How To Choose the Best Solar Battery?

You’ll need to consider several factors to find the best solar battery for your system.

Battery Capacity

Battery capacity is measured in kilowatt-hours (kWh) and indicates the amount of energy that can be stored at once. Usable capacity measures the amount of energy that can be used from the battery. This measurement is lower than the actual battery capacity because a portion of the stored energy is used to run the battery.

Battery capacity should match your solar power production. Batteries that are too big won’t use their full capacity, while undersized batteries won’t keep up with the amount of energy your system produces. Look for batteries with a capacity of 10 kWh, enough for most homeowners’ energy needs.

Coupling Options

Solar systems generate direct current (DC) electricity that must be converted to alternating current (AC) electricity for your home’s appliances. In an AC-coupled system, the energy is converted to AC electricity at the inverter, converted back to DC to be stored in the battery, and then converted to AC for use in your home. In a DC-coupled system, energy is converted only once.

AC-coupled batteries work best as add-ons to existing solar power systems. However, they’re less efficient than their DC counterparts because some energy is lost in each conversion.

DC-coupled batteries are better for new solar installations. They’re more efficient and can be charged by your solar panels when the grid system is down. However, they’re complicated to install and could increase installation costs.

AC coupling has been used more commonly in residential systems, but DC coupling is becoming more popular as more options become available.

Depth of Discharge

Depth of discharge (DoD) refers to the percentage of the battery discharged relative to its overall capacity. This affects lifespan: Regularly discharging a battery at a lower percentage will yield more useful cycles than frequently draining the battery to its maximum DoD.

Many battery manufacturers limit DoD to ensure the battery will perform long-term. The industry standard is 80% to 100% for lithium-ion batteries and 50% for lead-acid options.

Power Rating

Power ratings indicate the amount of electricity that can be produced in a specific time frame. These ratings are measured in kW or amps and broken into two categories:

• Continuous power: This indicates how much power can be produced over time.

• Peak power: This is the maximum amount of power that can be produced instantly.

Battery capacity and power ratings shed insight on solar batteries’ power potential. High-capacity batteries with low power ratings can run smaller appliances for longer. Low-capacity batteries with high power ratings offer more powerful bursts of energy but drain quicker.

We focus on continuous power in our reviews because it better indicates how efficiently the batteries will power your home.

Round-trip Efficiency

Round-trip efficiency indicates the energy that can be used after the battery is charged. According to the U.S. Energy Information Administration (EIA), the industry average is around 80%. The higher the percentage, the more efficiently the battery can generate usable energy.

Warranty

A 10-year warranty is the industry standard for solar batteries. However, many companies include a cycle clause or throughput clause that can end the warranty early. Look for batteries that have a higher threshold for both clauses.

Note: Reprinted from MarketWatch