What is the real cost of a battery failure at a remote site?

Rarely the battery. On a site several hours from the nearest depot, the cost is the vehicle and crew, the travel time, and the diagnostic visit that precedes the repair visit when the fault is not understood remotely. Add the equipment that was offline in between. Where the failure interrupts monitoring, dewatering or environmental compliance, add that consequence too. This asymmetry is why remote sites justify monitoring, planned replacement and higher-specification product on a whole-of-life basis that would not stack up at a metropolitan site.