompson's WaterSeal Wood Stain
• 2x4 Joists
• Channel strut hardware
• Blue thread lock

Process

The simplified process of assembly can be expressed in these steps:

1. Channel strut, wooden joists, and deck boards are cut to size
2. Wooden components are stained and sealed
3. Channel strut is mounted to ladder rack
4. Wood joists are mounted to the channel strut
5. Deck boards are fastened to wooden joists

{{< image src="images/truck-deck-night-photography.jpg" caption="Night photography from the deck" >}}

{{< image src="images/truck-deck-night-distant.jpg" caption="Deck at night from a distance" >}}