Commercial Battery Storage

Solar Battery storage systems within businesses are often provided with a capacity rating in kiloWattHours (kWh). Storage batteries for a grid connected solar PV storage system are typically around 2kW to 20kWh. This is the capability of the battery to provide power. All batteries lose some energy in charging and discharging (typically around 10%), though some have better ‘charge-discharge efficiency’ than others. Most batteries are not designed to be routinely fully discharged (can reduce battery life). Some have deeper discharge capability than others.

Adding battery storage to your solar PV system enables you to store any excess solar energy to use in your property at a later date. This means that at night or in low solar weather, the battery can power your property without needing to use the grid. This saves you money on your electricity bills as you will only start buying energy when the battery runs out. Many energy providers now have flexible tariffs where you can use a cheaper night rate tariff to charge your battery too.

A battery’s efficient lifetime depends on the technology and the way the battery is used – significantly on the number of ‘cycles’ (complete full battery charge and discharge) that they undergo. Manufacturers generally give an expected lifetime in years and / or in ‘charge-discharge cycles’.

Despite expectations, some storage systems will not provide power during a power-cut. Some solar battery storage systems however do have an ‘off-grid’ functionality, providing a limited amount of power to your home, or to essential equipment (such as your fridge-freezer, lighting etc). But a battery may run out of power before the power cut ends – or have already run out of power if it’s been discharging all evening and the power outage starts late at night or early in the morning. If you require your battery storage system to provide power during power-cuts it is important to talk this through with us from the outset as the system will need to be carefully designed and set-up to your specific requirements.

Most batteries that we install are rated as IP65, meaning they can be installed outdoors. However they should have a canopy over them to protect them from the elements. They can also be installed inside your property on a wall. They ideally need 300mm clearance around them for ventilation and cooling as well as access for any future maintenance. Dimensions of the batteries can be found on the datasheets.

If you have a medium to high consumption of energy, it is likely that a battery alongside your solar will be beneficial. We use our software to calculate how much of the battery you will use with your property’s consumption and can compare what your usage would be with and without a battery. You can then decide which system will work best for you and your energy consumption.

A fully-charged medium-sized system could store sufficient energy to power during the evening your lights and lower-powered items like your fridge-freezer, TV and laptop. Over four or five hours, all of these together will use at most a few “units” or kiloWatt-hours (kWh), of electricity. However, the battery will quickly run out if you put on high energy use devices like the washing-machine or tumble-dryer: these can consume 2 – 3kWh in a single use. The higher capacity your battery is, the longer you can run your home without buying power from the grid. And in winter, the battery might not receive enough energy from your solar panels to provide for even the lower-powered items for many hours. You can compensate for this though by automatically charging your battery up at night on a cheap off-peak tariff.