I don't think I've ever seen any battery bank give an output referred capacity rating. When everyone else is doing input referred it just makes the output referred product seem inferior even though the opposite may be true!
This one actually does on the label if you look under the Energy figure, 11,000Ah (LOL! wrong, it should be 11,000mAh at 5V/2A output). But they don't include that in any of the marketing at all.
@@EEVbloggood on them then. Even though the figures were wrong the heart was in the right place. I just remembered that I've seen battery banks artificially inflate their numbers by using 4.2V (max lithium voltage) to calculate Wh!
Yes, the battery pack capacity must be less than 100 Wh to allow on passenger aircraft, so that label is important. But the output referred capacity (or usable capacity) must also be mentioned.
I think the FTC should step in and require the output energy capacity at 100% continuous output power to be listed, similar to how they did for audio amplifiers in order to combat completely unrealistic output ratings.
One thing that has surprised me is how wildly the round trip efficiency of cheap usb power banks varies, i've seen some as low as 30 and as high as 90.
Yes. The cheapo classic 'big Clive' charge-discharge protection board with the TP4056 chip uses internal linear voltage regulators and dissipate a *lot* of heat while regulating(at least while charging).
The manufacturer of your tested battery pack seems to be one of the more honest ones because it also supplies 0:18 a rated capacity @ 5V / 2A in addition to the usual battery energy (marketing wank). If we ignore the typo of 11000 (m)Ah we get a quiet reasonable 5V * 11000 mAh = 55 Wh which aligns with your test @ 5V / 1A ± 10%.
you are right, the efficiency of converting will decrease by increased current, (or voltage like in fast charging 9V or 12V), so some manufacturers include rated capacity at standard 5V, and mention in user guide that it well be less in fast charging protocols.
Today I learned the mAh capacity advertised with battery packs (more often than not) is measured using the battery voltage as a reference and not the output voltage. I thought the manufacturer from the battery in the video was being particularly misleading, but apparently both my Xtorm and Xiaomi battery packs also use the same method. Worse still, the battery voltage every manufacturer uses is different. Xtorm uses 3.6V and Xiaomi 3.7V. That makes the mAh value mostly useless to compare against other battery packs. I guess having the battery energy in mAh using ~3.7V as opposed to 5V is kind of useful because then you can subtract the mAh of your (lithium) phone battery and get a reasonably accurate idea of how many charges you get out of the battery. But I do think this needs to be communicated better, by all manufacturers.
There is also losses on the phone side. To fully charge you should have a battery bank twice the capacity of the phone battery. That gives some extra margin. One should also beware power banks with fake mAh ratings.The rating correlates well with te weigh. A 5000 mAh power bank weighs some 100 grams. Amazon sells a million milliampere hour power bank. Such a thing would weigh 20 kg.
I'm so early I only see the spam bots commenting. Anyway, this is a great reminder for tech specs. I've been reviewing a lot of LiFePo4 batteries and finding many of them don't achieve their rated specs. some go beyond though.
No. The unit consumed around 64.12mA when in high brightness displaying the metering screen. With dimmed brightness, consumption fell to 54.18mA. These values have no significant impact on the final result.
Not to say that input referred capacity is a better measurement, but wouldn't output referred capacity be variable and significantly dependent on output load and converter quiescent power draw?
That's what I thought. You'd actually want the "input capacity" and a couple of graphs to figure out the coefficient and the "output capacity" for your load😅
Would be interesting to know how much power you need to charge it back to full. The input refered capacity is what the plane security asks for when they have a limit for battery capacity in the cabin. And the last ting I wonder is of you take the cells in series, you dont have 20Ah and 3,8V, but you then have lower Ah and higher Volt. They still mark it as 3.8 and 20Ah....
I bought one specifically for travel, and I wanted basically as much as I was legally allowed. I assumed they gave the number that the flight folks ask for.
I've done a little testing of this myself over the years, I have a USB meter and have tested what it takes to fully charge the thing and what it takes to kill it (with a usb fan that draws .3A). It's useful because I can see how they're aging too and know when to get rid of them (I carry them while traveling and hiking).
I have the fnb58 also.. it's a kill3r piece of tech.. It even has a built in oscilloscope... You can go into the settings and turn it into a power supply also, for the different usb C standard voltages. I really like it. I wish they had something like this built into a recharable battery charger-- so I can follow all the outputs of the charger and track what my batteries are doing. I don't like being blind to what my chargers are doing for all my different rechargable batteries I have spread everywhere.
I've been testing mAh (now I know better) with input and output, on three powerbanks and efficiency is even lower, with output being around 50% of stated capacity. I've noticed that USB-C socket output (for typical phone charging) gives a lower figure than USB-A socket. I don't know whether that's due to the type of port or different voltages (or protocols) used. In any case, for 'normal people' we can expect half of the stated capacity. I decided I was too 'normal' to make a video about it 😊
Great video. Although evident to some, these things needed to be said. Every power tool battery lists Ah, although it is miningless, considering the voltage can be wildly different (12 to 60+). Even voltage is reported however the marketing department decides. Some use nominal voltage, other use peak. This is aside from the efficiency of the electronics inside.
Thanks for the reminder! The only reliable way to check the actual output capacity is through measurement, as we can't rely on the marketing department. 😉
G'day from NZ :) That was the shortest EEVBlog video Ever! Didn't know you had it in you :) In terms of why the measured capacity in Wh was below 77 - there's another reason you didn't mention. Most battery capacities are rated at a specific discharge current, not sure what the standard is for Lithiums but for lead-acid it's c/20 eg. a battery rated at 60Ah will give that capacity at 1/20th that draw - so 3A in this case. If you want to get the full 60Ah you can only do it at a max constant draw of 3A In the case of the battery bank, the native Lithium voltage is being boosted to 5V by the converter, so this will effectively increase the current draw off the Lithium. To test this carefully, you should a) assume the capacity is battery-related, then b) find out how the Lithium's capacity is rated - c over what... then arrange a 5V load on the output such that you're pulling no more than that current off the battery. Then measure the watt hours provided at the output, that'll give you the true converter efficiency.
I actually have a Hama power bank that is sold as 10000 mAh , but on the back it actually says that it has usable 6605 mAh usable capacity. it's something.
Remember that when the battery is at about 3.8V and your load receives 5V, the mAh figure at the load will always be much lower than at the battery. That is why the Wh figure is much more usable to begin with.
@@Rob2 That is not in itself relevant. The voltage is raised at the output which lowers the current but at the phone battery end the voltage is again lowered. What counts is that the process has losses, not the fact that the voltage on the transmission is higher pr se.
I don't actually care since it has become the unofficial standard to either put the sum cell mah (mostly liion, so close enough) or just outright lie. I would prefer if companies don't start using mwh to get a bigger number!
Are the cells actually 3.85V nominal or is the manufacturer trying to boost their Wh for customers to think "ooh big Wh! Nice!"? On the other hand, some manufacturers claim 3.63V nominal to try to reduce their Wh so that customers can get the powerbank on a plane.
@@okaro6595yeh Nar. It’s 3.6 or 3.7 nom for li-ion. This 3.85 might be the scam we’re all looking for. That being said, even 3.6 x 20 is still way above the 61Wh tested.
3.85V nominal per cell is typical for a LiHV cell. They get more capacity in a smaller, lighter cell in exchange for wearing out faster. They are good for drones, but should be avoided when weight isn't critical.
Ive always known that, i mean if you based it on mAh befpre we even consider the conversion loss, 20000mah at 3.7v is 14800mAh at 5v, im suprsrised those power banks didnt provide datasheet with multiple test condition and temperature with graph at different load like what you will get on battery datasheet or component datasheet Maybe they can also include output ripple, efficiency, voltage accuracy, especially now that PD power bank is common that you can get different efficiency at different output voltage
@EEVblog There is a bit of a faff with this at the moment. FTC made a new amplifier rule that basically means amps must all spec maximum power at 20khz, right where we need it, lol.
Gotta love those 100000 dB horns from Wish, apparently producing pressure waves capable of obliterating the universe and all of it's parallels a million times over
Then there is the limit on flying with powerbanks in the carryon. The manufacturers have to put a potential maximum on the specs so any airport security can check it's under maximum alllowed.
Dang, I've just assumed most of this for about half my life. Maybe I'm not as stupid as I thought I was. I also assume that anything over 15000 mah is lying if it fits in a pocket. I also disagree that it's mostly the marketing department's fault. Others have already explained it well, so I won't do so here.
I think mAh is fine if they are referring too battery cells in parallel since the voltage is the same. I've also always assumed ratings were based on battery cells and not the actual output at the USB port. Consider me not surprised.
Did you measure the energy required for charging as well? I would expect that it is even more than 77 Wh, because the USB PD to cell voltage conversion causes a similar ~20% loss. So it's not even real input referred, just the internal battery capacity. Your are basically buying a lithium cell with the specification + some circuitry/ports for convenience. I noticed while traveling with solar panels that almost 50% is lost when it goes through a power bank instead of charging the target directly. I agree that every power bank should include a full efficiency and output energy specification too.
1:01 You might wanna PSA regarding voltage as well. Newer power banks now have 21V with the new PPS standard, As expected iphones are late once again. Higher voltage, lesser current = lesser loss.
Yup, Anker 10000mAh runs flat after charging a 5000mAh phone, because of fast charging. It's written there on the battery. but still their advertisement should be honest: either it's a quickcharge 5000mAh OR a regular 10000mAh, but not mislead it's BOTH
But Dave, surely this depends on the value of ‘future’ electricity, as opposed to ‘present’ electricity? In an alternating economic environment, current affairs can significantly alter the potential difference between your calculated values. 🧐
ok, but can you look though your batterypacks you have at hand how much the converters varies between the manufactures for a fixed load? if every converter needs 20% then the packs are comparable with the input-ref values.
It is not really marketing, by law and transport compliance the product need to bear rating label with the energy that is in the cell. If you would specify the output rating it is illegal. Still to make the output Wh number the input Wh number still is needed to produce it. The 80% efficiency Wh to Wh number is pretty bad actually. Would expect >90% from better quality power bank.
Can you link to an example product like this one which shows the capacity as would be measured by a load like your example? Cos I know of none. They will almost always list the capacity this way: that of the cells (spec not tested).
At least it now seems the powerbank marketing numbers are matching the actual batteries. I remember seeing "10,000mAh" batteries 10 years ago and them being suspiciously light. Got to love marketing rubbish.
Is it marketing though? I thought it was so that the energy capacity (of the battery) was accurately stated for safety, transportation, and similar purposes. (If it blows up, you know the pottential magnitude of the inferno...) I'm sure that marketing departments exploit any parameters to their best advantage, but I think this one is at least honest, even if it does nothing to describe the true input to output efficiency and is therefore of only limited value to the user.
That's not really proportional to the rated capacity, but mainly battery chemistry. Either way Wh would be the battery rating for "dangerousness", since higher voltage chemistries are usually more dangerous.
@@GodmanchesterGoblin It seemed to me like you were referring to the mAh rating, seeing as that is what the video was about and you not mentioning any particular units. Sorry for the misunderstanding.
and also, no one is covering nonsense claims of manufacturers claiming their chargeable batteries are close to 99% efficiency. also electric car enthusiasts don't want to see their charge/discharge efficiency of batteries make their electricity consumption much higher than they calculate with. if you put 1kW/h into charging, you don't get 1kW/h out. you could be glad if you get 70% back. but producers don't tell you this. marketing strategy lies. as usual.
Yes, BUT output voltages can vary with USB PD: 5 or 9 or 15 or 20 Volts. So we don't just need A (singular) output-referred Wh number, we really need graphs that factor in the DC-DC efficiency @ different output voltages over the supported current ranges. If any mfgr is listening: that would make for a fine product picture. Imagine you advertised your products on the merits, (almost) for free because you should already have that data.
This is a relatively good specification. There are many instances that the seller cheats and writes ten times higher ratings. And when you write to him about that he sometimes says "sorry" but he won't fix the error on the website/store.
"I didn't know that" "my supplier gave me that specification!" "I am a poor guy who has a family" but of course they know just as well as the 32TB USB stick sellers know what is happening...
Only the nominal operating voltage is indicated on power tools. But already on batteries for these tools, the nominal capacity is additionally indicated. This capacity is true, moreover, because there is no conversion from a lower voltage to a higher voltage here, as is the case with powerbanks.
I have new USB-C phone and charger which can do 20 Volts 66 watts. One might assume there is less losses in transit, because much less current. I have not seen a battery bank which can do 20 volts, only 12 Volts, but it might be coming one day soon.
it makes sense. DC-DC efficiency is depended on the load, sometime it's 10-15% between worst and best case. Using battery rated will give you solid number. Also dont forget your phone also has DC-DC block inside, to convert the input voltage to battery-approriated voltage. So there is another loss
Like power tool battery Ah rating, checked both brand new Makita and Milwaukee 18V battery's, only get about 85% of the name plate Ah rating. Theres no inverter in them so it’s all marketing fibs.
Bloody marketing, if you see a rating of 20000mAh that's 20A for one hour...hmmm I don't think so, bit like bloody ISP's using megabits/sec instead of megabytes/sec as it sounds bigger ! Scotty from marketing is all over this !!!!
To be fair, the bits rather than bytes per second thing comes from the way serial port (and Ethernet) speeds are labelled. And serial ports were in bits since they could do different length items or "characters", for instance 5, 6, 7 or 8 bits, with or without parity each with a start bit and 1, 1.5 or 2 stop bits. Would they have been able to sell a broadband connection of 64KB/s (bytes/second) to users who already had a 56kb/s (bits/second) dial-up modem? Maybe, but it'd be much easier to sell a 512kb/s (bits/second) broadband connection. (This is the actual speed of my |First broadband connection, which I got in 2002). Even that's an oversimplification, since although dividing 512k by 8 gets you to 64k, that's quite a bit higher number than the amount of usable data in bytes that can actually be transferred because of packet headers and similar hidden things needed to make it work.
As we say... Its good enough for government work... Plus if everyone is comparing input wattage, then they should be all about the same ball park. 80% efficient is about average for a DC/DC converter. you are just splitting hairs if you are +/- 5%
Trouble is, the efficiency of the Dc-Dc varies with current, so depending on your load you get a different Wh rating.. As for comparing batteries, as long as it's apples to apples, it doesn't really matter which figure you're comparing.
I also think this constant marketing hype of making the figure look good by specifying mA unnecessarily. Why say 20,000 mA when they should just say 20A
@@redpheonix1000 exactly, that's why Americans use their stupid measures to sound more important. Why say 1tonne when you can say 2,413million sardine heads or whatever other stupid measurement they use.
I was looking into this about one or two years ago. I thought the way it’s labeled, these high-capacity packs should not be legally allowed onto airplanes (carry-on anyhow). However when you do some of the math, including efficiency, and try to work backwards, they do squeak under the airlines’ policies. I doubt the average luggage inspector could do the math in their heads. So while big numbers are great for marketing, they may unduly alarm the baggage inspectors. They’re not likely to be electronics wizards. They’re not expected to open up the battery packs to see what cells are really in there and to be able to intelligently counteract the marketing exaggerations so it’s a real dilemma. Maybe they just have a chart where they look up different “marketing” ratings and scale it down accordingly. Laptop batteries are usually worse… but then they are required to be check-in baggage… I think there’s a cut-off capacity. Trouble is, airlines use one rating whereas the numbers on cases use another scheme. Consumer confusion is the name of the game. I doubt anyone in an airport has 1/10th the wisdom of Dave or even that of a decent electronics hobbyist.
Don't they all just list the total Watt hours of the contained battery cells? This is what the airlines care about and is apples to apples across laptop packs, flashlight batteries , tool batteries and power banks. This will be the highest figure. If there's some future push to list net output Wh, I think they will have to list two numbers(in turn exposing the efficiency of the DC/DC converter. a good thing ...)
@@alexdrockhound9497 Interesting. I’ll have to look into that. I hope they made it a lot clearer what criteria they use: milliamp hours vs. watt hours (conveniently omitting battery voltage versus voltage booster output… so there’s still all that confusion I’m sure).
You were very lucky to find any figure that specified energy capacity at all. The whole battery capacity quoting business has become a complete and utter mess. There are manufacturers quoting ludicrously large mAh figures and nothing else because they know the figures are as good as meaningless, but they are all that's needed to make a battery sell. It stinks.
The problem with output referred is there’s no single number since the efficiency of the dc/dc stage is not static. While it might be 80% at one current level, it might be 85% or 90% at another Input referred is actually a more reliable figure to compare with if the needed current level isn’t static
3.85v on a lithium battery. Give me a break. Unless these guys have formulated their own cells, or buying alien technology they should be using 3.7v. There is a 4% boost in capacity right there. Most of the cheap Chinese boost converters will run 90%+ efficient, but there may be a sweet spot so you may need to run a bigger load to get this, A 5w load may be more appropriate
Reminds me of computer drives where Marketing decided "megabyte" was going to be "1,000,000 bytes" when stating capacity, not the binary 1,048,576 bytes. It makes drives seem bigger to customers...but not to computers.
With RAM, bases of 2 make sense because of how RAM is constructed. With storage (and network), bases of 10 are consistent with all of physics and engineering.
@@crackwitz Not really, non-volatile storage capacity is best represented as base-2 because it's binary all the way down (to sectors). It's 100% marketing ploy, like using *bits* instead of *bytes*.
@@hanifarroisimukhlis5989Nah. Did you know that HDD storage density is expressed in bits per square inch? I understand you're angry because Windows divides by 1024 and you think you're being robbed of your money. You can blame Microsoft for that, or simply accept that it's irrational to count these quantities in multiples of 1024.
As a consumer, not building your own, you should not be bothered with the internal workings. It is a black box. It's capacity should be measured as such
I don't think I've ever seen any battery bank give an output referred capacity rating. When everyone else is doing input referred it just makes the output referred product seem inferior even though the opposite may be true!
This one actually does on the label if you look under the Energy figure, 11,000Ah (LOL! wrong, it should be 11,000mAh at 5V/2A output). But they don't include that in any of the marketing at all.
@@EEVbloggood on them then. Even though the figures were wrong the heart was in the right place. I just remembered that I've seen battery banks artificially inflate their numbers by using 4.2V (max lithium voltage) to calculate Wh!
Also, the battery energy is arguably the most important, given the restrictions on battery pack capacity that you are allowed to carry on a plane.
Yes, the battery pack capacity must be less than 100 Wh to allow on passenger aircraft, so that label is important.
But the output referred capacity (or usable capacity) must also be mentioned.
@@aveekbh They got rid of that rule, it's now up to the airlines as to what capacity they will allow.
I think the FTC should step in and require the output energy capacity at 100% continuous output power to be listed, similar to how they did for audio amplifiers in order to combat completely unrealistic output ratings.
One thing that has surprised me is how wildly the round trip efficiency of cheap usb power banks varies, i've seen some as low as 30 and as high as 90.
I'm guessing the inefficient ones to charge use a linear regulator to drop from 5V to battery charge voltage.
Yes. The cheapo classic 'big Clive' charge-discharge protection board with the TP4056 chip uses internal linear voltage regulators and dissipate a *lot* of heat while regulating(at least while charging).
The manufacturer of your tested battery pack seems to be one of the more honest ones because it also supplies 0:18 a rated capacity @ 5V / 2A in addition to the usual battery energy (marketing wank). If we ignore the typo of 11000 (m)Ah we get a quiet reasonable 5V * 11000 mAh = 55 Wh which aligns with your test @ 5V / 1A ± 10%.
you are right, the efficiency of converting will decrease by increased current, (or voltage like in fast charging 9V or 12V), so some manufacturers include rated capacity at standard 5V, and mention in user guide that it well be less in fast charging protocols.
Today I learned the mAh capacity advertised with battery packs (more often than not) is measured using the battery voltage as a reference and not the output voltage. I thought the manufacturer from the battery in the video was being particularly misleading, but apparently both my Xtorm and Xiaomi battery packs also use the same method.
Worse still, the battery voltage every manufacturer uses is different. Xtorm uses 3.6V and Xiaomi 3.7V. That makes the mAh value mostly useless to compare against other battery packs.
I guess having the battery energy in mAh using ~3.7V as opposed to 5V is kind of useful because then you can subtract the mAh of your (lithium) phone battery and get a reasonably accurate idea of how many charges you get out of the battery. But I do think this needs to be communicated better, by all manufacturers.
That's what I always assumed, it's a bigger number and that's what's important when you're talking about what you are allowed to take on a plane.
I guess that much is true.
Thank you for making this video, I have left comments on UA-cam “reviews” about this issue exactly, and I’ve had comments removed. Curious…
There is also losses on the phone side. To fully charge you should have a battery bank twice the capacity of the phone battery. That gives some extra margin.
One should also beware power banks with fake mAh ratings.The rating correlates well with te weigh. A 5000 mAh power bank weighs some 100 grams. Amazon sells a million milliampere hour power bank. Such a thing would weigh 20 kg.
In some regard yes.... but some uses pouches, other cells in metal and others even add an iron slap just for 'stability' (and weight) in the bank
Just under 3 minutes. If that was filmed square it could be a short under the new UA-cam shorts rules.
Nice thumbnail and great explanation.
Eh, we have enough UA-cam sharts.
My screen isn't square though.
@maxine_q Yeah, but your head sure is.
If it was uploaded as a short, I wouldn't have seen it. I use an addon to block them since they are usually tiktok style crap.
Who said a square aspect ratio was a requirement? I'm very skeptical of that one, for very obvious reasons.
I'm so early I only see the spam bots commenting.
Anyway, this is a great reminder for tech specs. I've been reviewing a lot of LiFePo4 batteries and finding many of them don't achieve their rated specs. some go beyond though.
I nuked the titty bots.
@@EEVblog They used to bother my channel but I think they finally realized my videos don't get enough views. haha
Hey, nice to see you here :)
@@KeritechElectronics Shameless self-promotion works 😁
The Problem here is the Marketing Department 😉👍
Does that USB power meter thing also counts it's own power consumption?
No. The unit consumed around 64.12mA when in high brightness displaying the metering screen. With dimmed brightness, consumption fell to 54.18mA. These values have no significant impact on the final result.
@Tab7.6.Tab7.6 So it consumed 3 Wh to 4 Wh during that 12 hours 👍
I think this gets even more complex with USB-PD and the different voltage profiles. Maybe time for a deep dive. I am interested.
Not to say that input referred capacity is a better measurement, but wouldn't output referred capacity be variable and significantly dependent on output load and converter quiescent power draw?
That's what I thought. You'd actually want the "input capacity" and a couple of graphs to figure out the coefficient and the "output capacity" for your load😅
Would be interesting to know how much power you need to charge it back to full.
The input refered capacity is what the plane security asks for when they have a limit for battery capacity in the cabin.
And the last ting I wonder is of you take the cells in series, you dont have 20Ah and 3,8V, but you then have lower Ah and higher Volt. They still mark it as 3.8 and 20Ah....
I bought one specifically for travel, and I wanted basically as much as I was legally allowed. I assumed they gave the number that the flight folks ask for.
I've done a little testing of this myself over the years, I have a USB meter and have tested what it takes to fully charge the thing and what it takes to kill it (with a usb fan that draws .3A). It's useful because I can see how they're aging too and know when to get rid of them (I carry them while traveling and hiking).
I have the fnb58 also.. it's a kill3r piece of tech.. It even has a built in oscilloscope... You can go into the settings and turn it into a power supply also, for the different usb C standard voltages. I really like it. I wish they had something like this built into a recharable battery charger-- so I can follow all the outputs of the charger and track what my batteries are doing. I don't like being blind to what my chargers are doing for all my different rechargable batteries I have spread everywhere.
I think the 3.85V is 'nominal' and calculated by dividing the measured 77Wh by the designed 20Ah
all manufacturers who are not outright lying will give the spec that makes the number look biggest
I've been testing mAh (now I know better) with input and output, on three powerbanks and efficiency is even lower, with output being around 50% of stated capacity. I've noticed that USB-C socket output (for typical phone charging) gives a lower figure than USB-A socket. I don't know whether that's due to the type of port or different voltages (or protocols) used. In any case, for 'normal people' we can expect half of the stated capacity.
I decided I was too 'normal' to make a video about it 😊
Great video. Although evident to some, these things needed to be said. Every power tool battery lists Ah, although it is miningless, considering the voltage can be wildly different (12 to 60+). Even voltage is reported however the marketing department decides. Some use nominal voltage, other use peak. This is aside from the efficiency of the electronics inside.
well they did write just below that it has 11000 mah rated at 5v which gives 55Wh
Yes, I would say this was an exceptionally well-marked battery pack. To have figures that actually mean anything at all is rare now.
Well, you read it wrong. It says 11000 Ah, not 11000 mAh!
@@babbadge it is likely an honest typo though, since the figure matches reality.
Thanks for the reminder! The only reliable way to check the actual output capacity is through measurement, as we can't rely on the marketing department. 😉
The airport security only care about what's printed on the case. 105Wh is too high. 95Wh is acceptable.
Good info.
Also, the efficiency could vary depending on the load - so make sure to test with a load similar to the intended use case.
This weekend will be the 3rd date and I'll be "delivering my full load". Just saying. Thank you. I'm here all week Ausiland RoCks!
or it takes 77Wh might be a measurement of power it takes to charge the power bank
...no. we don't need to guess. It's the rated capacity all the cells summed up.
G'day from NZ :) That was the shortest EEVBlog video Ever! Didn't know you had it in you :)
In terms of why the measured capacity in Wh was below 77 - there's another reason you didn't mention. Most battery capacities are rated at a specific discharge current, not sure what the standard is for Lithiums but for lead-acid it's c/20
eg. a battery rated at 60Ah will give that capacity at 1/20th that draw - so 3A in this case. If you want to get the full 60Ah you can only do it at a max constant draw of 3A
In the case of the battery bank, the native Lithium voltage is being boosted to 5V by the converter, so this will effectively increase the current draw off the Lithium.
To test this carefully, you should a) assume the capacity is battery-related, then b) find out how the Lithium's capacity is rated - c over what... then arrange a 5V load on the output such that you're pulling no more than that current off the battery. Then measure the watt hours provided at the output, that'll give you the true converter efficiency.
I actually have a Hama power bank that is sold as 10000 mAh , but on the back it actually says that it has usable 6605 mAh usable capacity. it's something.
Remember that when the battery is at about 3.8V and your load receives 5V, the mAh figure at the load will always be much lower than at the battery.
That is why the Wh figure is much more usable to begin with.
@@Rob2 That is not in itself relevant. The voltage is raised at the output which lowers the current but at the phone battery end the voltage is again lowered.
What counts is that the process has losses, not the fact that the voltage on the transmission is higher pr se.
Usable capacity is a very flexible concept...
I don't actually care since it has become the unofficial standard to either put the sum cell mah (mostly liion, so close enough) or just outright lie. I would prefer if companies don't start using mwh to get a bigger number!
Let's not forget about your meausurement device imperfection with can be in about 1-2 % :)
Are the cells actually 3.85V nominal or is the manufacturer trying to boost their Wh for customers to think "ooh big Wh! Nice!"? On the other hand, some manufacturers claim 3.63V nominal to try to reduce their Wh so that customers can get the powerbank on a plane.
That is what Li-Ion cells roughly are. Some say 3.7 V, some 3.8 V.
@@okaro6595yeh Nar. It’s 3.6 or 3.7 nom for li-ion. This 3.85 might be the scam we’re all looking for.
That being said, even 3.6 x 20 is still way above the 61Wh tested.
3.85V nominal per cell is typical for a LiHV cell. They get more capacity in a smaller, lighter cell in exchange for wearing out faster. They are good for drones, but should be avoided when weight isn't critical.
Ive always known that, i mean if you based it on mAh befpre we even consider the conversion loss, 20000mah at 3.7v is 14800mAh at 5v, im suprsrised those power banks didnt provide datasheet with multiple test condition and temperature with graph at different load like what you will get on battery datasheet or component datasheet
Maybe they can also include output ripple, efficiency, voltage accuracy, especially now that PD power bank is common that you can get different efficiency at different output voltage
20,000,000,000nAh!!!! **Obviously doctored picture of tiny battery bank on the tip of a finger**
1980's ghetto blaster 2000W Peak Music Power Output! (PMPO). Good times.
@@EEVblogPretend Maximum Power Output is what my friends called it.
@EEVblog There is a bit of a faff with this at the moment. FTC made a new amplifier rule that basically means amps must all spec maximum power at 20khz, right where we need it, lol.
Gotta love those 100000 dB horns from Wish, apparently producing pressure waves capable of obliterating the universe and all of it's parallels a million times over
@@EEVblog My 5,000 watt early 2000s eMachines computer speakers would blow the cones off that unit.
Then there is the limit on flying with powerbanks in the carryon.
The manufacturers have to put a potential maximum on the specs so any airport security can check it's under maximum alllowed.
Dang, I've just assumed most of this for about half my life. Maybe I'm not as stupid as I thought I was. I also assume that anything over 15000 mah is lying if it fits in a pocket.
I also disagree that it's mostly the marketing department's fault. Others have already explained it well, so I won't do so here.
I think mAh is fine if they are referring too battery cells in parallel since the voltage is the same.
I've also always assumed ratings were based on battery cells and not the actual output at the USB port. Consider me not surprised.
Did you measure the energy required for charging as well? I would expect that it is even more than 77 Wh, because the USB PD to cell voltage conversion causes a similar ~20% loss. So it's not even real input referred, just the internal battery capacity. Your are basically buying a lithium cell with the specification + some circuitry/ports for convenience. I noticed while traveling with solar panels that almost 50% is lost when it goes through a power bank instead of charging the target directly. I agree that every power bank should include a full efficiency and output energy specification too.
Is there any video from the channel that explains what a DC/DC converter is?
1:01
You might wanna PSA regarding voltage as well. Newer power banks now have 21V with the new PPS standard, As expected iphones are late once again. Higher voltage, lesser current = lesser loss.
Yup, Anker 10000mAh runs flat after charging a 5000mAh phone, because of fast charging. It's written there on the battery. but still their advertisement should be honest: either it's a quickcharge 5000mAh OR a regular 10000mAh, but not mislead it's BOTH
And then the 5v DC/DC voltage is converted back down by your phone/device to battery voltage for another 20% loss. (If it is even switchmode.)
And the same is true for the input side.
But Dave, surely this depends on the value of ‘future’ electricity, as opposed to ‘present’ electricity? In an alternating economic environment, current affairs can significantly alter the potential difference between your calculated values.
🧐
Unbelievable!!! 😀Dave put out a actually useful video that is under 3 minutes 😀
No worries Dave, I still like you 😁
ok, but can you look though your batterypacks you have at hand how much the converters varies between the manufactures for a fixed load? if every converter needs 20% then the packs are comparable with the input-ref values.
Can understand watt/ hours, that makes more sense
Hey there! I know some people who think their output is an input. Know what I mean? Wink, wink, nudge nudge, say no more! Great video.
Like PMPO for audio equipament, in 90's era
It is not really marketing, by law and transport compliance the product need to bear rating label with the energy that is in the cell. If you would specify the output rating it is illegal. Still to make the output Wh number the input Wh number still is needed to produce it. The 80% efficiency Wh to Wh number is pretty bad actually. Would expect >90% from better quality power bank.
And again, I hope I learned something!
Good Point, that might bring some light in the solar...
Can you link to an example product like this one which shows the capacity as would be measured by a load like your example? Cos I know of none. They will almost always list the capacity this way: that of the cells (spec not tested).
Why did they put the crappiest boost converter in such an expensive power bank? They should have spent $0.20 more.
Thanks Dave 👌🏻
At least it now seems the powerbank marketing numbers are matching the actual batteries. I remember seeing "10,000mAh" batteries 10 years ago and them being suspiciously light. Got to love marketing rubbish.
There are a million mAh batteries being sold by Amazon.
Is it marketing though? I thought it was so that the energy capacity (of the battery) was accurately stated for safety, transportation, and similar purposes. (If it blows up, you know the pottential magnitude of the inferno...) I'm sure that marketing departments exploit any parameters to their best advantage, but I think this one is at least honest, even if it does nothing to describe the true input to output efficiency and is therefore of only limited value to the user.
That's not really proportional to the rated capacity, but mainly battery chemistry. Either way Wh would be the battery rating for "dangerousness", since higher voltage chemistries are usually more dangerous.
@Max24871 Which is why Ampere-hour rating, Watt-hour rating and nominal voltage are specified.
@@GodmanchesterGoblin yes they are, but that doesn't make your original comment any more correct
@Max24871 I talked about energy capacity (which is Watt-hours as you know). To be honest, I'm not sure why you regard that as incorrect.
@@GodmanchesterGoblin It seemed to me like you were referring to the mAh rating, seeing as that is what the video was about and you not mentioning any particular units. Sorry for the misunderstanding.
and also, no one is covering nonsense claims of manufacturers claiming their chargeable batteries are close to 99% efficiency. also electric car enthusiasts don't want to see their charge/discharge efficiency of batteries make their electricity consumption much higher than they calculate with. if you put 1kW/h into charging, you don't get 1kW/h out. you could be glad if you get 70% back. but producers don't tell you this. marketing strategy lies. as usual.
Why do they keep putting the charge specification of phone batteries and power banks, even hand tools? energy is the only one that matters
Also WTF they mean by this "Rated Capacity: 11000Ah(5V 2A)" written there XD 55000 Wh lol?
That looks like a typo. It should have been 11Ah or 11,000mAh.
Yes, BUT output voltages can vary with USB PD: 5 or 9 or 15 or 20 Volts. So we don't just need A (singular) output-referred Wh number, we really need graphs that factor in the DC-DC efficiency @ different output voltages over the supported current ranges.
If any mfgr is listening: that would make for a fine product picture. Imagine you advertised your products on the merits, (almost) for free because you should already have that data.
I should sell input-referred solar panels
Airlines typically want the battery capacity not output capacity, and at least in the US FAA regulations limit the maximum size.
In put 77Wh - load 61.8Wh = 15.2Wh heat. Do you feel the heat?
This is a relatively good specification.
There are many instances that the seller cheats and writes ten times higher ratings.
And when you write to him about that he sometimes says "sorry" but he won't fix the error on the website/store.
"I didn't know that"
"my supplier gave me that specification!"
"I am a poor guy who has a family"
but of course they know just as well as the 32TB USB stick sellers know what is happening...
Hi Dave, how are the kids doing ?
But dave, all the battery operated tools are in Volts!
Only the nominal operating voltage is indicated on power tools. But already on batteries for these tools, the nominal capacity is additionally indicated. This capacity is true, moreover, because there is no conversion from a lower voltage to a higher voltage here, as is the case with powerbanks.
I have new USB-C phone and charger which can do 20 Volts 66 watts. One might assume there is less losses in transit, because much less current. I have not seen a battery bank which can do 20 volts, only 12 Volts, but it might be coming one day soon.
There are plenty of 20V capable powerbanks. Most 65W and 100W can do 20V
Yes, look for laptop compatible power banks - those will have 20 V output.
if you like accurately described electro mechanicals , don't ever check out air compressors!
it makes sense. DC-DC efficiency is depended on the load, sometime it's 10-15% between worst and best case. Using battery rated will give you solid number.
Also dont forget your phone also has DC-DC block inside, to convert the input voltage to battery-approriated voltage. So there is another loss
Like power tool battery Ah rating, checked both brand new Makita and Milwaukee 18V battery's, only get about 85% of the name plate Ah rating. Theres no inverter in them so it’s all marketing fibs.
How did you carry out the tests?
@@Tab7.6.Tab7.6
Used my Rigol DL3021 battery test function, 1A load till fully discharged.
Wow, isn't 80% very low efficiency for DC to DC?
Rather typical for this type of device.
Bloody marketing, if you see a rating of 20000mAh that's 20A for one hour...hmmm I don't think so, bit like bloody ISP's using megabits/sec instead of megabytes/sec as it sounds bigger ! Scotty from marketing is all over this !!!!
To be fair, the bits rather than bytes per second thing comes from the way serial port (and Ethernet) speeds are labelled. And serial ports were in bits since they could do different length items or "characters", for instance 5, 6, 7 or 8 bits, with or without parity each with a start bit and 1, 1.5 or 2 stop bits. Would they have been able to sell a broadband connection of 64KB/s (bytes/second) to users who already had a 56kb/s (bits/second) dial-up modem? Maybe, but it'd be much easier to sell a 512kb/s (bits/second) broadband connection. (This is the actual speed of my |First broadband connection, which I got in 2002). Even that's an oversimplification, since although dividing 512k by 8 gets you to 64k, that's quite a bit higher number than the amount of usable data in bytes that can actually be transferred because of packet headers and similar hidden things needed to make it work.
I am sure you can get 40A at .1V for 1 hour. The current is meaningless if voltage is not spevified
Marketing people being dishonest?? never!
Not only this, but a lot of these Chinese power banks have completely fake battery capacities.
As we say... Its good enough for government work... Plus if everyone is comparing input wattage, then they should be all about the same ball park. 80% efficient is about average for a DC/DC converter. you are just splitting hairs if you are +/- 5%
Input wattage?
No.
Input POWER!
Now do it in a cold environment. Then its even less 😅
Trouble is, the efficiency of the Dc-Dc varies with current, so depending on your load you get a different Wh rating.. As for comparing batteries, as long as it's apples to apples, it doesn't really matter which figure you're comparing.
I also think this constant marketing hype of making the figure look good by specifying mA unnecessarily. Why say 20,000 mA when they should just say 20A
Or, you know, (m)Ah
Because bigger numbers are more betterer
@@redpheonix1000 exactly, that's why Americans use their stupid measures to sound more important. Why say 1tonne when you can say 2,413million sardine heads or whatever other stupid measurement they use.
I was looking into this about one or two years ago. I thought the way it’s labeled, these high-capacity packs should not be legally allowed onto airplanes (carry-on anyhow). However when you do some of the math, including efficiency, and try to work backwards, they do squeak under the airlines’ policies. I doubt the average luggage inspector could do the math in their heads. So while big numbers are great for marketing, they may unduly alarm the baggage inspectors. They’re not likely to be electronics wizards. They’re not expected to open up the battery packs to see what cells are really in there and to be able to intelligently counteract the marketing exaggerations so it’s a real dilemma. Maybe they just have a chart where they look up different “marketing” ratings and scale it down accordingly. Laptop batteries are usually worse… but then they are required to be check-in baggage… I think there’s a cut-off capacity.
Trouble is, airlines use one rating whereas the numbers on cases use another scheme. Consumer confusion is the name of the game. I doubt anyone in an airport has 1/10th the wisdom of Dave or even that of a decent electronics hobbyist.
Don't they all just list the total Watt hours of the contained battery cells? This is what the airlines care about and is apples to apples across laptop packs, flashlight batteries , tool batteries and power banks. This will be the highest figure. If there's some future push to list net output Wh, I think they will have to list two numbers(in turn exposing the efficiency of the DC/DC converter. a good thing ...)
The airlines in the us just got it changed so you can take much bigger batteries onto planes.
@@alexdrockhound9497 Interesting. I’ll have to look into that. I hope they made it a lot clearer what criteria they use: milliamp hours vs. watt hours (conveniently omitting battery voltage versus voltage booster output… so there’s still all that confusion I’m sure).
Few words why mAh is bad?
You were very lucky to find any figure that specified energy capacity at all. The whole battery capacity quoting business has become a complete and utter mess. There are manufacturers quoting ludicrously large mAh figures and nothing else because they know the figures are as good as meaningless, but they are all that's needed to make a battery sell. It stinks.
Hmmmm, what's that smell ?
The problem with output referred is there’s no single number since the efficiency of the dc/dc stage is not static. While it might be 80% at one current level, it might be 85% or 90% at another
Input referred is actually a more reliable figure to compare with if the needed current level isn’t static
That 20000mAh seems to be default figure they print on powerbanks, even when selling them empty. 😂
Next you're going to tell me that the 9000mAh 18650 battery I got with my 200,000,000 lumen Amazon flashlight isn't real.
3.85v on a lithium battery. Give me a break. Unless these guys have formulated their own cells, or buying alien technology they should be using 3.7v. There is a 4% boost in capacity right there. Most of the cheap Chinese boost converters will run 90%+ efficient, but there may be a sweet spot so you may need to run a bigger load to get this, A 5w load may be more appropriate
Albo logic?
This video 4 years late...
TWENTY MILLION µAh!
Thank you Dave, now everyone knows the marketing trick.
what-watt-watt-what
Time for ProjectFarm to test!
😊
Reminds me of computer drives where Marketing decided "megabyte" was going to be "1,000,000 bytes" when stating capacity, not the binary 1,048,576 bytes. It makes drives seem bigger to customers...but not to computers.
With RAM, bases of 2 make sense because of how RAM is constructed. With storage (and network), bases of 10 are consistent with all of physics and engineering.
@@crackwitz Not really, non-volatile storage capacity is best represented as base-2 because it's binary all the way down (to sectors). It's 100% marketing ploy, like using *bits* instead of *bytes*.
@@hanifarroisimukhlis5989Nah. Did you know that HDD storage density is expressed in bits per square inch? I understand you're angry because Windows divides by 1024 and you think you're being robbed of your money. You can blame Microsoft for that, or simply accept that it's irrational to count these quantities in multiples of 1024.
A megabyte is a million bytes. You cannot redefine the prefixes. A mebibyte is 1048576 bytes
Scam battery packs just take half of the mAh number, that is what is real 😂
As a consumer, not building your own, you should not be bothered with the internal workings. It is a black box. It's capacity should be measured as such
+1
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Another day in chinesewhery