A Beginner’s Guide to Off-Grid Solar Power
Solar power can be confusing. So, we’ve prepared this guide to help answer the most common questions in very simple, non-technical, easy to understand language.
The internet is filled with videos, blogs, pictures, recommendations and other information that’s often contrary or downright ridiculous. Online calculators are also common, meant to help you choose the right ‘package’ for you. But in most cases these calculators don’t take into account that every application is different, and the actual requirements are as unique as the individual – so we work with customers & provide recommendations not just for solar energy products but their entire off-grid living experience. That’s because making some minor changes to your lifestyle or choosing the right appliances can have a significant impact to the size (and ultimately the cost) of your solar power system.
The first step is to understand what off-grid means, and the differences between off- grid and grid-tied solar power systems:
- Off-grid systems are autonomous, meaning they are designed to be completely independent of the local power These systems are used for off-grid homes, cottages, cabins, RV’s, boats, and other applications where access to grid power isn’t possible or impractical. These are the systems that The Cabin Depot Ltd.™ specializes in.
- Grid-tied systems use solar panels to offset energy consumption in your home. These systems require the approval of the power utility, site inspections, and certified electrical contractors to The Cabin Depot Ltd.™ does not offer these systems today, but we can recommend companies in your area who would be happy to help.
So, if your application is for off-grid use - terrific! Then read on…
Off-Grid Solar Power System Components
All off-grid solar power systems are made up of four key components:
- Solar panels = converts sunlight to DC (Direct Current)
- Batteries = stores the DC energy that is produced by the solar
- Charge controller = ensures proper charging of the battery
- Inverter = converts DC energy to household 120/240vAC (Alternating Current)
People get very excited over solar panels, often rushing out to buy them first before properly sizing their system. Solar panels purchased because they are ‘on sale’ may seem like a bargain at the time, but if they aren’t the right type or size, they can actually cost you more money when finally installed. The reality is that your batteries are the most important component of an off-grid power system!
The size and type of these components will depend primarily on the electrical loads that you want to service. This can be confusing as the jargon can become more technical,
but here’s the bottom line: To significantly reduce the size (and cost) of a solar power system, you will want to avoid (when possible) powering any appliances or devices used for heating or cooling air, water, and food electrically.
Electrical loads are the things that you will have “plugged in” to power electrically.
Examples would be:
- Small Loads: LED lights, LED television, satellite receiver, radio, cell phone charger, small diaphragm water
- Large Loads: Keurig coffee machine, microwave, hair dryer, hot plate, air conditioner, AC powered refrigerator, deep well pumps.
When it comes to solar power equipment selection, you must consider your electrical loads first. Your total investment will be much lower if the system is used to power small loads because you won’t require as much energy. You can still power large loads using solar, but your system components will need to be larger in order to store the additional energy required.
There is a direct correlation between your overall loads and the system cost.
Reducing Electrical Loads
You will need to balance convenience with practicality. For example, it would be nice to have an air conditioner at the cabin, or to run the AC in your RV, but the cost of a solar power system to run one will add many thousands of dollars to a system cost. So, thinking specifically of ways to reduce cost, here are some examples:
- Heating: use wood as your primary heat source, or a direct-vent propane heater as a secondary option. Heat water using an on-demand propane tankless water heater. Cook food on a wood stove, or more commonly, an off-grid propane
- Cooling: install a propane or solar/DC refrigerator, or select a smaller portable AC/DC powered fridge/freezer. Utilize high-efficiency / low power cooling fans or ceiling
Refrigeration is usually the largest consumer of power in an off-grid application. A typical household refrigerator uses 120vAC to operate. They usually have auto-defrost, ice makers, and other accessories that ramp up energy consumption. Even a basic 120vAC refrigerator will be rated for around 250 watts operating, with a surge (when the compressor starts) approaching 1000 watts. Furthermore, in an off-grid application, you would be using DC power from your batteries and converting that to AC power via an inverter to run your refrigerator. Inverters suffer from conversion loss (when taking battery DC power and converting to household AC power), so you can count on ‘wasting’ anywhere from 5% to 15% of your energy through this conversion. As such, customers wanting to run an AC refrigerator will need to invest in a larger solar power system to operate it, which typically costs more than replacing the refrigerator with a solar/DC model designed for off-grid use in the first place.
A solar/DC refrigerator is designed with energy efficiency in mind. They have more insulation, a specially designed DC compressor, and connect directly to your battery bank. Since there’s no inverter required, there’s no conversion loss to worry about. There are many models of solar/DC refrigerator, but most are rated for around 55 - 65 watts when operating. So, as a customer, you’re able to use a much smaller solar power system to operate one.
Estimated Solar Power System Cost
Just like buying a car, your budget and lifestyle will determine how much money you will eventually spend on a solar power system. And just like buying a car, there are many options and accessories available. If you want more bells & whistles, or more convenience, you’ll spend more money. It’s that simple.
Below are some examples which demonstrate the typical differences in cost:
- Uses 12vDC battery power only (no inverter required).
- All electrical loads connect directly to the battery
- Can operate 12v LED lights, 12v water pump, 12v ceiling fans, 12v refrigerators,
- Typically used for hunting camps, weekend-use cabins, RVs, boats,
- A small inverter could be added to run a TV or radio for a few hours at a
- Approximate cost: $350-$2000 for a complete
- May use a 12vDC (or 24vDC battery bank with the use of a step-down converter) to power the same 12vDC devices listed in the ‘small system’ above, but adding a small inverter to supply 120vAC power for small AC loads such as radios, TV’s, DVD players, cell phone chargers, CPAP machines, etc.
- Typically used in seasonal cottages, camps, or cabins where you may spend weeks at a
- Can operate solar/DC refrigerators and other appliances designed for off-grid
- Will typically use a gas or propane generator to run larger load items as needed i.e. coffee maker, hair dryer, air conditioner, This is usually more cost-efficient vs increasing your solar system size to run these items for short periods of time. If you don’t want to use a generator, you can expect to add ~$1000+ to the system cost.
- Approximate cost: $1000-$3500 for a complete
- Uses 120vAC and/or 240vAC
- Uses 12vDC battery power only (no inverter required)
- Typically operates household electrical loads year-
- Some exceptions, such as electric baseboard heat, electric ranges, or electric clothes They are usually replaced with propane models.
- Northern climate off-grid houses will always have a backup gas or propane generator, used occasionally in the winter months to charge the battery bank after consecutive days of poor weather
- Approximate cost: $7500 (with careful energy management) to $25,000+ for a complete
It’s important at this point to remind you again that every solar power system is as unique as the individual using it. Buying a “kit” that is too small or not expandable will leave you without power when you need it the most and limit your ability to expand. Buying a kit that’s too large for your application is just a waste of money. So, remember - BIGGER IS NOT BETTER! Our primary goal is to ensure your off-grid solar power system is suitable for your specific
application and lifestyle, so we always recommend building it for future expansion. That way you can start off with what you ‘think’ may work and add to it in the future without having to replace all of your key components or wiring.
We hope you found our beginners guide helpful. If you have any questions, or are considering an off-grid solar power system – contact us! We’d be happy to help.
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