Temperature Effects on PHI Batteries vs. Lead Acid
When it comes to the negative effects of temperature on lead acid batteries, lithium iron phosphate provides an ideal solution for lead acid’s many limitations.

Loss of efficiency at low and high temperature
In ambient temperatures lower or higher than 25℃, lead acid battery efficiency is reduced.This can result in the loss of available capacity. Efficiency and available capacity decreases over time as the temperature moves further from the ideal 25℃.
By contrast, even in temperatures far above and below the ideal 25℃ “standard temperature mark,” PHI LFP batteries continue to operate reliably without losing efficiency — even in temperatures as low as 0℃. Although a system user might experience some efficiency loss, it will be minimal compared to a lead acid battery and often can be easily mitigated by slowing down the charge rate of the PHI LFP battery at lower temperatures.
Loss of capacity and EOL
“EOL” is a phrase describing a batteries warrantied “end of life.” When evaluating the majority of lead acid batteries, you will not find a warrantied EOL. If cycles are estimated, there is no guarantee of how much capacity will be left at the end of the battery’s life. This is likely due to the fact that lead acid batteries lose capacity quickly over time. In addition, temperatures varying from 25℃ can speed this capacity loss. Also of relevance is that lead acid batteries lose capacity over time regardless of whether they are used or not. As a result, they are not a good solution for backup power.
PHI LFP batteries have an EOL of 80% — meaning that at the end of the warranty period (10 years, 10,000 cycles) we expect to see 80% of original capacity. High or low temperature exposure within warrantied guidelines does not significantly accelerate PHI battery capacity decline.

Wider temperature window warrantied
Now that you know the the difference between lead acid and LFP batteries when it comes to temperature-related performance, take note of the specific temperature ranges included in lead acid and SimpliPhi warranty guidelines.
Lead Acid:
Operating Temperature: 0F – 115F
Charging Temperature: 40F – 113F
PHI Batteries:
Operating Temperature: -4F – 140F
Charging Temperature: 32F – 120F