I've read before that it's pretty hard to kill a nickle-iron battery. You can't do it by overcharging or letting it sit discharged. Or so I've heard. This artic

I've read before that it's pretty hard to kill a nickle-iron battery. You can't do it by overcharging or letting it sit discharged. Or so I've heard. This article also claims at least a 40-year lifespan. They're not without downsides though.