So, after distributing kits to kids at hillhacks last year few complained that fully charged lantern is getting discharged even when the lantern was switched off via switch U1 in the previous schematics. After a closed inspection I realised that q5252 ic has some leakage current which discharges the battery within one day. To fix this I have added an another switch SW1 next to the battery (just for this version though, see below schematics). So now people can store a charged lantern in dark by switching off this switch and there won't be a leakage of current.
Caveat is that to switch on the lantern again we will have to switch on two switches now, i.e. both SW1 and U1. This is not the best design whch I will try to fix in the next version.