Float Charge
Float voltage is the voltage a battery should be kept at when it is used for standby, as it is in emergency lighting.
Three things to know
Voltage follows the charge
A battery's voltage falls as it discharges, and rises as it charges.
Batteries self-discharge
All batteries slowly lose charge, even when they are not being used.
The label isn't the full story
The voltage on a battery's label is usually lower than its voltage when fully charged.
Everyday batteries and standby batteries
Phone or camper battery
Charged to 100%, then used. A full charge gives the longest run time.
Emergency lighting battery
Waits, unused, for most of its life. Kept fully charged for long periods it wears out sooner; left off charge it self-discharges and won't be at its best when it's needed. So it's kept at its float voltage: near full, for a long time.
Temperature changes the float voltage
Float voltage depends on the battery's chemistry and on the temperature around it: the warmer it is, the lower the float voltage.
How smart chargers handle it
- 1Charge the battery until it's full
- 2Relax to the float voltage
- 3Hold it there until it's disconnected
How Z10 does it
Z10 batteries are lithium-ion, and we hold them at 80% of capacity. When the charge drops to 79%, a short top-up takes it back to 80%: fast, efficient and kind to the battery.
Up to a 5 year warranty on the luminaire and battery. Register your products within 6 months of purchase.
