I would ask the manufacturer, not a forum, for critical specifications on any product.
Or, just relocate the battery to the passenger footwell, to keep it at ambient temperature.
I asked Mageti Marelli some weeks ago but did not get the courtesy of a reply. I also asked MCR-Motorsports who are the UK agent for MM's lithium batteries for motorsport but as yet, no reply either.
The foot well on the passenger side is too short to reduce its length by around 30cm with a battery. I also would not want a lithium battery, even the safer LiPo variety, inside the passenger compartment with me. I suspect I will just carry on with the lead acid batteries, as although they only last around 3 years, they are relatively cheap at about £55 for a Bosch or Yuasa battery, so more than 4 lead acid batteries for the price of a lithium one. In that I am currently coming up to 78 years old, I cannot see me driving the M3W for another 10 years. Also where it used to be stored over the winter, people kept unplugging the battery tender to use the mains socket for something else and forgetting to plug the tender back in afterwards. Where it is now stored in the showroom of Provence Retro Classic Cars, I would hope that the battery will be better tended, so it may now last longer than three years. The Bosch lead acid battery in my 1977 911 RSR is now 14 years old and still working perfectly. The battery in my brother's 1909 London to Edinburgh Rolls Royce Silver Ghost is 1920's vintage wooden and glass cased lead acid battery and again, still starts it with no problems.
Wilson
