Application
Supercapacitors for Industrial Backup Power
Ride-through and safe-shutdown energy for controllers, drives, and data loggers.
Power requirements
Industrial backup typically needs seconds to minutes of hold-up so a controller can save state, close a valve, park an actuator, or finish a write cycle after mains loss. Loads range from a few watts for a PLC to hundreds of watts for a motor brake.
Why supercapacitors fit
Supercapacitors can be charged quickly, tolerate high cycle counts, and do not require the periodic replacement that many backup batteries need. For short, well-defined hold-up windows, they can reduce maintenance.
Selection factors
- Required hold-up time and load power, including the DC/DC converter's minimum input voltage.
- Worst-case temperature — capacitance decreases and ESR increases at low temperature.
- End-of-life capacitance (often specified as −20% or −30% of initial).
- Charge time available after power returns.
Limitations
- Not practical for long runtimes (tens of minutes to hours) at high power
- Requires a charger and often voltage balancing
Worked example: 10 W for 5 s
Energy needed = 10 W × 5 s = 50 J. With a 5.0 V → 2.5 V usable window and ~85% converter efficiency, C ≥ 2·(50/0.85)/(5.0² − 2.5²) ≈ 6.3 F. Adding 30% end-of-life margin gives ≈ 8.2 F at 5 V — e.g. two cells of ~16 F or more in series (balanced). Verify with ESR drop at peak current.
Supercapacitor types
Winding-Type Supercapacitors
Cylindrical cells built from wound electrode foils — the workhorse format from a few farads to thousands.
Explore
Snap-In Supercapacitors
Larger cells with snap-in PCB terminals for higher currents and capacitance.
Explore
Supercapacitor Modules
Series/parallel assemblies with balancing, housed for system-level voltage and energy.
Explore
Sizing a supercapacitor for industrial backup power?
Send your load profile and we’ll suggest suitable parts.