How Long Will A Home Battery Last? Should You Even Buy One?
A home battery backup system can keep your devices powered during an outage. But how long does one last and is it worth the investment? Batteries are a convenient tool to store energy and power your home during an outage, but unfortunately, they do have a limited life span.
This behavior isn’t exclusive to just your smartphone or laptop battery. Pretty much all systems will see their battery capacity reduce over time and eventually need replacement. The same goes for batteries connected to the solar systems, which are giant lithium-ion batteries that act as a backup power source for your home. They also have a limited lifespan.
When considering the purchase of a battery for a photovoltaic (PV) system for residential use, here are the key considerations to keep in mind:
1. Energy Needs and Consumption Patterns: Assess your household’s energy consumption. Analyze your utility bills to understand your energy usage and how much power you might want to store for later use.
2. Battery Type: Different types of batteries (lithium-ion, lead-acid, etc.) have varying lifespans, charge cycles, efficiency, depth of discharge, and costs. Research which battery type aligns best with your system’s needs.
3. System Size and Compatibility: Ensure that the battery capacity is compatible with your solar panel output and inverter. The size of the battery should meet your backup needs without being oversized.
4. Cost: Consider the initial investment for the battery and installation, along with potential financing options. Evaluate the long-term savings versus the upfront costs. Look into incentives or rebates available in your area.
5. Backup Power Requirements: Determine how long you want to have power during outages and whether you need the battery to support essential services or the whole house.
6. Self-Consumption vs. Exporting: Decide whether to use the stored energy for self-consumption during peak rates or to sell excess energy back to the grid, which may impact the amount of storage you need.
7. Maintenance and Lifespan: Understand the maintenance requirements of the battery system and its expected lifespan. This will influence long-term costs and battery replacement.
8. Environmental Impact: Evaluate the environmental footprint of battery production and recycling. Consider the sustainability of the battery technology you choose.
9. Grid Connectivity: Check local regulations and utility policies regarding grid-tied systems, including net metering and interconnection standards.
10. Future-Proofing: Consider the potential for future expansion of your system or changes in energy consumption patterns.
How long does a home battery last?
The most common types of home batteries, typically made of some sort of lithium-ion chemistry, degrade over time just like any other battery. Each time you charge and discharge your battery, it loses some of its capacity to hold a charge. It’s so inconsequential that you won’t notice it at first. After a few years, you might start to notice that your battery can’t hold a charge quite like it used to.
Your home battery could last 10 – 15 years, under the right conditions.
Look closely at the warranty
Almost all home batteries on the market come with a 5-year warranty. That doesn’t necessarily mean your battery will be totally dead in 5 years. The thing you really want to pay attention to on your battery’s warranty is its cycle life or expected energy throughput. Both of these give you a good indicator of how long your battery will really last, according to the manufacturer.
Every time you drain and recharge your battery it completes a “cycle.” On your warranty, the manufacturer guarantees your battery will be able to deliver up to a certain amount of cycles while under warranty. The expected life for home batteries is usually between 3,000 to 6,000 cycles.
Similarly, you might see an expected energy “throughput” listed somewhere on your warranty. This is another way the manufacturer estimates your battery’s lifespan. Your battery’s throughput, usually measured in megawatt-hours, is the total amount of energy that your battery should deliver to your home during its lifetime while still under warranty.
Since your battery’s maximum energy storage capacity decreases over time, most manufacturers will also include some form of end-of-warranty capacity guarantee, promising that your battery will still be able to retain up to a certain amount of its original maximum capacity by the time your warranty expires. Most manufacturers will guarantee up to at least a 70% capacity retention rate. You can still use your battery after your warranty period is up — possibly for another five years, even. Just don’t expect the battery’s performance to be as good as it was when you first had it installed.
Factors that can affect your home battery’s lifespan
Not all batteries are created equal — and even batteries that are similar won’t all last the same amount of time. That’s because several external factors can affect your battery’s lifespan. Here are a few things to consider.
Exposure to extreme temperatures
Sometimes the things that can affect your battery’s lifespan are things that are completely outside of your control, like the weather. If you live in an extremely hot or cold climate, that can shorten your battery’s lifespan. When you’re thinking about where to put your battery, try to keep it somewhere that reduces its exposure to temperature extremes.
If you live in a hot climate, keeping it indoors, or at least somewhere shaded, can help your battery last longer. If you live in a cold climate, keeping it insulated from the elements will also help. If your home has a garage, consider having it installed there.
Depth of discharge
The way you use your battery can also affect its lifespan. A battery’s depth of discharge refers to the amount of energy you can safely drain relative to its maximum capacity. If you drain your battery all the way to zero before you recharge, that can actually hurt your battery. Many battery systems won’t even let you discharge that far for this precise reason, as a way of protecting battery health.
Number of charging cycles
Battery lifespans of 10 or 15 years assume that you’ll run a certain number of charging cycles. Each time you drain and recharge your battery, it reduces the lifespan a little bit.
So if you end up cycling your battery more than what’s recommended by the manufacturer, you might end up with a lower-than-average battery lifespan. It gives wear and tear. Check your battery’s warranty to see its expected cycle life.
Physical damage
It probably goes without saying, but you’d be surprised how easy it can be to accidentally damage your battery. You could damage the battery by incorrectly installed. For example, stacking and wall mount batteries should be placed on the right angle. If you damage your battery, it’s probably going to reduce its lifespan.
When scoping out a location to install your battery, work with your installer to find a spot that’s both easy to access and has a low risk of accidental damage to the battery.
Is installing a home battery worth it?
Whether a home battery is worth it depends on what kind of return on investment you’re looking for. Home batteries can help you save money if you pair them with solar. You still have to overcome the initial upfront cost of the battery to start saving money
Many homeowners install home batteries for a different reason: They’re a backup power source to supply electricity to their home during an outage. In this case, the return on investment might be less about numbers and more about comfort.
What should I use during a power outage: a home battery or a portable generator?
If the upfront cost of installing a battery-based power backup system isn’t feasible, a portable generator is a solid quick fix. However, in the long run, getting a home battery system that’s powered by solar can be the ideal fix to safeguard against power outages.