Why Watts Should Replace mAh as Essential Spec for Mobile Devices (theverge.com)
- Reference: 0176899265
- News link: https://tech.slashdot.org/story/25/04/02/0449217/why-watts-should-replace-mah-as-essential-spec-for-mobile-devices
- Source link: https://www.theverge.com/tech/638559/watt-vs-mah-battery-measurement
> The Steam Deck gaming handheld is my go-to example of how handy watts can be. With a 15-watt maximum processor wattage and up to 9 watts of overhead for other components, a strenuous game drains its 49Wh battery in roughly two hours flat. My eight-year-old can do that math: 15 plus 9 is 24, and 24 times 2 is 48. You can fit two hour-long 24-watt sessions into 48Wh, and because you have 49Wh, you're almost sure to get it.
>
> With the least strenuous games, I'll sometimes see my Steam Deck draining the battery at a speed of just 6 watts -- which means I can get eight hours of gameplay because 6 watts times 8 hours is 48Wh, with 1Wh remaining in the 49Wh battery.
Unlike megahertz, wattage also indicates sustained performance capability, revealing whether a processor can maintain high speeds or will throttle due to thermal constraints. Watts is also already familiar to consumers through light bulbs and power bills, but manufacturers persist with less transparent metrics that make direct comparisons difficult.
[1] https://www.theverge.com/tech/638559/watt-vs-mah-battery-measurement
I see this with RVs as well... (Score:2)
I've seen this with RVs. However, people get used to stuff like a 12 volt battery bank with 1200 Ah is something that can power an air conditioner for 8-12 hours, depending on the BTUs of the A/C [1]. Switching that to 14400 watt-hours or 14kWh makes sense, but people don't really like that change.
[1]: BTUs, tons (1 ton being 12,000 BTU), etc... IMHO, it would be nice to just do that with watts. Same with horsepower. However, I'd be tarred and feathered saying that someone's 300 hp engine is 223 kW.
Re: (Score:2)
BTU seems to be popular when dealing with heat. Not sure why, I prefer SI units I commonly use. Actually I was reading the specs on an Extreme X435-8P-4S switch, [1]https://documentation.extremen... [extremenetworks.com], as I was interested in the power consumption and noise. The "Table 8. X435 Power Consumption" had both "Minimum Heat Dissipation (BTU/hr)" and "Maximum Heat Dissipation (BTU/hr)" which meant nothing to me. Fortunately they also had "Power Consumption (W)" which was good for me. No mAh figures so I guess the m
[1] https://documentation.extremenetworks.com/extremeswitching/GUID-33A3AA86-39D3-4594-9E84-837FF61A393B.shtml
Re: (Score:2)
geez BTU's is even more out of date.
Watts (Power) is USELESS fort CAPACITY (Score:1)
Watts (volts x amps) is great for knowing how much POWER the battery can output (peak watts, constant watts - the size of the gasoline pipeline), but USELESS to know how big of a battery (how much gasoline/fule the tank holds) it is. mAh at the very least lets us calculate the battery capacity by multiplying the battery's voltage spec to get ENERGY (how much gasoline it holds). Ideally we'd know all of the above--ENERGY (in watt-hours, kilowatt-hous), CURRENT capacity (peak and safe max average amperage c
Re: (Score:2)
My vote is simply amp-hours and amps
other units are just noise - why does it matter to you that its a 6 volt, 12 volt, or 24 volt thingamabob?
the point of throwing around voltage at all, and thus bringing in any desire at all for watts, is for compatibility with external power sources, but there is no need with cellphones since the power plug ensures a high level of safety there
Re: (Score:2)
Funny
Re: (Score:2)
And yet my 5Ah battery pack stores way more energy than your 12,000mAh one, and can charge a lot more devices.
Mines a drill battery with a USB charging attachment. Ah are just a proxy for energy, i.e. J or Wh, but one dependent on the battery voltage. I think it's better to stick to the units you actually want not proxies with hidden scaling factors.
For example: how long would your expect a 10W charger to charge a 5Ah battery. Now do the same calculation for a 100Wh one.
Re: (Score:2)
> other units are just noise - why does it matter to you that its a 6 volt, 12 volt, or 24 volt thingamabob? It matters if your device needs a 6 volt, 12 volt or 24 volt power supply and doesn't work with a different voltage.
>
> It's like an ancient 3 1/2" floppy disk. It doesn't matter how big it is; what matters is that a 3 1/2" floppy disk is a floppy disk that fits into a 3 1/2" floppy disk drive. Or button batteries where the size is printed on the batteries; you don't care about the actual size, you just care that you have the right size that fits your device.
Re: (Score:2)
TFS specifically mentions watt-hours, and we know that's what the author means, so you're just being pedantic. If there's anything to criticize here, it's that when only a mAh spec is given, you can usually assume the device is running on a 3.7v nominal LiPo cell and do the math yourself. More often than not, when you're dealing with a device powered by multiple cells in series, a watt-hour rating will be provided and/or the nominal voltage of the pack will be specified.
The big notable exception that stan
Re: (Score:2)
The headline may be misleading, but the summary I think is pretty clear, the author is calling for battery capacity to be specified in Watt-Hours, and for power draw in Watts to be a key spec given for devices - the example's right there - he's not calling for battery capacity to be specified in Watts.
Re: (Score:2)
I suspect they actually mean Watt hours, not Watts, which is far more useful than mAh as you don't know what the voltage they have chosen to use is and if there is any system losses that should be applied.
So while you are technically right, and it is worth point out Watts are not a measure energy storage, maybe you are being a bit pedantic in the way you make your point?
Re: (Score:2)
On the other hand, we could use Joules, being the SI unit you are looking for.
Verge is ignorant (Score:2)
Somehow they thing that giving them watts will magically allow them to estimate battery life completely ignoring non-linear power drain of batteries but are too dumb to do a basic multiplication to get the watts they so truly want.
They trivilise a complex matter while thinking a unit change will fundamentally improve things.
A country that still uses Fahrenheit (Score:2)
Is not the place to demand sensible units.
Re: (Score:2)
As someone who lives in Florida, I can tell you precisely what is wrong with Celsius: A set point of 23C will run the air conditioning until it is too cold, and 24C will let it get too hot before it kicks on. Whereas a thermostat with a 1 degree swing set at 74F is just heavenly.
I guess folks who are just used to being miserably uncomfortable in their homes all the time don't get it. Certainly, the same thing could be accomplished by adding a decimal of precision to the Celsius mode, but it seems like th
Re: A country that still uses Fahrenheit (Score:2)
That's not really a problem with units, but with thermostat makers user interface, sadly. My Carrier infinity system thermostats supposedly measure 1/100th of a degree internally (not sure if F or C), in each of the 10 zones, but the screen and hard buttons don't display a decimal point, or allow one to be set, unfortunately. I left my system on F, because I like finer control as you do, though not specifically 23/24C. But even after living 29 years in the USA, it continues to bug me to see temperatures in
Wh, not W (Score:3)
The capacity of a battery can usefully be specified in Wh. Power draw is in W, multiply by the time that power is drawn to get the capacity you used.
Wh is superior to Ah: if you only know the Ah, you have to find out the voltage of the battery to find out what capacity it has. Power draw for devices is generally specified in W, not A.
Why we should quote EV battery capacity in Joules (Score:4, Insightful)
I'd rather like it if instead of telling me my battery is 85KWh, I could have a 300 MegaJoule battery.
Battery manufacturers could have competitions about who will be the first to get a gigajoule into an SUV, and we could quote battery density in Joules per cubic meter .. oh, the beauty of SI units and the metric system.
Re: (Score:2)
> I'd rather like it if instead of telling me my battery is 85KWh, I could have a 300 MegaJoule battery.
I can't tell if you're kidding, or if this is the same mentality as the people who voted for a $15/hr minimum wage so that they could still be minimum wage earners but relish in the sight of a larger number on their paychecks.
If your EV's battery being "only" 85kWh bothers you, I bet you'd really hate having to figure out how much things cost in Bitcoin.
Re: (Score:1)
I'm English.
Pretty much everything I say can be interpreted at least two ways. I mean to be serious, it has always gently irked me that we would quote KwH when there is a perfectly good single SI unit "Joule" that does the job - but I am more than capable of multiplying numbers by 3,600 if I need to convert. II wuold like to know why we don't use Joules, KJ, MJ etc.
It's always bothered me that we quote batteries in mAh - like 2000mAh, which means I have to go find out what voltage it is before I know
Re: Why we should quote EV battery capacity in Jou (Score:2)
I hate to ask, but what's the logic behind your argument about raising minimum wage? Leaving it at the same level for 25 years makes no sense. The minium cost of living obviously went up. Why wouldn't the minimum wage rise too?
Isn't there some proper ancient non-SI unit? (Score:1)
Using Watts or AmpereHours, i.e. SI-based units is definitely and uncomfortably un-american. Especially in the current political climate.
Re: Isn't there some proper ancient non-SI unit? (Score:3)
Why not go with calories then? 3000 kCal is something your regular American could relate with on a daily basis.
The Marketing Problem. (Score:2)
The entire summary essentially proved that watt consumption depends considerably on the specific game and how it stresses the hardware, giving a most extreme example of a game draining the hardware in two hours.
I’d love for the one who wrote that to sell me how they’re going to market that. Battery will last anywhere from 2 to 27 hours, depending on usage? Good luck, because we can’t guesstimate any better than that?
Yeah a kid can do the simple math. Now tell that kid to go market and s
Re: (Score:2)
Pray tell, what is this "incredibly useful information" that isn't obvious from the watt, unless you're a braindead retard?
Re:Dumbfucks (Score:5, Informative)
> W = V*A. Do the math yourself, it's not that hard.
Actually that maths is impossible in some cases, unless you open the product, because many products don't say what battery voltage is.
Traditionally they were simply talking about the mAh rating of the single Li-Ion cell in the power banks of the early days with a boost converter to give the 5V people needed. Also most Li-Ion cells refer to a nominal voltage of 3.7 or 3.8V which is charged to 4.1 or 4.2V and discharged to whatever the boost converter and over discharge circuit limits are set to. So the mAh rating of a cell may be, say, 3000mAh. So right away the first pet peeve. That is simply 3Ah, saying "three thousand thousandths of an Ampere" is just plain stupid, but you can not seem to tell a marketing type that.
Next problem is the cell may be spec'd for that Ah when discharged to, say, 2.8V where as the circuit may stop boosting at 3.2V, making the actual Ah rating less when used. Then you get losses in the boost converter. So combine those two losses and you might only be getting 70% of the cell's spec. If we were to say the cell has 3Ah based on a nominal voltage of 3.8V that would be 3Ah x 3.8V = 11.4Wh but add in the losses from boosting and limited cell voltage range and you could be looking at only 8Wh. At 5V that is actual 1.6Ah even though the marketing person has insisted that to be labeled and advertised as 3000mA.
About now someone is reading this and thinking "Well actually..." and will come up with different answer. That will merely point out that the current system is flawed. The basic premise proposed, that mobile devices power should be spec'd in watts, is a good idea, regardless of how simple the maths may appear.
Side note: Go to the electronics store as ask the customers there if they know the formula for converting voltage to wattage. I bet the number of people who can do your "not that hard" maths will be rather low.
Re: (Score:2)
> Actually that maths is impossible in some cases, unless you open the product, because many products don't say what battery voltage is.
And I don't care for example what the voltage of my iPhone battery is, I just care that it is right for the iPhone so that the iPhone works.
Now imagine Apple uses say 9V batteries. Then some marketing guy who knows a little bit about physics asks "can we replace the 9V battery with a 1.5V battery with 6 times as many ampere hours". And suddenly the Ah are 6 times larger with no benefit for the customer.
On the other hand, "Watt" is stupid as well. My MacBook has a _maximum_ number of watts - if all cor