Enphase IQ batteries: overview and specifications

If you’re looking for a solar storage battery for your home, Enphase offers several options with its IQ series.

Enphase is best known for its microinverters. Most solar homeowners these days are choosing power optimizers or microinverters over conventional central inverters, and Enphase dominates the North American microinverter market with its IQ7 and new IQ8 series.

Meanwhile, lithium batteries are getting cheaper all the time, utility companies are having scheduled blackouts (aka power safety shutoffs) due to wildfire risks, and utilities continue to attack net metering. Because of all this, home storage batteries are becoming more popular with solar homeowners.

The Tesla Powerwall 2 is the most well-known product in the battery market, but Enphase has offered batteries for a few years now. Originally branded the Enphase Encharge, their batteries now use the same branding as their microinverters and are known as the IQ series.

We’ll get into the nitty gritty details, but first here’s an overview of why you might want a battery with your home solar system.

Why would you install a battery with a solar panel system?

Most home solar systems don’t include batteries and don’t need one. The vast majority of solar installations are grid-tied, which means they are connected to the public electric grid.

When the solar panels generate more electricity than the home can use, the excess power is sent into the grid where it can be used by neighboring homes. If the solar panels produce less than the home needs - such as at night - the home uses electricity from the grid.

However, during a blackout, a grid-tied solar array will shut down automatically even if the sun is shining brightly. This is to prevent the panels from energizing downed power lines and putting utility workers at risk.

Batteries can also be useful for avoiding peak-hour utility rates. By using stored electricity, solar homeowners who have a battery can take advantage of different time-of-use rates to save money.

There are a lot more considerations too, so to learn more you can read our guide to home energy storage.

Enphase IQ Batteries: Overview and basic specs

There are four batteries in the IQ series: the 3, 3T, 10, and 10T.

The 3 and 3T batteries have a storage capacity of 3.3 kilowatt-hours (kWh), while the 10 and 10T can store 10 kilowatt-hours of power.

The “T” models have the same technical specs, but come in slimmer and taller dimensions that might fit better in your chosen installation space.

Here’s a list of basic features that are common to all of the IQ batteries:

• AC-coupled battery system
• Lithium iron phosphate (LFP) battery chemistry
• Off-grid capable with included IQ microinverters (also requires IQ System Controller)
• Self-consumption, maximum backup, and time-of-use (TOU) optimization modes
• Fanless passive cooling
• 89% round-trip efficiency
• Mobile app-based monitoring
• Warranty: 70% capacity, up to 10 years or 4000 cycles, extendable to 15 years

Several of these items require more explanation, which we’ll get to later in the article. In the meantime, here are the specifications for the four models in the current IQ Battery lineup:

Why make such a small battery?

By itself, a single IQ 3 battery doesn’t have enough capacity to be useful for most homes. So why does Enphase offer it?

Expandability. You can add multiple IQ batteries together to reach the capacity you need for your home. In fact, underneath its housing, the IQ 10 battery is actually just three IQ 3 batteries packaged together.

The product option of a large and small battery gives you more flexibility than the Tesla Powerwall 2, which comes only in a 13.5 kW capacity, or the LG Chem batteries that only have larger 9.6 kWh and 16 kWh capacities.

With the smaller 3 kWh size, a homeowner has more options for getting exactly the amount of storage capacity they want. Enphase doesn’t specify a maximum number of batteries that can be installed together, so if you have large energy requirements, you could have multiple IQ 10 batteries to achieve very large storage capacities.

Lithium iron phosphate (LFP) vs Lithium nickel manganese cobalt oxide (NMC) batteries

Enphase’s IQ batteries are lithium iron phosphate (LFP), which differs from the more popular lithium nickel manganese cobalt oxide (NMC) used in other batteries such as the Tesla Powerwall 2 and LG Chem.

LFP and NMC are both types of lithium-ion batteries, but they use different chemistry.

NMC batteries have higher energy density, which means that they store more electricity than an LFP battery of the same weight. This is important in electric vehicles, but much less so in stationary applications such as home storage.

The advantages of LFP batteries are that they are less prone to thermal runaway (ie. catching on fire) when damaged, and are significantly more durable.

According to research done by the Department of Energy, an NMC battery can be expected to have a cycle life of 1,200. (Cycle life is the number of charge and 80% discharge cycles the battery can provide over its lifespan.)

An LFP battery (like the Enphase) can be expected to have a lifespan of 2,100, which is 75% more.

This is a big advantage in a home storage application, where you want a long lasting product that you can install and forget about. Because of the much longer expected lifespan, the Department of Energy says that LFP is a cheaper choice for storage applications:

While capital cost for lithium-ion LFP was only marginally lower than lithium-ion NMC, its annualized cost is significantly lower ($93/kWh vs. $140/kWh) due to its higher cycle life.

Keep in mind that this price analysis is for large utility-scale installations and not homes, but it’s something to keep in mind when comparing the price between the Enphase battery and its NMC competitors. (You can read the full DoE report (PDF) for all the details.)

Enphase IQ is an AC-coupled battery with 89% efficiency

There are two types of storage batteries. DC-coupled batteries are charged directly by DC current from the solar panels, and then use an inverter to deliver AC-power to your home.

An AC-coupled battery, on the other hand, is charged by AC power that has already been converted from DC. Internally, the AC-coupled battery has a bidirectional inverter that converts the incoming AC power into DC power that charges the battery. When discharging power to your home, the internal inverter turns the battery’s DC power back into AC power.

Those extra conversion cycles mean some power losses. The Enphase claims 89% efficiency for a AC-DC-AC cycle.

Going off-the-grid

Having a solar battery doesn’t automatically mean you have the ability to operate in a blackout. For that, you need additional equipment that detects when a grid failure happens and disconnects your solar system from the public grid to allow it to continue to run independently.

The Enphase IQ System Controller 2 is the component that does this for an Enphase IQ Battery system. It’s a separate component that is priced at $1,707 on their online store.

It’s not strictly necessary to buy this component. If your intended use of the battery is to avoid peak rates or an unfavorable non-net metered arrangement with your utility company, then the additional price might not be worth the ability to handle occasional blackouts.

(Tesla has a similar component called the Backup Gateway.)

Enphase Battery software

Like other “smart” batteries, the Enphase has built-in software that can be monitored and configured from a smartphone app.

If you have Enphase microinverters (and you probably will if you choose an Enphase battery), the same app is used to monitor the status of the solar panels and the battery. This means you can see the power output of the solar panels, and the charging or discharging status of the battery from the same app.

The Enphase IQ battery has three configuration modes.

In Savings Mode (also known as time-of-use), the battery is aware of utility time-of-use rates and will automatically discharge the battery to help you avoid using grid electricity at the most expensive times. The battery can be configured to retain some spare capacity in case of a blackout.

Self-consumption mode ignores time-of-use rates and instead tries to minimize the amount of grid electricity you use. This might be a good choice if you have net billing or no net metering from your utility company.

In Full Backup mode, the battery only discharges when there is a grid blackout. This might be a good choice if you have critical needs, such as personal medical equipment.

You can learn more about these profiles and the Enphase app in their FAQ.

Product availability

According to several installers in my network, the Tesla Powerwall is currently backlogged six months or more and is difficult to obtain. This makes sense, as the same batteries are used in Tesla vehicles, which are experiencing through-the-roof demand. (The commpany announced record deliveries in the last quarter of 2021.)

The Enphase IQ battery, on the other hand, is generally available now. If you don’t want to wait, that alone might be the deciding factor in your purchase decision.

Overall recommendations

For most solar homes, a battery isn’t necessary. However, if you want to avoid blackouts or minimize your reliance on grid electricity, a battery can be a good addition to your setup. In some cases, you might even save money by avoiding peak hour rates.

The Enphase IQ Battery is a worthy competitor to popular offerings from Telsa and LG. The LFP chemistry makes it more durable, helping to offset any potentially higher upfront price.

If you have Enphase microinverters, the all-in-one smartphone app makes it convenient to see everything going on with both your solar panels and battery.

Pricing isn’t listed by Enphase, but you can expect the cost to vary by installer. Anecdotally, I’ve heard that Enphase is usually more expensive than some competitors including the Powerwall.

However, the Enphase IQ Battery has several advantages including long battery life, software integration with Enphase microinverters, and good size options. For this reason, it’s worth taking a closer look.