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100 Watt Solar Panel Van Kit

This guide for a 100 watt solar panel van kit gives you a list of everything you need to buy to properly connect your solar panel system. Read below to find a step-by-step guide describing which order to connect the wires, and the tools necessary to build a solar system. A basic 100 watt solar kit produces between 30-55Ah on a sunny day depending on exposure and charge controller efficiency. This is enough electricity to power small electronics such as a laptop or cell phone, or one large item such as a refrigerator or vent fan.

If you are looking for more power, checkout our guides on installing a 200 Watt solar panel system, and a 400+ Watt solar panel system (COMING SOON).

How to wire 100 watts of solar panels for a van

Shopping list for 100 Watts of Solar

100 Watt Solar Panel

Choose one of the following panels:

Mounting Hardware (Optional)

Charge Controller (PWM)

Choose one of the charge controllers below. Note: if you choose to purchase the solar suitcase above, that unit comes with a charge controller so you will not need to purchase a second one.

Deep Cycle Battery

  • 12 Volt, 85Ah flooded marine battery. Because shipping this battery type is expensive, we recommend buying one at a box store. Flooded batteries need monthly maintenance and need to be vented. Autozone carries them for about $90
  • M24-SLD-G 12V 74 Amp Hour Gel MK Battery (upgrade option)

Inverter (Optional)

An inverter is necessary to charge 120V AC (household) electronics. A 100W solar system is not very large so many people skip the inverter and buy DC chargers for their electronic devices to reduce inefficiency.

Wires

Wiring is cheapest at automotive and hardware stores. We recommend keeping with red/black for safety and convenience when running wires. Some wire is sold in colored pairs as 14AWG, 12AWG, 10AWG, and 4AWG inverter wires.  Make sure to purchase multi stranded wire so that it is easier to snake through your vehicle and more secure for connectors.

The wire sizes listed here are approximate and the length will depend on your setup. Using these exact wire sizes will work in most situations. If you need to run longer wires, such as 12ft. you should use a thicker AWG rating (lower number is a heavier wire) to reduce voltage loss. Remember, the longer and smaller your wire size, the less efficient your system will be.

  • 10ft or less, 12AWG wire (to run from the charge controller to the fuse block)
    • Use a 20A in-line fuse or a fuse the size of your charge controller rating for this line (whichever is smaller). We recommend this 12AWG in line fuse holder
  • 12AWG wire (to run from the charge controller to the battery). Use the same fuse holder as above.
  • 10AWG wire (to run from the battery to the inverter)
    • A 400W inverter should only need 30A fuse. At max pull it will draw 33 Amps, so if you find you’re blowing it then replace with a 35A fuse. We recommend this fuse holder

Wires running from the fuse block to the DC electrics will vary in size based on the Amps each electric device uses. Use one fuse size up from the amperage produced. For devices listed in watts, divide by system voltage (12V) to get Amps.

For example, a 75 Watt string of lights will draw up to 6.25 Amps (75Watts/12Volts). In this case, use a 7.5A fuse because it is the next fuse size above 6.25 Amps. Wires need to be able to handle the current. See the Fuse Block section below for device wire sizing.

Fuse Block

For safety purposes, all positive (red) wires should be fused. The primary purpose of a fuse is to protect your wiring if something happens to your electronic device or you have a short, such as a wiring rubbing and touching the frame. For this reason, you should never use a higher amperage fuse than the wire can handle. The fuse should always be the weakest link in your power system!

The fuse block organizes power from your battery into separate power circuits for each electronic device you have. This way if there is an issue with one device or wire it doesn’t affect the other ones, and is easier to diagnose issues.

For this system, use the wire sizes below for the max fuse size that you can use for each amperage. You can always use a smaller fuse, but should never use a larger one. If your wire can handle 15 Amps but your electrical component can only handle 5 Amps, it is completely fine to put in a 5A fuse to protect the device.

  • 16AWG wire: 10 Amps
  • 14AWG wire: 15 Amps
  • 12AWG wire: 20 Amps
  • 10AWG wire: 30 Amps

If your wire can handle 15 Amps but your electrical component can only handle 5 Amps, it is completely fine to put in a 5A fuse to protect the device. If your wires are longer than 10 feet, we recommend going down a fuse size for the gauge.

  • Automotive blade fuses for your fuse block can be purchased at any auto store.

Connectors and Terminals

Most panels come with MC4 connectors. You can buy connectors on your own or a pair of extension cables with connectors attached.

For your wiring, the battery will likely not come with terminal connectors. Connectors on the posts of your batteries allow you to attach wires to the batteries.

To attach wires to the batteries, ring connectors are recommended for easier and safer assembly. Make sure to use a connector that is appropriate for the wire size. They are usually labeled. Spade connectors are used to connect wires to your fuse block. If you need both connector types, it is usually more economical to buy everything in one kit.

Connectors can be used to connect the negative (black) wires from your DC electronic devices to metal on the vehicle frame. Then connect the negative post of your battery bank to the frame as well. This means that your entire vehicle frame is grounded. Do this only for your powered devices. Your inverter and charge controller negative wires should be connected directly to your battery bank.

Total Cost of a DIY 100 Watt Solar Panel Kit:

When purchasing just the basics, you are going to spend around $300 on a 100 Watt kit. Choosing to upgrade the battery, charge controller, mounting hardware and adding an inverter will raise the cost to about $500.

If you don’t feel comfortable piecing together your own parts, Renogy offers a partial solar kit for about $200 in which case you need to add about $100 worth of battery, connectors and wiring.

A full system Goal Zero kit can also be purchased for ~$1750. This would be the equivalent of a 100Watt solar suitcase paired with a 100Ah AGM battery and 1200 Watt inverter. Our estimate the DIY version of this sytem would be around $600.

Tools For Installation

Aside from general wrenches and drills for mounting, some basic wiring specific tools that are necessary:

  • Digital Multi Meter (DMM). This is critical for anyone doing electrical work as well as troubleshooting many electrical issues. For basic wiring you don’t to spend more than $20 like this Craftsman DMM.
  • Wire stripper and crimper. You can spend a good amount of money on a separate stripper or crimper and they are definitely better tools, but when just getting started a basic combo tool will do just fine.
  • Dielectric grease. This is used to keep bare metal connections from corroding. Vaseline works for this as well if you already have some.

Tips On Wiring Your Solar System

Wiring 12V systems is relatively safe. You can short wires or start a fire but you are not likely to shock yourself like you can with household electricity.

  • Wire connecting order:
    • When wiring solar panels, always connect the panels to the system at the very end and disconnect them first. You don’t want that voltage connected with nowhere to go.
    • After the above tip, it’s a good habit to disconnect the negative (black) battery terminal before working on electrical systems. The order of assembly should be: 1) Connect all system wires 2) Connect negative battery terminal. 3) Connect solar panels to charge controller. Disassembly is in reverse of this.
  • Here is a good video on how to crimp wires.
  • There are two schools of thought for ground wires. You can run a ground wire from each component back to a bus bar. This often is easier because you don’t have to find frame grounds. Or you can ground each component to the nearest bare metal. This uses less wire and is easy if you have a lot of exposed metal.
  • Avoid running wires in areas where they may rub or chafe and cause a short. Along a similar vein, it’s good to lay out your wiring so that you have access after the van is built in case you need to troubleshoot or add more components.
  • Shade is the enemy of PV solar panels. The cells are arranged in a way that if one cell is shaded, the whole row loses power. So make sure to mount your panels on the van in a way that they will not be shaded by other objects on the roof. In certain cases, if 10% of a panel is covered, 90% of it won’t be producing electricity.

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