Batteries constitute the heart of any off-grid energy system. Since the availability of solar radiation is irregular, variable and unpredictable during different hours of the day or different seasons, throughout the year at any particular location. Thus to overcome this shortcoming, solar energy storage system is required to ensure the smooth supply of power.
Depending on the type of system, the excess solar energy can also be fed into the electricity grid to provide credits and further reduce the cost of electricity.
The Off-grid system is a system that is not connected to the electricity grid and therefore requires battery storage. The off grid system must thus generate enough power throughout the year and have enough battery capacity to meet the home’s requirements, even during the coldest winter months when not a single ray of sunlight could be seen.
So, on a quest to disconnect from the grid, or to make a decent living with 24/7 electricity supply in a remote corner of the World, a battery with low maintenance, low cost, tailored to your specific demands stands to be a vital component. However, while assessing the best battery catering to your personal requirements, one must weigh its vitality on a few factors:
Capacity & Power:
A battery’s capacity is its ability to run as many appliances, on its power. It is measured in Ampere per hour. The more the ampere per hour, the more electricity it can store. A power rating is the amount of electricity that a battery can deliver at one time. It is measured in kilowatts (kW).
A battery which has a high capacity and a low power rating would deliver a low amount of electricity (enough to run a few crucial appliances) for a long time. Whereas, a battery with low capacity and a high power rating could run your entire home, but only for a few hours.
Depth of Discharge (DoD):
The depth of discharge (DoD) of a battery is the the amount of a battery’s capacity that has been used by it. A maximum DoD would mean optimal performance.
Round trip efficiency:
A battery’s round-trip efficiency is the amount of energy that can be used as a percentage of the amount of energy that it took to store it. In simple terms, it is the economic value out of your battery.
Battery life & Warranty:
It is natural that a battery’s performance degrades over time. Therefore manufactures provide a cover for your battery for a fixed time period. Say for 1 year or 6 months.
So, for selecting the best off -grid battery, there are three available technologies with their respective pros and cons, tailored for different needs:
These batteries are the tried and tested ones, are cheap, and available in both sealed and unsealed variety. They however, have a short life cycle, a low DoD and are bulky. The major players of this type are: Trojan, Crown, Surrette-Rolls, Solar-One, Outback.
This type comes with a high initial cost, not to overlook its long cycle life and excellent DoD makes it much more cost effective in the long run.
Nickel Iron Batteries:
This type is recently trending for cost effectiveness and durability. It however lags in battery life and requires high maintenance.
Hope you find it useful! May you find your best off-grid battery.
By Rashi Sharma