Lithium-Ion vs. Lead-Acid Batteries

Lithium-ion batteries are trending in the energy storage market. These reliable batteries are popular for several reasons including further depth of discharge, higher cycle life and longer overall lifetime expectancy.

Lithium-ion batteries have a further depth of discharge at up to 100 percent. Standard lead-acid batteries have a discharge depth of around 50 percent. This means that your lithium ion battery bank does not need to be as large as a lead acid battery solution and can reduce space requirements as well as balance of system components cost.

Lithium-ion batteries also have a significantly higher cycle life, which is the number of times a battery can discharge power and be recharged before it loses potency. Lithium-ion can typically cycle 5,000 times or more compared to just 400-500 cycles in lead-acid batteries. Be sure to read the manufacturer spec sheet to see the cycle life expectancy for the depth of discharge you are choosing.

Lithium-ion batteries can also reuse old battery cells, making them a more sustainable choice. These and other factors mean that lithium-ion batteries have longer life-spans and are more reliable than lead-acid batteries overall.

Though lithium-ion are more expensive, the cost has decreased dramatically over the past several years. Prices are projected to continue downward. Plus, the longer life-span of a lithium-ion battery will save money over time.

Different Types of Lithium-Ion Batteries

Here are some common lithium-ion batteries with the longest life-spans.

Standard Lithium-Ion

These batteries have a high energy density. Because they’re so powerful, their temperature can be unstable and they may require a cooling system. No matter how you charge these batteries, they lose almost no memory capacity over time. They’re very common and generally very safe.

Top Lithium-Ion Battery Brands for Your Rooftop Solar System

Looking for a reliable and tested solution that’s approved for use in grid-tie battery backup systems? Here’s a list of some top battery brands for home energy storage.

Tesla’s Powerwall Battery is one of the best-known standard lithium-ion battery options available. With 14 kWh of energy capacity, Powerwall supports solar and backup power and will soon support time-of-use load shifting. It’s compatible with SolarEdge StorEdge grid-tie battery backup inverters.

Panasonic supplies the cells to Tesla for their Powerwall batteries. But Panasonic also offers its own 8 kWh lithium-ion battery. It’s currently available to homeowners in Australia.

LG Chem Battery is another highly trusted lithium-ion battery storage option. It offers 9.8 kWh of energy. Like the Powerwall, LG Chem is compatible with SolarEdge StorEdge grid-tie battery backup inverters.

Mercedes has joined the solar battery market by partnering with Vivint Solar to produce a lithium-ion solar backup battery with 2.5 kWh of energy storage capacity. The batteries are “stackable,” so you can buy as few or as many as you need. If space isn’t an issue, you can combine up to eight batteries and scale your system to 20 kWh, which could give you a lithium-ion battery bank with one of the longest life-spans available.

Top Lithium-Iron Battery Brands for Your Rooftop Solar System

Lithium Iron Phosphate – With better chemical and temperature stability, these batteries have a high discharge rate and sometimes a longer cycle life. Their basic chemistry makes them safer, but it also means they have lower voltage and energy density rates.

Discover Battery is a lithium-iron-phosphate battery with 6.65 kWh of available energy. Like the Powerwall, Discover batteries are scalable up to 10 batteries for maximum storage. These batteries are compatible with the XW+ Inverter System.

SimpliPhi has several lithium-iron-phosphate battery options that are compatible with OutBack Radian inverter systems. The largest energy capacity they offer is 3.5 kWh, but you have the option of adding as many batteries as necessary to meet your storage needs.

Benefits vs. the Additional Cost of Lithium-Ion and Other Batteries

Do the benefits of home energy storage batteries outweigh the additional cost? They certainly can, especially if you live in a region where power outages are common because of weather or high population and energy demands on the power grid.

With grid-tied energy storage, you’re still connected to the grid and can pull power from it when needed. With net metering, you receive credit when your solar panels generate enough energy to feed back into the grid. But net metering is going away in some places. If you won’t be paid back for the energy that your rooftop solar system generates, then you can essentially pay yourself back by storing the energy to use later.

Is your utility company switching from tiered rates to time-of-use rates?

Time-of-use rates are higher at peak times, like when you (and your neighbors) all get home from work and cook dinner or watch TV. Having a battery backup to draw from at those times would save a lot of money.

Choosing the right battery for your system isn’t something you have to figure out on your own. Give us a call at 760.597.0498 to have your questions answered. We look forward to speaking with you!

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