I'm putting an ad in the For Sale section for selling electric car battery modules. I am using a few now, and, will be wiring up more real soon. Electric rates here are going crazy. I say screw the companies.
I have some of this type I use for winching logs to my mill area on the farm, and they were previously used in my home built electric motorcycle. I have Chevy Volt modules in the moto now, and, am building a 3 wheeler with another set of Chevy Volt batteries.
I also am planning to hook up an electric battery drive system on my sawmill. No need for expensive ($6.00/gallon) gasoline or diesel, listen to all the noise smell the fumes, etc. Use a small generator away from the mill to charge as I saw.
With a little checking and maintenance, these type batteries last a very long (10 years +) in cars, so, could work well into 15 years or more at slightly reduced capacity. They don't crap out after a few years like Lead Acid.