I made the mistake of trying to charge them 2 hours before I left. The largest had a built in solar panel but was empty, the smaller ones had some charge. So I was hoping that between them all I'd have at least 1 full charge for my phone.
The solar panelled one did not do its job. So was basically dead weight. The other was a camp light which was v useful but obviously meant had no charge left. The last one had a lille oomph left.