April 5, 2020

How to Build a Portable Solar Charging System

There are many uses for a portable solar charging system even if you don’t own an RV. For RV owners, its primary use is for charging batteries while boondocking. This portable solar charging setup I put together for my RV, could even be used as your primary source of solar energy. I use it primarily to extend the capability of my existing RV solar array. In the early morning or late afternoon hours the sun is low on the horizon and I can position this panel wherever I need it.

If you are new to solar and are looking for an inexpensive way to learn and benefit from it, then this is a great DIY project to start with. It won’t require you to make any mods to your RV either. Building your own also allows you to pick your own equipment. Plus you’ll know how to expand it with more panels in the future as your needs grow…and they will.

Sure you could buy a portable solar charging kit, but why not make your own and learn something new in the process?

The basic components of this portable solar setup are the same as for any off-grid solar setup, only on a smaller scale. You’ll need a solar panel, solar charge controller, solar extension cable and battery connectors.

Everything you need can be purchased on Amazon and delivered to your door. You can also pick up cables, fuses and and wire at Walmart or at a nearby auto parts store.


Solar Panel

Start with a single 100 watt solar panel designed for a 12 volt battery system (a 17V-20V panel). A 100 watt panel is enough to keep a single 100 amp hour deep cycle battery fully charged. I used a semi-flexible solar panel for this project because it is easy to store in my RV, but any traditional solar panel will do just fine.

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Solar Charge Controller

Charge controllers range in size and ratings. The maximum output of a 100 watt solar panel is typically 5-6 amps so a 7-10 amp PWM solar charge controller should be adequate for this setup. You can get a decent one with multi-phase charging capability for roughly $50 on Amazon

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Extension Cables with MC4 Connectors

Solar panels usually come with attached cables, but they are short. You will need extension cables in order to move your panel around to where the sun is. The length of cable you will need will depend on your battery location, size and layout of your RV. Consider getting enough length to reach either side of your RV.

Newer solar panels usually come with standard MC4 connections. So purchase cables with MC4 connectors and they will plug right into the solar panel’s cables.

You will need one extra extension cable for connecting the battery. It can be a short one. Cut the extra cable in half and strip the cut ends of the cable to expose the wire. Wire the cut ends of the cable to the positive and negative battery output on your charge controller.

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Battery Connection

Use 10 or 12 gauge wire with alligator clips to connect the charge controller to your battery. You can generally get those at Walmart, auto parts, or boating stores. I took mine off of my Battery Tender which came with several types of connectors. Premade outboard engine starter cables (found at Walmart or boating stores) come pre-assembled with 10 gauge wire and are a good option to consider.


Consider adding an inline fuse between your solar panel and the charge controller. This will protect your charge controller and RV in the event of a short circuit condition or lightning strike (yikes!). A 10 or 20 amp fuse should be sufficient.

That is everything you’ll need. Be sure to watch the video and see how I hooked it all up. Enjoy!

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Often confused as Tito, Brian answers to both. Other known aliases are "Obi Wan Titobi" and "Brito". He thinks solar power is cool and enjoys being off-grid teaching others how to do the same.

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