Michael,
I'm sorry, but I don't quite understand the question. If you're concerned about an EarthX bursting into flames like other lesser lithiums we've seen in the news, be advised that this Lithium IRON PHOSPHATE battery has a different chemistry than those other batteries, and is not susceptible to such thermal runaway.
I'm not sure what "fail under charging" means. In any case, the battery management circuits well give you an indication of problems long before the battery simply fails.
If you're concerned with an over-voltage from the charging system, this battery internally disconnects incoming charge at 16.0 volts, while still sending outbound battery power to the rest of the system. As we saw in Indwarrior's post above, that power lasts a long time.
Hey, Kathy, in the past year, have any ETXs simply failed?