No. It lasts years because pacemakers have a really tiny power draw.
There's not a miniature nuclear reactor in there, it's just a RTG, which is simple but also very inefficient. So it doesn't get the crazy amount of power from a tiny amount of material a fission reactor does.
> There's not a miniature nuclear reactor in there, it's just a RTG,
I believe these are not RTGs (radioisotope thermoelectric generators.) Rather they use radiovoltaic conversion, probably alphavoltaic conversion judging by the use of Pu-238. Such devices convert alpha or beta radiation directly to electricity using semiconductors, not unlike photovoltaic cells.
But your point still holds, these atomic batteries produce a tiny amount of power.
It would take about 50,000 hours (5.7 years) to charge a 10 Wh iPhone. A solar cell on the back of the iphone would take roughly a full sunny day to charge an iPhone, with ~2 watts peak output.
> Even weak indoor light would eventually charge it.
No, it wouldn't. Sunlight is ~1 kW per m^2. A medium-sized room has maybe a couple 60 watt bulbs, spread over 10+ m^2, each of which radiates ~10 watts of actual light.
Light indoors is pretty easily 1000x less than outdoors. Eyes work exceptionally well in low light conditions, so we don't even realize the enormous difference in brightness.
Current 60W bulbs are about 10W, probably giving off 3W of light.
If it's on for 8hrs a day and you capture all of it, on 1/5000th of a room, you get... 4mWh, or in reality, 0.7mWh because panels aren't perfect?
You could make a call in a few months of charge time. with a 3x3inch panel. But yeah, I suppose I was wrong and "eventually" is a bit of an understatement.
For actual power, no it would be wildly impractical. However there is a concept of a nuclear top-off battery which keeps your main chemical battery from draining during long periods when not it use. So you could throw a charged phone in a drawer and come back months or years later and it's still good to go. Good for applications like an emergency kit.
There's not a miniature nuclear reactor in there, it's just a RTG, which is simple but also very inefficient. So it doesn't get the crazy amount of power from a tiny amount of material a fission reactor does.