How can I convert 18v cordless drill battery to recharge laptop, compact camera charger?

I have 2 rechargeable 18v battery pack from cordless drill which I'm thinking of using as laptop charger and compact camera battery charger.  These packs comes with 220v adaptor.  Me and my 12yo son will be doing a week-long research for his school project (climate change) this Xmas break, backpacking in a remote island.  I was thinking of using this packs to recharge our gears and then send the depleted 18v battery for recharge, and so on.  Will this be possible?  Thanks everyone for the help.

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