Tesla Powerwall Vs. Enphase IQ [Buyer’s Guide]


Tesla Powerwall Vs. Enphase IQ [Buyer's Guide]

Over the past decade, solar power has come into its own as a viable and trendy alternative or supplement to household energy needs. However, to take full advantage of solar energy and energy conservation, an energy storage device (aka a battery) is essential.

While solar energy is not a new idea by any means, it has come into its own with the emergence of Tesla. The addition of Tesla’s Powerwall has pushed Tesla to the forefront of the solar energy and home battery market. The release of the Enphase Encharge, now rebranded as Enphase IQ, hopes to challenge that. Read on to find out more about the competing Tesla Powerwall and Enphase IQ batteries.

Buying a Home Battery

Whether or not you have a solar system in your home or not, having a home battery is a good idea for several reasons.

  • Enables you to offset peak energy hours
  • Provides energy during power outages
  • Allows you to store surplus solar power to use at night

For many, the main reason to buy a home battery is to take advantage of net energy savings. In short, your home battery is connected to the grid and charges during the “off-hours” or non-peak hours when energy prices are lower. This stored energy is used to offset energy usage during peak energy hours when energy costs are higher.

Another important consideration for purchasing a home battery is the capability to continue to use energy and power home appliances during power outages. With these top-of-the-line offerings, you should not notice any disruption in the grid, enabling you to proceed with your day as usual. You can even choose to direct your solar power to your battery if you know big storm is coming and a power outage is likely.

Finally, a home battery allows you to take full advantage of a solar array. Solar panels produce energy so long as the sun shines. Paired with home batteries, excess solar energy is stored and used at night. This way you are not wasting the extra power made by your solar panels during the day.

While all home batteries on the market should accomplish similar operations for your home, narrowing down your choice between the Powerwall and the Enphase IQ takes more nuance.

Tesla Powerwall Vs. Enphase IQ

A glaring difference between the Tesla Powerwall and the Enphase IQ is the relatively recent debut of the Enphase IQ. While the Powerwall is by no means ancient (and thereby tried and true), it does have the advantage of being on its second generation. This seniority allows the Powerwall a certain pedigree and a large user base compared to the new Enphase IQ.

However, there are other factors on which the two batteries can compete.

  1. Cost
  2. Warranty
  3. Size (Capacity and Power)
  4. Efficiency

Without a proven track record for either offering, you will have to look at the various aspects of each product and let them speak for themselves.

1. Cost

The cost should not be the main determining factor when selecting a home battery. After all, a more expensive battery may save you money in the long run. However, the cost is still an important consideration, and all things being equal, a deciding factor.

These costs include installation and supporting hardware as Tesla does not allow DIY installation.

How Much Does The Tesla Powerwall Cost?

Since its start, Tesla has had a significant impact on the solar and energy industry. With innovation and unique marketing, Tesla has pushed solar to become more reliable, efficient, and cost-effective. These factors have made it possible for users to purchase top-of-the-line products at a reasonable price.

The Tesla Powerwall costs around $10,500 installed (13.5 kWh capacity).

Each additional Tesla Powerwall costs around $6,500 installed (13.5 kWh capacity each).

If you buy a second Powerwall, and stack them together, you can create a 27 kWh capacity battery. You can stack up to 10 Powerwalls together.

For home batteries, this price is as low as it gets for this level of quality and reliability. However, it should be noted that the Powerwall is sold in one size with a capacity of 13.5 kWh.

Pro Tip: Ordering a Tesla Powerwall? Get an instant discount by using a Tesla referral link from another Tesla owner.

How Much Does The Enphase IQ Cost?

With its newest offering, Enphase has released what hopes to be a direct competitor to the Tesla Powerwall. Similar to the Powerwall in many aspects, the Enphase IQ differs in that it offers the large home battery Enphase IQ 10, and a smaller Enphase IQ 3 as well.

The Enphase IQ 10 cost between $8,000 and $11,000 installed (10.1 kWh capacity).

The Enphase IQ 3 cost between $4,000 and $5,000 installed (3.36 kWh capacity).

Conclusion: Cost Comparisons

When it comes to cost, Tesla Powerwall is the clear winner. Tesla has been making a name for itself in the solar industry by offering state-of-the-art technology, at the lowest cost, and the Powerwall is no exception.

 Tesla PowerwallEnphase IQ 10Enphase IQ 3
Capacity (kWh)13.510.13.36
Cost ($)$10,500~$10,000~$4,500

Since the Tesla Powerwall comes in one size, you will have to buy another full Powerwall even if your first Powerwall is just slightly underpowered, however the second Powerwall is only $6,500 rather than the full $10,500.

With the Enphase IQ, a smaller Enphase IQ 3 added to the Enphase IQ 10 could fill smaller increments of additional energy need, but overall the cost is still going to be higher.

When you look at the cost per kWh of Powerwall vs Enphase IQ, the cost difference becomes clear.

Tesla Powerwall: $778 per kWh (first Powerwall), $481 per kWh (second Powerwall and on)

Enphase IQ 10: $990 per kWh

Enphase IQ 3: $1339 per kWh

No matter how you break it down, the Tesla Powerwall is the lower cost option compared to the Enphase IQ series.

2. Warranty

Under normal circumstances, a home battery will charge and discharge once per day (one cycle). Like any battery (think of your car or mobile phone), these cycles deteriorate the battery over time and diminish its capacity to store energy. The warranty guarantees the battery to meet a certain threshold over a given period.

While the warranty may seem like a small thing to consider, it becomes imperative if your battery suddenly malfunctions or fails to meet the energy production rates you expected. To fully understand what is covered, let us look at the fine print.

Tesla Powerwall Warranty

Tesla guarantees the Powerwall to maintain a 70 percent capacity over 10 years under normal usage conditions.

For Tesla, these normal conditions constitute one charge and discharge cycle per day. These conditions are usually associated with solar storage and energy backup.

For those who choose to use their Powerwall to take advantage of off-peak energy and solar, multiple cycles a day will cause the battery to deteriorate at a faster rate. In this case, the warranty’s fine print does not guarantee the battery for 10 years but 3,200 cycles instead.

Enphase IQ Warranty

The Enphase is guaranteed with a 70 percent capacity over 10 years or 4,000 cycle warranty regardless of usage.

This simple warranty allows you to use the home battery in several ways without worrying about exceeding the warranty, up to 4,000 cycles.

Conclusion: Warranty

Both home batteries have a guaranteed warranty of 70 percent capacity over 10 years. However, Enphase IQ offers it’s warranty for 4,000 cycles, which is 800 cycles more than Tesla Powerwall’s 3,200 cycles under warranty.

 Tesla PowerwallEnphase IQ
Standard Use (Discharge once/day)10 Years 70% Capacity10 Years 70% Capacity
Non-Standard Use (Discharge >1/day)3,200 cycles4,000 cycles

Although the 10 years and 70% capacity is equal between the two batteries, the warranty favors Enphase IQ by covering 800 more cycles under warranty.

3. Size (Capacity and Power)

The size of a battery ultimately dictates how much energy you can store and use at any given time. Its power and usable capacity define the size of a battery.

  • Power, measured in kilowatts (kW), is the amount of available energy at a given time.
  • Total power is the maximum power that can be released (usually for a few seconds).
  • Continuous power is the amount of power that can be safely released over a long period.

The battery’s total capacity, which is measured in kilowatt-hours (kWh), indicates the maximum storage capacity of the battery. However, in general, we are interested in the usable capacity, which indicates the maximum energy available in a fully charged battery.

One can think of power and capacity in terms of water running through a pipe. The pipe size correlates to power (larger pipe equals more power), while the amount of water available correlates to the usable capacity. The larger the pipe (higher power), the more water (usable capacity) will flow through it.

In this scenario, a larger pipe can deliver more force (power) but decreases the water supply (usable capacity) rapidly compared to a smaller pipe. Therefore, houses with large appliances that use a lot of power need high power and high capacity.

Tesla Powerwall Size (Capacity and Power)

The Tesla Powerwall clocks in with an impressive usable capacity of 13.5 kWh capacity, and 5.0 kW of power.

The Powerwall can put out a peak power of 7.0 kW but only for 10 seconds at a time.

Enphase IQ Size (Capacity and Power)

The Enphase IQ 10 falls slightly short of the Powerwall in power and capacity, with a usable capacity of 10.8 kWh capacity, and 3.84 kW of power.

The Enphase IQ 10 can put out a peak power of 5.7 kW but only for 10 seconds at a time.

The smaller Enphase IQ 3 follows up with a usable capacity of 3.36 kWh capacity, and 1.28 kW of power.

The Enphase IQ 3 can put out a peak power of 1.92 kW but only for 10 seconds at a time.

Conclusion: Size (Capacity and Power)

The Powerwall wins in both Capacity and Power. It can simply store more energy, and power items with higher energy requirements.

 Tesla PowerwallEnphase IQ 10Enphase IQ 3
Total Capacity (kWh)13.510.503.36
Usable Capacity (kWh)13.510.083.36
Peak Power (kW)7.05.71.92
Continuous Power (kW)5.03.841.28

If you have a large number of high energy requirements, you may need the increased power of the Powerwall. With its larger usable capacity, the Powerwall will last longer at low power and perform well at high continuous power as well.

4. Efficiency

The efficiency of a battery is reflected by 3 factors:

  • Its depth of discharge
  • Its round trip efficiency
  • Battery degradation over time

The Depth of Discharge (DoD) is a measurement that compares the total amount of energy that a battery discharges relative to its total capacity. When looking at the DoD of a battery, a high DoD translates into a highly efficient and high-quality battery.

The roundtrip efficiency is a measurement that indicates the amount of charge is lost during charging and discharging. Ultimately, this measurement indicates how efficiently a battery can store and release usable energy(or how little is lost). Therefore a higher round trip efficiency suggests a more efficient battery.

Finally, the degradation of a battery is precisely that; the amount the battery degrades over time. Since all batteries are expected to lose a portion of their functionality throughout their life, manufacturers define acceptable degradation over a set period. A battery that meets this criterion is considered to be efficient.

Tesla Powerwall Efficiency

With a DoD of 100 percent, the Tesla Powerwall certainly meets the criteria for efficiency. Combined with a round trip efficiency of 90 percent (10 percent energy lost), the Powerwall is one of the most efficient batteries on the market.

Finally, an expected degradation of 3 percent reflects the high quality of the product.

Enphase IQ Efficiency

The Enphase IQ (both sizes) also boasts a DoD of 100 percent; however, the round trip efficiency comes in 89 percent. As with the Powerwall, a degradation of 3 percent indicates a high-quality product.

Conclusion: Efficiency

Since the Powerwall and the Enphase IQ display the same metrics, you might think they are equally efficient besides a mere 1 percent difference in round trip efficiency. However, that 1 percent difference translates into an extra 0.1 kWh more output per 10 kWh, which results in a substantial difference over the battery’s lifetime.

 Tesla Powerwall 2Enphase IQ 10Enphase IQ 3
Depth of Discharge (%)100100100
Degradation (%)3.03.03.0
Round Trip Efficiency (%)90.089.089.0

When looking at efficiency, it is clear that over the long term, the Tesla Powerwall beats out the Enphase IQ series.

Additional Considerations

If the critical metrics discussed above are not enough, or if you want to be fully informed before making a decision, consider the following battery aspects:

  • Chemistry
  • Thermal Cooling
  • Inverter

These are not always on a consumer’s priority list when comparing home batteries, but they can be important in decision making.

Chemistry

Based on a Lithium Nickle Manganese Cobalt Oxide (NCM) battery, the Tesla Powerwall has a higher than average density and an average power rating. Additionally, the use of cobalt increases the safety of these batteries. The relatively cheap cost of production for NCM makes them a suitable choice.

Unlike the Powerwall, the Enphase IQ batteries are a Lithium Iron Phosphate (LFP) variation. This variation tends to have a high power rating but comparatively low energy density when compared to other lithium-ion variations. The use of iron increases the safety of the unit as they do not overheat and require no additional cooling.

  • Both the Powerwall and the Enphase IQ are considered safe and have extensive safety ratings.
  • The Enphase IQ LFP variation is the safer option as it inherently produces less heat.

Beyond this consideration, the NCM batteries are able to store more energy while the LPF provides more power, so both have their advantages.

Thermal Cooling

Hand in hand with battery chemistry, thermal cooling is essential for the dissipation of heat during battery usage. This cooling is critical during peak and high power usage. While extreme heat dramatically affects the function of batteries and may cause them to fail dramatically, extreme cold can also prevent them from functioning correctly.

With an NCM battery, the Powerwall produces a significant amount of heat. This excess heat is offset by a liquid cooling system unique to the Powerwall. This system allows the Powerwall to operate at high capacity and function in a wide range of temperatures. This ability to offload heat quickly extends the lifespan of the battery.

  • Like other batteries, the Powerwall has an optimal operating temperature range from 32℉ to 86℉ (0℃ to 30℃). However, the liquid cooling system allows the Powerwall to operate in temperatures from -4℉ to 122℉ (-20℃ to 50℃).
  • At low temperatures, the Powerwall can preheat cells in what is called preconditioning, enabling them to function.
  • Like the Powerwall, the Enphase IQ operates best from 32℉ to 86℉ (0℃ to 30℃) but is still able to operate with ambient temperatures reaching from 5℉ to 131℉ (-15℃ to 55℃).

Using the LFP variation of the Lithium-ion battery, the Enphase IQ eliminates the need for a cooling system. In other words, it is adequately cooled through passive cooling, allowing it to be fully enclosed without fans or other moving parts.

Both the liquid cooling system of the Powerwall and the passive cooling of the Enphase IQ provide advantages and disadvantages.

The primary disadvantage of requiring a cooling system is adding a point of failure in the battery. If the cooling system were to fail for any reason, the battery would cease to function until repaired (barring thermal runaway). 

However, the advantage of this system lies in its ability to function at extremely low temperatures. Lithium-ion batteries cannot charge adequately at temperatures below 5℃. The thermal regulation system allows the Powerwall to overcome this obstacle and operate at freezing temperatures.

Inverter

Both the Powerwall and the Enphase IQ home batteries are AC batteries. This requires the use of a battery inverter to convert between AC and DC. The primary reason for this inverter is for use with solar arrays. However, as both units come with inbuilt inverters, they can be used without solar and used for backup.

  • The Powerwall, like many home batteries, functions with a single large inverter. This inverter may be sourced from several companies.
  • Departing from the standard single inverter design, the Enphase IQ is designed with a unique array of 12 micro-inverters that work together.

The unique design of the Enphase IQ unit has a significant advantage and one slight disadvantage compared to the single inverter of the Powerwall.

Using an array of twelve micro-inverters, Enphase ensures that if one goes out, you still have access to the energy stored in the battery while losing merely a fraction of the power (less one inverter allows for 92% of the total power). On the other hand, a failure of the Powerwall inverter results in battery function.

The disadvantage of the micro-inverter design is the difficulty in locating the inverter that has ceased to function. Fortunately, all of the inverters are provided by Enphase, allowing a single company to deal with the issue.

Is It Worth Getting a Tesla Powerwall?

With the competition on the market growing, it is fair to wonder if it is worth it to buy the Tesla Powerwall since it is no longer the only choice. However, this decision is still up to you and your needs.

Based solely on the factors considered above, the Tesla Powerwall is still worth it to purchase. Even with the competition, the Powerwall stands out as a mighty home battery. Its efficiency, power, and price cannot be beaten. However, the Enphase IQ gives the Powerwall a run for its money in other areas, such as incremental additional storage options, and warranty cycles.

If you want to stick with a tried and true name you trust, it is worth it to buy the Tesla Powerwall. If you want to branch out to a newer product that has fantastic specifications, that does not seem like a bad idea either. Between either of these two home batteries, you cannot go wrong. It all comes down to your size, power, and cost needs.

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Greg

Hi, I'm Greg. My daily driver is a Tesla Model 3 Performance. I've learned a ton about Teslas from hands-on experience and this is the site where I share everything I've learned.

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