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How Long Do Solar Batteries Last?

Solar power has widely gained popularity among homeowners for its affordability and reliability. Since it draws its energy from the sun, you need a solar battery to enjoy power 24/7.

This battery will store the remaining energy from the solar panel for use at night or whenever there’s no sun. But for how long do they last?

What’s the Lifespan of a Solar Battery? 

A high-quality solar battery should last between 5 to 15years. That said, the actual lifespan depends on factors like:

  • Battery use
  • Solar battery type
  • Temperature and humidity
  • Charging and maintenance

On the other hand, a solar system has a more extended lifespan, between 25 to 30years. With this information, you now know that you’ll have to replace your solar battery once or twice over the system’s lifespan. 

Thankfully, there are ways you can extend the lifespan of your solar battery.

  • Ensure they don’t remain discharged for long
  • Only use distilled water for regular watering
  • Rotate the batteries frequently
  • Use the correct sized solar batteries for the panel
  • Though you may need more batteries for more connections, try as much as possible to limit the number

You’ll need to shop for a quality solar battery even before thinking about its longevity. Here is a table detailing vital things you should consider when purchasing solar batteries for home use.

Things to considerHow it works
Battery type and compositionThe three most common types currently in the market are lead-acid, lithium-ion, and saltwater batteries. Each has its advantages and disadvantages. Lithium-ion is perhaps the best for home energy. They’re light, have a higher DoD, and will serve you longer due to their extended lifespan.
Depth of discharge (DoD)DoD is the amount of charge on the batteries, shown in percentage, once you discharge them. This percentage is relative to the battery’s total capacity. The higher the DoD percentage, the better.
Power output/capacityThe amount of energy in kilowatts that the batteries can generate in a given cycle. The higher, the better.
Life expectancyHere, you can check on both the warranty period and usage cycles. Most solar batteries have a 10year warranty.
Round trip efficiencyThis reading is the amount of energy stored vs. what you used. The higher the round trip efficiency, the better.
how long do solar batteries last

Factors That Determine the Lifespan of Your Battery

As mentioned above, four factors will affect the longevity of your solar batteries.

Battery Use

Like many battery-powered systems, the lifespan of a solar battery deteriorates over time between charges. It’s like the batteries get affected by how often you charge them.

Most solar batteries will start showing this fallout after completing a particular number of cycles. The cycles, in this case, hugely depend on the type of solar battery you’re using.

The question now is, how often do you use your solar panel? This frequency depends on the type of solar system you have installed in your home.

For an off-grid system, the batteries won’t last you as much compared to an on-grid system since you entirely rely on the solar system. 

To increase the lifespan of your solar batteries, see how much they can discharge the energy before recharging. That is their DoD, which you really should pay close attention to so your batteries can serve longer.

Never allow your solar batteries to discharge energy more than the recommended percentage. Doing this will shorten the lifespan of the batteries.

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Solar Battery Type

There are three solar battery types common in the market today: lead-acid, lithium-ion, and saltwater.

Lead-acid Solar Batteries

Lead-acid batteries have been in the market for a long period. Though other better technologies have emerged, homeowners still use them since they’re reliable and affordable.

These batteries are also robust, making them suitable for an off-grid system. However, their lifespan is wanting. And although they’re cheaper to buy, you may incur more costs replacing them due to their short lifespan.

To prolong their lifespan, don’t discharge them too much. You can only discharge lead-acid batteries up to half of their total capacity. That’s because the highest DoD a lead-acid battery has is 50%.

Lithium-ion Batteries

This type of solar battery is the best choice for residential homes. While they haven’t been on the market for long, they still pose as the greatest competitor to lead-acid batteries.

Lithium-ion solar batteries have a longer lifespan, are lighter, compact, and with a higher DoD. So, if you’re looking for a solar battery that will minimize your dependency on the grid, take lithium-ion. With these batteries, you can discharge as much as 80% without affecting their lifespan.

There are two main concerns about these types of solar batteries. They’re expensive, but you’ll surely get value for your money. Lithium-ion batteries are also combustive if not correctly handled.

Saltwater Batteries

If you’re looking for safety in your solar energy, saltwater batteries are the safest option available today. Different from the above two, these batteries store and discharge power using salt.

Besides being eco-friendly and easy to recycle, saltwater batteries are more reliable than lead-acid batteries. They have a higher DoD and a longer lifespan.

Temperature and Humidity

Whether hot or cold, the temperature can significantly affect the life expectancy of your solar batteries.

Heat, for instance, will make your solar battery work harder, which in turn shortens its longevity. On the other hand, cold temperatures will slow down your battery’s chemical reactions, hence draining its energy faster.

What then is the best temperature for your solar energy? To prolong the lifespan of your solar batteries, you must store them at room temperatures, 77°F.

But still, depending on the type, the three batteries react differently to temperature and humidity changes.

The most vulnerable to temperature changes is the lead-acid battery. Manufacturers recommend storing these batteries at a temperature range of 40-80°F.

Lithium-ion can work below 0°F and higher than 140°F, while saltwater batteries will operate at 23-104°F.

The ideal storage location for solar batteries is a room in your house, preferably the basement or garage, where they don’t get exposed directly to the elements. This way, they’ll last longer than expected. Those who stay in temperate regions can store their solar batteries outdoors.

If you’re unsure where to install them, it’s always a good idea to look for a solar advisor to help you out.

picture of a solar technician

Charging and Maintenance

It’s advisable not to leave your solar batteries uncharged for long. Doing this can easily damage your batteries, reducing their lifespan. The best option is to leave the charging system on to allow continuous charging.

To prolong the lifespan of these batteries, you must ensure sulfation doesn’t occur. Sulfation in solar batteries usually occurs due to uneven charging. It can also occur if you fail to use your charged batteries for long.

You can prevent sulfation through the battery equalization process, where you’ll be safely overcharging the batteries.

Please note that regular maintenance on your solar batteries will surely prolong their lifespan. It will save you money in the long run that you would otherwise use on repairs and battery replacements.

Always follow what the manufacturer recommends for each battery type. Lead-acid batteries, for instance, require frequent watering. You must keep checking and refilling whenever there’s a reduction in water level.

No solar battery should be left undercharged or uncharged for long, so you don’t damage them. Remember only to overcharge if you’re performing a battery equalization process to remove sulfation. You can hire a solar expert to offer maintenance services.

FAQs

Below are some answers to common questions regarding solar batteries.

The average cost of replacing solar batteries is about $200 to $15,000, depending on several factors. Replacing lithium-ion batteries, for instance, may cost you between $7,000 to $14,000.

Factors affecting the solar battery replacement cost include:

1. Battery manufacturer

2. Battery type

3. Number of solar batteries to be replaced

4. Load panel

5. Labor cost

Replacement process

You can’t replace the solar batteries yourself unless you’re a professional. The solar battery replacement process is usually risky and must be handled with care.

If you’re not careful, you could inhale lithium gas, leading to severe health risks. An explosion and corrosion can also happen, causing injuries or even death. These are the reasons why it’s costly to replace solar batteries.

Several factors influence the price tags of solar batteries.

One is the chemistry behind each battery type. It’s hard and expensive to produce these solar batteries.

The energy storage capacity also plays a prominent role in determining the prices of solar batteries. These batteries can store up to 20kWh of power.

For these reasons, the cost of solar batteries ranges between $5,000-$9,000, minus installation/replacement cost.

There are a lot of benefits one can enjoy from using solar batteries. The solar battery ensures you have power in your home throughout, whether the sun is up or not. It also reduces your dependency on a grid, so you become energy independent.

It can reduce your electricity bills, so you get to save money every month. A solar battery is even more suitable in regions with unstable electricity grids.

And since solar batteries are environmentally friendly, you get to reduce your home’s carbon footprint.

With all these benefits, it’s worth getting a solar battery for your home.

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