Do rechargeable light bulb charge when the switch is off?
The answer is NO!
The switch when turned off has physically cut the electricity supply to the light bulb so it is impossible to have electricity flow to recharge the bulb.
Rechargeable light bulbs need to be charged or used as normal during times of power so that the battery is fully charged for the next power outage.
Please also remember that sometimes the time needed for the batteries to recharge is longer than the periods between load shedding events so your battery may not be fully charged next time it is needed. This may result in run times less than advertised but this is normal as the product did not have enough time to fully charge.