Batteries

The picture above is supposed to be of our new battery, the heart of our off-grid system. Its wonbok though. Because I still have not managed to get the battery.

Of all the challenges of completing this project so far battery acquisition is the most difficult. Not just any battery, the right one. Windstorms, all of our new screen houses blowing over, a new pig invasion, all not as much of a headache. There is light, though, at the end of the tunnel. A nice light powered by a lithium cell, I can just tell. If you are in Hawaiʻi check out  Battery Bill's. Bill supplies not only batteries but  charge controllers, all kinds of equipment for off grid solar. You want the Mapunapuna store on Ahua St.

Batteries, as I said above, are the heart of a stand alone energy system whether solar or wind, which is also solar... Anyway, it's the Amp hours (AH) available at any given time that powers tools, light, pumps, not how many solar panels there are out there in your array. Those are important for recharging the batteries, but it's the batteries that feed your hungry tech. So in an off-grid situation you want as much battery as you can get, which is limited by money, mostly. But also shipping, especially if you want a nice powerful lithium type battery, which you do, and here is why.

There are three basic types of batteries out there, well four, in order of high tech-osity, efficiency, and power storing properties.

1) Lithium. This includes lithium-iron, lithium-phosphate, lithium-whatever. It's the lithium. Lithium batteries are efficient, relatively light for the power, much longer lived, and of course modern with monitoring tech and power maximizing tech, very nice. But the best thing is that you can discharge them at high intensity repeatedly, down to 20% or less (some sources said to 0% but that is not a real thing I don't think). This is important if you , say, want to run cold room  AC unit with a coolbot all night. Which we do.

Pros: Long lived, durable, excellent discharge/recharge properties.

Cons: Expensive. Sometimes very expensive. Also they don't like very cold weather, and shippers hate, hate, hate to ship them. So they charge a lot IF they are willing to do it. I mean if you live on an island. Not like, Long Island. Kauaʻi. Maybe it's the velociraptors, I don't know.

2) Absorbed Glass Mat (AGM). AGM batteries are very much like regular lead acid batteries. In fact that's what they really are, but instead of having the electrolytes slosh around in the battery case (and maybe spill out if they tip over), the electrolytes are absorbed into layers of glass matt stuff inside there. This means they can be mounted sideways if you feel the need to do that. They are exactly as heavy as a regular lead acid battery though so, hmm. Anyway they tend to live longer than the old lead acid ones and are very durable, and they gas less. They are often used for backup systems. And shippers have less agida about them than lithium-whatever batteries. And they are cheaper-ish. The battery is cheaper, yes, around half the price of a lithium based one, yay! But the downside is you cannot repeatedly discharge them intensively down to zero, or they will die the real death. Dead. You can discharge them about 20-30% maybe repeatedly. So you need a lot more of them for anything except a backup system, like if you are on the grid but need a little backup just in case.

Pros: Pretty cheap! Also reliable, rugged, nonspillable. And they last about 6-8 years if treated nicely

Cons: Really crappy discharge/recharge properties. Yeah, they last 6-8 years when treated nicely, but you won't treat them nicely. You're a farmer, dammit! But Cheap!!

Regular Lead Acid (RLA, I made this acronym up). Regular lead acid batteries are super cheap on the cheap-to-expensive battery scale. They are also easy to find (marine supply places; big boats have giant batteries), and easy to recycle (basically any NAPA or similar auto store). They have awful charge retention, gas explosive poison when in use, and die for any reason, or even no reason at all. Super cheap though. One could put a bunch of these, and it would be a lot, in parallel and get decent energy storge, for about 3 years. 

Pros: Cheap! Available wherever deep cycle batteries are sold (I think Walmart has them)

Really cheap!

Cons: Leaky, explosive gasses and corrosive liquid, yay! Die fast (the batteries).

All of the above is to say you want some type of lithium battery. Whatever is most popular right now, and I will leave it to you to research that because it changes pretty frequently. Lithium is the key term, that has been pretty stable for the past 10 years. Oh yeah I said there are four types of battery. The fourth type is:

Amazing breakthrough battery design (ABBD). This is an incredible battery not based on lithium at all but a new and overlooked material easily mined from non-post-colonial hotspots and involves little environmental cost. It is slightly heavier that lithium battery designs and slightly worse energy storage and release properties. But it is incredibly durable and long lived. 

Pros: Significantly better both cost wise and for the environment than Lithium types. 

Cons: It does not exist. Except in breathless hype. Can't wait for it to be real. No, I really, literally cannot wait. It's like waiting for Elon's truck, or Godot. 

Next: Has battery?