I asked Shorai if they have a built-in BMS in their batteries. Here is a reply I got. This is just for completeness of information.
"The Shorai LFX batteries have an internal balancer that turns on if a cell exceeds 3.65V. At this time Shorai has elected not to use a low voltage cut out because our testing shows that the cells are very durable and can tolerate rare occurrences of over discharge as long as they are recovered with the Shorai BMS01 charger which provides battery diagnostics and more precise balancing. We have found that in too many real world situations the use of a full BMS design can prohibit battery use in critical times and create customer inconvenience. Our approach is to build a very good cell pak that can tolerate occasional abuse and permit full use of the batteries abilities."
Building a Panther, but lurking here, like many others