Gotta love that, the devices users pay the largest markup for and apple choose cost saving measures over functionality. I guess as long as the user base continues to accept mistreatment that is exactly what they will get.
Yeah, a "cost-saving" measure on a device selling for upwards of $1000 and with a huge profit margin. Sold by one of the richest corporations in the world.
"Profit-saving" measure is the proper word here.
As you said however, gullible Apple fans deserve it. "There's a sucker born every minute" - and at least every 5 minutes it's an Apple fanboy.
There may be a rationale for 5W versus 20W chargers that has to do with making the phone batteries degrade slower and reduce the risk of fire.
But I do know that my phone gets pretty warm when it is charging and though heat flux does not scale perfectly linearly with temperature, for small differences it's linear enough to say that if you double the charging rate you will double the temperature rise.
Since I'd not want a phone that was 3 times hotter than room temperature rise than it gets now I think this battery charge rate is fixed by this. The only way to do better would be to make the charging heat loss closer to the thermodynamic limit. it's possible different batteries can have different charging heat losses but I'd guess that every phone maker uses the most efficient one currently possible.
Some fixed fraction of every watt that fluxes into storage goes into heat. I'm not quite sure what that amount is, certainly the laws of thermodynamics put a lower bound on that but if it's like most things it's way more than that, probably in double digit percentages.
So that goes to heat. The battery has a fixed surface area to volume ratio. So the rate at which is can dissipate this heat to it's surroundings is fixed by that, which apple can control, and the surroundings which apple cannot control. e.g. is it in the foam padded (insulating) pocket of your back or jacket? Is it under a pillow or a sheaf of papers. Is it standing up in the air or flat in on a table?
If you plan for a reasonable first case, and then build in thermal protection for the rest, then one can figure out how much the temperature inside the battery can get up to for any given charge rate.
At some point the battery is harmed by this temperature. It might just degrade its lifetime but in some cases that degradation also increases the chance of fire or battery swelling.
In any case there is some maximum advisable charge rate for a given size battery. if this is the limit, then It would seem reasonable that an ipad with many times the surfaces area (and volume) could sustain a higher charge rate than an iphone.
I cant say that apple is bumping into this limit because it's too hard to guess without knowing what the battery limits are. But given how warm the phone gets now I'd say they can't charge much faster without making it a lot hotter.
Finally I'll note that this is slightly different than short term fast charging. Since the phone and batter also have a heat capacity, it's possible to temporarily charge the phone up to some total energy without appreciable temperature rise. SO you may be able to partially charge the battery quite fast. But at some point you would have to fall back to the thermodynamic limit described above.
There may be a rationale for 5W versus 20W chargers that has to do with making the phone batteries degrade slower and reduce the risk of fire.
So then why does Apple sell a 12W charger that charges the iPhone at 12W, rather than just 5W? Is it because the degradation of the batteries and risk of fire are lower with a 12W Apple charger?
The comeback is, well then how come apple doesn' sell a 50 watt charger? Evidently there is some limit and I discussed what the sources of the limits are.
I would strongly speculate that the 12 watts charger only really runs at 12 watts under optimal cooling conditions or for part of the cylce. It's may possibly be more of a fast-charger as I noted at the end.
You have a good point about battery longevity. We have a slow charger in the bedroom, and a fast one in the car (which is only used when needed), for that same reason. But this seems like something that Apple could address in software. It might need tighter integration between the USB controller and the OS, but Apple controls all of that.
I'm not too familiar with how Apple lighting chargers work, but with USB the device negotiates the voltage and current with the charger. It seems possible that iOS could no
According to all the latest reports, there was no truth in any of the
earlier reports.
bend over. (Score:1)
Re: (Score:4, Insightful)
Yeah, a "cost-saving" measure on a device selling for upwards of $1000 and with a huge profit margin. Sold by one of the richest corporations in the world.
"Profit-saving" measure is the proper word here.
As you said however, gullible Apple fans deserve it. "There's a sucker born every minute" - and at least every 5 minutes it's an Apple fanboy.
Fire saving and battery lifetime extension? (Score:3)
There may be a rationale for 5W versus 20W chargers that has to do with making the phone batteries degrade slower and reduce the risk of fire.
But I do know that my phone gets pretty warm when it is charging and though heat flux does not scale perfectly linearly with temperature, for small differences it's linear enough to say that if you double the charging rate you will double the temperature rise.
Since I'd not want a phone that was 3 times hotter than room temperature rise than it gets now I think this battery charge rate is fixed by this. The only way to do better would be to make the charging heat loss closer to the thermodynamic limit. it's possible different batteries can have different charging heat losses but I'd guess that every phone maker uses the most efficient one currently possible.
Some fixed fraction of every watt that fluxes into storage goes into heat. I'm not quite sure what that amount is, certainly the laws of thermodynamics put a lower bound on that but if it's like most things it's way more than that, probably in double digit percentages.
So that goes to heat. The battery has a fixed surface area to volume ratio. So the rate at which is can dissipate this heat to it's surroundings is fixed by that, which apple can control, and the surroundings which apple cannot control. e.g. is it in the foam padded (insulating) pocket of your back or jacket? Is it under a pillow or a sheaf of papers. Is it standing up in the air or flat in on a table?
If you plan for a reasonable first case, and then build in thermal protection for the rest, then one can figure out how much the temperature inside the battery can get up to for any given charge rate.
At some point the battery is harmed by this temperature. It might just degrade its lifetime but in some cases that degradation also increases the chance of fire or battery swelling.
In any case there is some maximum advisable charge rate for a given size battery.
if this is the limit, then It would seem reasonable that an ipad with many times the surfaces area (and volume) could sustain a higher charge rate than an iphone.
I cant say that apple is bumping into this limit because it's too hard to guess without knowing what the battery limits are. But given how warm the phone gets now I'd say they can't charge much faster without making it a lot hotter.
Finally I'll note that this is slightly different than short term fast charging. Since the phone and batter also have a heat capacity, it's possible to temporarily charge the phone up to some total energy without appreciable temperature rise. SO you may be able to partially charge the battery quite fast. But at some point you would have to fall back to the thermodynamic limit described above.
Re: (Score:2, Insightful)
There may be a rationale for 5W versus 20W chargers that has to do with making the phone batteries degrade slower and reduce the risk of fire.
So then why does Apple sell a 12W charger that charges the iPhone at 12W, rather than just 5W? Is it because the degradation of the batteries and risk of fire are lower with a 12W Apple charger?
Re: (Score:2)
The comeback is, well then how come apple doesn' sell a 50 watt charger?
Evidently there is some limit and I discussed what the sources of the limits are.
I would strongly speculate that the 12 watts charger only really runs at 12 watts under optimal cooling conditions or for part of the cylce. It's may possibly be more of a fast-charger as I noted at the end.
Why not address it in software? (Score:2)
You have a good point about battery longevity. We have a slow charger in the bedroom, and a fast one in the car (which is only used when needed), for that same reason. But this seems like something that Apple could address in software. It might need tighter integration between the USB controller and the OS, but Apple controls all of that.
I'm not too familiar with how Apple lighting chargers work, but with USB the device negotiates the voltage and current with the charger. It seems possible that iOS could no