Energy Systems

Nickel Iron Batteries

A Solar System Secret

As my wife Emma and I are finally piecing together a homestead of our own, we are doing our best to find the most ecological means of putting a home together. Unfortunately, building codes in North Carolina have required us to use a lot of materials we would not have otherwise chosen. Nevertheless, to get through the process legally, we have begrudgingly adhered to certain systemic situations that don’t sit right. We repurpose where we can, but sometimes the code has left little, to no wiggle room.

One place we have managed to stick to our guns, at least so far, has been solar power. More or less, the lone company serving North Carolina’s power need is Duke Energy, an enterprise that seems endlessly involved in troublesome litigation. Since we’ve been here, they’ve been in court, in particular, over coal ash pits that have contaminated local water sources. They are refusing to clean them up. In short, we don’t want to be involved with them.  We do want to use solar power, and we’ve thus far managed to reject tying into the grid, which would put us in collaboration.

Having originally planned to settle in Central America, where grid-tied solar power isn’t the status quo as it is here, we’d always assumed we’d be having solar batteries, i.e. a true off-grid system. We had no idea that it was unusual for solar power to work that way in the US, but in fact, most people, it would seem, don’t even have “battery back-up” for their panels. People who use solar panels feed the grid and essentially get a discount of normal, grid-supplied electricity when the sun isn’t shining. In fact, for my brother in Utah, it’s actually illegal to back up his own house with his solar array because he’s connected to the grid.

For us, this notion is problematic because we’d essentially still be supporting a company that is steeped in environmentally unsavoury activity business we take pains to avoid. As we’ve researched and plotted, contacted solar power providers, sought information with regards to code-compliant solar power, we’ve noticed a curiously raised eyebrows at the thought of having a battery bank. The reaction became even more skeptical when we brought up nickel-iron batteries.

No joke, the specialist—our second contact in a large local company, sent specially to deal with our situation—at a solar contractor actually recommended that we go elsewhere because he’d never heard of nickel-iron batteries. I wasn’t all that surprised: The solar power providers we’ve vetted here in NC seem to be somewhat cookie-cutter operations, and there are literally only two providers of nickel-iron batteries that I’ve found in the entirety of the United States.

To be honest, I’d not heard of them until watching a Geoff Lawton video, and aside from seeking them out, I’ve not heard of them since. That said, they’ve been around for over a century and are renowned for being “bulletproof” batteries.

 

Some Problems with Other Battery Back-Ups

Emma and I have been trying to find the most environmentally friendly ways of doing what we need to do. While not particularly wealthy, we’ve accepted that doing so often costs a little more. When first looking into nickel-iron batteries, the cost seemed a bit out of reach, but after factoring everything, the choice felt right, both ecologically and economically. Battery banks on the whole are pretty problematic.

  • Though increasingly recyclable, most batteries contain corrosive and toxic materials, such as lead, lithium, cadmium, and mercury. The materials used to produce lead-acid batteries are extremely worrying, and the materials in the increasingly popular and affordable lithium ion versions have problems,
  • Longevity is another issue with typical battery back-ups. A well-maintain, lightly used lead acid battery might last 10 years, but more likely less than half of that. Tesla’s Powerwall has a 10-year warranty with a guaranteed decrease in its ability to hold a charge during that time.
  • These batteries are expensive in the first place. Replacing them frequently is even more expensive.
  • Deeply discharging either lead-acid or lithium ion batteries will significantly reduce their life. Essentially, these batteries should only be drained to about half their capacity before recharging them. In other words, not only do they have relatively short lifespans in the best conditions, they are also susceptible to serious damage.

 

What’s So Great About Nickel-Iron Batteries?

 Nickel-iron batteries addressed a lot of our concerns about the other batteries.

  • Nickel-iron batteries don’t have the toxic chemicals that lead-acid, nickel-cadmium, or lithium ion batteries do, so their impact on the environment is less. What’s more, there is no acid, thus no concern of spills. The materials aren’t hazardous.
  • What’s more, these batteries are known to last for decades, with a minimum life expectancy of 30 years, not to mention batteries dating back to WWII but still functioning after all that time. They have thousands upon thousands of cycles in their lifespan, and what’s more, they can be rebooted to essentially start anew. Nickel-iron batteries were used in the original electric cars in the 19-oughts, and some still work today.
  • Compared to the lithium ion batteries, nickel-iron batteries are very inexpensive. When considering the number of times a lead-acid battery would need replacing next to nickel-iron, the cost is significantly less here as well. In short, they are the most economic choice in addition to being the most ecological one.
  • They have the capacity for deep discharging. While other types of batteries generally call for no more than 50% discharge, nickel-iron can regularly be taken down 80% without any depletion of its life. Discharging this way isn’t damaging to the batteries.
  • They also handle a wider temperature range than other batteries, holding strong well below freezing and at highs hotter than anywhere on the planet currently gets.

 

The Catches of the Nickel-Iron Battery Back-Up

Without a doubt, the nickel-iron battery bank does come with some unique challenges. Point of fact, the system was invented by Thomas Edison in the early 1900s, but it isn’t the premiere solar battery bank. Why? Well, these are things that we decided we could live with:

  • Nickel iron battery banks are large and heavy. For anyone who has picked up a lead-acid solar battery, the thought of something heavier is scary. In other words, if moving the battery bank around is necessary, this choice might have been troubling. We don’t need to do that.
  • While these batteries don’t have toxic materials, they do off-gas hydrogen, which is highly combustible. As a result, nickel-iron batteries require enclosures with ventilation that releases the hydrogen outside. That didn’t seem problematic since we aren’t moving the batteries around anyway.
  • They require the monthly task of adding distilled water so that the electrolysis required for charging can take place. While this does mean looking in on and dealing with the batteries regularly, we want to understand our system and look after it. This will keep us in tune with our system, and luckily not doing this maintenance with perfect timing won’t damage the battery.
  • They don’t always work with standard solar equipment. However, for the most part, they work with quality equipment, and they do have plenty of options. We had no problem finding what works, but it did mean not buying any old thing.

 

To Each Their Own

By no means, not even stretching the truth to its limits, are either Emma or me solar power experts. We are simply people hoping to have a relatively modest amount of electricity, enough to run some lights, a couple of laptops, WiFi, a chest freezer, and the occasional kitchen appliance. We wanted a quality system to provide that, one that would last and not cause too much damage when all was said and done. Nickel-iron is what we settled on. Because it seems to be relatively under the radar here in the US, I just wanted to share some of the information we’ve gathered.

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Jonathon Engels

The financially unfortunate combination of travel enthusiast, freelance writer, and vegan gardener, Jonathon Engels whittled and whistled himself into a life that gives him cause to continually scribble about it. He has lived as an expat for over a decade, worked in nearly a dozen countries, and visited dozens of others in the meantime, subjecting the planet to a fiery mix of permaculture, music, and plant-based cooking. More of his work can be found at Jonathon Engels: A Life About.

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