Is my EarthX battery going to fail because I have it hooked up to an alternator designed to charge lead acid batteries?
Good question. Yes and No and "it depends". I think most important, follow the manufacturers instructions. Second, read up on LiFePO4 batteries, lots of good articles out there. Note I typed "LiFePO4" and not "lithium" batteries. EarthX is a Lithium Iron Phosphate, not Lithium Polymer, HUGE difference in safety and performance.
LiFePO4 will not "explode" any different than a lead acid battery. The historically "exploding" lithium batteries are LiPoly's. Any battery, regardless of chemistry, can have a failure event with smoke and fumes and heat.
There's a lot of misconceptions out there along with some good and bad information.
The biggest misconception I notice is folks with bad experiences with lithium polymer batteries assigning the entire history of lithium batteries to every new lithium battery that comes out. Not all lithium battery chemistries are the same. LiFePO4 (EarthX, others) is far safer than LiPoly (RC Helicopters, airplanes, cars, etc).
Also, some misunderstanding regarding how things work. EarthX advertises as a "drop in" replacement which sure, sort of true. You can certainly drop it in and it will work. But LiFE batteries will hold constant voltage until they are basically dead and then there is a sharp drop to near zero.
So they do require the user understanding this and their application. It's good, because your system gets that 14v the entire battery cycle. Bad, because if you don't understand that you give yourself no warning when it's dead. So, the non-drop-in part of an EarthX relies on you, the user, to know the differences.
For example, set a battery warning for 11.5v (edit: 13.5v is their official recommendation, see post #25) because that's right before the LiFePO4 packs drop off to near zero. So where a lead acid battery will have a more constant drop and less useful the last third of it's charge cycle, a LiFePO4 battery will hold the voltage until the very end.
If you are using an EarthX and it's at 11.5v you have a problem.
If you set a voltage warning for a lead acid battery and then upgrade to an EarthX and don't change it ... well ...
My current project, a Carbon Cub EX-3, has the battery right under the pilot seat. I find myself contemplating these issues again. I don't want to being flying with *ANY* battery under my arse and something decide to meltdown.
But I've had great luck with LiFePO4 in past hobbies and now in the RV-14. Super easy starts, reliable, but like anything, not infallible.