Yes, you're right. I didn't know the right name, but after I found it, here is something I found:
"Nickel-iron batteries (NiFe), also known as iron electrodes, are the most important commercial rechargeable system using iron electrodes. They are nearly indestructible, have a long life, and can withstand electrical abuse (overcharge, overdischarge, short-circuiting, etc.). They generally cost more than lead acid batteries and have a low cell voltage, low power density, and lower energy density than competitive systems. "
It seems that I could use them for my mountain cabin. Watering them isn't a big problem, and since they are placed outside the cabin, in separate concrete "box", I thing that gasses they produce while charging are not going to make any damage.
Thanx!