Should I use lithium or VRLA at a telecommunications site?

It depends on temperature, cycling and access, and the honest answer is not always lithium. Lithium wins where the cabinet runs hot (VRLA life halves per 10 °C above 20 °C), where footprint or weight limits achievable autonomy, or where the site cycles rather than sitting on float. VRLA remains competitive for pure standby duty in a controlled environment, where no BMS is wanted in the DC path, and where the unrestricted transport classification matters for a remote site. Worth knowing as evidence rather than opinion: the 2021 Mobile Network Hardening rollout across 341 regional and remote base stations, 22 MWh, 12 hours of autonomy, designed for a minimum ten years, used gel VRLA, not lithium.