Are you like some homeowners who ask, “how long do solar batteries last?” The question makes perfect sense, especially if you want to get the most out of your solar panels. You will want your batteries to last as long as your solar system.
Unfortunately, solar battery life expectancy is a bit shorter than your solar system. How short, you ask? Let us find out.
How Long Can I Expect My Solar Batteries to Last
Most solar power systems can last up to 30 years. Meanwhile, the life of solar panel batteries can last 5 to 15 years, depending on several factors.
That said, if you can buy high-quality deep cycle batteries and keep them in tip-top shape, you can expect to replace your power bricks only once before replacing the solar system.
Unfortunately, poor-quality solar batteries, shoddy maintenance routines, and other less-than-ideal battery conditions can increase battery replacement frequency by up to six times before the solar power system reaches its life expectancy.
Do Different Solar Battery Types Have Varying Life Expectancies
The battery’s design can impact its depth of discharge (DOD) – the amount of DC electricity the battery can discharge relative to its total capacity without damaging it.
For example, suppose a solar battery has a 10 kWh capacity and a 95% DOD. In that case, you can expect the battery to discharge up to 9.5 kWh without causing substantial damage to the power brick.
As a rule, the higher the battery’s DOD rating (in percent), the less frequent its charging cycle. The lower the charging frequency, the longer the battery’s lifespan.
As mentioned, solar batteries come in different types that affect solar batteries lifespan.
The most common solar batteries are lead-acid, either flooded or sealed. These batteries have been around for decades, making them the go-to power systems for people living off-grid.
Unfortunately, FLAs and SLAs have a modest DOD rating of 30-50%, which should be sufficient for about 50 to 100 cycles. Lead-acid batteries can last 5 to 7 years.
Lithium Iron Phosphate Batteries
Lithium iron phosphate solar batteries have more charge-discharge cycles, with up to 100% DOD rating.
On average, LiFePO4 solar batteries can discharge between 2,000 and 3,000 times. However, there are LiFePO4 units that can discharge up to 12,000 times. A LiFePO4 solar battery could last over 10 years.
There are also lithium-ion batteries with a higher DOD rating than lead-acid batteries. On average, Li-ion batteries can discharge up to 90% of their power load. Hence, a 10 kWh Li-ion battery can give up 9kWh without harming itself.
Although lithium-ion solar batteries cannot match LiFePO4’s cycle durability, they are better than lead-acid batteries. Li-ion solar batteries have a charge cycle of around 10,000 times. It allows Li-ion batteries to last 6 to 10 years, based on a weekly discharge cycle.
A new generation of solar batteries combines the remarkable attributes of Li-ion and LiFePO4 systems. Saltwater batteries have a maximum DOD rating of 90% (similar to Li-ion) and impressive cycle durability of up to 5,000 charge-discharge cycles.
Hence, it is not unusual to expect these solar batteries to last at least 15 years.
What Other Factors Can Impact a Solar Battery’s Lifespan
Battery type not only impacts its depth of discharge and lifespan. Other factors can also contribute to the solar battery lifetime.
As a rule, the more frequently you use your batteries, the more often they undergo a cycle. Hence, the estimates we calculated above can be lesser or greater, depending on battery usage.
For example, suppose you use solar batteries to run everything in your house, from the lights to air-conditioning, refrigerator, TV sets, computers, and other appliances. In that case, these devices’ power requirements can drain your solar batteries faster than if you only have the lights relying on solar power.
Some home appliances have greater power requirements than others. For example, a 16-cubic-foot refrigerator can draw 1.2 Wh per day, while an LCD TV might use only 150 watts.
Batteries require an optimal temperature to work efficiently. Most solar batteries have a 77-degree-Fahrenheit rating, although their ideal operating temperatures are 50 to 85 degrees Fahrenheit.
In general, batteries lose ten percent of their power capacity for every 15-20 degree Fahrenheit drop from 80 degrees Fahrenheit. The reduced power capacity results from slowed-down chemical processes, increased resistance, and reduced charge acceptance.
A 10 kWh solar battery will only hold 9 kWh of charge if you live in 60-65-degree Fahrenheit areas. People living in 40-50-degree Fahrenheit places can only expect a 10 kWh battery to hold 8 kWh.
Hence, it would be best to place the solar batteries in areas with the ideal temperatures. For example, if you live in milder climates, you can position the batteries outdoors. The basement is an excellent choice if you live in colder regions.
Lithium-ion, sealed lead-acid, and lithium iron phosphate solar batteries do not require any maintenance. However, flooded lead-acid batteries do.
It is essential to frequently check the battery fluid level and maintain the battery terminal’s integrity. Failure to do so can undermine the flooded lead-acid solar battery’s lifespan.
Why Do You Need Batteries for Your Solar System
Homeowners contemplating installing a solar system often ask why they need a battery for their setup. After all, the solar panels gather sunlight and convert it into usable electricity.
However, the sun does not always shine. Although there is still light at night, it will be insufficient to generate electricity to satisfy your needs. The same happens on cloudy days. Your solar power system continues to collect energy, but the amount is inadequate to meet your electricity requirements.
That is why you need batteries to store solar energy-converted electricity. The solar batteries provide you with electricity in power outages, emergency situations, at nighttime, and on cloudy days.
You can imagine what will happen if you have a battery with a short lifespan.
How Can I Extend My Solar Battery’s Lifespan
Here are some tips on how you can extend your solar battery’s lifespan, regardless of battery type.
- Limit the number of solar batteries in your power bank to only four. The more batteries you have in the bank, the greater the resistance you create, leading to unequal charging. You can also use larger-gauge battery interconnect cables to reduce overall resistance.
- Rotate the power bank’s solar batteries at least once every three to four months. This tip only applies to power banks with more than four solar batteries. It would be best to rearrange the batteries to ensure adequate charging for each unit.
- Observe proper solar battery charging and discharging. It would also be best to connect your batteries to a trickle charger to maintain their charge, even if you do not intend to use them.
- It would also help to overcharge your batteries periodically to enhance plate equalization. Plate sulfation can occur with insufficient charging. Because charge controllers suppress overcharging, you might want to turn these devices off as you overcharge your batteries.
You now know that five to fifteen years is the answer to the question, “how long do solar batteries last?” A solar battery’s lifespan reflects its battery type or composition, depth of discharge, cycle durability, maintenance requirements, battery usage, and operating temperatures.
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Hi, I am Eddie, Cleanenergysummit’s content editor. It’s so much joy to work alongside Justin, as the idea of providing knowledge about using clean energy excites us.
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