One of the advantages of owning Violet the campervan since 2018 is that I have learned what works and what doesn’t when it comes to house battery systems. Naturally, that assumption is based on my particular needs. However, I’m pretty generic, so my needs are likely similar to many others.
Who am I to inform you? Am I an electrical engineer or an expert in solar energy? Not at all. I understand electronics (I hold an advanced amateur radio license), am comfortable with technology, and have worked with various power systems in my van since 2018. In addition, I have tested quite a few solar generators and solar panels, as I’m an official reviewer for a large online internet marketplace (side gig). Based on this, I would call myself an informed consumer.
Individuals choose a part-time or full-time life in a vehicle for many reasons. Some enjoy the adventure; others do it for economics. Vehicles exist in various sizes, impacting what you can and can not do. Are you living full-time in a Prius or vacationing in a converted school bus? These are two very different environments. Lastly, different people have different desires. Some want a minimalist lifestyle, while others desire all of the comforts of home. A financially secure individual in a class C motor home who camps at RV resorts has completely different needs than someone boondocking full-time in their Astrovan.
It is impossible to come up with a one-size-fits-all scenario because of this. In today’s post, my goal will be to help the reader to start thinking about their power needs as I offer some potential solutions.
Fit yourself loosely into one of these three categories:
-Minimalist: Your power needs are minimal. Your electronics consist of your smartphone. You don’t use a refrigerator and instead rely on daily shopping or only eating shelf-stable foods. You may have a few USB chargeable items, like a headlamp or light pucks.
-Average user: You use a 12-volt fridge and may use other items like a vent fan. You like to travel with your tablet or energy-efficient laptop, but you don’t regularly do computer-intensive activities like video editing.
-Power-user: You need a reliable and constant energy source to power your fridge and other electrical devices like a blender, induction cooktop, and microwave. You may have advanced electronics like a Starlink internet connection. You use a powerful laptop regularly. You consider your vehicle your home on wheels and want to live a life of modern conveniences.
It is essential to determine your van life situation. A weekend warrior can charge a large battery at home before and after a trip. A weekend warrior’s power needs will differ from someone who has to rely on their power system in a permanent boondocking scenario.
Where are you going to camp? Will you spend your winters in sunny Arizona or live in the often overcast Pacific Northwest? I have 400 watts of solar on my roof, and in an ideal sunny situation, those panels have an output of around 360 watts. However, their output can be as little as 10 to 25 watts on an overcast day. If you plan on spending a lot of time in cloudy environments, you will need more than solar panels to keep your battery system healthy.
Appliances can use different amounts of power at different times. Let’s look at a fridge for an example. A fridge running in a 70F environment will use less power than one that keeps your food cold in a 90F environment. A full fridge will be more efficient than one that is empty. Likewise, a fridge will use less power than a fridge/freezer.
Some devices use constant power, while others use power intermittently. A roof fan uses continuous power. If it is rated at 35 watts, it will use 35 watts in one hour. A small electric pressure cooker may be rated at 700 watts. It uses full power to bring the unit up to pressure, but then it may power on only 20% of the time to maintain pressure. This can make it difficult to determine your power needs. The easiest solution is to use a wattage meter (“Kill-A-Watt”) to get a general idea of the wattage used based on the quantity and type of food you cook.
This is all that you need to know:
If you are an average or above user, get the largest power system that you can:
- Fit into your vehicle without compromising your living space.
- Keep charged by whatever means available to you.
Build or buy?
Building a battery system will be less expensive than buying an all-in-one solar generator, but only if you build the system yourself. Hiring a technician to create a custom system can be costly. The technical knowledge to develop your system can be acquired by reading articles and watching YouTube videos. It is essential to match your components and to do things correctly. You need to use the correct gauge wire and many other considerations. Although I have the skill to build a system, I have always used solar generators for my van’s house power needs. The remainder of this post will focus on solar generators as they are the easiest and best solution for many. Your mileage may vary.
The price of solar generators has dropped considerably over the last few years. I love their “plug-and-play” ability and portability. All of the parts of a solar generator are matched, so everything works well together. Typically, their footprint will be smaller than a comparable custom system. Their downside is that if one component fails, it can take down the whole system. However, I have never had that happen in my years of van life.
Lead acid/AGM batteries.
The original battery type used in solar generators These batteries are heavy and have many disadvantages over newer battery chemistries. However, they can operate and charge at a wider range of temperatures than newer battery types. For many, this technology is obsolete for a vehicle’s house battery needs.
This is the battery chemistry of choice for most. There are several chemistries for this battery class, but for simplicity’s sake, I’ll split them into two types: Lithium-ion and Lithium Iron Phosphate (LifePO4).
Lithium-ion batteries are often used in electronics (like phones) and EVs (electric vehicles) because they are more energy-dense than LifePO4 batteries. This means the batteries are both smaller and lighter than a LifePO4 system. There are cases where these batteries can enter an uncontrollable self-heating state and catch fire. This will more likely happen with poorly manufactured batteries with cheap BMS (battery management system) circuitry.
LiFePO4 (lithium iron phosphate) batteries are not likely to enter into an uncontrollable thermal cascade. Additionally, they can be charged and discharged many more times than a lithium-ion cell. However, they are significantly bulkier and heavier than a similarly capable lithium-ion battery.
Both battery chemistries are reasonable to use in a solar generator. If you need the lightest/smallest package, go with lithium-ion. If you want the safest option that will also last longer, go with LiFePO4. The overall trend in solar generators is to use LiFePO4 batteries.
Lithium batteries can be discharged to around 10% of their total charge compared to lead acid/AGM batteries, which should only be discharged to about 50% of their capacity. Solar Generator companies will list how many times a battery can be discharged and recharged before it degrades. They usually list the number of charge cycles before a battery is reduced to 80% capacity. However, other companies fudge these numbers and will give you the number of cycles to 70% capacity, so be aware of what you are reading. If you are a part-time van dweller, most solar generators will last you many years. If you live in your van 365 days a year, use a battery system that can be discharged many times before its performance degrades.
How big of a battery system should you get?
As stated above, as much as you can. However, here are some basic guidelines.
First, a caution. Solar generator manufacturers sometimes list the power of their unit’s AC inverter front and center. They may say something like “1000-watt solar generator,” but the actual battery bank may only be 600 watt/hour, while the AC inverter is 1000 watts.
Look for “watt/hours” to determine the capacity of a solar generator. However, knowing an inverter’s power is also essential, as a larger inverter can allow the end user to use more powerful appliances, like a small microwave. Watt/Hours tells you how much power storage you have; inverter size tells you what you can run on AC.
You lose some of your battery power in “translation,” additionally, the unit’s BMS will never allow for a full battery discharge. Therefore, the actual run time will be less than the calculated run time. For example, you have a 500-watt/hour unit. The overall runtime of an appliance that uses 500 watts will be less than an hour (500/500 = 1.0 hour, minus overhead energy use), and the overall runtime of an appliance that uses 250 watts will be less than 2 hours (500/250 = 2.0 hours, minus overhead energy use).
The 300-watt/hour range systems are great for charging cell phones and running simple devices like USB fans. They are small, so they recharge quickly. Their size makes it possible to take them into public places (like a coffee shop, workplace, or library) and discretely charge them. Naturally, do this only with appropriate permission.
Systems in the 700-1500 watt/hour range are helpful for the average van dweller. They are reasonably priced and have enough capacity to run your fridge even if you have a cloudy day or two and your system can’t get enough solar. Higher capacity units may be enough to power some electric appliances.
Systems in the 2000 watt/hour and beyond range open up the possibility for power use. These units typically have large inverters to energize power-hungry devices like a small microwave or an induction burner.
Features to look for in a Solar Generator.
-The ability to accept higher-powered solar panel systems. More input will mean faster charging.
-The right size pure sine wave inverter (as opposed to modified sine wave inverter) that converts DC power to the AC power home appliances need.
-A regulated 12-volt power output. Batteries will drop their voltage as they discharge. Some appliances (like 12-volt fridges) and medical devices (like CPAP machines) need a constant voltage to operate. A regulated output accomplishes this. However, this circuitry will use more battery in the regulation process.
-Fast charging from an AC source. Some newer solar generators can recharge very fast when plugged into shore power. Older design units may take many hours to accomplish what a more recent device can do in a single hour. I have an older Jackery that charges at 65 watts/hour, while my new (and very high capacity) Pecron can charge at almost 1000 watts/hour.
-Pass-through charging allows you to use your devices simultaneously while charging.
-The right port complement will make your life easier. For instance, if your computer can charge via USB C, having this available on your solar generator will be more efficient than using the power inverter to convert DC to AC for your computer’s power adapter and then having the adapter convert it back to DC for your computer’s charging circuitry.
-The right-sized inverter. An inverter converts the DC current from your battery to the AC house current that many appliances use. If you plan on using power-hungry appliances (like a small microwave), you will need an inverter sized to accomplish this. For instance, a typical 700-watt (output) dorm microwave requires an input power of around 1,100 watts. A solar generator with an inverter with a capacity of 1500 watts would be the minimum requirement in this situation.
Note that AC Inverters use energy to convert battery DC power to AC power. Larger inverters use more conversion power than smaller units. Therefore, you want to pick a solar generator with an inverter that is “big enough” but not so large that you are wasting power by just keeping the AC on.
Pro Tip: If you are changing from one solar generator to another, pay attention to the new unit’s solar panel requirements. Low Watt/Hour units often require low voltage solar panels in the 12-24 volt range, while larger units typically require solar panels that may be in the 36+ volt range. If you have multiple solar panels it is simple to increase your panel’s voltage by connecting them in series instead of parallel. Two 18 volt panels connected in series will yield 36 volts (18 + 18 = 36 volts).
Pro Tip: I only turn on the AC when I need to run something that needs it, and I immediately turn it off when I am done. Continuously leaving an inverter on can drain a large battery bank in a day, even if it isn’t powering any appliances. Beyond my AC-powered cooking appliances, most of the things that I use are run on DC power (fridge, fan, heater).
All appliances list their maximum power draw on a label located on the back or the bottom of the unit. My current solar generator has a 2000-watt inverter built in, which is enough for my “all-electric” van’s needs. I can carefully use an induction burner, microwave, coffee pot, and even a three-quart Instant Pot, but only one at a time.
-There may be other solar generator features that could be important to you, like the ability to control the unit with an app or a wireless charging pad for your phone. I like newer units that have their AC recharging circuitry built into the unit (instead of an external power brick). However, I don’t consider that to be a mandatory requirement.
You can go small if you are creative.
People do operate 12-volt fridges with small solar generators. However, they do this with compromise. Some use two small 300-watt/hour units. They use one to run the fridge while they charge the other one with a folding solar panel. Others use small solar generators and load their fridge with purchased ice (turning it into a temporary ice chest) when they have a run of cloudy days. The less you rely on electricity, the smaller the system that you need.
Ways to recharge your solar generator.
Rooftop solar panels
I have 400 watts of solar power on my van’s roof, and this has served me well.
Advantages: Set and forget. My panels are always charging my batteries when the sun is present.
Disadvantages: It can be expensive (if you use a professional installer) or mildly complicated (if you do it yourself) to mount. Being flat on the roof, the panels have a sub-optimal angle for solar charging. They don’t generate power if I’m parked in the shade.
Folding solar panels.
Advantage: No installation, simple to use. You can place them at the proper angle to capture the most solar energy. You can place them in the sun while keeping the van in the shade.
Disadvantages: May not have a high enough voltage needed for larger solar generators. Clunky. They can only be used when you are stationary. They can be stolen.
I have an inverter connected to my car’s battery, and my solar generator’s charging brick is connected to the inverter.
Advantage: I can run the AC appliances independently off this unit if I idle my van. When I drive, I can charge my solar generator at a high rate. Caution, as some brand-X inverters are not what they say they are. I had a 1500-watt unit that could only produce around 900 watts of power. I now have a Xantrex unit that was at least twice as expensive, but it does the job.
Disadvantage: An additional expense. It may stress smaller vehicle’s electrical systems.
Car accessory (cigarette lighter) socket.
Advantage: Using this is as simple as plugging in a patch cord into your cigarette lighter and then into your solar generator.
Disadvantage: At most, you can only charge at 10 Amps ( 10 Amps x 12 Volts = 120 Watts). In many cases, your system will only allow you to charge at 65 watts. This may work for small solar generators or folks who are constantly driving, but more is needed for most.
These are relatively small gas generators that have a pure sine wave AC power output.
Advantage: You can keep your battery charged regardless of sky or shade conditions. They are very efficient, so a little gas goes a long way. Such a generator could charge up a solar generator for a relatively small cost. Honda is the class leader but is expensive. There are a number of Chinese brands that offer a similar capability for a fraction of the price of a Honda unit. However, they may not have the longevity of a Honda. I have a cheap Chinese unit, but I have never needed to use it.
Disadvantage: These generators take up space, and you also have to carry gasoline.
AC Mains Power.
Advantage: If you have access to regular AC power, use it to keep your solar generator topped off. I take advantage of AC power whenever I am able. I just plug the solar generator’s charging brick into the AC to keep the solar generator’s batteries fully charged.
Disadvantage: You have to have an outlet handy. This won’t be the case in many National Parks or in any boondocking situations.
When you have to rely on a potentially unreliable power source, it is important to have some sort of backup. Although I do the majority of cooking with electricity, I also have a small butane stove. Additionally, I have battery operator lights and even a battery-operated fan. On a recent trip with my son, my 12-volt fridge mechanically failed. Luckily, we had enough emergency shelf-stable foods to “carry on.” There are no emergencies for those who are prepared.
We all know the big brands, which are often excellent products. I have used Goal Zero, Jackery, and Bluetti systems, and they are good. Off brands are mixed, but most are OK (I have tested many). Some less-known brands stand out. I have been especially pleased with my current Pecron system, and I have also heard good things about the Oupes brand.
I have changed my power system several times, initially out of need, now more out of tweaking interest. However, most users can be “one and done” with a little thought.
I hope that this post has helped new van-dwelling get an understanding of the ins and outs of van-life power.