If you have regular access to power, a dynamo hub or solar charger isn't that necessary, but how about a big battery? There are enough wall plugs in the world (even in the most remote regions) that we could've easily lived without our dynamo hub. Batteries are small and light enough these days to keep your devices going between wall plugs.
Some of these battery packs will connect directly to dynamo hubs or solar panels, holding saved power for when you need it most.
Battery Pack Recommendations
Note: There are lot and lots of external batteries available, but these are from the larger brands with a more established reputation. Please check for connectivity to solar panels.
Anker – Well priced products with batteries ranging in size from 2600-20000mAh.
Brunton Impel/Sustain – Super well made products with a power capacity ranging from 2800-13000mAh. Slightly more expensive than the competitors, but they are worth it. Check out the small waterproof battery!
Energenie – Decent products available with between 1800-20000mAh juice.
Hyperjuice – Big batteries for laptop charging: 60-222Wh power, but all this comes at a cost (360-2130g weight). This is the system we would use if we needed to use a laptop in remote areas.
Innergie – A nice looking range of products for laptops and USB devices.
Just Mobile – A cheap, punchy 5200mAh option in a small casing.
Mophie – From the makers of iPhone battery cases, these products range from 4000-6000mAh and are of a great quality.
Powertraveller – A good range of external battery products for everything from phones to laptops.
Scosche – The goBAT II is a nice looking 5000mAh battery that is available at a great price!
Veho Pebble – Very well priced and shiny black 5000mAh battery!
Voltaic – Neat products at a great price. 3000-16000mAh is available for USB devices. Their large laptop battery is 60Wh.