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What Finally Killed AirPower

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Re: What Finally Killed AirPower

#121

Post by teraflop »

accatyyc wrote: post #111
gpm wrote: post #90

Earlier quoted context omitted.

Possible positive? If it keeps it in the 20-70% range I'm told we are supposed to keep our devices in.

The things that kill smartphone batteries today are age and power cycles. It doesn’t matter if you charge from 0% to 100% in one go or from 90% to 100% ten times. Both add up to one power cycle. To keep your battery fresh for as long as possible, always keep the phone connected to a charger. No battery cycles. It will get worse after a few years anyway.

> It doesn’t matter if you charge from 0% to 100% in one go or from 90% to 100% ten times.

This isn't really true, as far as I know. If you avoid fully charging or deeply discharging a lithium-ion battery, the wear per unit of energy extracted is smaller.

There are some statistics quoted here (https://batteryuniversity.com/learn/article/how_to_prolong_l...) showing that if you, say, halve the amount of energy you retrieve from a battery in each cycle, the battery lasts for more than twice as many cycles.

This paper arrives at a similar conclusion (see figure 4): https://www.researchgate.net/publication/318292540_Analysis_...

Re: What Finally Killed AirPower

#122

Post by ulfw »

atarian wrote: post #105
_bxg1 wrote: post #53

Earlier quoted context omitted.

It takes something easy and makes it effortless . Like AirPods, this has a surprising number of implications that you really don't think about until you try it. If I'm just setting my phone down on my desk and it's at 50%, and my cable is right there, I may not bother to plug it in. Especially if I might get up again in 5 or 10 minutes. But if I can just set it down in a particular place and regain a couple percentag…

That was a very well-worded argument. Now I'm even sadder that they're not releasing AirPower.

You know you can do that with any of the thousands of Qi chargers on the market, right?

Re: What Finally Killed AirPower

#123

Post by quotemstr »

oska wrote: post #106
quotemstr wrote: post #43

Earlier quoted context omitted.

> Which for charging phones is a small amount until you think of every person on the planet charging their phone every day. It is a small amount of power though. There are about 4.68 billion mobile phone users; let's assume each has one phone. Let's be conservative and assume that all these phones have high-end battery packs, on the order of 4,000 mAh. Let's be even more conservative and assume each phone is used to…

Thanks for doing the math but I don't think one product that consumes one one thousandth of the world's energy production is negligible. (How many coal power stations is that?) And a 40% increase in this consumption for a very minimal increase in 'convenience' (itself debatable) is not negligently wasteful.

> I don't think one product that consumes one one thousandth of the world's energy production is negligible.

Amdahl does though: https://en.wikipedia.org/wiki/Amdahl%27s_law

> And a 40% increase in this consumption for a very minimal increase in 'convenience' (itself debatable) is not negligently wasteful.

That's your opinion. I have a different opinion. How do we choose which of us is right? In general, we decide on the allocation of scarce resources through markets and price signals. Electricity is metered almost everywhere. If wireless charging's 40% increase in energy use doesn't hurt adoption, it means that the utility gained from wireless charging outweighs the resources consumed. That you personally have different utility function doesn't invalidate anyone else's, and you certainly don't get to make people use your utility function instead of their own. If you think electricity is too cheap and doesn't incorporate necessary externalities, you can argue for some kind of extra climate tax. But arguing against specific products here because you personally don't find them useful isn't the right approach.

Re: What Finally Killed AirPower

#124

Post by dymk »

xenospn wrote: post #107
tedivm wrote: post #65

Earlier quoted context omitted.

They're just going to remove local syncing and stick with cloud based solutions.

Doesn't really work when you're developing locally, tho. Can you imagine loading binaries from the cloud into your phone every single time?

At that point you drill out the sealed cover to the JTAG pins, a-la debugging the Apple Watch ;)

Re: What Finally Killed AirPower

#125

Post by accatyyc »

Phlarp wrote: post #117
accatyyc wrote: post #111

Earlier quoted context omitted.

The things that kill smartphone batteries today are age and power cycles. It doesn’t matter if you charge from 0% to 100% in one go or from 90% to 100% ten times. Both add up to one power cycle. To keep your battery fresh for as long as possible, always keep the phone connected to a charger. No battery cycles. It will get worse after a few years anyway.

Age, cycles and heat. Inductive charging loops are going to generate a ton of waste heat, and worse yet a good chunk of that is going to be coming from the coil inside the phone.

Yeah, but a battery gets hot when charging fast. Keeping it connected at 100%, the phone stays cool in my experience. And charging often makes the window where it generates heat from charging smaller

Re: What Finally Killed AirPower

#126

Post by Phlarp »

wickedsmile wrote: post #18
brian-armstrong wrote: post #11

So my phone is charged by a cable. It plugs into the wall on one side and then plugs into my phone on the other. This system works great - I plug my phone in when I go to bed and unplug it when I wake up. The cable is long enough to plug into my phone even if I want to use it in bed. It's easy, cheap and failproof. What is the draw of wireless charging? What is it that I'm missing? Did anyone ask for this?

Charging phone when you are off to bed is really very bad. Lithium charging protection circuit could fail anytime due to one of the components in the circuit malfunctioning and your lithium battery inside the phone can catch fire. Many houses have been burned down to ashes from lithium fire. Just YouTube for 'lithium fire' and you'll see how dangerous it can be. I usually charge the phone in an empty place where lith…

residential lithium fires are unlikely to be coming from phones. (unless people still have those exploding Notes still kicking around)

Far more likely to be lithium batteries being used or abused in a hobbyist capacity. E-cigs and RC are both ripe for it when users have lower quality cells to begin with, routinely discharge them above the rated current and then charge with sometimes questionable chargers. Worse yet when people try to charge them above the max voltage.

Re: What Finally Killed AirPower

#127

Post by NickNameNick »

dodobirdlord wrote: post #81
darkpuma wrote: post #41

Earlier quoted context omitted.

I can get an Amazon Basic's brand USB-C cable for $4.17 per meter. Apple sells theirs for $19 per meter. Is Apple selling these cables at cost, or are they making a profit from them? Amazon isn't a brand I trust either, but from the magnitude of that difference I'm pretty sure Apple is making a tidy profit on these cables. I don't think Apple is a trillion dollar company because of cable sales, but from where I sit i…

The USB-C standard is arcane and cables can have wildly different functionality and quality and still comply with the standard. Occam's razor suggests that there is not some cable markup conspiracy going on here. Higher quality cables + luxury brand tax is a far more reasonable solution.

Apples cables don't have to implement the entire USB-C spec. Only the parts that apple want to use.

Re: What Finally Killed AirPower

#128

Post by accatyyc »

teraflop wrote: post #121
accatyyc wrote: post #111

Earlier quoted context omitted.

The things that kill smartphone batteries today are age and power cycles. It doesn’t matter if you charge from 0% to 100% in one go or from 90% to 100% ten times. Both add up to one power cycle. To keep your battery fresh for as long as possible, always keep the phone connected to a charger. No battery cycles. It will get worse after a few years anyway.

> It doesn’t matter if you charge from 0% to 100% in one go or from 90% to 100% ten times. This isn't really true, as far as I know. If you avoid fully charging or deeply discharging a lithium-ion battery, the wear per unit of energy extracted is smaller. There are some statistics quoted here ( https://batteryuniversity.com/learn/article/how_to_prolong_l... ) showing that if you, say, halve the amount of energy you r…

Thanks for the links!

Also, I want to add that what I wrote above is only regarding smartphones. I don’t know how much stress/extra heat etc that EV batteries are subject to, but I imagine they drain/charge at more intense rates relatively.

Re: What Finally Killed AirPower

#129

Post by accatyyc »

pkulak wrote: post #116
accatyyc wrote: post #111

Earlier quoted context omitted.

The things that kill smartphone batteries today are age and power cycles. It doesn’t matter if you charge from 0% to 100% in one go or from 90% to 100% ten times. Both add up to one power cycle. To keep your battery fresh for as long as possible, always keep the phone connected to a charger. No battery cycles. It will get worse after a few years anyway.

I dunno. All the EV manufacturers still recommend not charging to 100% daily.

Thanks. Updated my post to say smartphones - I have no idea about what EV batteries are exposed to.

Re: What Finally Killed AirPower

#130

Post by Phlarp »

accatyyc wrote: post #125
Phlarp wrote: post #117

Earlier quoted context omitted.

Age, cycles and heat. Inductive charging loops are going to generate a ton of waste heat, and worse yet a good chunk of that is going to be coming from the coil inside the phone.

Yeah, but a battery gets hot when charging fast. Keeping it connected at 100%, the phone stays cool in my experience. And charging often makes the window where it generates heat from charging smaller

The act of charging the battery does itself generate some heat, as does the charging circuitry within the phone. This will happen with either method of charging. Wireless inductive charging will also generate significantly larger amounts of waste heat.

Fundamentally, wireless charging is less efficient. Theoretically you could be putting 16w of heat into the phone but only getting 8w of charging.

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