Some reputable experts claim that Li batteries are not suitable for applications in the low winter temperature environment of -30C and below and this is to summarize and share our findings. Let us compare the fundamental differences between Lithium and GEL/AGM batteries pricing for off-grid solar-powered lighting installations concerning operating temperatures, lifetime cycles, and costs. Operating temperatures and Lifetime Cycle The most commonly used Li batteries for solar applications are LiFePO4 and NCM (NiCoMnO2). LiFePO4 batteries excellent longevity 5-8 years and lifetime cycles, however for many regions in Canada they don’t stand up very well to cold temperatures of -15C and below and for that reason, we decided not to standardize on it. These batteries excel, however, in a warm climate. NCM battery technology has evolved and improved greatly over the past few years and the low-temperature version has shown excellent results in applications with winter temperatures of -30/35C and lower. AGM & GEL batteries are reliable and low temp versions can still function at -40C however the charge and discharge efficiency become sluggish, unreliable, and don’t stand up to such low temperatures maintained over several days. The average useful life expectancy of these batteries is about 4-5 years, depending on the environmental conditions. Regarding the Lifecycle vs DOD (Depth Of Discharge), we did not record any significant difference. Costs and space requirements The costs of Li batteries are generally nearly twice as AGM/GEL. Premium of 60-80% is normal. Besides a longer life expectancy, the Li batteries require significantly less space of about 30-40% depending on battery capacity and Voltage. This is a great advantage in off-grid lighting applications where the batteries ore installed on or below the pole. Extreme cold temperatures -35 and below Upplands Energy Inc. has developed two proven systems for operating both AGM/GEL and Li batteries in extremely cold temperatures of -50 or below and both designs have already been installed in Northern Alberta, Manitoba, and Ontario. The company developed several design configurations that meet local site conditions. Battery Vault Modular design prewired for below ground installation. The robust vault design can be installed near and above the frost line and not only provide excellent protection against extreme cold and windchill but puts the batteries out-of-site thus eliminating theft. Battery/Control Enclosure Installed on or below the pole, the insulated IP65 rated cabinet includes a thermal module to keep the batteries safe in an environment of no lower than -30C while the outside ambient temperature is -50C.