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Here they are unboxed as they say on youtube. The total size is 20.5" wide x 22" deep x 14" high and each cell weighs 92#. The BMS (battery management system) is in a real nice pvc box that is too large for where I want to install it in the compartment so I'll pull it apart and mount the shut-off contactor and a couple other components on the wall of the compartment. I'll put the BMS circuit board in a small pvc box and mount that on the wall. The 4 cells will be connected with copper straps. Each cell is 3 volts nominal so together will produce 12 volts. Actual voltage stays pretty constant at about 13.8 volts even with large amp draws.
The total cost with shipping for the 4 cells + the BMS and connectors was $3247.84 from Balqon.com I will still need to buy a SOC (state of charge meter) and these run anywhere from $70 to a couple hundred depending if you want wifi capabilities so you can check the batteries on your phone. The voltage stays pretty constant until they are almost fully discharged. Hence the need for the BMS that shuts down the batteries before they are damaged. So you can't go by the voltage like you can with lead acids or agms.
I might have to change the alternator regulator to a Balmar MC-614 which has a temperature sensor. The lithiums when low can accept such a large charge it is possible to burn up your alternator. The Balmar de-rates the alternator output based on the alternator temperature. This is about $300.
So the total cost will probably be around $3800-4000. About the same as a set of agms!
But I probably won't get much done until next week. Gotta take care of the new grandkid!