Battery Storage

What is the useable capacity of a battery?

The capacity is the amount of energy in kWh, or units, that the battery can store. However, the batteries should never be drained completely as this can damage the cells. ‘Useable’ capacity is the important figure to note when researching batteries, although sometimes brands will quote a ‘total’ capacity which is misleading.

What is a cycle?

A cycle is one full discharge and one complete charge of the battery, although the battery may only discharge 25% and then recharge 25%, which would account for a quarter of a cycle. When it comes to the warranty of a battery, you need to know how many cycles the battery is warrantied for so you can calculate the number of kWhs, or units of electricity, that the battery is intended to deliver over its warrantied lifespan.

What capacity should I look for in a battery?

Each customer’s needs are different, so it depends on your individual requirements as to the capacity size you should look for. If you want to install EV chargers, you’ll need a larger battery to allow for this. Likewise, if you plan on grid trading, a larger battery capacity will allow for more charging at a cheaper rate and a greater quantity of power to sell back to the grid.

For some people, the decision to install energy storage is to become more sustainable, not  for financial benefits. Battery storage can enable properties to become less dependent on grid electricity suppliers and to reduce their overall carbon footprint. In these instances, the capacity requirements may be different again.

Contact us to discuss your requirements and we’ll be happy to advise you on the options available.

Solar Power, Day or Night

You may wonder whether solar panels work at night?  The short answer is no, but battery storage can enable you to use solar energy at any time. During the day, your solar panels may generate more power than you’ll need for your property. With battery storage, you’ll be able to use that excess energy later when the panels are no longer providing power, helping you to avoid using power from the grid.

AC Coupling versus DC Coupling

When you purchase a solar battery, there’s the option of AC coupling or DC coupling – each has its own pros and cons to bear in mind before you make your decision.

AC coupled require separate inverters for the battery and panels. This allows for flexibility in terms of location and enables you to optimise the position of your equipment – batteries operate best at room temperature while inverters work best at cooler temperatures. You’ll get more power from the combination of the battery and panel inverters, and they work well with any solar PV system. However, they can be more expensive and are often between 1-3% less efficient in terms of power transfer than DC.

DC coupled battery and panels share the same inverter, which provides a more efficient power transfer than AC by up to 3% and could be cheaper overall. However, if there’s a fault with the inverter, it could render the battery useless since a compatible inverter might not be available, and there’s limited access to power. There’s also less flexibility with where these battery units can be installed.