What temperature range can a ModX2 operate in?
ModX2’s battery system discharges across −20 °C to +60 °C and charges across −10 °C to +55 °C, in a fan-cooled stainless steel enclosure.
The reason the charge and discharge windows differ is the lithium plating constraint described above, the battery can deliver power in cold conditions but cannot safely accept it. In practice this means a cold site loses charging hours in the morning rather than losing capacity, which is usually manageable but must be modelled.
At the hot end, the constraint is different: capacity is preserved but calendar life shortens. This is where lithium’s advantage over lead-acid is most pronounced. A VRLA battery loses roughly half its life expectancy for every 10 °C of sustained temperature above 20 °C, a 10-year design-life VRLA in a 40 °C enclosure is a 2.5-year battery. LiFePOâ‚„ does not degrade on anything like that curve, which is precisely why it has displaced lead-acid in unairconditioned remote enclosures.