29th Jul, 2020
A few decades back, the notion that one could fulfill their electricity requirements through an off-grid power solution seemed to be absurd. However, in that timeframe, renewable energy, specifically solar power, has made great strides. It is now very possible for people to abandon the grid system by moving towards solar powered and battery solutions to power their words.
An off-grid solar power system is incomplete without batteries as it would be quite risky to rely on a direct supply of solar-powered electricity alone.
In other words, the battery storage steps in if, for any reason, the solar system is not able to provide the necessary amount of energy.
To understand this topic further, we will look at the different aspects of going off-grid with a focus on batteries.
Firstly, let's look at some basic estimates that would give us an understanding of how many batteries or how large of a battery bank a homeowner would need to power an average-sized house.
This will help to calculate a basic installation cost and assist in choosing the best possible options in terms of voltage ratings and energy capacity.
The average household can consume around 300 kilowatt-hours (kWh) of electricity in a day. This means that around 30 fully charged 12 V 100 Ah batteries would be needed to power the house for a day without any direct input from solar power.
Keeping budget constraints in mind, you could possibly rely solely on your batteries to provide power for 2-3 days at most. From a solar perspective, you should have enough PV solar panels to sustain the energy demands of your home through solar energy for the rest of the month.
Let's shift our attention towards the natural requirements needed for a solar-based off-grid solution. As mentioned earlier, it is simply not economically feasible to rely on batteries for extended periods as this will lead to high costs because you have to create a very large battery bank.
That is why, when opting for the off-grid option, the selection of the solar site plays an important part in the long term success of the setup. The chosen location for installing the solar panels must have clear access to sunlight without any impediments like trees or hills. In fact, in general, the location should ideally receive ample sunlight throughout the year so that there are no prolonged periods of no-light.
Before going into the specifications of the battery, we need to understand what type of battery would be best suited for this job. We will look at this subject from two different perspectives. First, we would look at the broad category of batteries and then look at specific types of batteries within that category. In doing so, a better purchase decision can be made that will yield the best possible results from your investment.
Broadly speaking, there are 2 categories of batteries that one would find in the market. The first is the starting, lighting, and ignition (SLI) batteries. More commonly used as automotive batteries and their purpose is to provide initial bursts of high magnitude current in order to start the car.
The second battery category is the deep cycle battery. They are designed for frequent deep discharges. Deep cycle batteries deliver a steady magnitude of current over longer durations and if we compare the two categories, deep cycle batteries are far more suitable for an off-grid solar system solution given the nature of their application.
When exploring the market, ensure that you choose an option that belongs to the correct category of batteries. This is because most specific types of batteries exist in both SLI and deep cycle categories. When it comes to creating an off-grid solar power system, 2 options are highly popular and recommended by experts. They are lead-acid batteries and lithium-ion batteries. Both of these types have their own pros and cons. It also comes down to the buyer's requirements and constraints.
In order to differentiate between these 2 popular options, let's look at the details.