If you're reading this right now, there's a very good chance you're doing it on your phone or computer.
You've probably charged both from an outlet without even thinking about it.
However, for small residents and those interested in alternative lifestyles, it is not so simple.
Luckily there is a solution.
Solar power systems have improved massively over thatlast decade or so. They've finally reached a point where they can provide all the power needed for a comfortable off-grid lifestyle.
Today we cover the basics of sizing your solar system, the main components and an introduction to putting the whole thing together.
The first steps towards solar self-sufficiency
When planning a tiny home solar power system, you should start by writing down exactly what you need to power. Add things like:
- domestic appliances
- Laptops
- Telephone
- lighting
- TV
- game console
- air conditioners
Once you know everything that draws electricity, you canCalculate how much solar energy you need.
It's always a good idea to add a bit of headroom to that total in case you need extra performance for anything.
This allows you to size both your solar panels and your battery bank.
Next you need to decide if you want to build your solar system for a small house yourself or go for a commercial solar system.
The basics of a DIY solar system
Off-grid solar systemsseem intimidating at first, but are actually quite simple once you take them apart.
Solar panels convert the sun's photons into electricity.
That connects to a battery bank via a charge controller, which then flows to an inverter and becomes usable household power.
There's definitely more to the details, but the bones of the system are pretty easy to figure out.
A big disclaimer before we go any further.
Working with electrical energy is always associated with risks. If you're not 100% happy with your tiny home's wiring, hiring an electrician is a very good idea.
They have the specialized training and know how to properly interface with your solar system and the rest of your tiny home's electrical setup.
Even if you decide to build the system, you should probably have it checked out by a licensed electrician before turning anything on.
You may be able to spot something you missed that could have serious consequences.
solar panels
Solar panels are the largest and usually the most labor intensive part of building your solar system.
You need to position them for maximum sun exposure and mount them properly.
If you're installing them on a Tiny House On Wheels (or THOW), it's imperative to make sure your attachments can withstand the wind while you're driving.
When comparing solar panels, you should look at two basic numbers:
- Watt
- solar cell efficiency
A watt is a unit of measurement of electricity.
The wattage of a solar panel indicates how much electricity a particular panel produces in one hour under perfect sun conditions.
Most modern home panels generate around 100 to 200 watts per panel.
Cell efficiency determines how effectively a solar panel captures the sun's energy.
A panel with 20% efficiency would generate 100 watts of power per square meter.
Higher cell efficiency solar panels produce more power for their size, but are generally more expensive.
If you're looking for solar panel recommendations, I've put my best suggestions in this recent review I wroteflexible solar panels. Be sure to check it out.
You also need to decide how you want to wire multiple solar panels together in your solar system. You can wire them in eitherparallel or in series.
Parallelverdrahtung
If you wire your solar panels in parallel, you must connect all positive poles and all negative poles together.
This has the effect of additively increasing the amps produced by the panels.
The advantage of parallel cabling is redundancy. If one panel or connector fails, the entire system does not stop working and power continues to flow from the other panels without interruption.
If you are using a PWM charge controller you will need to wire your panels as follows.
series connection
When connecting in series, you must connect the positive pole of one solar panel in series with the negative pole of another until you have connected the entire solar bank to the charge controller.
This has the effect of additively increasing the voltage produced by the panels while the amps remain the same.
A good way to think about daisy chaining is with old Christmas lights.
Current flows through the system from panel to panel, as well as from bulb to bulb.
This has the same disadvantage that the old Christmas lights had: if one panel goes out, the entire system stops working.
The benefit of wiring panels in series is that it existsless line loss.
This isn't a huge consideration for most small residents, but if you're building an off-grid homestead with your solar panels some distance from your home, it's something to consider.
If you plan to use an MPPT charge controller, be sure to wire your panels in series.
Charging rules
A charge controller takes the energy generated by the solar panels and regulates it to charge your batteries.
Batteries are actually quite delicate, so it's important to have a quality charge controller in your system.
Charge controllers work by controlling the voltage and rate of charge of the batteries.
They also prevent your batteries from overcharging and damaging themselves.
There are two main categories ofSolar charging ruleson the market today:Pulse Width Modulation (PWM) and Maximum Power Point Tracking.
They each rely on different principles to charge your batteries, but work in very similar ways.
PWM charge controllers were once a major breakthrough but have now been overshadowed by MPPT charge controllers.
While PWM are adequate for small solar systems, they are not the optimal choice.
MPPT charge controllers, on the other hand, can absorb up to 30% more power from solar panels than PWM charge controllers.
One of the biggest disadvantages of direct current (DC) is the line loss caused by low-voltage transmissions.
And while PWM charge controllers can only handle voltages up to about 18V, MPPT charge controllers can handle much higher voltages and convert them into amps.
This has the effect of limiting line loss and capturing the extra power that would have been lost.
In summary, when it comes to the quality of charge controllers, there is no question: MPPT charge controllers are the best option. (sorry PWM…)
Build your battery bank
The solar panels are just one part of a solar powered tiny house.
In order to use the electricity generated by your panels, you need a way to store and regulate it. This is where solar batteries come into play.
Sizing your battery bank
When sizing your battery bank, it is very important that you consider how much current you will need between charges.
Most batteries have a shorter lifespan as you increase their Depth of Discharge (DOD).
This is based on a percentage of their total battery capacity, measured in ampere-hours (Ah).
Increasing the depth of discharge decreases the number of charge/discharge cycles the battery has before it fails.
A good rule of thumb is to double the power requirement.
That gives you about as much power as you need on a regular basis while preserving battery life.
types of batteries
There are countless different battery types available, but only lithium and lead-acid batteries will work for most small home and off-grid needs.
They hit the sweet spot of functionality and price that makes them perfect for our purposes.
lead acid (AGM)
Lead acid batteries have been used for decades. Your car battery is a lead-acid battery, like most large batteries you have encountered in your life. They work with lead plates suspended in a sulfuric acid solution.
Historically, lead-acid batteries required a significant amount of maintenance and care, but advances in absorbent glass mat (AGM) batteries have made them much easier to work with.
These are sealed batteries that require almost no maintenance compared to older generation lead-acid batteries.
They still need to be de-aerated for safety, but you don't need to add distilled water to them.
Lithiumeisenphosphat (LFP)
LFP batteries have only recently become available for solar use in small homes.
They have a number of advantages over lead-acid and other types of batteries, but can be quite expensive.
One of the best things about LFP batteries is their allowable depth of discharge. You can regularly shut down a lithium-ion battery up to 80%.
This gives you significantly more usable power than a similarly sized AGM battery.
They are also lighter and allow far more cycles than AGM batteries.
Many have up to 10 year warranties compared to the 3 year best for AGM batteries.
They cost more upfront but are much easier to manage and give you superior energy density.
If you can afford the upfront cost, LFP batteries are always the way to go.
inverter
An inverter is designed for thisIncrease DC poweryour batteries to theStandard alternating current used by modern devices. They come in two different varieties:
- Pure sine wave
- Modified or quasi-sine wave
Modified sine wave inverters are cheaper and less effective.
They're fine for things like large devices, but not for sensitive electronics.
If you want to charge your smartphone, laptop or TV, you need a pure sine wave inverter.
Pure sine wave inverters are more expensive than modified sine wave inverters, but much more effective.
They allow you to provide nearly the same quality of power from your DC batteries as you would from a regular household outlet.
Circuit breakers, fuses and disconnectors
This depends a lot on your design and how much extra protection you want to build in.
However, there are some components that you should always use to protect your investment. These include:
- inline fuses
- Low Voltage Disconnect Switch (LVD)
- circuit breaker
inline fusesshould run between the solar panels and the charge controller, the charge controller and the batteries, and the batteries and the inverter.
These allow you to protect the various components of your system from a short circuit or an overload that shuts down part of the system.
The fuse you place in it depends on the size of your solar system and the wattage of each line.
The circuit breakers should be in the same locations to allow you to fully power down the system for maintenance.
Make sure you follow the correct shutdown order.
First disconnect the solar panels from the charge controller, then the batteries from the inverter, and then the charge controller from the batteries.
The low voltage isolator goes between the inverter and the batteries. It prevents the inverter from over-discharging the batteries when you go too long without the sun.
All these systems should be connected to the positive cable.
Put everything together
When you connect the different parts of your solar system, there is a very specific order in which you should do it.
You should also ensure that all circuit breakers are turned to the "off" position when you connect the system.
First things first: never connect your solar panels to your charge controller before you have connected your charge controller to the battery bank.
The solar panels should be the last thing you plug into an otherwise complete system. If you connect the panels to the charge controller, you can initially burn out the system or, in extreme cases, even cause it to explode.
Once you connect the batteries to the charge controller, it should power up and go through some settings.
Follow your manufacturer's instructions for setup, then connect the inverter to the batteries.
Only then should you connect the solar modules to the charge controller.
Ready solar systems
If you're looking for something a little more plug-and-play, you have several options.
By far the best will come from a company known as Goal Zero.
They make completely self-contained solar power generators that combine a charge controller, battery, and inverter into one easy-to-use device.
This allows you to either connect them directly to Goal Zero's portable solar panels or to your own.
Yeti 1250
The Goal Zero Yeti 1250 is a complete solar power generator that gives you a ready-to-go system right out of the box.
It is designed to connect directly to any of Goal Zero's solar panels, but can also be connected to standard panels via an adapter.
It can absorb up to 240W of power from solar panels.
The basic system includes a 100Ah AGM battery.
It is designed to power up to 10 devices simultaneously and can power a standard refrigerator for over 20 hours at no additional cost.
This alone gives it considerable power, but what really sets it apart is its chaining capability.
You can also connect the Yeti 1250 to other 12V batteries to charge it.
This means that up to several hundred Ah of electricity are available to you at once.
The Yeti 1250 is a great system if you have very limited power needs and don't want to go through the hassle of fully wiring your small home.
It allows you a lot of flexibility while still providing your excellent utility.
Interested in diving a little deeper into solar products? We have great depthCheck Here Best Off Grid Solar Kits.
Sustainable solar life
With a properly set up solar system for small homes, you can go anywhere you want without depending on the grid.
This gives you the flexibility to live in the middle of a city or in the middle of nowhere.
Now that you've figured out your tiny home solar system, don't forget to plan your water and bathroom needs as well.
Would you like to find out more? Check out our other great solar themed content:
- The 5 best off-grid solar kits that won't break the bank(Ready to buy? Find a great promo in this piece!)
- How to power a small house with solar energy