We recently built our own demo Lithium Ion battery system
and took it to the Annapolis Boat show. We wrote a Blog Post
to describe the system, the logic behind it, a cost comparison
with conventional batteries, and all the technical details.
We took this display to the Annapolis Boat Show to demo these batteries. The entire system is hooked up to the internet and can be viewed around the world. The state of charge, power consumption, battery voltage and useage statistics are shown on this Victron Color Control GX display and then connected by WiFi to the Victron remote site where anyone can look at it. Here is the link if you want to take a look in real time.
The upfront cost of Lithium batteries is high but when you look at the cost over time it can be less than conventional batteries despite delivering vastly greater performance.