What you need to know about solar battery maintenance

Whatever device you're reading this article on likely has a battery in it, meaning that you are at least a bit familiar with battery performance and, whether you realize it or not, battery maintenance. Think about all of the rules around how and when to charge your cell phone to extend the battery's life: you're supposed to run the battery as far down as possible before plugging your phone back in, and you shouldn't leave your phone plugged in all the time or else the performance of the battery will degrade. While your cell phone battery–hopefully–doesn't require any maintenance over its lifetime, the decisions you make around how and when to charge it can be considered a form of maintenance to extend its life.

Solar batteries are no different–there's very little if any, ongoing maintenance that they require, but there are ways to take preventative action to provide the ideal conditions for your solar battery to have as long a life as possible.

The short answer? None!

The longer answer? As usual, it depends, this time, on the chemistry of the battery. While lithium-ion battery technologies–the most common type of solar battery installed in homes and businesses–require very little or no maintenance, other types of batteries may require a trained technician to perform an annual check-up. For instance, with flow batteries, you'll need to check to make sure that the level of the electrolyte (editor's note: don't ask, that's a different post) is sufficient, topping off the tank if any has been lost. You may also need to clean a membrane or an air filter to maintain peak performance. For lead acid batteries, corrosion is a major concern: it's important to regularly check your battery's terminal connections to ensure they're securely fastened and to take action to stop rust in its tracks.

The same way your phone's battery begins to hold its charge for less and less time, the longer you've had it, the performance of solar batteries will degrade over time. To get a feel for what level of degradation is normal, many manufacturers list their warranty as having guaranteeing a certain level of performance at the end of the warranty term: i.e., 80% performance in year 10.

Most of those performance metrics are based on a certain level of operation for your battery–are you charging and discharging it once a day or once a week, or once a month, how deeply are you discharging the battery each time you use it, what's the environment the battery is in? Think about your cell phone: if you're somewhere cold, your phone battery might drop from full to close to zero very quickly. Larger batteries can operate much the same way.

At the end of the day, the way to get the most out of your solar battery comes down to a few key considerations:

• Depth of discharge: depth of discharge measures how much of your battery's charge you use before recharging it. For instance, if you use all of the stored energy in your battery, that's 100% depth of discharge. Batteries with different chemistries are designed to operate best at different depths of discharge–what's routine for a lithium-ion battery might be bad for a lead acid battery. Work with your installer to better understand how much of your battery's capacity you can use at once without impacting its long-term performance.

• Cycles (overall and per day): each time you discharge and recharge your battery is one cycle, whether you use some, most, or all of the energy stored in the battery before topping it up. Many lithium-ion batteries are designed to be cycled daily so that you can charge them from solar panels during the day and use them to offset your usage after the sun sets in the evening. Batteries frequently come with a warrantied or expected number of cycles, typically between 5,000 and 15,000 cycles, which is a big difference: a battery warrantied for 5,000 cycles run once a day is designed to last for 13 years, while one with 15,000 cycles is designed to last over 40 years!

• Operating and storage temperature: Not all batteries are designed for both indoor and outdoor usage. When working with your installer to design your battery system, be sure to consider whether your battery needs to be installed in a conditioned space, like a garage or basement, or if it can be installed outdoors. Subjecting your battery to temperatures outside its operating range can have a big impact on its overall performance.

With those three considerations in mind, it's best to think about solar battery maintenance as coming down to 1) system design and 2) system operation. To get the best performance out of your solar battery system, install it in a place where the temperature won't exceed its operating requirements (i.e., don't install it outside if it can't operate below freezing but you live in the Northeast), and be sure to follow recommended operating procedures when using the battery (i.e., don't override factory defaults that could cause the battery to go to a greater depth of discharge or cycle more frequently than it's designed for).

Thankfully, when you work with an EnergySage installer for your solar plus storage system, you'll install a system that's been professionally designed to optimize the performance of your battery: our installers know what conditions batteries like and adhere to those conditions when installing a battery in your home or business. What's more, nearly every major battery on the market today comes with a pre-set, integrated battery management system, which is software that controls the battery's operations so you don't have to worry about accidentally asking the battery to function in a way it wasn't designed for. It's easy to get quotes for professionally designed solar plus storage systems on EnergySage: sign up for a free account today, and you'll start receiving custom quotes from prescreened companies in your area in no time.