EarthX batteries are rated up to 60°C or 140°F for normal operation, and for short term operation (30 mins) is 65°C. After shut down with a hot engine compartment (no operation) it is rated for 85°C or 185°F. Higher temperatures mean shortened battery life. The batteries do come with heat monitoring that will illuminate the LED with a 2 second on/off light and you would need to mititage the heat for a longer battery life. EarthX batteries have been installed in engine compartments with no trouble, however if heat is still a concern we do offer thermal battery boxes.