In my experience, if you're getting an actual 6,000 mAh from a 'dirt cheap' power bank advertised at 12,000 mAh, you're doing well. There are a few things to keep in mind: The advertised capacity is almost always optimistic. Quality 18650 cells cost money, and these power banks are too cheap to have quality cells in them. There are always going to be conversion losses. The boost converter inside the power bank is only 80-90% efficient, so you lose 10-20% of the capacity on the way to the USB output. The same is true for the charging circuitry inside the phone, so you lose more on the way from the USB input to the phone battery. The display is wildly inaccurate. It may sit at 80% for a long time, and it may also jump from 30% to zero in an instant. This power bank has 4 18650 cells in parallel. A capacity of 12,000 mAh would require 3000 mAh cells. You can get those from quality manufacturers, but one cell costs about as much as the whole power bank, so what you actually get in these power banks are generic Chinese cells, usually with a capacity of <2000 mAh/piece. Considering the lower true capacity and the conversion losses, I would expect to get about 2 full charges out of it. Answer from bal00 on reddit.com
PITAKA
ipitaka.com › blogs › news › 1000mah-to-120000mah-whats-the-best-capacity-for-a-power-bank
1000mAh to 120000mAh: What's the Best Capacity for A Power Bank? – PITAKA
So one full charge of a 10000 mAh power bank can charge the iPhone 16 from 0 to 100% twice (7000 divided by 3561), while it can charge the iPhone 16 Pro Max about 1.5 times (7000 divided by 4685).
Powerbankguide
powerbankguide.com › powerbank-capacity-explained
Powerbank Capacity Explained: A Quick Guide – PowerBankGuide
So for a good 10,000 mAh power bank, it will be about 6,600 mAH or about 2 full charges for the iPhone 17/17 Pro, 16/16 Pro, 15/15 Pro, 14/13/12 Pro and for a good 20,000mAh power bank it will be about 14,000 mAH, or about four full charges for the iPhone 17/17 Pro, 17 Pro Max, 16/16 Pro, ...
Videos
Quick charge anywhere! #powerbank #powerbankcharger #phonecharger ##charger #chargingcord #ad | TikTok
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I Tested this 12,000mAh Magsafe Power Bank - Any good? - YouTube
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How Reliable Is the CHUSII Magsafe 12,000mAh Power Bank? - YouTube
05:51
Should you buy the Anker Prime 130 Watt 12K Power Bank? - YouTube
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I Tested 12+ Of The Newest Battery Banks - Here Are My Top 5! - ...
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UGREEN 100W Nexode 12000 mAh Fast Charging Power ...
Reddit
reddit.com › r/askelectronics › phone charging powerbank (12000mah) question.
r/AskElectronics on Reddit: Phone charging powerbank (12000mAh) question.
January 30, 2015 -
So I bought this power bank that's supposed to be 12000mAh from a chinese shop for dirt cheap and I wasn't sure what to expect.
link
It came charged while my phone was almost dead so I plugged it in and it charged my phone to 50% and the power bank was left with 80 percent according to the display.
This means I can charge my phone 2.5 times if the bank is charged fully.
Shouldn't it charge my phone ~5 times if you calculate 12000/2300 or does it not work this way?
Top answer 1 of 2
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In my experience, if you're getting an actual 6,000 mAh from a 'dirt cheap' power bank advertised at 12,000 mAh, you're doing well. There are a few things to keep in mind: The advertised capacity is almost always optimistic. Quality 18650 cells cost money, and these power banks are too cheap to have quality cells in them. There are always going to be conversion losses. The boost converter inside the power bank is only 80-90% efficient, so you lose 10-20% of the capacity on the way to the USB output. The same is true for the charging circuitry inside the phone, so you lose more on the way from the USB input to the phone battery. The display is wildly inaccurate. It may sit at 80% for a long time, and it may also jump from 30% to zero in an instant. This power bank has 4 18650 cells in parallel. A capacity of 12,000 mAh would require 3000 mAh cells. You can get those from quality manufacturers, but one cell costs about as much as the whole power bank, so what you actually get in these power banks are generic Chinese cells, usually with a capacity of <2000 mAh/piece. Considering the lower true capacity and the conversion losses, I would expect to get about 2 full charges out of it.
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12000mAh at Li-ion voltages. Boost that to 5V, and you lose capacity in both having to draw more current, and having to use a boost converter. Then take into account cheap crap batteries that are so totally not the advertised capacity.
Reddit
reddit.com › r/batteries › i have a power bank (12000mah) which tells me it has a life span of 1000 cycles. how many times i can charge a phone of 5000mah battery 15w input?
r/batteries on Reddit: I have a power bank (12000mah) which tells me it has a life span of 1000 cycles. How many times I can charge a phone of 5000mah battery 15W input?
September 15, 2023 -
So my calculations that I made were 1000 cycle 1 cycle can charge my phone approx 2.5times So that means it can charge my phone 2500 cycles. Please correct me if I am wrong
Quora
quora.com › How-much-time-can-my-phone-be-charged-by-a-power-bank-of-12-000-mAh
How much time can my phone be charged by a power bank of 12,000 mAh? - Quora
Answer (1 of 3): A typical phone has some 3000 mAh so you in theory get four charges but in practice the process is not 100 % effective so you probably get 2–3 charges. Note it is not goo to push up to 100% with a power bank as the last charge ...
Quora
quora.com › How-much-time-does-a-12-000-mAh-power-bank-take-to-charge
How much time does a 12,000 mAh power bank take to charge? - Quora
Answer (1 of 5): Try to find a power bank with a Qualcomm QC3.0 or better charging INPUT (as well as output) to get the fastest recharge speed. You’ll of course need a ‘wall wart’ adapter with QC3.0 outputs to connect to the recharge input of the power bank.
Reddit
reddit.com › r/batteries › 10000mah powerbank advertised to charge 4300 mah phone 1.3 times?
r/batteries on Reddit: 10000mAh powerbank advertised to charge 4300 mAh phone 1.3 times?
October 4, 2024 -
Can someone explain the discrepancy in the numbers? If the 10k powerbank capacity isn't made up, then I would naively expect it to fully charge 5k phone 2 times. However, here the manufacturer advertises it to charge a 4350 iphone battery just 1.3 times, which I don't understand.
Also, what even is this discrepancy among different brand phones. Here it says xiaomi phone with 4500 mAh battery capacity can be charged more times than iphone with 4350 mAh battery? If I had to guess the answer to my first question, it would be something along the lines of energy loss, but this doesn't even begin to make sense for me. Educate me please what's going on here
Top answer 1 of 9
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Losses in the charging circuit and wire. That's why
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There's inefficiency everywhere. The batteries are 90% at best, but will be much lower because of high current draw. Then a DC converter (90%). Then the charging battery, quick charging of course. You could probably get close to 2 full charges if the converter is suitable and you limit the current. Of course, this product, nor an iPhone are going to give you that option.
Anker
anker.com › home › blog center › chargers › what is mah? (milliamp hours) and how does it affect chargers?
What Is mAh in Portable Chargers and How Much Do You Need? - Anker US
December 3, 2024 - When selecting a portable charger, the ideal milliampere-hour (mAh) capacity depends on your device and usage patterns. For smartphones, a charger with 5,000 to 10,000 mAh typically means one to two full charges, suitable for daily use.
Vegerpower
vegerpower.com › blog center - veger › how many mah to charge iphone? complete guide
How Many mAh to Charge iPhone? Complete Guide 2025
May 20, 2025 - For instance, a 5,000mAh power bank can charge your iPhone once, while a 20,000mAh power bank supports multiple charges. A power bank with a higher mAh capacity can charge your iPhone multiple times and may provide faster or more efficient charging.
PITAKA
ipitaka.com › blogs › news › 5-things-you-need-to-know-before-buying-a-power-bank
5 Things You Need to Know Before Buying A Power Bank – PITAKA
The conversion efficiency of most ... (rated capacity of the power bank) / 3,110mAh (capacity of the iPhone 11 battery) =2.25 times...
Reddit
reddit.com › r/explainlikeimfive › eli5 how much battery a 20,000 mah battery pack is
r/explainlikeimfive on Reddit: ELI5 How much battery a 20,000 mAh battery pack is
May 21, 2022 -
Someone gifted me an external battery pack to use when I go hiking. Ive been using it for a few months now and never seen it make it below 75% charge (im charing it one night a week and it gets used 2 or 3 days a week)
Can someone put into laymans terms how many times this pack should charge a phone?
Top answer 1 of 4
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Depends on the phone. In perfect conditions, the 20,000 mAh battery pack will charge a 5,000 mAh phone battery 4 times from 0% to 100%. Realistically it's less than 4 times but the math is simple as that.
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mAh is milliamp hours, a measure of the amount of energy in a battery. Mobile phones have batteries too. You can imagine the battery pack as a big bottle full of water, which we measure in milliliters. We can imagine a phone that runs on water, so it has a tank (battery) in it that you can fill with water (electricity). You can fill (charge) the phone from the big bottle (battery pack) by pouring some of the water out of the bottle into the tank in the phone (charging the phone from the battery pack). How many times you can refill (charge) the phone’s tank (battery) from the bottle (battery pack) depends on how many ml of water (mAh of electricity) there are in the bottle (battery pack) and how many ml of water fit in the phone’s tank (mAh in the phone’s battery). You know how many mAh fit in the battery pack (20000 mAh), so what you really need to know is how big the phone’s battery is; different phones have different battery sizes. Google tells me that an iPhone 12 has a 2815 mAh battery. So, you charge it from empty to full about 20000 / 2815 = 7.1 times. It could be different for a different phone. Important: you always get a little less. You’ll notice that the batteries warm a little while charging. That’s energy lost during charging - it’s not 100% efficient (in the metaphor above, you spill a little when pouring from the bottle into the tank).
Baseus
baseus.com › home › content › content
What is mAh? A Guide to Power Banks
May 20, 2024 - When you’re talking about a battery or power charger, mAh expresses the flow of electrical current per hour. The mAh metric represents the capacity for one milliampere for one hour. So, 1,000 mAh means 1,000 milliamperes per hour. For example, a device with 5,000 mAh can deliver a current of 1 milliampere for 5,000 hours (meaning 5 amperes for one hour). Now, 5,000 mAh is a low capacity for a power bank.
RAVPower
blog.ravpower.com › 2017 › 10 › many-times-can-power-bank-recharge-smartphone
How Many Times Can My Power Bank Recharge a Phone? - RAVPower
November 9, 2020 - How come my power bank charges my phone 7 times? We take a look at the math behind how many times a power bank can recharge your smartphone.
Reddit
reddit.com › r/steamdeck › how many times can a 20000mah power bank charge the steam deck?
r/SteamDeck on Reddit: How many times can a 20000mAh power bank charge the Steam Deck?
July 21, 2023 -
I got a Jsaux power bank with 20000mAh capacity. I believe the Steam Deck is 5200mAh capacity. I naively thought the Deck could therefore be charged about 3.7 times by the power bank, but I'm only getting about 1.3-1.5 before the power bank runs out.
Jsaux support claim my experience is within production expectations.
Can someone tell me what I should really be expecting, and if you have personal experience and not just theory, then even better!
Thanks in advance.
Top answer 1 of 13
85
Because It's not a 3.7v battery but a 7.7v. Your power bank has a capacity of 20 000mah for 3.7v. Wich could charge a phone 4x if It has a 5000mah battery. For a battery with twice the voltage, it will charge it 2 times less.
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Ignore mAh, as they can be advertised differently depending on random voltages and not always universal. Use watts per hour instead. Your power bank is about 80w, the steam deck battery is 40w. So in theory, you would get about 2 charges, but the unfortunate reality is power banks will almost never actually give you what they are rated for, but closer to 70-80% of advertised. So your “60 watt” battery (75% of 80w) should give you roughly 1.5 charges.
Quora
quora.com › How-long-will-a-12-000mAh-power-bank-last-for-a-typical-smartphones-battery
How long will a 12,000mAh power bank last for a typical smartphone's battery? - Quora
Answer (1 of 3): The mAh of a cheap power bank are approximated/rounded (heavily upwards) the current capacity of all cells together, without considering the conversion losses. With the necessary conversion of 3.6V to at least 5V that’s almost halved, so it may charge a 5000mA smartphone ...
EverGreat Technology
evgreat.com › purchasing-guides › frequent-ask-questions › how-do-you-calculate-the-actual-output-capacity-of-your-10000mah-power-bank
How Do You Calculate The Actual Output Capacity Of Your 10,000mAh Power Bank? | EverGreat Technology
May 10, 2025 - Let’s use a 10,000mAh power bank as an example. Understand the Battery Voltage: Most power banks use 3.7V lithium-ion batteries. Understand the Output Voltage: USB charging standard is 5V. Calculate Capacity after Voltage Conversion (Theoretical): (Labeled Capacity (mAh) x Battery Voltage (V)) / Output Voltage (V) (10000mAh x 3.7V) / 5V = 7400mAh
Reddit
reddit.com › r/batteries › estimating power bank capacity
r/batteries on Reddit: Estimating power bank capacity
August 20, 2023 -
I don't have any electronics tools or meters, but want to get a rough estimate of a new power bank's capacity.
My phone supposedly has a 5000 mAh battery that I ran down to 50% before plugging it into the power bank, which showed a remaining charge of 84% on its display. About 90 minutes later the phone was fully charged and the power bank showed a remaining charge of 64%.
So by my calculation, the power bank used 20% of its capacity to give the phone a 2500 mAh charge. Just doing a simple extrapolation tells me the power bank's capacity is 12,500 mAh. Is that reasonable? If not, where is my reasoning faulty?
Top answer 1 of 2
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Your estimation looks right as far as it goes. Typical cellphone charger power banks are 10,000mAh. It probably says what it is somewhere on the label. What they don't tell you is what Voltage that is at. Typical is powered by lithium ion which is 3.6V. [email protected] is 36Wh of energy. That is the gross capacity of the bank. Same goes for your phone. [email protected] is 18Wh. Calculating is easy in Wh rather than mAh of unknown Voltages and percents. Due to losses in charging and not being able to use 100% of the power bank energy you can charge your phone fully once with some left over for a partial charge.
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What power bank do you have?
Coolblue
coolblue.nl › telephony › power banks › how do you choose a power bank with the right capacity?
How do you choose a power bank with the right capacity? | Coolblue
December 1, 2025 - Tablet batteries have a capacity ... has a 13,300mAh capacity, which allows you to charge your tablets and laptops at least 1 time....
Anker
anker.com › home › blog center › power-banks › 20000mah power bank how many charges for your devices?
20000mAh Power Bank How Many Charges Can You Get? - Anker Canada
August 21, 2025 - So, a 20000mAh power bank can fully charge a 4000mAh smartphone about three times. Is a 20000 mAh power bank good? The answer is yes.
EcoFlow
ecoflow.com › ca › blog › what-can-run-with-10000mah-power-bank
What Can You Run with a 10000mAh Power Bank | EcoFlow DE
Most modern smartphones fall between 3000mAh and 4500mAh, which means a 10000mAh power bank can typically charge them two full times, sometimes a bit more. Older or smaller models may get up to three full charges.