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100 microwatts isn’t much. I’m curious how long other comparable batteries would last if you were only drawing 100 microwatts from them. I’m curious what you c

100 microwatts isn’t much. I’m curious how long other comparable batteries would last if you were only drawing 100 microwatts from them. I’m curious what you could run on that little power. But I guess something a bit larger could probably be batteries in a smoke alarm, or other home security sensors? Idk how much power those draw but if it’s just making a WiFi ping sporadically it probably isnt much.

danboarder 3y ago
Good question. I think an array of these as cells in a series would bring it up to levels that could power an eInk display, etc that practically never needs additional batteries for its lifetime. Super cool.
roarcher 3y ago
> I’m curious how long other comparable batteries would last if you were only drawing 100 microwatts from them. The article claims they have about 10 times the energy density of Li-Ion batteries. So assuming their numbers are correct, maybe 5 years. Purely in terms of energy density, these are cool but they're quite a long way from "phone that never needs to be charged" territory. Maybe a phone would need to be charged every few weeks instead of every couple days...except these can't be recharged at all.
kedikedi 3y ago
There’s also the self discharge aspect of things: cells lose energy even if you draw no current at all. This is dependent on many things including chemistry, quality, buildup, temperature and whatnot. I am not including lithium batteries (not bare cells) which need to have some kind of protection circuitry that also draws a bit of power.
- gus_massa 3y ago
  It's not a chemical battery. The energy comes from the nuclear desintegration of radioactive nickel. So the charge is inmmune to most of the usual problems. On the other hand, I don't know how strong are the layers that aborb the radiation and cretes the electricity.
  - kedikedi 3y ago
    Ah, you’re right! I was talking about the “comparable” batteries, assuming them being chemical batteries
talldrinkofwhat 3y ago
P=IV (power = current * voltage) Lipos -> 3.7V nominal once you're in the meat of it. 100uW -> 27uA @3.7V, which is a __VERY__ generous current budget with modern microcontrollers and effective use of sleep modes. AAA Cells -> 1200mAH @27uA -> 5rs AA Cells -> 2200mAH @27uA -> 9.3yrs C Cells -> 9000mAH @27uA -> 38yrs Then just remember that this thing is smaller than all of those, has no self discharge which typically steals 2-3% of the battery capacity year-over-year, and that with lipo's you can't use the last chunk of nameplate capacity due to precipitous voltage drop at the end of the discharge curve.
SOLAR_FIELDS 3y ago
You had me until WiFi ping. One thing you learn doing electronics with batteries pretty quickly is that WiFi just destroys battery. Even just turning the radio on (which you must do for any low power device, they are idling in deep sleep otherwise) is going to cost you orders of magnitude more power than anything non radio related. The most efficient devices that ping something on battery use some alternative low power protocol that isn’t full WiFi. The story around BLE is significantly better but also the rise of thread and Matter makes these alternative ways of communication more viable these days.

danboarder 3y ago

Good question. I think an array of these as cells in a series would bring it up to levels that could power an eInk display, etc that practically never needs additional batteries for its lifetime. Super cool.

roarcher 3y ago

> I’m curious how long other comparable batteries would last if you were only drawing 100 microwatts from them. The article claims they have about 10 times the energy density of Li-Ion batteries. So assuming their numbers are correct, maybe 5 years. Purely in terms of energy density, these are cool but they're quite a long way from "phone that never needs to be charged" territory. Maybe a phone would need to be charged every few weeks instead of every couple days...except these can't be recharged at all.

kedikedi 3y ago

There’s also the self discharge aspect of things: cells lose energy even if you draw no current at all. This is dependent on many things including chemistry, quality, buildup, temperature and whatnot. I am not including lithium batteries (not bare cells) which need to have some kind of protection circuitry that also draws a bit of power.

gus_massa 3y ago
It's not a chemical battery. The energy comes from the nuclear desintegration of radioactive nickel. So the charge is inmmune to most of the usual problems. On the other hand, I don't know how strong are the layers that aborb the radiation and cretes the electricity.
- kedikedi 3y ago
  Ah, you’re right! I was talking about the “comparable” batteries, assuming them being chemical batteries

talldrinkofwhat 3y ago

P=IV (power = current * voltage) Lipos -> 3.7V nominal once you're in the meat of it. 100uW -> 27uA @3.7V, which is a __VERY__ generous current budget with modern microcontrollers and effective use of sleep modes. AAA Cells -> 1200mAH @27uA -> 5rs AA Cells -> 2200mAH @27uA -> 9.3yrs C Cells -> 9000mAH @27uA -> 38yrs Then just remember that this thing is smaller than all of those, has no self discharge which typically steals 2-3% of the battery capacity year-over-year, and that with lipo's you can't use the last chunk of nameplate capacity due to precipitous voltage drop at the end of the discharge curve.

SOLAR_FIELDS 3y ago

You had me until WiFi ping. One thing you learn doing electronics with batteries pretty quickly is that WiFi just destroys battery. Even just turning the radio on (which you must do for any low power device, they are idling in deep sleep otherwise) is going to cost you orders of magnitude more power than anything non radio related. The most efficient devices that ping something on battery use some alternative low power protocol that isn’t full WiFi. The story around BLE is significantly better but also the rise of thread and Matter makes these alternative ways of communication more viable these days.