Electric Basics for Your Small Travel Trailer
Small travel trailers aren’t too complex, but one important system you should know something about is the electrical system and how it works. The most important reason for this is so that you always have the power you need to at least run the most essential functions necessary to keep your trailer operating (e.g. LED lights, water pumps, heater, and perhaps an electric tongue jack). Most small travel trailers are powered by an on-board 12 Volt DC battery when off-grid or 110V AC onshore power when hooked up to a campsite’s electrical outlet (which is then converted to 12V DC). Your trailer’s battery is about 12.7 volts when fully charged and a good rule to ensure long battery life is to never let your trailer’s battery go below 12 volts (about 50% of its capacity). A battery voltage meter should always be used to monitor your trailer’s battery voltage throughout each trip (we had Scamp install one when our 2020 Scamp 13’ was being built and Scamp now installs them on its 2021 models).
A good way of explaining how electricity works in your small travel trailer is by using the water/hose analogy. Your trailer’s battery can be thought of as a water pump; the charge of your battery is water, voltage is the water pressure pushing the water through the hose (trailer’s electrical cables), the current being the flow of the water (measured in Amps), and power is the total amount of water flowing in a given time (measured in watts). Most campgrounds offer 110V AC 30 amp outlets (typically the amperage used in small travel trailer electrical systems) and sometimes 110V AC 50 amp outlets (used for large RVs – for running two or more high-powered devices simultaneously like an electric water heater and AC). The higher number of amps means more power can be supplied to your trailer at any given time. Campgrounds may also offer 15/20 amp outlets at 110V AC (like the ones typically found at home). These outlets provide less power capacity than 30 / 50 amp outlets (meaning you may not be able to run your AC and electric water heater at the same time without tripping the circuit breaker) and generally should only be used as a last resort if a 30 amp hookup is not available for your small travel trailer (or if you are at a home using a 110V Male to 30A Female adapter). It’s also a good idea to have an auxiliary battery power bank, like a Jackery 500, for use when you are off grid and want to preserve your trailer’s 12V battery power for essential devices.
Your small travel trailer will likely have a converter which converts 110 volt power coming in from your campground hookup outlet into 12 Volts. This enables all the 12 volt devices in your small travel trailer to work off 110V, like your LED lights, pumps, etc. When hooked up, you will also be able to use the 110V outlets inside your small travel trailer to power other plug-in devices you bring along with you on your trip (being careful not to exceed the circuit limits in your trailer – often 15 or 20 amp fuses / circuit breakers). However, if your small travel trailer has 110V outlets, they are unlikely to work without hookups because most small trailers don’t have inverters (allows your 12V battery to power 110 volt outlets). Common devices running off electricity inside your small travel trailer are LED lights, a fresh water pump that pressurizes your water system and allows you to use your fresh water tank (city water provided by a hose hookup does not require a pump since it in itself provides continuous water pressure), a water pump under the shower floor to keep the shower water draining into the grey tank and preventing the shower floor from flooding, the bathroom fan, the main overhead fan, TV, the electric furnace blower fan which blows the hot air typically produced by the propane heater, and other electric ignition systems used for lighting gas powered devices like the water heater, and potentially others.
One very important item that should be with your small travel trailer at all times is a 110V Male to 30A Female dogbone adapter. This will allow you to connect your trailer’s 30A power cord into a regular household 110V outlet. It’s essential when you want to hook up at a house or anywhere there is just a regular 110V outlet. Since we store our Scamp travel trailer in our garage, we constantly use the adapter to keep our battery charged and also run the Scamp lights and other appliances when necessary. Additionally, we often use the adapter so we can power our Scamp’s refrigerator the day before we leave on a trip so we can put our groceries in early [since our Scamp has 3 modes for running the fridge – AC, 12V (when driving), and Propane (when no electricity is available at the campground)]. Lastly, it’s very common for us to stop at a relative’s house during our trips and we use the adapter for power when we driveway camp.
A large external independent battery power bank can power many of your essential devices while preserving your travel trailer’s battery power for your super essential appliances like lights, fans, and pumps. We purchased the Jackery 500 which has 518Wh of power (which can power a lot of devices for a long time). To calculate how long the Jackery 500 (which is rated at 518 Wh) will run devices, simply divide the device’s total energy in the powerbank (518W) by the appliance’s energy draw (measured in Watts). For example, our 12V TV draws 28W, so it should run about 18.5 hours (518Wh/28W). We recently used our 12V TV powered by the Jackery on a trip from San Diego to Oregon and watched two hour movies each night for five nights and there was still about 50% charge left on the Jackery, confirming this calculation. When boondocking (no power hookups), use your battery power bank to run your TV, charge your batteries (phone, camera, drone, etc.) and other portable battery powered devices. This will ensure your small travel trailer batteries are completely dedicated to your essential devices. The Jackery 500 has a 12V cigarette socket, USB ports, and even a 110V outlet. It can even be used to run a portable air compressor. You can charge it in your car while driving between camping locations, with 110V power outlets at campsites, and also with a solar panel.
Just because your small travel trailer is connected up to a 30A hookup, doesn’t mean all that current can flow through to your devices. Your small travel trailer has fuses for each circuit to protect devices within your trailer. Many of these circuits are allocated only 15 or 20 amps to protect the devices on the circuit and the 15/20 amp fuses protecting these circuits will blow if too many lights and appliances draw power from the circuit. If this happens, the metal ribbon inside the fuse will melt and the circuit will go dead (meaning all the devices on the circuit will be rendered temporarily useless until the fuse if replaced). This is designed to protect your appliances from getting too much power and, in turn, damaged. So, it’s important you don’t plug anything in which may place too much demand on your small travel trailer’s electrical system (e.g. hairdryer). So, when adding new 110V plug-in devices to your trailer, check the device’s power requirements (divide the device’s Watts / 110 volts = # of amps). For example, if you want to use a small electric ceramic space heater, calculate the device’s amps and make sure it will draw less than the circuit can handle (let’s assume 15 amps) when also considering all other appliances on the circuit. Each fuse in your small travel trailer should be labeled so you know what circuit it represents. In this case, if there are already devices which are running at 6 amps on the circuit you want to use (you would have to figure out and calculate each device’s power requirements on that circuit if you want to be extra precise), then the ceramic space heater should use no more than 9 amps since 6 amps + 9 amps = 15 amps (and preferably less to be conservative). If more than 15 amps is drawn, then the fuse will blow. We just purchased a small electric space heater for our Scamp and calculated its current draws at medium (600W / 110v = 5.5 amps) and high heat settings (1200W / 110v = 10.9 amps). We haven’t calculated all the devices’ power requirements on each circuit, but are comfortable we should be ok using the heater on the medium setting since the draw is only 5.5 amps (we wouldn’t risk using the high heat setting as just this heater alone is getting close to 15 amps and there could be other devices on the circuit we plug the heater into). Alternatively, we could plug the heater straight into our Jackery 500 and run it on medium heat setting for about 50 minutes (518Wh/600W) or on the high heat setting for approximately 25 minutes (518Wh/1200W). As you can see from this example, the ceramic heater draws too much power to run it for hours off a small portable auxiliary battery power bank. In turn, it would be best to run this heater off of hookups at the campground or using the trailer’s propane powered furnace when off grid.
Some great electrical accessories to have in your small travel trailer are a good surge protector, a big box of fuses (in case you blow one), an electrical tester, and a solar panel.
- Good surge protector: It is common to hear stories about bad wiring at campgrounds. And, plugging your travel trailer directly into a bad circuit or getting a power surge could cause damage to your trailer’s electrical system and appliances. To avoid the risk, it’s best to use a good surge protector every time you plug in your trailer. We have used the Progressive Industries EMS-PT30X for almost a year and have had a really good experience with it. The scrolling digital display shows if there are any errors with the campground wiring and provides peace of mind that the power is clean. It has a weather shield and a secure locking bracket to prevent theft.
- Big box of auto fuses: It would be extremely annoying if an entire trip was ruined because no lights and other devices worked as a result of a blown eight cent fuse! We purchased this 120 fuse set on Amazon (make sure to check your small travel trailer accepts standard-sized auto fuses) and we store it under one of our kitchen dinette benches in our Scamp. Alternatively, there are also super cool GLOW fuses that glow when they are blown (but expect to pay more for these)!
CLICK HERE TO BUY THE GLOW FUSES (50 pack)!
CLICK HERE TO BUY THE GLOW FUSES (10 pack)
- Electrical Tester: a digital multimeter is a great tool to check electrical continuity (such as seeing if a fuse is blown it’s not visible) or checking if power is coming out of the solar panel cables.
- Solar Panel: a 100W solar panel is a great option to help recharge your small travel trailer batteries daily when camping without hookups. We’ve found our solar panel can maintain our Scamp’s battery at 12.5V (a good place) for days on end as long as the sun shines. The solar panel may also be used to recharge your independent power bank.
Disclaimer: You will get the same great Amazon price by clicking on the links here compared to buying directly on Amazon, but by buying here you will also be supporting the continuation of this website as we get a small commission from each sale. These are products and procedures we use for our own Scamp that we selected and developed from our own research and experiences. However, we do not endorse any specific product and cannot guarantee that the products we use are exemplary and the procedures we use are complete, accurate, detail the correct recommended procedures, or apply to your model small travel trailer. It’s always best to double check with your manufacturer or operation manuals to ensure you are doing everything correctly. I’m not an electrician or electrical engineer, so I just write about the basics above based on our experiences with our Scamp 13’ travel trailer. Please consult a professional if you need expert help.
