They certainly have problems, but my dad has been living with lead acid batteries for his solar array, as lithium was too expensive at the time. The batteries will need replaced soon, but lead acid still looks like the way to go. The memory affect sucks, and power density is horrible, but they are pretty darn safe. I wouldn't want to short the system, but if you dropped a wrench on the output terminals it wouldn't be nearly as serious as doing the same on a lithium system, provided the protection circuitry failed. He may go lithium, but if so those batteries are getting moved into a pit external to the house, the potential failure mode is too ugly to have that bank inside the garage. I wouldn't want any portable device with lead acid, that's for damn sure, but they are still pretty darn viable for stationary use.