I took this from an article I found,
History: Nickel Iron Batteries Have a 100+ Year Track Record
Thomas Edison patented and produced Nickel Iron batteries in the early 1900’s, designing them to be “far superior to batteries using lead plates and acid”. Nickel Iron batteries were used in the very first electric car in the early 1910’s. Even though they were not adopted as the starting battery for internal combustion engines during the birth of the automobile, they found their niche in numerous railroad, forklift, and standby power applications throughout the 20th century. Nickel Iron batteries are experiencing a rebirth in the 21st century for renewable energy applications due to their incredibly long life and robust, durable qualities..
Best Investment in Energy Storage: 10% – 35% the Cost of Other Battery Options.
Nickel Iron batteries have the Lowest Total Cost of Ownership of ANY battery chemistry available today.
Amortized over the life of the battery, Nickel Iron batteries cost as low as 9 cents per usable kWh! That’s lower than most electric utility rates! Most lead acid batteries cost 25 to 80 cents per usable kWh. [Purchase Price ÷ (Usable Capacity × Cycle Life)]
Longest Lasting: 30+ Years of Reliable Service
30+ Year Life Expectancy is actually an understatement for Nickel Iron batteries. Because Nickel Iron batteries use Nickel plates and an alkaline electrolyte, they don’t experience the plate degradation and short life of a lead plate in acid. It is common to see 50+ year old Nickel Iron batteries still in service today, with some dating back to the 1940s!
Largest Usable Capacity: 80% Depth of Discharge
Unlike most other battery chemistries, Nickel Iron batteries’ life expectancy is NOT impacted by the battery’s depth of discharge. This is why you can discharge a Nickel Iron battery up to 80% DAILY, and still get 30+ years of life from this battery!
Most Rugged: Over Charge/Discharge Capability and Extreme Temperature Tolerances
It’s common knowledge that over discharging a lead acid battery just once will catastrophically shortened its life expectancy. This is the case with most battery chemistries actually, but not Nickel Iron batteries! Discharging a Nickel Iron battery 80% or more will not negatively impact its life expectancy, which is why they can be discharged like this on a daily basis and still provide decades of worry free service.
Nickel Iron batteries can handle over charging as well, without impacting their life expectancy. Nickel Iron batteries perform best when they are aggressively charged (C/4 charge rate or better), which makes them optimal for solar applications because they can be fully charged in 4 hours!
Most batteries don’t like extreme temperature conditions… except Nickel Iron batteries. With an operating temperature range of -22 to +140F (-30 to +60C), Nickel Iron provides worry free service in extreme cold and hot conditions. From the jungles of Central America to the Arctic Circle, Nickel Iron batteries are providing customers with reliable energy storage where other batteries struggle.
Compatibility:
Nickel Iron batteries are compatible with most quality battery inverters and solar chargers on the market today. Using industry standard 12 volt, 24 volt and 48 volt configurations, Nickel Iron batteries work well with products from MidNite Solar, Magnum Energy, Schneider Electric, Outback Power, and SMA just to name a few. If your solar charger or battery inverter support custom charge parameters, it will likely work well with a Nickel Iron battery. Chargers and battery inverters designed exclusively for lead acid batteries will work as well, but may struggle to fully charge a Nickel Iron battery. .
.Maintenance:
Nickel Iron batteries are a flooded battery, which means there’s minimal maintenance they will need throughout their life.
Watering your batteries every 1-3 months is the biggest maintenance requirement. Electrolysis takes place inside the battery during charging, resulting in the loss of pure water in the form of hydrogen and oxygen off gassing. This water must be replaced periodically by adding distilled water to the batteries. .
Equalizing… NOPE! Unlike lead acid batteries, Nickel Iron batteries do not need to be equalized on a regular basis (although you won’t hurt them if you do). One less thing to worry about if you’re upgrading from a lead acid battery bank.
Checking Specific Gravity… DON’T BOTHER! The alkaline electrolyte of Nickel Iron batteries does not change based on the battery’s state of charge, so that’s one less maintenance task former lead acid owners need to do.
Battery Enclosure is needed for Nickel Iron batteries. While charging Nickel Iron batteries will off gas hydrogen, a combustible gas that can be dangerous of not properly addressed. LIke other battery chemistries, a Nickel Iron battery bank should be installed in an enclosure that will properly capture and vent this hydrogen outside. Nickel Iron batteries also should not share an airspace with other electronics or possible ignition sources.
I recommend an electrolyte replacement every 10 years for optimal performance and energy capacity. Nickel Iron batteries will experience a slight degradation of electrical capacity over time due to carbonate buildup in the electrolyte (typically 1% loss per year). Replacing the electrolyte can recover this capacity loss.
