Van life is a beautiful, adventurous lifestyle that many people partake. Unless you have unlimited resources to purchase gasoline or electricity to fuel your van, you should know how much energy you employ daily to determine what size solar system you’ll need.
What is an amp hour?
An amp-hour (or amp-hour) is the basic unit of electrical charge used to measure the energy stored by many types of batteries. A battery’s capacity is measured in amp-hours. The more amp-hours your battery holds, the longer it will last per charge.
How to Calculate AH
- Find your battery’s AH rating.
- Multiply the amp-hour rating by the number of days you plan on being camping.
Here’s an example (your results may differ depending on your battery type):
You have a 100AH battery, and you plan to be camping for five days straight without using shore power. So, we multiply 100AH x 5 days = 500AH. You have 500AH to power your rig for five days.
- Divide the number of AH by the average daily wattage you use for power (usually 10-20W per day)
500 AH / 10-20W = 5 AH per day is needed to keep your rig charged. Your solar system should be able to provide this amount to charge your battery once a week fully.
These calculations should be viewed only as an estimate. Use this knowledge to make a better decision when purchasing your next solar system for your van life.
Knowing your battery’s AH is also very important to upgrade from an existing solar system. An upgrade will most likely improve the performance of your solar system. That means the panels can provide more wattage, or more panels can be used on your rig.
More panels = more amp hours (theoretically)
Having too many amp-hours is not usually a problem, but a lack of amp-hours could be. When you pick out the panels and batteries, make sure they have the proper amp-hour rating for your van. If necessary, you can add more. It’s also important to size your panels correctly. More wattage does not always mean better performance.
It is often hard to understand when going solar for the first time, so you can use calculators online to help determine what size system will work best for your needs.
Campgrounds and your Electrical System
To be confident that you have enough electric power for camping, you should install a basic electrical system in your camper. It will include a 100 amp-hour (AB) deep-cycle marine battery that will function as your primary power source. It will also include a 12 volt, 80 amp-hour (AC or DC) bank that you can charge from your car battery.
If your job requires you to walk outside, you should invest in a portable solar panel system that will enable you to charge your batteries while working. This type of system is compact and lightweight.
Solar System Sizing Calculator
When choosing a solar system for your van, RV, or cabin, start by determining the total wattage you will need to charge your batteries.
The best way to do this is with a solar system sizing calculator. Solar system sizing calculators are available in most major solar panel manufacturers. You’ll be asked questions about your battery, solar panel, and daily power needs. Once you input all the information, the sizing calculator will provide you with a recommended system.
As part of your search for an ideal solar system sizing calculator, you can read this article and observe how each one does it. It’s also a good idea to visit online forums and ask the people who were in the same place you are now.
How many amp-hours do I need camping?
Solar power is excellent for people that want to go off the grid and live a sustainable lifestyle. The solar panels you use for your camper rely on sunlight to work. So, unless you live in a region with lots of sunlight, you’ll experience problems charging your batteries without an adequate solar system.
That’s why it’s essential to determine how much wattage you will need before settling on a solar system. The wattage you need will be based on the amount of power your batteries can provide and your daily needs.
For example, if you need to use 12V lights in your camper and have a 100AH battery that carries 200 Watt-hours, then you need a solar system that can provide at least 50W to offer enough power to recharge your battery.
A solar system that generates 50W (300W peak) is recommended for this scenario. It will have enough electricity to charge your battery and also provide enough power for your lights.
The above example is an essential guide on how much wattage to choose from and how to find the best system based on the type of solar panels you use. Other factors may impact a solar system’s ability to charge your battery, such as weather conditions, location, and even the size of your rig.
Portable Battery Chargers
For your solar power system to be effective, you’ll have to charge your battery whenever it runs low. When you wish to use the power from your van, camper, or cabin, you’ll have to plug it in with a portable battery charger. That is because your van and solar panels are not connected.
It’s important to understand that portable battery chargers are not made for deep cycle batteries. They’re designed to recharge your 12V lead-acid batteries, which are not made to be charged deep cycle.
Therefore, you must determine the type of battery you have before looking at portable battery chargers. A typical 12V lead-acid battery will be charged with a 24V or 48V charger, but never by anything less than 24V. That is why you must choose a portable solar charger with the correct charging voltage for your battery.
How to calculate the ideal battery capacity
The numbers in this section show the number of amp-hours a battery should have. The amp-hours is the amount of amperage that can be pushed through a battery when it’s fully discharged.
- 26400 Ah– This is the standard voltage and capacity for a battery used in caravans, camper vans, and boats, as well as RVs.
- 35000 Ah– A battery with this high capacity is perfect for high draw systems and solar energy systems.
- 48000 Ah– This is an excellent battery for vehicles used every day, for example, boats and RVs.
- 72000 Ah– If you need extra capacity, this is the battery for you. It will fit in most trucks, sub-compact cars, and larger cars.
- 96000 Ah– If you are looking for a battery that will last a long time without a recharge, this is it. The capacity of this battery is great for larger vehicles such as trucks and RVs.
- 120000 Ah– This is the most powerful battery on our list, with more than enough room for high-draw applications. It also fits larger trucks and vans well, but we do not recommend it for smaller vehicles.
A Word of Caution
It might be a bit confusing for those who are not familiar with the terms used in solar panel sizing calculators, so we’ll try to explain some of the key concepts here. For most people, the biggest challenge is choosing how many amp-hours to include in their batteries. It also requires knowledge about how much energy you use daily and what type of batteries you need. Remember that the number of amp-hours you need in your battery determined from these calculators is based on charging your battery every day. That means that if you are planning on living off-grid (not relying on power from other sources) or using shore power for charging, you need to take this into account.
Therefore, be very careful when choosing several amps based on the calculator information. If you choose too few, your battery will not get enough power. If you choose too much, it could result in overcharging your battery.
Calculating AH For Solar Panels
To calculate the number of amp-hours you require from your solar panel set, you must consider the wattage it provides at its peak and how long it takes to charge your batteries.
For example, a solar panel that generates 100W of power at peak and can charge your battery in two hours will have a voltage of about 25V. That is, if you purchase a lead-acid battery that only has 24V. As you already know, this type of battery requires more than the standard 24V charging voltage. In this case, the solar panel will generate more than enough wattage to charge your battery. It means that if your solar panel generates 100W at peak, it will take two hours to charge your battery. Therefore what you need in amp-hours directly depends on the amount of time it takes to charge your battery.
Be careful not to add more amp-hours than necessary. That can cause your battery to overcharge and lose its ability to hold a charge very quickly, which is very expensive and frustrating for any solar power system.
The Two Types of Solar Panels
Solar panels are available in two forms that you can use for off-grid living. These are monocrystalline and polycrystalline panels. Polycrystalline panels are more expensive than mono ones, but they generally have a shorter lifespan. They wear out faster, but a well-made poly panel will last 5 to 10 years if well maintained.
Panels made of monocrystalline crystals cost more than polycrystalline but last longer. They are the most common and come in sizes ranging from 100 to 180 watts. There are also high-end mono panels that can generate several hundred watts, making them suitable for off-grid applications.
Types of Solar Batteries
Like solar panels, there are two main types of solar batteries: flooded lead-acid and sealed batteries. Sealed batteries have a superior life span to the flooded variety. They also tend to be lighter and more powerful. They require little maintenance, but they cost more than the flooded variety.
Flooded batteries are the most common batteries for small solar power systems. They’re cheaper, heavier, and charged up to 50% if you store them in a sealed state. Taking care of these batteries will allow them to last a few years before you have to replace them entirely with new ones.
Just remember that these batteries are less powerful and need more maintenance than sealed ones. They also take up more space in your van, camper, or cabin.
Common Battery Sizing Systems
When sizing a battery for your camper, van, or cabin, you must use a battery sizing system. These systems let you determine how much power your battery needs to power everything you want in your home.
It is easy to determine how big a battery you need is to use the amp-hour system. It calculates the number of amps your battery should hold by dividing the number of amps your solar panels can produce at their peak by the number of hours it takes to charge a battery fully.
For example, if you have a 50AH lead-acid battery and 24V solar panels that can produce 100W at peak, you divide 100W by 5 hours (the number of hours it takes to charge your battery fully). The result is 30 amps.
It means that your lead-acid battery will hold 30 amps for 10 hours at full charge before it needs a recharge. In other words, if your solar panels produce 100W of power at peak, your battery will last for 10 hours before requiring recharging. That is how you get the number of amps you need from your solar panels and battery.
Choosing the Best Solar Battery Options
These days, there are many types of solar battery options available, such as lead-acid and gel. Each type has its advantages and disadvantages. But before you go for a particular model, you should consider what it will need to power your rig. That is because most solar panels and batteries are not made to be used together.
If you don’t already have a solar panel, we recommend you purchase one as well. That’s going to work together to keep your batteries charged. It will allow you to use the power from your van, camper, or cabin whenever you want.
Rated Power Output from Solar Panels
The amount of electricity your solar panels generate varies tremendously. For example, some produce more electricity when the sun is low in the sky, whereas others are most efficient at midday. That is why it’s essential to measure your solar panels before you choose them. Otherwise, you might end up with a high-output panel that can’t transfer any extra power to a battery.
Summary
To recap, one of the most important things you need to consider when sizing your off-grid solar power system is the battery. It’s essential to have enough amp-hours so your van or camper can last for a long time. Take note that not all batteries, even if they have the same amount of amp-hours, are compatible with each other.
It would be best to choose the correct size battery that will fit under the hood or floor of your camper or van. It’s possible to do this in two ways. You can either use a battery sizing calculator or measure the space storage in your vehicle where you plan to place your battery to see if it fits.
If you want to install a solar panel in your van or any other vehicle, we recommend buying a portable solar charger that’s capable of charging high-draw systems. That way, you can use the power from your solar panels whenever you want or be part of the change and move towards sustainable options, like electric vans.