150 watt hours ... or about 1/4 what my £60 car battery holds (with it's built in 12v outputs ... or 230v and 1.5 thru 9v via a cheap inverter and even cheaper DC-DC converter). Hmm.

And charging up in "just" 15 hours of sunlight (or as we would call it here in the UK at this time of year, "at least three whole days if not a full working week"), ie a maximum of 10 watts continuous, or less than five watts average across the whole year if you're between the arctic and antarctic circles (preferably between the two tropics)...

Yeah, you better not expect to run any high-drain devices off this. You can keep a mobile phone going OK enough, and probably a low-end tablet. High end tablets will require a bit of discipline, and laptop use would have to be carefully rationed, especially if you want to use lighting, a radio receiver/ghetto blaster, 2-way radio or, say, a (slowly) pump-filled water tank as well.

Desktop PCs, televisions, high powered audio equipment, bright lighting, cookers, kettles, toasters, refrigerators, AC and even desk fans are completely out of the question. Unless you want, say, to make just two cups of tea and a single 4-slice round of toast from each full charge.

Plus, consider this: if civilisation collapses, how's your wireless cellular internettings device going to connect to the web? The towers, if they haven't been knocked over, need grid power to keep running beyond whatever short outages their UPSes are rated for, as do the switches at your ISP, and the servers at all those data centres...

There are some needs I could see it being rather useful for, but don't get your hopes up too high for it being the saviour of mankind. ;-)