Energy Storage

There are several key differences between the Iron Edison Lithium Iron battery and the Tesla Powerwall. First, an Iron Edison Lithium Iron battery is available in traditional nominal voltages of 12V, 24V and 48V, making it fully compatible with common battery-based inverters and charge controllers from major manufacturers like Outback, Schneider Electric, Magnum, MidNite Solar and SMA.

Luke Simmons | Iron Edison

Iron Edison offers batteries for solar that are longer lasting and more durable than traditional lead-acid batteries. With an emphasis on customer service, we include lifetime technical support on all our batteries and can assist in the overall design of an off-grid or battery backup solar (PV) system. The Iron Edison Nickel Iron battery is the longest lasting battery for solar storage, offering 11,000 cycles – which is 30 years with daily use. It is non-toxic, contains no heavy metals, and is completely recyclable. The Iron Edison Lithium Iron battery is a zero-maintenance solar battery solution using the safest lithium-ion chemistry available – Lithium Iron Phosphate. Rated for 5,000 cycles, it offers more longevity and a smaller footprint than sealed lead-acid batteries.

There are several key differences between the Iron Edison Lithium Iron battery and the Tesla Powerwall. First and foremost is compatibility -- an Iron Edison Lithium Iron battery is available in traditional nominal voltages of 12V, 24V and 48V, making it fully functional with common battery-based inverters and charge controllers from major manufacturers like Outback, Schneider Electric, Magnum, MidNite Solar and SMA. The Tesla Powerwall is a high-voltage battery only compatible with high-voltage equipment, many of which is not yet available or still under development.

Next, the Lithium chemistry itself is different between the two batteries. The Tesla Powerwall uses a more volatile lithium-ion type that requires a liquid cooling system. The Iron Edison battery employs Lithium Iron Phosphate cells, which are the most thermally stable and safest lithium type. Even under extreme stress, it's impossible for Lithium Iron to have a "thermal event" which has been publicized recently in the news regarding hoverboard fires that use lithium-ion batteries. So, we feel very confident stating that Lithium Iron Phosphate is the safest lithium chemistry for residential and commercial energy storage.

As added layer of safety, all Iron Edison Lithium Iron battery systems have an integrated Battery Management System which constantly monitors cell voltage and temperature and keeps the entire pack balanced. The BMS logs battery data that can be used to evaluate performance. The BMS is tied to an on-board DC disconnect that further protects the battery from overcharge, over-discharge, and system faults.

Tesla has been very vague about their battery's performance and availability. They were originally offering two models – a battery for daily cycling and a purely backup model. Then last month, the backup model disappeared from the website. The economics of the Lithium battery call for the battery to be cycled daily, which can help in Time of Use rate structures or for load shaving. Our battery shines in this use, and is available in more sizes and configurations than the Powerwall. Additionally, we can custom-build larger capacities for commercial uses, and have found great interest in the telecom industry.

Iron Edison's Lithium Iron Phosphate is the safest, most stable lithium chemistry, and is available in nominal voltages of 12, 24 and 48 Volts. This makes it a consumer-ready product, ready for use in retrofitted battery systems or new systems using available industry-leading equipment from the major solar manufacturers.

It's difficult to compare price because Tesla's battery requires a host of other supporting equipment to use, so it's really going to cost the consumer more than the advertised price. The Iron Edison battery is "plug and play" and can be used in many different system configurations, with no additional parts or components. Until Tesla releases more information about the number of cycles expected relating to the depth of discharge, an "apples to apples" comparison can't be made.

Nickel Iron is an alternative to lead acid that is much longer lasting, easier to charge and completely recyclable with no heavy metals inside. The Nickel Iron battery was invented by Thomas Edison as he searched for an "ideal" storage battery. Perhaps the best way to think of the differences between the two types is by looking at the Redox chemical reactions that happen inside the battery. As a lead-acid battery charges and discharges, its lead plates dissolve and are reformed, but never recover to their original condition. Slowly, sulfate crystals build up on the lead plates, which reduce capacity and eventually kill the battery. Nickel Iron, on the other hand, has electrodes that are insoluble in the electrolyte, so no plate degradation ever occurs. This leads to its extremely long life, which is at least 5 times longer than a traditional flooded lead acid. The Nickel Iron is tolerant of abuse, overcharge, and undercharge, and actually performs better when worked hard. This is exactly the kind of battery that is ideal for PV energy storage.

Because there is no sulfation inside Nickel Iron, an equalization charge is not required, and overall charging parameters are simpler and more straightforward. The battery is simply transferring oxygen from one plate to another during use.

Nickel Iron uses an alkaline electrolyte comprised of potassium hydroxide, lithium hydroxide and water. Just like a lead-acid battery, water is decomposed inside the battery during use and must be periodically replenished.

Ultimately, Nickel Iron batteries present a much better long-term value for consumers and are truly a "lifetime," non-consumable product. Lead acid has a lower initial cost, but the highest cost of ownership over the life of a PV solar system.

Our philosophy is to understand a customer's needs and recommend a system that meets these needs. Many of our customers are DIY-ers who will buy complete system from us, including solar panels, inverters and charge controllers, and install it themselves. Other work with a solar installer in their area and will just buy the batteries from us. We’ve worked with enough installers over our six years in business that we have a network across the country and can recommend a qualified professional to work with.

Iron Edison is based in Colorado and doesn't offer installation services, but can do just about everything else – from system design, to electrical diagrams, to permit packs, to technical support. One thing we do with all our customers is provide battery setup so the system is programmed with our recommended set-points to ensure proper charge and system longevity. We back our batteries with lifetime customer support.

Many people call us looking to add batteries to their existing solar system because they want to be able to power their home in a grid outage. This trend is definitely growing in popularity, and can be achieved with the addition of a battery-based inverter and battery bank in an AC-Coupled system.

Electric utilities in many areas are also rolling out time-of-use rate structures, and a battery can help mitigate the impacts of these new rates. It makes sense for a customer with a PV system and battery bank to use their self-produced energy during peak rate times, and rely on the grid during cheaper billing periods.

Finally, batteries also make sense in grid-tied systems where the utility has changed net metering policies (see Nevada). Batteries help preserve the retail rate of a kWh of energy produced, and more people are interested in self-consumption which doesn't require a net meter.

Our company has seen tremendous growth over the past year as people look for ways to become more self-sustainable and independent from an electric utility as their sole source of power. Batteries are obviously a key part of this equation, because grid-tied systems only produce power when the grid is active. So, we definitely see both off-grid and battery backup systems increasing in popularity. The Federal Tax Credit for PV systems is very generous, and our customers will include the cost of batteries in the total system cost that is eligible for the credit. This tax credit significantly offsets the additional cost of including batteries in a PV system.

The size of the system really depends on the energy needs of the home. We start by looking at utility bills, and if it's new construction, we will conduct a loads analysis to determine the daily energy needs of the home. Our most popular package is our Freedom Package, which includes a 2 kW solar array and a Nickel Iron battery with 12 kW of usable storage. This can cover loads of a small off-grid cabin, or supplement a larger residential house and provide backup power in a grid outage.

It's important to understand battery-based PV systems are limited by the output capabilities of the battery inverter, so we typically recommend leaving large loads like hot tubs, central air and electric heating off of the system. Whenever possible, shifting cooking and heating loads to gas or other forms of energy will make for a smaller, more efficient PV and battery storage system.

We are very excited about our Lithium Iron battery, which is assembled by hand at our facility in Colorado. We are using the highest quality materials, including a Battery Management System and a military grade DC disconnect which protects the battery. Every battery comes in a rugged steel enclosure with no on-site assembly required. The battery is truly "plug and play" and is a simple, no-maintenance option that uses the most powerful and proven type of battery available today.

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