mAh is a bigger number than Wh and looks better on packages.
Why are batteries in phones always measured in mAh instead of Wh like for example notebooks?
Submitted 1 year ago by Tywele@lemmy.dbzer0.com to [deleted]
Comments
Some_username_u_have@lemmy.world 1 year ago
Hamartiogonic@sopuli.xyz 1 year ago
Wait until you hear about µAh. This is the one secret the engineering team doesn’t want the marketing department to know.
piecat@lemmy.world 1 year ago
Lets use coulomb hours or electron-per-second-hours.
ian@lemmy.sdf.org 1 year ago
And mWh is even bigger.
Granixo@feddit.cl 1 year ago
Rentlar@lemmy.ca 1 year ago
Generally Li-ion (3.7V nominal) batteries were used so they could just base it off of current usage rather than power usage and you could get a decent idea comparing between smart phones.
Laptop batteries tend to use an operating voltage of multiple times that (2-cells would use 7.4V-ish, 3-cell would be 10.8 to 11.4V nominal, 4-cell would be 14.8V and so on), but the number of cells can vary wildly per model, so Wh is easier to compare numbers between laptops.
thericcer@reddthat.com 1 year ago
EE Here, I like this answer.
WUED@lemmy.world 1 year ago
Can I add a follow up question: Why don’t normal batteries have any useful measurements on them, at least in the UK anyway, not sure about elsewhere. Rechargeable batteries will have an Ah rating but normal AA or AAA etc will just say “Ultimate” or “Advance” etc, like why can’t we just have an Ah or Wh or even just a standardised rating based on a fixed current discharge or something? It’s infuriating that in 2023 I’m buying something with know way of quantifying its content other than the inference of the product name.
WhoRoger@lemmy.world 1 year ago
If you mean non-rechargeables, all batteries of the same technology are really the same in capacity. Doesn’t matter if you buy an expensive brand or the cheapest bulk store brand, the difference is a couple percent and depends more on the age of the cell and how it was handled.
Just get cheapest store-brand alkaline if you must, but really best avoid altogether and use rechargeable.
boraca@lemmy.world 1 year ago
Alkaline batteries range from 3-5 Wh (docs.google.com/spreadsheets/d/…/edit#gid=2136035…), Zinc batteries are around 0,6Wh
DeltaTangoLima@reddrefuge.com 1 year ago
The reason phone vendors can advertise capacity is because the load (the phone) is a known quantity. They made the phone, so they can reliably estimate the battery’s capacity based on average use by that phone.
Similarly, power bank manufacturers can do the same, because the load is controlled by them. The USB port might only provide 5V at 1.5A or 3A - whatever the power bank manufacturer put in - so they can reliably estimate how much current over time the battery can provide.
But makers of alkaline batteries don’t have that knowledge. They have no way of knowing if you’re going to put them into a kid’s toy that pulls only 20mA, or a DC motor for a rotisserie that pulls 1A. So they can’t possibly provide you any measure of Ah that is going to satisfy all consumers. If they did, they only open themselves up to legal problems for making misleading claims about their product.
bigdog_00@lemmy.world 1 year ago
I don’t find that to be a particularly compelling argument though. If you go to buy a lead acid battery for solar usage, for example, they give you the capacity based on a 20-hour discharge (or, 1/20th C rate). The same could absolutely be done for primary batteries
deegeese@sopuli.xyz 1 year ago
Laptops predate cell phones in mainstream use. When laptops started, there were a variety of battery types in use with no standard charging voltage so Wh was the fair way to compare.
Cell phones have pretty much always been 3.7v lithium so mAh is a fair comparison and gives a bigger number than Wh.
zomtecos@feddit.de 1 year ago
You could just put it in mWh. BAM, bigger number.
3000 mAh * 3.7V = 11.100 mWh Much bigger. Much better.
I hate mAh… it’s absolutely no information how much energy is inside without taking the voltage into account. If you use directly (m)Wh, you directly have the amount of energy the battery can contain.
marcos@lemmy.world 1 year ago
The thing is, batteries are measured in Ah, and not Wh. That’s because their voltage changes all the time, and is mostly the same for the same kind of chemistry, and also because for most of their uses, the current is the actually useful information.
Phones are just using the standard metric. It’s laptops that are weird.
Reygle@lemmy.world 1 year ago
For the same reason Audi didn’t sell the Audi “5”, Pontiac never sold a “9LE”. and Saab didn’t try to sell the “9 turbo”. It sounds more impressive with the zeros added.
JackGreenEarth@lemm.ee 1 year ago
Why 5000 mAh rather than just 5 Ah?
ott@sh.itjust.works 1 year ago
Batteries often have a rating like 3250mAh, which is arguably clearer than 3.25Ah, especially on a datasheet.
rufus@discuss.tchncs.de 1 year ago
And it gets more obvious once you compare two phones and see which one to buy. I can tell you at once, between a battery with 3450mAh and 4200mAn there’s a 750mAh difference.
But i have to look twice at the numbers if it’s 3.45Ah and 4.2Ah.
13esq@lemmy.world 1 year ago
How is it arguably clearer?
It’s only clearer to absolute mongloids that can’t get their head around the idea of “bigger number better!”.
13esq@lemmy.world 1 year ago
Marketing. It just sounds better. Any other answer is just an excuse.
theKalash@feddit.ch 1 year ago
My laptop shows my battery capacity as 8790 mAh.
Tagger@lemmy.world 1 year ago
Aren’t most notebooks measured in gsm?
Granixo@feddit.cl 1 year ago
[deleted]stevestevesteve@lemmy.world 1 year ago
It is neither amperes per hour nor watts per hour. Those imply division (1 watt, over two hours, would be 1/2 a watt per hour. Useless as a unit for most of us). Ah and Wh are amps or watts multiplied by hours, pronounced as amp-hours or watt-hours (1 watt, for 2 hours, would be 2 watt-hours)
Synthead@lemmy.world 1 year ago
The voltage of your battery decreases as it is used, like pretty much any other battery.
realcaseyrollins 1 year ago
That's a good question, I've actually been wondering the opposite.
ott@sh.itjust.works 1 year ago
The vast majority of cell phones use a single-cell Li-Ion battery, so their capacities can be directly compared using mAh. Laptops almost always contain multi-cell Li-Ion batteries, so their capacity cannot be directly compared using mAh (e.g. a 4S battery rated for 2500mAh has more energy than a 3S battery rated for 3000mAh).
So why don’t we use Wh for phones too? Simply because manufacturers would rather advertise a battery size of five thousand mAh (wow, so much capacity!) instead of 19 Wh.
The same issue happens with portable USB battery packs - they’re all advertised in mAh even though they use a wide variety of chemistries and cell configurations internally. What manufacturers do is take the total Wh of the pack and convert it back to the equivalent mAh of a single-cell Li-Ion. It’s annoying, and I really wish they would just use Wh directly.
fubbernuckin@lemmy.world 1 year ago
But why not advertise in mWh? 19000 is bigger than 5000
cecilkorik@lemmy.ca 1 year ago
I don’t think they know about metric prefixes, Pip.
Imagine if the marketing people discovered that they could advertise that it has 19 million uWh (in Doctor Evil voice). Don’t say it too loudly though, someone at Apple might hear.
ott@sh.itjust.works 1 year ago
That would be ideal, but I think at this point there’s just too much marketing momentum using mAh, and switching to mWh would be too confusing to consumers. But yeah, I agree, mWh is definitely the most appropriate unit to use.
GamingChairModel@lemmy.world 1 year ago
Isn’t that just 5 Ah though
PetDinosaurs@lemmy.world 1 year ago
Yeah, but it’s 5 billion nAh.
meco03211@lemmy.world 1 year ago
And 19000 mWh. I’d rather have 19000 of something rather than 5000. I feel cheated and no amount of telling me it’s exactly the same will change my mind.
SpaceNoodle@lemmy.world 1 year ago
Yeah but then you don’t get to say thousand
hansl@lemmy.world 1 year ago
Goodbye dream of knowing how many times my car can charge my phone.