TOOLS
Калькулятор батареи аварийного освещения
See how long your battery can power your lights. Or find the capacity needed for your target runtime.
Battery-bank voltage (V DC)
Nominal voltage on the battery pack, not the mains supply.
Rated battery capacity
Whole-bank capacity. Switching units converts the value.
Emergency lighting power (W)
Use emergency-mode watts, not the normal lighting rating.
Target runtime (min)
Target runtime (custom) (min)
Choose the duration required by your project.
Efficiency & capacity settings
Efficiency (%)
90%
Доступный (%)
80%
Margin (%)
20%
Understanding the estimate
A battery does not deliver every watt-hour stamped on its label at every load. Two deratings matter: the conversion efficiency of the driver between battery and LEDs, and the usable capacity available from the battery under a realistic discharge. The calculator converts your load to a battery-side draw, then divides usable energy by that draw to get runtime.
Battery-side draw (W) = emergency load (W) ÷ efficiency · Usable energy (Wh) = rated capacity (Wh) × available %
Emergency-mode watts
The load in the lit emergency state, usually far lower than normal lighting. Enter the watts the lights actually draw in emergency mode.
Efficiency
The driver/charger is not 100% efficient. 90% means 10% is lost converting battery power to the LEDs, so the battery side draws more than the fixture rating.
Available capacity
Not all nameplate amp-hours are usable. At high discharge rates and with age, 80% is a common conservative planning assumption.
Capacity margin
Regulations and good practice ask for headroom. 20% extra capacity covers aging, cold and tolerance so the runtime still meets code at end of life.
Runtime (min) = usable energy (Wh) ÷ battery-side draw (W) × 60 · Rated capacity needed = draw × target h × (1 + margin) ÷ available %
Your runtime estimate · Updates as you type
ESTIMATED RUNTIME
2 h 09 min
Covers target + margin
10 Ah at 12 V · 90 min target
White: target 90 min · Orange: 108 min equivalent with 20% capacity margin · Estimated runtime 129 min
Usable energy
96 Wh
Battery-side draw
44.44 W
Needed incl. margin
8.34 Ah
80% of rated energy available · 90% conversion efficiency. Conditional estimate; default settings are examples.
Good to know
Which power rating should I enter?
Enter the watts the luminaire draws in its emergency mode, not its normal lighting rating. Many emergency drivers drop output or dim the fixtures, so the emergency watts are what actually load the battery.
How do I find the available capacity percentage?
It comes from the battery manufacturer’s discharge data at your expected current and temperature. 80% is a common conservative planning value; if the battery data sheet says otherwise, use that.
Do I enter one battery or the whole bank?
The whole bank. Enter the total capacity of all series/parallel cells together and the bank voltage, because the lights draw from the combined pack, not one cell.
Why separate runtime from extra capacity margin?
The margin is planning headroom, not runtime you can count on. Sizing for 20% extra capacity keeps the runtime above target as the battery ages and in colder conditions, without claiming that extra runtime as code compliance.
Can I replace the battery with a larger one?
Usually yes, if the emergency driver and enclosure accept the chemistry, voltage and charging current. Recheck the charge time, thermal limits and the discharge performance at the new load after changing capacity.
Does reaching 90 or 180 minutes mean compliance?
No. Compliance needs a full-duration discharge test at the required light output, checked against your local code (such as EN 50172, BS 5266 or your national requirement). This estimate only sizes the energy.
How is the estimate calculated?
Battery-side draw = load ÷ efficiency. Usable energy = rated Wh × available %. Runtime = usable energy ÷ draw. Capacity needed = draw × target hours × (1 + margin) ÷ available %. See the Understanding the estimate module above.
Can I save this without an account?
Yes. Use Save results to store the inputs and result locally on this device, or Copy results / Share calculation to keep an editable copy offline.
Share your lighting requirements and selected equipment with our team.
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