With the cost of batteries going down and the electric industry upgrading and creating new grid infrastructure, home energy storage systems are very much in demand. Now, with the SGIP (Self Generation Incentive Program) subsidy in full swing, we may see a renewable energy revolution that makes distributed generation mainstream for all consumers.
Residential customers typically use battery storage to reduce their electric bill by shifting grid energy consumption from on-peak to off-peak hours. Battery storage may also make residential solar installations viable in areas without net metering. But in order to find the best solar battery options available for your home, a thorough evaluation is in order. But before you schedule your site survey with a local solar energy company (and we hope you’ll call Day One), you’d better ‘bone up’ on some of the terminology so you’ll know what questions to ask.
The most important ones to pay attention to are the battery’s capacity and power ratings, depth of discharge, round-trip efficiency, warranty, and manufacturer.
– Capacity is the total amount of electricity that a solar battery can store, and while it tells you how big your battery is, it doesn’t tell you how much electricity a battery can provide at a given moment. To get the full picture, you also need to consider the battery’s Power Rating – the amount of electricity that a battery can deliver at one time. A battery with a high capacity and a low power rating would deliver a low amount of electricity enough to run a few appliances for a long time. A battery with low capacity and a high-power rating could run your entire home, but only for a few hours.
– The depth of discharge (DoD) is the amount of a battery’s capacity that has been used. Most solar batteries need to retain some charge at all times and if you use 100% of a battery’s charge, its useful life will be significantly shortened. A higher DoD means you will be able to utilize more of your battery’s capacity, so you need to look at the battery’s optimal performance DoD percentage.
– A higher round-trip efficiency means you will get more economic value out of your battery. If you feed 10 kWh of electricity into your battery and can only get 8 kWh of useful electricity back, the battery has 80% round-trip efficiency, which is still an acceptable ratio.
– Every solar battery has a warranty that guarantees a certain number of cycles 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. Therefore, it’s important to know what brand of battery to buy and how much capacity it might lose over time.
– Whether you choose a battery manufactured by a cutting-edge startup or a manufacturer with a longer production history, the warranties associated with each product need to be thoroughly evaluated to choose the best energy storage solution.
We at Day One Solar has reviewed many solar battery options currently available for your home and would be happy to offer our expertise to assist you with your solar+energy storage projects.