I did it my way…

Edison nickel iron (Ni-Fe) battery cell – homemade construction…

 A labour of love

By Dorian Stonehouse


THERE is nothing quite like it: to see the fruits of one’s labour ripening – construction taking shape. 

So here is a homemade Edison Nickel Iron battery under construction – one cell at a time ⇓⇓.

20 mesh is rolled into a jar for sizing up
Peanut butter jar with mesh inserted

Homemade Edison nickel iron battery cell takes shape

The correct way to construct a Ni-Fe battery is to use a thin coating of black Iron Oxide for the negative plate; but that stuff is just too messy to use.

So, for the negative terminal I will be using (cleaner) brown rust from an old quarry, which will be thinly deposited between two layers of 20 mesh wire gauze⇓⇓.

Jar with mesh now inserted Mesh to be added to the bottom of the jar
Jar with mesh now inserted Mesh to be added to the bottom of the jar

So it’s off to the quarry to get that rust.

In the meantime, the positive terminal of the homemade Edison cell can be constructed, and this is how I did it⇓⇓.

Nickel pocket containing nickel hydroxide, and spot welded together using battery tabs
Nickel pocket

Old batteries can be fun, but can get hotter than the Sun

The Nickel Hydroxide was a bit of a challenge to source, so to get the nickel, I dissected several dead AA Nickel Metal Hydride cells. 

The nickel pocket is about 4 inches long
Nickel pocket with ruler by its side

Nickel harvesting  is dangerous, because the Metal Hydride part of the cell is exothermic (it can burn in air). 

Bag of brown rust sits on the bench ready for crushing into powder.
Bag of brown rust sits on the bench

The first time I attempted to harvest the Nickel Hydroxide for my homemade Edison cell, the AA cell started burning and I lost the lot!  

Back from the quarry with plenty of iron ore 

Brown rust granules are prepared to be ground to powder
Brown rust granules with rubber gloves

Edison nickel iron (Ni-Fe) battery cell: homemade construction

Mesh is removed and bound with stainless steel to prevent un spooling.
Mesh is removed

Edison nickel iron (Ni-Fe) battery cell: homemade construction 

 

Mesh cage is sealed at the bottom - tied with wire
Mesh cage

Edison nickel iron (Ni-Fe) battery cell: homemade construction

Jar with iron oxide next to the glass, with mesh over it.
Jar with iron oxide next to the glass

Try not to make a mesh

First mesh is removed and placed against the glass wall, then another mesh roll is placed over the first one. The iron oxide is pushed in between meshes.
Second mesh

After sizing up the mesh, the first layer was ⇑⇑ used to reinforce the inside wall of the glass jar and to improve conductivity.

Homemade Edison cell gets the iron treatment

I inserted the next mesh layer, ⇑⇑ before filling up the space in between with powdered iron oxide.

Pot noodle pot, with base removed as insulator for the base of the cell
Pot noodle pot

The negative terminal is made from battery tab nickel strip, which is forced down between the mesh layers.

Oodles Of Noodles

The base insulator is made from the base of a pot noodle pot, and  ⇑⇑is pushed down at the bottom of the cell; providing good insulation for the positive pocket.

Positive pocket is insulated at the sides by a split pipe. This stops the positive inner pocket touching the surrounding steel cage.
Positive pocket again

Edison nickel iron (Ni-Fe) battery cell: homemade construction

I insulated the sides of the positive pocket ⇑⇑, to prevent it from short-circuiting to the negatively polarised mesh.

A plastic pipe slit down the sides and glued on using alkali resistant epoxy adhesive does this job very well.

Final check: the positive pocket is inserted on top of the insulator.
Final check: the positive pocket is inserted on top of the insulator.

Edison nickel iron (Ni-Fe) battery cell: homemade construction

The jar is completed, with the top put on.
The jar completed

Charging the homemade Edison cell:

another labour of love

Preparing and charging the NIFE cell is like making a cake:

Ingredients: deionised water, potassium hydroxide (caustic potash), alkali-proof container, alkali resistant spoon and car battery hydrometer.

Method: Carefully add a sprinkle at a time of potassium hydroxide (chemical symbol KOH) to the deionised water and stir in with a tablespoon. 

Swirling and stirring

The solution gets quite hot, but I kept stirring in a little more KOH to the solution, until the electrolyte reached a specific gravity about 1:25.

This action can be dangerous due to spillage, so gloves and face protection are must haves! 

A variac transformer for connecting to the battery charger.
A variac transformer

Edison nickel iron (Ni-Fe) battery cell: homemade construction

To charge the cell: I use a variac transformer, with its ac output connected to the mains input of an ordinary car battery charger⇑⇑

Better safe than sorry

Safety notice: Variac’s are not usually isolated, so I always connect an isolating transformer between it and the raw mains, to avoid a (potentially) lethal electric shock.

Charge it

The ideal situation is to adjust the charging voltage to just over 1.69 volts per cell, which should equate to a current of about 2 amps for this particular cell.

As the current falls, the voltage will rise, so the voltage has to be reduced again to just over 1.69 volts.

Keeping things just right

I turned the voltage up sufficiently to get a higher current of about 4 amps to flow.

This is the only way to get the juices going – to get the cell fizzing away nicely.

Note: The current must not be too high, or the electrolyte will “boil” and spill over the sides of the jar!

Come in number one, your times up!

It normally takes a minimum of 24 hours to charge a new cell. The current should then be as low as it is going to get.

When disconnected, the  voltage across my cell started to fall to around 1.45 volts, eventually reaching a little above 1.4 at around 1.42 volts.

At 1.4volts the battery is still fully charged.

…and here for all to see is my finished creation – enjoy:

Success: A glowing Edison cell:
A glowing Edison cell – A1

Edison nickel iron (Ni-Fe) battery cell: homemade construction 

Success: A second glowing Edison cell in black and white.
Success: A glowing Edison cell:

Edison nickel iron (Ni-Fe) battery cell: homemade construction

Success: A glowing Edison cell - again, but in colour.
Success: A glowing Edison cell:

Edison nickel iron (Ni-Fe) battery cell: homemade construction

Success: A glowing Edison cell with safety cradle.
Success: A glowing Edison cell:

Edison nickel iron (Ni-Fe) battery cell: homemade construction

 

Highly recommended material on the Edison cell:

 

http://www.nutsvolts.com/magazine/article/february2012_Noon

 

https://en.wikipedia.org/wiki/Nickel%E2%80%93iron_battery

 

P.S.

Please may I ask all visitors to post links on their social media accounts directing visitors to electrosparkles.com so that more people can enjoy the website, and join in to present their technical ideas for featuring.

Heartfelt thanks

Dorian.