Some battery storage systems only deliver 800w of power; but bear in mind that a kettle needs 2,000 watts. Also, if you are generating 4kW but the battery can only take on 3kW then 1kW of your free electricity will be wasted by being sent to the grid.
It is important therefore that you check the power output before you buy, otherwise you may find yourself drawing a lot of energy from the grid even though you have energy in your battery.
Batteries will ‘cycle’ (charge and drain) daily and just like in a mobile phone, its ability to hold a charge will gradually decrease the more it is used.
A solar battery will have a warranty that guarantees a certain number of cycles and/or years of useful life. Because battery performance naturally degrades over time, most manufacturers will also guarantee that the battery keeps a certain amount of its capacity over the course of the warranty. So when the question regarding the lifespan of a battery is raised, then the answer will depend on the manufacturer of the battery and how much capacity it will lose over time.
If a battery is warrantied for 5,000 cycles or 10 years at 70 percent of its original capacity it means that at the end of the warranty, the battery will have lost no more than 30 percent of its original ability to store electricity.
Most systems are designed just for storage. However, some offer backup capability to provide power when there is a power cut. To prevent damage to your battery or appliances some of your circuits may need to be rewired. In addition, you will need a larger storage capacity to keep some power in reserve.
The type of battery that is installed will determine whether it requires regular maintenance and if so, how much is needed.
NMC batteries, like LFP batteries, require zero maintenance.
With certain exceptions, nearly all types of solar-driven batteries are sealed, so there is no need to refill them. One such exception is a solar lead acid battery where at the appropriate times you lift the cap off it and replace the solution. However despite the lower initial price, this type of lead-acid solar battery is highly inefficient when compared with lithium-driven solar batteries.
Solar batteries do not last as long as solar panels. Currently, a high-quality solar battery will last for approximately10-15 years, which is dependent on the quality of the equipment, the skill used in the installation and how much use is made of the battery over a period of time.