Where devices get energy.
WHAT OPTIONS EXIST
Primary batteries, not rechargeable Rechargeable batteries Mains power Solar
Other harvesting: vibration, thermal, radio
WHAT PRIMARY BATTERIES PROVIDE
Long life with no charging infrastructure.
WHAT THEY COST
Replacement visits, and disposal.
WHAT RECHARGEABLE BATTERIES REQUIRE
A charging source, and management of charge cycles.
WHAT SOLAR PROVIDES
Indefinite operation where light is sufficient.
WHAT IT REQUIRES
Sizing for the worst period, not the average Storage carrying through darkness and cloud Panels that stay clean
WHY THAT LAST POINT MATTERS HERE
Dust accumulation substantially reduces output, and harmattan periods compound it.
WHAT TO SIZE FOR
The longest expected period of poor generation.
WHAT MAINS POWER REQUIRES CONSIDERATION OF
Outages, which are routine Voltage fluctuation and surges Whether the device must survive and resume automatically
WHAT TO IMPLEMENT
Backup capacity carrying through outages Protection against surges Automatic recovery on restoration
WHY AUTOMATIC RECOVERY MATTERS
Nobody will visit to restart a device after every outage.
WHAT TO TEST
Repeated power interruption, including during writes.
