Nickel Iron Batteries invented by Thomas Edison and some are still in use today over 100 years later!

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NiFe (Ni = Nickel, Fe=Iron), a chemistry which lasts pretty much forever if you simply keep your batteries watered.  When considering which batteries to choose when designing an off grid battery system for your solar, wind, or hydro project, you’ll really should consider ongoing replacement costs every few years, deinstalling and reinstalling your new batteries, and disposing of your old batteries and possibly paying a fee to do so.    If you undersize your battery system because you want to save money, at some point off grid, you’re going to take your SOC or – State of charge down below 50%.  If you do that on lead acid batteries on a regular basis, your battery system will only last 2-3 years or less!  So lets think about this.  You’re gonna spend around $300 per battery including shipping for lets say 10 batteries.  Sure you’ve got a great Amp hour rating and depending on how you configure them, you could do that in a 12v, 24v, or 48v system.    Lets say you abuse the heck out of your batteries.  You’re gonna be spending $3000 + De-/Reinstall labor and time and if you have someone else do this for you — factor in about $1000 for the labor.    So your $4000 over 3 years is equal to a monthly electric bill of $111.00.  Lets say you really abuse your batteries and a few times you take them down to a SOC (State of charge) of 20%, and you only get 2 years of usage out of them, now your replacement costs monthly go up to : $166.00.   I thought you wanted to GET RID OF YOUR ELECTRIC BILLs?
Lets say you get an average of 3 years out of those batteries, and that cost is $12,000.  For this price you’d be able to buy Nickel Iron formulated batteries that if you keep them watered to the recommended min-max line, and you get to use these batteries for lets say the next 50 years, and you paid $12000 for this system, your monthly cost for this system, even if you went down to a SOC of 10%, the monthly cost for this system is ONLY $20/month.    Always remember like in the days of inkjet printers.  The more you pay for the machine up front, usually the LOWER the ongoing consumable products (ink) would cost.  Today the entry cost of these printers are less than $100, and the ongoing replacement costs of ink are averaging for – actual brand name ink, $35 per replacement cartridge.
You must think about the environment.  Lead Acid batteries create sulfuric acid and sulfate the plates inside as a by product of creating, storing, and releasing energy.  NiFe batteries – do not sulfate the plates.  The electrolyte just becomes weaker over the years.  Nickel Iron batteries are simply emptied and refilled with fresh electrolyte about every 7 years.  And the only maintenance is topping off the batteries with distilled water every 60-90 days.  Less in the winter, and a little sooner in the summer.  You an also get self watering systems for these types of chemistries.
We have suppliers we have purchased from and depending on your time schedule — we can double the size of your system for about the same price of local / or should I say USA vendors — by purchasing from the only manufacturers of these types of batteries from China and who have been manufacturing these for over 100 years.
Feel free to reach out to us on our contact page and for a flat consultation fee we can direct you to the right vendor for your needs maximizing your bang for your bucks.
Here is a background on Nickel Iron batteries:

Nickel Iron Battery

The basic components used in Nickel iron battery are nickel(III) hydroxide as cathode, iron as anode and potassium hydroxide as electrolyte. Nickel sulphate and Ferrous sulphide are added to the active material. Thomas-Edison

Construction of Edison Batteries

The capacity of Ne-Fe cell depends upon size and number of positive and negative plates. The appearance of both positive and negative plates in this type of battery cells is same. Both of the plates consist of rectangular grid made of nickel-plated iron. Each of the grid holes are filled with shallow and finely perforated nickel-plated steel box. Although both of the plates are appeared to be same, but they contain different active materials. Perforated nickel-plated steel boxes of positive plates contain a mixture of oxide of nickel and pulverized carbon and some of the negative plates contain fine grains of oxide of iron with fine dust of carbon. In both the plates, fine dust of carbon, mixed with active materials, helps to increase electrical conductivity. 20% diluted caustic potash is used as electrolyte. nickel iron edison battery Nickel plated iron gets used to make the vessel containing electrolyte and electrodes. Ebonite sticks are placed between the plates of different polarities to prevent them from coming into direct contact and causing short circuit. There is another specialty in the construction of Edison battery or nickel iron battery, that the number of negative plates is one more than that of the number of positive plates, and the extreme negative plate is electrically connected to the container. Plates of same polarities are welded to a common strap and they make a cell, and combining several cells, the battery gets constructed. ni fe

Operation of Nickel Iron Batteries

We already know that the main operation of the nickel iron battery is the chemical reaction within the battery which is known as electrolysis. Electrolysis is nothing but the chemical reaction taking place when there is current flow, it can be both cause and result of the chemical reaction. The chemistry of nickel iron cell is very much complicated because the exact formula for positive active material is not well established yet. But if we can assume that the material to be Ni(OH)3, then we can explain it to some extent. During charging, nickel compound at the positive plates, gets oxidized to nickel peroxide. Charging process changes iron compound to spongy iron in negative plates.

In the fully charged condition, the active material of the positive plates is nickel hydroxide [Ni(OH)3], while that in pockets of the negative plate is iron, Fe. When the cell delivers current to load, the active material of the positive plate changes from Ni(OH)3 to Ni(OH)2 and that of the negative plate changes from iron to Ferrous hydroxide (Fe(OH)2). The electrochemical process in the Edison battery can be expressed by the equation The equation expresses both the phenomenon of charging and discharging. The right side flow of the equation is the reaction of the discharging phenomenon and the left side flow of the equation expresses the charging phenomenon. The reaction occurs by transfer of electrons through the external circuit to the positive plate during discharge. There is a provision for giving off the corrosive fume which is generated during the electrolysis inside the battery, so that no special care is needed in mounting the cell.

Characteristics of Nickel Iron Batteries

The emf of a fully charged Edison battery is 1.4 V. The average discharge voltage is about 1.2 V and the average charging voltage is about 1.7 V per cell. The characteristics of this type of battery is shown below in the figure. characteristics of edison battery The voltage characteristics of the Nickel Iron battery are similar to that of lead–acid cell. As the fully charged emf 1.4 V and it slowly decreases to 1.3 V and then very slowly to 1.1 or 1.0 V during discharge. From the graph, we can see that there is no lower limit for discharging emf beyond which the output of the battery will be zero. That’s why after a certain period the battery stop to any output. The emf of a battery is directly proportional to the temperature, which means the emf of the battery increases with increase in temperature. The average time of charging of a battery is 7 hours and discharging time is 5 hours. Another characteristic of Edison battery is that continuous operation at higher temperature decreases the life of the battery, same thing happens if the battery is charged for more than the average time of charging. The ampere-hour and watt-hour efficiency of this nickel iron battery are 85 % and 60 % respectively. At 4oC temperature, the capacity of Edison battery falls to zero, that’s why the battery should be heated up before operation though during operation the I2R loss keeps the battery hot and running.

Advantages of Nickel Iron Batteries

There are various Advantages of Edison battery , these are listed below.

  1. The weight of these battery is lower than other types of battery because they need less amount of electrolytes and plates are also lighter.
  2. The service life of the battery is much higher because of various provisions made.
  3. These types of battery are stronger, have rugged construction because of steel body. For this reason they are not affected by vibrations, jolts or shocks, heavy currents and do not suffer during short circuits.

Disadvantages of Nickel Iron Batteries

There are certain disadvantages of Edison battery, like the initial cost needed for making these battery are pretty high as the materials used are highly priced. Another drawback of these type of battery is the low efficiency. For this few reasons the use of these battery are restricted, they are mainly used in the areas where high mechanical strength, lightness, freedom from acid fumes are needed.

Application of Nickel Iron Batteries

From the above discussions, we already know that the said battery are mainly used in extreme conditions or it can be said that where there is no other way than using Edison battery. These battery are mainly used in industrial trucks for propulsion purpose. They are also used in mine locomotives and for railway, car lighting and air conditioning because they have pretty high mechanical strength.

Maintenance and Care of Nickel Iron Batteries

We already know that the these battery need lower maintenance than other types of battery. The main precaution taken for these types of battery is to maintain the level of electrolyte present inside the battery. Because, if the level of the electrolyte becomes lower than the plates inside, the battery get damaged very quickly and the battery suffer irreversible damage. To prevent this, the battery should get filled with distilled water at least once in a week. Another maintenance which is needed for these battery is to change the electrolyte solution time to time, whenever the specific gravity of the solution falls below 1.16 the electrolyte gets changed. Lastly, it is important to consider that the battery should be discharged to zero volt before taking it out for servicing for a long period.

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