The yield from a sustainable energy system can vary greatly in supply during the day. Batteries can store the surplus and release it again when the energy demand increases. For example, the stored energy can be used at a different time, for example when it is evening or when there is little solar radiation or wind. Most batteries have an autonomy of a few hours to one day.
The period that the energy can be stored in an off-grid system varies per application. Different types of batteries can be used for a sustainable energy system, below we will discuss some types. Would you like personal advice on which type of battery is suitable for your application? Contact us by e-mail or phone, we always respond within 48 hours.
Lithium-ion batteries have a high energy density, require little maintenance and a relatively low self-discharge. This type of battery is suitable for a rapidly fluctuating energy demand and can also be empty for a while without damage. However, different lithium batteries can differ from each other. It does not necessarily have to be the case that one battery has a lower quality than the other, but can simply be built according to different specifications. One of these is the energy release and energy intake of the battery. Lithium batteries are very suitable for delivering and absorbing a lot of energy in the short term. It can therefore make a big difference if you use a lithium battery when you only have radiation on your solar panels or have a supply of wind for a small part of the day.
It can also shorten the running time of a generator, so it can save a lot of fuel in an autonomous off-grid energy system. The manufacturer of a battery has a clear idea of the market for which he is designing the battery. Do you use the battery in an application where the energy will be discharged in a reasonably quiet way (such as with a home storage system)? Then sometimes a type of battery that is designed to release its energy less quickly will suffice. This obviously has a significant effect on the costs for the battery, as it becomes cheaper due to the less stringent design requirements. When there is an off-grid system in which a lot of energy has to be extracted from the batteries in a short period of time, it is useful to choose a battery whose internal structure is such that it can also handle this.
Lead-acid batteries generally have a lower production cost and are a robust choice. Compared to lithium-ion batteries, these types of batteries have a larger volume and can release energy less quickly. The battery can also be discharged less deeply. The battery must also be regularly fully charged, which can sometimes be difficult in an off-grid system or a home storage system. If you leave the battery bank in an uncharged state for too long, sulphation of the battery will occur, causing you to lose part of your battery capacity. It is advisable not to discharge a lead-acid battery too deeply, as this will not benefit its life. With our autonomous systems, we advise the customer as much as possible to ensure a long lifespan of the off-grid system. We also try to achieve the longest possible lifespan of the system by means of a monitoring system. Lead-acid batteries come in different types, we will discuss a few.
The AGM battery
The abbreviation AGM stands for absorbed glass matt. The lead plates are separated by thin mat structures. The battery is designed in such a way that there is a high contact surface, so the battery can release its energy relatively quickly. AGM batteries are relatively often used in starting applications (for example cars), but the AGM battery can also be used well in off-grid energy systems with high peak consumers. A disadvantage of the AGM battery is that the battery is also very subject to wear when empty (sulphation). These batteries have a low self-discharge and a longer life than the standard lead-acid batteries. The AGM battery can be stored longer without being recharged (compared to a normal lead-acid battery) and is maintenance-free. In addition, this type of battery (unlike the wet lead battery) does not necessarily have to be mounted upright, which gives more freedom in the application.
The gel battery
Gel batteries are built in roughly the same way as traditional lead acid batteries, but without the use of liquid. They contain a more solid gel substance instead. Gel batteries are sealed and therefore maintenance-free, so they do not need to be topped up, just like the AGM battery. This can be very practical in an autonomous off-grid energy system. Gel batteries release energy slightly less quickly than AGM batteries and can therefore be used less for an application with fast energy release. Since the battery packs do not gas, they can also be set up indoors.
The wet traction battery
In a wet traction battery, the cells are filled with a liquid mixture (electrolyte) of sulfuric acid and water. This type of battery is relatively inexpensive and can handle high amperage. In addition, this type is relatively easy to recycle compared to other battery types. A disadvantage of a wet battery is that they are relatively heavy batteries, can only be mounted upright and there is a risk of leakage. They also need to be topped up regularly, so this type requires significantly more maintenance than the other types of lead-acid batteries. The battery is not suitable for off-grid systems that are installed indoors. The batteries must be placed in a well-ventilated place where gases released during the charging process can easily escape.
Do you have questions about the above battery types? As a specialist, the Off-Grid Factory can answer all your questions and help you make the choice for the right battery set. Call or email us on +3185-0706688 or firstname.lastname@example.org for tailor-made advice.