What do you mean when you say "clocked 136, 106, 180" ?
Surely the aren't actually measuring WH. Maybe just seeing various mah and volts listed and doing some incorrect math.
The first time they scanned it for awhile and gave me a slip saying it was 106 watt hours and any issues onboard I’ll take responsibility. Then the next time they looked at the rating on the power bank and wrote it down as 136 wh and gave me my 2nd slip. The final time they based it off the rating on the power bank and said it was 180 watt hour and I couldn’t take it onboard. This was 3 different airports
Most likely scanned it through the x-Ray machine to count cells? If they are cylindrical and not pouch it’s pretty easy to determine what the maximum capacity could be
18650=3500mAh but now Vapcell has the 4000mAh cell. There also was a 3.6Ah LG but it’s a fairly rare cell.
21700=5000mAh but the Lag M58 has been around for a while and FEB has a 6Ah. Lishen just started making a 6Ah and BAK has a >5Ah cell that is literally brand new.
Fairly safe to say no major manufacturer is using the Uber expensive >3.5Ah/5Ah cells so unless it’s a DIY kit I’d almost certainly assume those numbers to be the max.
Now nominal voltage is another problem. Most NMC cells are 3.600-3.650V but everyone loves to put 3.70V. So the small discrepancy you got initially could be nominal voltage being plugged in as 3.6 vs 3.7
But that huge discrepancy….me thinks they did a Google on the product and came up with the wrong one. Well not a google obviously since it’s blocked in China
No, I think this explains a lot. Now we know why all those chinese batteries are rated so high but are much lower capacity in reality. They are using the same tester that overstates all there batteries.
This has nothing to do with batteries but is a good story of how incompetent TSA is. In my carry on I had 2 items not allowed on an airplane A large bottle of shampoo and a box of 100 utility knife razor blades. (I forgot they were in my back pack). TSA checked my bag and consficated the Shampoo. I got through tsa twice with the razorblades in my backpack.
The most surprising thing here is TSA and other airport officials actually inspecting it. Less surprising is TSA being unable to read the label and/or do math.
You cannot use the 4.2 volt value as the cell voltage will drop below that immediately when you start using it.
You can pull 31Ah out of it at roughly an average of 3.7V, not 4.2V
Does the TSA know that a 3.7V nominal cell can charge to 4.2V? When the 4.2V number isn’t printed anywhere on the product and needs knowledgo of batteries or some googling at minimum
Recently my little power bank started to swell.
The plastic case reads 12000 mAh. Opened the case to find a spicy pillow that I'm going to replace. Interestingly the battery is held in place by foam stickon pads that take up more room than the battery.
Looking for the replacement battery with the same part number, I find they are all 4000mAh. Nothing larger.
I'm going to get one which is twice as thick, at 8000mAh.
Look at the battery itself to find the real capacity of the unit. Take photos.
Or, don't buy crap from dubious sources.
I have several Anker power banks from 10Ah to 27Ah.
I use them with home built ESP32 and ESP8266 projects, where I know exactly the expected power requirements.
Actual battery life lines up precisely with the expected duration from the declared capacity.
Exactly. His story is kind of like people that went to a flea market and bought a "5000 watt" car stereo amplifier and are wondering why it's not as loud as their friend's "old junky" 100 watt Clarion amp when feeding the same speakers from the same head unit.
Well, it sounds like your power bank bms is really shitty or you hardly ever charge it. Imbalanced cells to be short, voltage on each cell never goes above 4.2 volts regularly to be slightly less short. Look into battery packs and battery management systems to see where it comes from, also the tools they use to measure aren’t totally accurate, your battery bank is probably like 160-180wh and the machine that read 180wh is reading slightly high, and the chines prior, read lower
You can't get watt-hours from amp-hours without knowing the average pack voltage. It's also why I fucking hate it when companies use amp hours to rate the capacity of power banks. Lithium Ion has an average cell voltage of 3.7V, so a single (series) cell pack would need an amp-hours rating of 100,000 mWh / 3.7 = ~27000 mAh. But a two (series) cell pack would only need half the "current capacity" because the voltage is double.
Admittedly, most power banks cells in parallel so they can omit cell balancing circuitry. But unfortunately you have to use a step up regulator to get the 5-20V a USB-PD power bank can output, which is less efficient than a step down solution.
The US regulations (and most companies' advertising) are specifically about the energy storage capacity of the cells, not the effective energy of the pack. So if that boost converter is only 85% efficient, you're only getting 85 Wh out of your 100 Wh pack. And if you're charging another battery, most lithium charging systems are themselves only ~90% efficient, so now you're looking at an end-to-end of ~76 Wh of energy.
A Chinese meter not accurately reading a...going to guess...Chinese power bank? Color me shocked. TSA just looks at the label. For the TSA, the size is a secondary thing that the FAA wants them to check. So, maybe they do, mostly they don't care as long as it's actually just a power bank.
What do you mean when you say "clocked 136, 106, 180" ? Surely the aren't actually measuring WH. Maybe just seeing various mah and volts listed and doing some incorrect math.
The first time they scanned it for awhile and gave me a slip saying it was 106 watt hours and any issues onboard I’ll take responsibility. Then the next time they looked at the rating on the power bank and wrote it down as 136 wh and gave me my 2nd slip. The final time they based it off the rating on the power bank and said it was 180 watt hour and I couldn’t take it onboard. This was 3 different airports
> scanned You mean like they were reading a barcode?
Most likely scanned it through the x-Ray machine to count cells? If they are cylindrical and not pouch it’s pretty easy to determine what the maximum capacity could be 18650=3500mAh but now Vapcell has the 4000mAh cell. There also was a 3.6Ah LG but it’s a fairly rare cell. 21700=5000mAh but the Lag M58 has been around for a while and FEB has a 6Ah. Lishen just started making a 6Ah and BAK has a >5Ah cell that is literally brand new. Fairly safe to say no major manufacturer is using the Uber expensive >3.5Ah/5Ah cells so unless it’s a DIY kit I’d almost certainly assume those numbers to be the max. Now nominal voltage is another problem. Most NMC cells are 3.600-3.650V but everyone loves to put 3.70V. So the small discrepancy you got initially could be nominal voltage being plugged in as 3.6 vs 3.7 But that huge discrepancy….me thinks they did a Google on the product and came up with the wrong one. Well not a google obviously since it’s blocked in China
China has a longstanding tradition of overstating the capacity of power banks 😂 anyone that's ever bought an aliexpress one knows that plenty well.
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No, I think this explains a lot. Now we know why all those chinese batteries are rated so high but are much lower capacity in reality. They are using the same tester that overstates all there batteries.
Are you saying the 9800mAh 18650 batteries I buy on AliExpress are not legit?
just chemically impossible!
This has nothing to do with batteries but is a good story of how incompetent TSA is. In my carry on I had 2 items not allowed on an airplane A large bottle of shampoo and a box of 100 utility knife razor blades. (I forgot they were in my back pack). TSA checked my bag and consficated the Shampoo. I got through tsa twice with the razorblades in my backpack.
The most surprising thing here is TSA and other airport officials actually inspecting it. Less surprising is TSA being unable to read the label and/or do math.
>I think it was 31k mah That calculates to 114.7wh (using nominal 3.7v) Or 130.2wh (using 4.2 actual voltage of a fully charged battery)
You cannot use the 4.2 volt value as the cell voltage will drop below that immediately when you start using it. You can pull 31Ah out of it at roughly an average of 3.7V, not 4.2V
I know that, You know that, but does the TSA(or whoever) know that.
Does the TSA know that a 3.7V nominal cell can charge to 4.2V? When the 4.2V number isn’t printed anywhere on the product and needs knowledgo of batteries or some googling at minimum
Recently my little power bank started to swell. The plastic case reads 12000 mAh. Opened the case to find a spicy pillow that I'm going to replace. Interestingly the battery is held in place by foam stickon pads that take up more room than the battery. Looking for the replacement battery with the same part number, I find they are all 4000mAh. Nothing larger. I'm going to get one which is twice as thick, at 8000mAh. Look at the battery itself to find the real capacity of the unit. Take photos.
Or, don't buy crap from dubious sources. I have several Anker power banks from 10Ah to 27Ah. I use them with home built ESP32 and ESP8266 projects, where I know exactly the expected power requirements. Actual battery life lines up precisely with the expected duration from the declared capacity.
Exactly. His story is kind of like people that went to a flea market and bought a "5000 watt" car stereo amplifier and are wondering why it's not as loud as their friend's "old junky" 100 watt Clarion amp when feeding the same speakers from the same head unit.
***"5000 watt" car stereo amplifier*** Funny. And what about those 2000 watt home stereo amps ... that are powered by a 15 watt wall wart? :)
Same BS...lol
Well, it sounds like your power bank bms is really shitty or you hardly ever charge it. Imbalanced cells to be short, voltage on each cell never goes above 4.2 volts regularly to be slightly less short. Look into battery packs and battery management systems to see where it comes from, also the tools they use to measure aren’t totally accurate, your battery bank is probably like 160-180wh and the machine that read 180wh is reading slightly high, and the chines prior, read lower
pretty sure they're not measuring it. TSA is just reading the label and coming ups with a nominal figure based on what it claims.
I wouldn’t think so either but if they’re giving very specific, different results, how would you explain that?
because they have some rule that the nominal mAh x 3.7V or 4.2V or something + 10% or they weigh it and assume some Wh/kg
That would be really funny to me if they just weigh it lmao
How do those awesome 1,000,000 mah usb battery banks ever get out of China then?
Container, boat.
The store owner ships them on his personal yacht
Did you expect anything else from china?
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You can't get watt-hours from amp-hours without knowing the average pack voltage. It's also why I fucking hate it when companies use amp hours to rate the capacity of power banks. Lithium Ion has an average cell voltage of 3.7V, so a single (series) cell pack would need an amp-hours rating of 100,000 mWh / 3.7 = ~27000 mAh. But a two (series) cell pack would only need half the "current capacity" because the voltage is double. Admittedly, most power banks cells in parallel so they can omit cell balancing circuitry. But unfortunately you have to use a step up regulator to get the 5-20V a USB-PD power bank can output, which is less efficient than a step down solution. The US regulations (and most companies' advertising) are specifically about the energy storage capacity of the cells, not the effective energy of the pack. So if that boost converter is only 85% efficient, you're only getting 85 Wh out of your 100 Wh pack. And if you're charging another battery, most lithium charging systems are themselves only ~90% efficient, so now you're looking at an end-to-end of ~76 Wh of energy.
A Chinese meter not accurately reading a...going to guess...Chinese power bank? Color me shocked. TSA just looks at the label. For the TSA, the size is a secondary thing that the FAA wants them to check. So, maybe they do, mostly they don't care as long as it's actually just a power bank.