Powering Telecom and Remote Sites: Solar, Battery and DC Plant Design

A telecom site cannot shed load when the weather turns. Design starts with the DC load (often 24V or 48V at a few hundred watts), the required days of autonomy, and the site's worst-month insolation. A site that runs on 500W average becomes a 3-4kW array once the winter derate and autonomy are applied.

DC-coupled architectures dominate here: the load is natively DC, so avoiding an inverter removes a conversion loss and a failure point.

LFP gives usable depth and cycle life but needs thermal management where winters are hard - charging below freezing damages cells. AGM or gel tolerates cold charging but gives roughly half the usable capacity and a shorter cycle life. Many operators end up with a heated LFP enclosure plus a generator for the worst weeks; the generator is the cheapest kilowatt-hour of autonomy.

1. 1

   Establish the DC load profile

   Average and peak current at the system voltage, including radio equipment duty cycles and any heating.

2. 2

   Choose system voltage

   24V for smaller loads, 48V above roughly 1kW to keep conductor sizes sane over long runs.

3. 3

   Size the battery for autonomy

   Use usable kWh, apply a temperature derate, and accept the generator as the last line of defence.

4. 4

   Size the array for the worst month

   Worst-month insolation plus a soiling/snow allowance; oversizing here is cheaper than more battery.

5. 5

   Design the enclosure

   Thermal management, ventilation, intrusion and remote monitoring - the site is unattended by definition.