Time to start Christmas shopping. My stepson needs a lamp to get him through power outages. What I am looking for is a lamp that he can use as a regular lamp in his living room, not a tiny camping lamp. When the power goes out, I would like it to switch automatically to an internal battery. Ideally it would be able to charge stuff with a USB outlet when using mains or battery power.
Perhaps my Amazon-foo is weak. Can anyone point me in the right direction?
Have you considered just getting him a UPS? In many ways it is more generally useful device, and he can keep his choice of lamp. Many simple UPS devices include USB power. There are a lot of UPSs about, and the market is pretty competitive, so you are likely to find better value than a specialised lamp.
Well honestly, no, I did not consider that. That would be the obvious solution. Thank you.
Seconding that advice (mostly).
While there ARE a bunch of battery-powered lamps on Amazon, I think you’d get both a better lamp and a better battery by separating the two. The main thing is the physical size of the battery — you can only fit a small one into the body of the lamp, giving you maybe 10-20 hours of light. Is that enough?
If you need a bigger battery, a UPS would work, but they are quite expensive for minimal capacity. This $200 one, for example, only has 108 Watt-hours of capacity (that’s 20 hours for a 5W LED, or 1 hour for a 100W incandescent).
Instead, a very similar category of device is the portable battery station, like one of these (or their much bigger ones, if you want whole-house power and not just a lamp). For about the same amount of money, you get 2.5x the battery capacity. For a little more money, you could get the 7x the capacity or more.
The UPS is designed for automatic switchover in case of an outage (you plug everything into it and they stay on through the outage), but you get less runtime per dollar. The power stations require you to manually plug things into them in the event of an outage, but you get much bigger capacities for the buck.
The other thing is making sure his lamp(s) have a good LED bulb instead of an incandescent or CFL, because they use much less power (5-10W vs the 100W of an incandescent). This directly translates into how long he’ll have light during an outage. If he doesn’t already have such a bulb, look for something with good CRI (color rendering index, ideally 95+ but at least 90+). Below that and it’ll look like crap. Also, a color temperature of 2700k would be close to an incandescent; lower numbers are warmer/redder, while higher numbers are cooler/bluer. They should be available at Costco, Amazon, or really any hardware store.
I have a small emergency light plugged into the outlet next to my bed. When the power goes out, this thing lights up so I can find it and then use it as a flashlight. (For one thing, I need to check that the circuit breaker didn’t trip.) If the problem is an extended power outage, this gives me enough light to get to the bin containing regular flashlights and batteries so I can put one together.
My wife stopped by to use the printer and told me our son does not need or want this. So that problem is solved.
Thank you.
Wise woman 
We have some battery powered bulbs. They look and act like ordinary bulbs when they are screwed in to a powered lamp, but they have an internal battery that charges from the mains power. When the power goes out, the battery takes over and the bulb continues to act like a normal bulb (turns on and off via the lamp switch). There are a number of models on Amazon if you search for “battery powered bulb”.
How does the bulb know the state of the switch, and distinguish this from a power outage?
One way to tell the state of the switch in a power outage: assuming the outage isn’t caused by a broken wire between your house and the transformer, when the power is out the bulb would still see a low DC resistance (DC resistance of the transformer) looking towards the line if the switch were closed and a high resistance if the switch were open. So if AC power is out put a small DC current out the line side of the bulb, if the voltage stays low then turn the light on, otherwise turn the light off.
I have no idea if this is how the bulb in question works, but it is one way to do it.
ETA: When I say “small DC current” I mean a microamp or lass.
I don’t know exactly how it works. I know that if you directly connect the bulb’s terminals (the threaded metallic part and the nub on the end) with a wire, the light will turn on. This will work even if the connection is through your body; eg. touch the thread with one finger and the nub with another finger and the light turns on.
Also, the Engrish instructions say
It is need a closed loop to make it glowing, so even during power outage, please keep your home main power electric brake / main switch on, keep your lamp plug into the plug prongs.
Maybe someone with more electrical knowledge than I have can put those pieces of evidence together to explain how it works.
[Moderating]
Oh, and since this is seeking advice, moving to IMHO.
See my post right before your. Your description matches my explanation.