Misleading Phone Battery charger at Costco? - Page 1
Forum section: electronics / general

author: edy
author_rank: Super Contributor
timestamp: October 16, 2016, 02:12:20 am
content: Hi folks,I thought Costco was more immune to this crap but I guess not. Purchased a 2-pack battery charger for phones, you know the ones... you carry them around just in case, then if you need to charge your phone you plug it in.Box advertised 4000 mAh with each pack, and said 2.1 mAh charging, and even said 40% faster charging with most phones (B.S. Alert).Honestly, I just wanted for make sure it would charge a modern smartphone at least 1x to full charge, maybe 2x if lucky.Soon as I opened the package and read the sticker on the back of the actual battery packs (hidden from view) they said INPUT 5V 1000mA, OUTPUT 5V 1000mA!Talk about misleading or deceptive advertising. I would expect this from some eBay no-name but not from Costco. These crap chargers will not charge any smartphone built in the last 2-3 years.My BlackBerry's all refuse to charge due to the low mA provided. Same goes for iPhone. All have 1.5-2 A wall warts and cannot juice up on 1000mA. Am I crazy here or can someone verify that a battery pack delivering 1000mA can't charge a phone? Or do you think they are defective? Or should I try to charge them up for 5 hours and see if they are accepted as charging sources then? The phones say to use another source for faster charging or they refuse to charge at all after trying for a few seconds.Please give me a reason not to return them, although I think they are garbage and not what they say they are.

author: edy
author_rank: Super Contributor
timestamp: October 16, 2016, 02:50:15 am
content: I included some attachments here... see photos of packaging.Clearly, it shows what looks like an iPhone plugged in to the charger. It says charge your SMARTPHONE up to 2X from one charge. It says 2.1 mA Fast Charging.Ok, so the wall-wart it comes with has 2 USB ports. So if they mean to say that you can charge BOTH battery-packs at the same time from the wall, yes then you are charging 1000 mA per device x 2 devices = 2000 mA draw from the wall wart. But if I can only draw 1000 mA from the battery pack, how in heck am I going to charge a Smart Phone?Also, look at the dimensions of this pack. Is there enough space for 4000 mAh battery in there? And what do they mean by the fine print (4000 mAh/5V DC 1A/WH: 14.8 ). Yes there it says DC 1A but it does not explain whether that is charging rate (input), discharge rate (output) and the 2.1 mA "Fast-charging" is misleading, along with "40% faster charging on most phones" and 2.1 mA fast charging seems to suggest that is what the input/output rate of the battery pack is... *NOT* the f&*king wall-wart it came with that has 2 USB plugs in it!I tried Google-ing the brand, it's nowhere to be found. I think Costco is peddling garbage, not what I expected from them. They better accept the return, given that I already had to practically destroy the package to get them out (another sign of a bad product, when they wrap it so tightly you need to practically destroy the package to get them out and feel bad returning it).

author: ez24
author_rank: Super Contributor
timestamp: October 16, 2016, 03:04:16 am
content: Quote from: edy on October 16, 2016, 02:50:15 amSeems that 2.1 mA is pretty low.One thing about crappy Costco items is that they are easy to return. So next time I am there, I will check these out.

author: edy
author_rank: Super Contributor
timestamp: October 16, 2016, 03:37:14 am
content: Quote from: ez24 on October 16, 2016, 03:04:16 amSorry... I meant to say 2.1 A.Either way, this product is way too fishy for my taste. Return it goes... I don't think 1000mA output (as labelled) is going to do the business on any modern smartphone.

author: Tim F
author_rank: Regular Contributor
timestamp: October 16, 2016, 03:52:38 am
content: I don't know about the current crop of smart phones but I was under the impression that you don't need a high current (>1A) supply to charge them. Besides, they can only expect 500mA from a computer USB port - does your phone charge from a computer port? My phone (Nexus 5) throws up a message saying "charging slowly" or some such if it is plugged into a wimpy power source.Most of them probably ramp up the current until the supply voltage sags too much from 5.0V. For this reason the charge rate actually depends on the USB cable you use as well as the power supply. If you use a crappy USB cable with small conductors there will be a larger voltage drop and therefore the charging current will drop as the phone sees a lower voltage for a given current draw. If the phone cannot even draw a small current (say more than 100mA - I don't know exactly, just pulling a figure out of the air) without the voltage dropping hard, then it probably gives up on charging .If the phone doesn't charge at all from the battery pack, then the battery pack is probably faulty - voltage sagging to much below 5V when any half-reasonable current is drawn, or the voltage is just too low period. To test this you would measure the output voltage on the battery packs USB socket, then attach a known load and see if it drops. Simplest way would be to attach something like a 10ohm power resistor across the output which will get you ~500mA draw.

author: edy
author_rank: Super Contributor
timestamp: October 16, 2016, 04:38:40 am
content: I used the charger and cable that came with the power bank. If that's got issues already out of the box, I don't feel very confident about it at all.I've attached another photo showing the back of the actual unit, where it explains the INPUT/OUTPUT current. With respect to USB, my understanding is that the USB does supply 500 mA max, but the newer USB protocols allow higher current draws (see here:https://en.wikipedia.org/wiki/USB). I know for sure the wall-warts that I usually need to charge my SmartPhones have to be at least 1.5-2 A rated. Anything I had before (800mA-1000mA range) no longer work for the latest phones.Regarding the Costco MobileGear PowerBank, I'll try to charge it fully and see if it does any better, and I'll use my own cable that I usually charge with (not theirs). Maybe the current draw caused a voltage dip if maybe the battery wasn't able to keep up with the load. But a fully charged battery certainly should be able to deliver (as they say) 1000 mA output at a constant 5 V, which would be like a 1000 mA wall-wart supply, no? Even then, as I mentioned, a wall-wart 1000 mA supply can't charge newer SmartPhones. So I'm not sure how USB can get away with it... certainly not at 500 mA... it must be ramping up according to the newer protocols.

author: edavid
author_rank: Super Contributor
timestamp: October 16, 2016, 04:42:14 am
content: Quote from: edy on October 16, 2016, 03:37:14 amYou are mistaken, e.g. Apple bundles a 1A charger with the iPhone 7.

author: SL4P
author_rank: Super Contributor
timestamp: October 16, 2016, 04:57:53 am
content: My iphone6 and iPad2 Air charge between 500mA to 1.2A o a metered charger.Perhaps your charger doesn't communicate with the device properly.. .?

author: edy
author_rank: Super Contributor
timestamp: October 16, 2016, 05:02:01 am
content: Quote from: edavid on October 16, 2016, 04:42:14 amI stand corrected.... Yes you are right. I just checked a bunch of my chargers... They range from 750 mA to 2A, and I know they will charge my phone.Something must be screwy then with the PowerBank. I have a feeling something is wrong with the "charge remaining" display or the crappy USB cable it came with. I'll charge it using my normal 2A wall-wart, and use a regular USB cable (not the wall-charger and cables it came with).By the way, I just checked another brand PowerBank I have "neo power", and it does clearly state output 5V/1000mA... and I have charged my phone correctly with it.So I suspect I jumped to the wrong conclusion when there is another issue going on. Time to investigate further, and shove my foot deeper into my mouth.[UPDATE:Ok, it's definitely the short little USB cable the PowerBank came with!!!! The phone (BlackBerry Z10) does not like this cable at all. It either says there is a faulty cable or will tell me that charge is too slow and to use cable that came with device, and stop charging after 2 seconds. I never had this issue with other PowerBanks and their cables, which is why this caught me a bit by surprise.]

author: Bud
author_rank: Super Contributor
timestamp: October 16, 2016, 05:05:29 am
content: Why dont you try charging your phone straight out of the costco wall adapter.Though i dont see how any higher rate adapter can speed up charging a phone which most likely has internal limit on charging current it is able to take.Edit: and yes when i charge my iphone from USB it takes longer, which is an indication of smaller current.

author: jonovid
author_rank: Super Contributor
timestamp: October 16, 2016, 05:19:49 am
content: is it Quick Charge 2.0 TM ® trademark . you get what you pay forhttps://www.qualcomm.com/products/snapdragon/quick-charge

author: edy
author_rank: Super Contributor
timestamp: October 16, 2016, 05:35:04 am
content: Quote from: jonovid on October 16, 2016, 05:19:49 am$24.99 Canadian for 2 of these chargers.... rated at 4000 mAh each. Is that a good price? I don't even know. The cables that the charger came with seem to be good only from the wall-wart to the battery packs, but NOT good to connect to the phone. To be sure, I should just use normal USB cables that came with the phone which are reliable.My suspicion is that to save money, the short USB cables that came with the charger have no data lines at all, just 2 power lines. The phone may need the data lines to negotiate with charger or detect a computer, to figure out what safe current draw to use (I believe the standard calls for certain resistors between the data lines and power lines). When my phone sees this cheap cable with "floating" data lines, it probably just assumes a failed cable or refuses to charge because it can't figure out what safe current limit it can use.

author: dannyf
author_rank: Super Contributor
timestamp: October 16, 2016, 10:30:16 am
content: QuoteYou are confusing a few basic concepts here.1) the ***capacity*** of the battery packs is 4000mah;2) the maximum current to be supplied by the battery pack is 1000ma;3) the maximum current to be supplied by the charger is 2.1amp (not 2.1ma).All clearly marked on the package.The mistake the designer failed to conceive is that such simple concepts can be incredibly confusing to the average joe.

author: Barryg41
author_rank: Contributor
timestamp: October 16, 2016, 10:47:59 am
content: Quote from: jonovid on October 16, 2016, 05:19:49 amThat's what I use also, bought from Amazon for $14.99 Prime.

author: Kilrah
author_rank: Unknown
timestamp: October 16, 2016, 12:49:13 pm
content: Sorry but as dannyf says everything on here is correctly labelled and checks out even if it might not be obvious or very complete.

author: edy
author_rank: Super Contributor
timestamp: October 16, 2016, 02:00:38 pm
content: @Kilrah @dannyfI agree, the labeling is technically accurate. What is confusing is when it states 2.1 A fast charging, it is referring to the USB wall adapter which has 2 USB ports to charge both packs at ~1000 mA each. The fine details are in the tiny print. You'd think the actual Powerbank OUTPUT was capable of 2.1 A (like my direct wall charger going to the phone).After some over-night testing, it looks like the culprits were those cheap-@$$ short USB cables that you use to either connect the PowerBanks to the charger, or to connect them to your phone. Just bending the cable slightly one way or the other at the neck causes a fail (open circuit). What, is there like 1 microscopic filament in each wire? Made of aluminum?I have used my own USB cables and can wiggle them around all over the place, no problem... always continuity, and the phones charge no problem. They are taking longer to charge though... if it is accepting 1000 mA, you'd think it would take 4-5 hours to charge up a 4000 mAh powerbank, no? Is there multiplier factor like 1.5x or 2x (will 4000 mAh pack take 6-7 hours)?One more issue which may seal the deal and cause me to give up on them:The banks have 4 lights which show the level of "fill". I've been charging both overnight for at least 6-7 hours already. Except one of the packs only shows 3 lights, the other shows all 4... What's going on? Why does one powerbank never get past the 3rd level out of 4? I'll swap the cables I'm using also and see if that speeds things up, or the USB slots on the wall-wart.(Just as I hit the "SAVE" button on this posting... I swapped the cables and lo and behold, the other one started to show a 4th light finally)Wow, what a pain these Powerbanks have been. It's not like these are the first ones I ever bought. My wife has one, I have an older one. I have good ones and I have cheap ones. These definitely seem to fall in the crappy quality.I still have one more thing to test... and that's to see how many times it will charge up my phone. I am using a BlackBerry Z10 with an LS1 1800mAh battery. It's a bit old now, but I expect it to be able to charge up to full (or almost full) possibly 2x on this 4000 mAh powerbank. Is that too much to ask?

author: dannyf
author_rank: Super Contributor
timestamp: October 16, 2016, 03:01:06 pm
content: Quoteyou are trying to compare apples and oranges.what determines charging speed is the charging protocol / current rating of the source. it has nothing to do with the capacity of the source <directly>, aside from the fact that bigger capacity banks tend to have higher current capacity.So a 4000mah battery pack (with a current limit of 1000ma) will charge up your battery as slowly as a 1000mah battery pack (with a current limit of 1000ma).

author: edy
author_rank: Super Contributor
timestamp: October 16, 2016, 04:26:37 pm
content: Quote from: dannyf on October 16, 2016, 03:01:06 pmThanks!Ok so for example, is there any way to get an estimate of how long it takes to charge up various capacity PowerBanks from the wall-wart/mains, given that the wall supplies are always 1000 mA? So how long to charge a 1000 mAh powerbank? What about 2000 mAh, 3000mAh or 4000 MAh? I thought it would be the capacity of powerbank divided by the charge current:1000 mAh / 1000 mA = 1 hour to charge. (charging 1000 mAh bank with 1000 mA source)1000 mAh / 500 mA = 2 hours to charge. (charging 1000 mAh bank with 500 mA source)4000 mAh / 1000 mA = 4 hours to charge. (charging 4000 mAh bank with 1000 mA source)At this point, my 4000 mAh powerbank has been plugged into a 1000 mA mains source for close to 8 hours and still blinking the 4th of 4 LED's on it (which indicate how full the powerbank is). The other identical one that came in this 2-bank package has already charged (all 4 LED's are solid).I guess because the charging curves aren't linear, and there are interactions between the charging circuit and the battery, and there is a "leveling off" of the curve near the capacity of the bank, that it will slow down the charge rate? So you can't do simple calculations like that?Same would then go for when you want to charge up the phone... So if your phone has a 2000 mAh battery, and your powerbank has 4000 mAh battery, due to inefficiencies you cannot get 2 full charges of your phone battery from the powerbank? Or if your phone has a 1000 mAh battery, you cannot get 4 full charges of your phone battery from the powerbank?One other thing... the battery sticker says 14.8 Wh. So if I am drawing 1 A of current at 5 V from the powerbank (output) to charge my phone, then it is running at 5 W (1 A x 5 V) and I can sustain this for about 3 hours ... since 5 W x 3 h = 15 Wh. Technically then would I not have only drawn out just under 3000 mAh from this supposedly 4000 mAh powerbank?Stated another way.... 14.8 Wh = 2960 mAh as per this calculator:https://milliamps-watts.appspot.com/The only clarity I think I have found somewhere has to do with the fact that the cells are 3.7 V and while the voltage needs to be boosted to 5 V for output, and something about efficiency also being 80-90%. So between 3.7 to 5 V, and 80-90% efficiency, is the reason these calculations are all off.Basically, if I take 5/3.7 x 2960 = 4000 the math makes sense again.I guess 4000 mAh is the capacity at 3.7 V, which multiplied gives 3.7 V x 4 Ah = 14.8 Wh. I shouldn't be using the 5V at all.I think I answered my own question....The confusion stems from the fact that the Li-Ion battery ratings are all based on the 3.7 V voltage of the cell itself, whereas I am treating the entire PowerPack as a 5V source and assuming the 4000 mAh is being delivered at 5V... whereas in fact it is what is being delivered at 3.7V.Essentially, 4000 mAh @ 3.7V = 2960 mAh @ 5V (and that is 100% efficiency in conversion of voltages). To add to the problem, what happens when it goes into the phone and has to then be converted to something that will charge the 3.7V battery in the phone.... Confusing even more!

author: System Error Message
author_rank: Frequent Contributor
timestamp: October 16, 2016, 07:21:07 pm
content: how about making our own, we just need to find a good source of batteries, make a good circuit, put it in a box and cut holes for usb. We could than determine how much capacity and actually use a chip for the negotiation with the phone. Perhaps a switch to switch between short on data or chip. I've watched videos where the amount of current the phone pulls is determined either by some sort of negotiation and if thats not available than it will pull current till the voltage drops below a certain point.

author: Kilrah
author_rank: Unknown
timestamp: October 16, 2016, 07:52:56 pm
content: Quote from: edy on October 16, 2016, 04:26:37 pmYou cannot know, because even if your wall-wart can supply 1A the powerbank may not draw that much, you'd have to measure the particular one you're considering to know.Most of those on the market only charge with around 500mA.

author: IanB
author_rank: Super Contributor
timestamp: October 16, 2016, 08:08:28 pm
content: Quote from: edy on October 16, 2016, 02:00:38 pmI think this is really clear on the packaging. It says "2.1 AMP FAST CHARGING Dual USB AC Charger". It is telling you directly that this is the capability of the USB wall adapter. I think you had something different in your mind and you therefore did not read what the packaging actually says.

author: edy
author_rank: Super Contributor
timestamp: October 16, 2016, 08:22:52 pm
content: Ok, Thanks! That makes sense. The wall-wart claims to be able to supply up to 2100 mA total, which I assume is 1.0 A per USB port (since it includes 2 USB connectors to charge both powerbanks simultaneously).If only 1 USB is being used at a time, I don't think it will provide 2100 mA through that single USB port alone. It is probably always giving about ~1A per USB port, for a maximum of 2A total when both USB ports are plugged in.I don't know if the wall-wart is built to a proper standard that tells a device that plugs in that it can only supply 1 A per port. It may even think it can only supply 500 mA. If the wall-wart has the proper circuitry to tell the device it can deliver higher amps, the device could draw up to 1 A. If the device that's plugged in is either faulty or ignores the protocol, then it could try drawing more than 1 A which may heat up the wall-wart (unless the wall-wart is also able to detect shorts or higher amp draw and shut things down for safety).On the other hand, the powerbanks themselves have INPUT 5V~1000mA, OUTPUT 5V~1000mA written on them, so I presume that is what they will be drawing and sourcing. So to charge them, they will need to be connected to AT LEAST a plug capable of delivering 1000mA to them? If I use a 500mA 5V supply, will the powerbank be able to still charge up the battery?I know I should have no problem plugging in my 2 A BlackBerry Wall-wart to charge the powerbank... the powerbank will charge fine on that but at no greater speed than plugging it into a 1 A wall-wart. I understand that.In any case, both powerbanks are now "topped up". They are both showing full 4 bars when plugged in, no longer blinking, which means they are at full charge. Next test is to see how many times they can bring my phone from 0% dead back to 100%. They are certainly not the fastest charging power banks I've had... they are the largest capacity I've owned thus far, and they still charge at 1000 mA which is same as my smaller ones (which may be even faked to lower capacities) so perhaps that's why they feel slow. I'll time the charge rate for the phone, and also how long it takes to fill from the wall-wart, so I know what to expect for future planning.

author: edy
author_rank: Super Contributor
timestamp: October 16, 2016, 08:25:54 pm
content: Quote from: IanB on October 16, 2016, 08:08:28 pmYes you are probably right.Notice how if you break up the sentence and change font sizes though it can come across differently. Like this:2.1 AMP Fast ChargingDual USB AC ChargerCharge up to 40% FasterSee? Very clever! They totally got me, those marketing package designers! Argh!I can't tell whether they mean the powerbanks are fast charging (which they aren't) or they output higher to charge your phone faster.The other thing is this... the actual wall-wart DOESN'T in fact charge the power bank any faster. It is 2.1 A but outputs 1 A to each USB port independently. It just means you can plug in both powerbanks at the same time into the wall-wart. But each powerbank still takes the same time to charge as a 1 A charger! The maximum input the powerbanks take is 1000 mA no matter how high the current rating of the wall-wart.... so I still think it was written with the intention to deceive. Or is "fast" considered anything higher than 500 mA?

author: Refrigerator
author_rank: Super Contributor
timestamp: October 16, 2016, 08:34:44 pm
content: Most smartphones these days ramp up their current draw and measure how the power source handles it when you plug them in.Whenever i plug my Xperia in the charger i can hear the squeal of the AC adapter change in steps.

author: IanB
author_rank: Super Contributor
timestamp: October 16, 2016, 08:37:20 pm
content: If I buy chargers or AC adapters, I always look for specific phone compatibility information on the packaging. For instance, for Apple devices, I make sure the packaging says "for iPhone or iPad". If it doesn't specifically say this, I don't buy it, since there are various compatibility standards for charging and I won't take the chance of it not working.As far as charge current is concerned, there should not be an issue with lower output currents than the maximum. Charging would just be slower. For example my iPad charges just fine when plugged into my iPhone charger (1 A instead of 2.4 A), and both devices will charge if plugged into a computer USB port (current limited to 500 mA).

author: timb
author_rank: Super Contributor
timestamp: October 16, 2016, 09:30:06 pm
content: Quote from: edy on October 16, 2016, 08:25:54 pmThe AC adapter most likely charges at 2.1A on at least one port. That's for iPads and other tablets. (Otherwise, they'd take forever to charge at 1A!)Some two-port adapters will go down to 1A if both ports are being used (then back to 2.1A when the second port stops drawing current).Other two-port adapters will put out 2.1A on each port, full time.2.1A will only help if you're charging a tablet, otherwise your phone/power bank will only pull 1-1.5A.

author: edy
author_rank: Super Contributor
timestamp: October 17, 2016, 01:44:03 pm
content: I charged up my phone to 100% last night from 0% (after the phone powered off) using a fully charged 4-LED indicator powerbank. The phone has a 1800 mAh removable battery in it. The powerbank (4000 mAh) now indicates 2 LED's (out of original 4 LED lit up). So I suspect it may have enough juice left in it to perhaps charge it up again to maybe 60-70%. We'll see later today what happens.Given the losses in converting from 3.7 V to 5 V, then into the phone, then down again to 3.7 V, plus other inefficiencies of charging, pumping 4000 mAh worth of energy into another battery capable of holding 1800 mAh worth of energy (I realize I am greatly over-simplifying here) is not just a simple division 4000/1800 = ~2.2x. I'll be lucky if I get ~1.6x (100% full charge from 0%, then another to 60% from 0%).

author: CJay
author_rank: Super Contributor
timestamp: October 17, 2016, 02:15:46 pm
content: Quote from: edy on October 16, 2016, 03:37:14 amI get by quite nicely on a very cheap single 18650 cell emergency charger, it's got me out of the mire a few times now.It's not great if I want to use the 'phone while I charge it but it will maintain it.I do agree on the charging current claims though, seems very misleading but as others have said, Costco is great for returns.

author: edy
author_rank: Super Contributor
timestamp: October 17, 2016, 06:05:18 pm
content: So I've contacted ESI (who make the chargers or at least the enclosures) and complained about the USB cables, and they said they'll send me new ones and a return envelope so I can send back the defective ones. I'm sure they are just assembling this product and getting pre-made cables from China, and they may only make the enclosures that house the batteries.I'll make a video in the meantime showing the shoddy quality of the old cables and how the slightest touch/movement causes loss of contact somewhere inside, resulting in no power going through. Also, I'll show how it fails to work to charge the phone, and compare it to my regular cables that do a proper job.Otherwise, the chargers so far seem ok for what I expect at this price point. I definitely over-reacted but I think they need to know from a Q.C. stand-point how their product may be perceived poorly by the average-joe Costco buying public.... Especially if they delivered a batch with bad USB cables.Certainly, it would tarnish the brand and result in a lot of returns for a silly stupid reason like somebody in ESI's order department used the wrong mini-USB cable supplier that had horrible quality, especially a part that probably costs 5 cents to buy in bulk, but is a critical component of your product getting charged and delivering a charge.By the way, ESI Cases & Accessories is a private company with not a very good reputation according to the BBB and also their website appears to have been hacked (according to Google) and shows a blank page or probably some malware script:www.esicellular.net. I'm not exactly sure what these guys do but I am pretty sure they are simply importers and branding outfit who deal with Chinese OEM's. There is almost no online presence otherwise, and the MobileGear brand (at least ESI's) practically appears nowhere online. They also sell headphones, cases, bluetooth gear, and all sorts of cellular-related accessories (as the name of the company implies). Once again, likely an importer of OEM stuff with brand/packaging/marketing and then distribution to various retailers. As you can see by the sticker on the back of the powerbank, they also seem to ownwww.duracellchargers.com. I'm not so sure they have any connection with the Duracell brand though or its parent company, but apparently Duracell offers licensing of the name to OEMs that manufacture stuff using their batteries.

author: edy
author_rank: Super Contributor
timestamp: October 18, 2016, 05:01:44 am
content: Ok, so I charged up my dead phone again and it only got up to 22%.... bugger!So you could say it charged my phone 1.22x.***Actually I am not totally sure because I didn't disconnect the powerbank from my phone when the first charge cycle got it to 100%.... I charged it over-night and I fell asleep and when I woke up the phone was at 100% and the powerbank may have stayed on longer than it needed to, giving it a "trickle charge" and topping it up constantly, losing more of it's charge capacity along the way***According to some rough formulas online, they say take powerbank mAh x 0.8 (80% efficiency) / phone battery mAh. In my case, 4000 x 0.8 / 1800 = 3200 / 1800 = 1.78x (which is what I estimated previously, or one time to 100%, and the next charge up to 70%).Or should my calculation also multiply by 3.7/5 to account for the 3.7V battery 4000 mAh versus the 5 V conversion as well to USB? So it becomes 4000 x 3.7 / 5 x 0.8 / 1800 = 1,31x ?So either the powerbank is not 4000 mAh, or the efficiency of conversion is lower, or my phone's battery is old and not charging as well, or I was trickle-charging the phone for some time and depleting the powerbank, or all of the above. Now I'm using the second power bank to charge the phone from 22% up to 100%.... and we'll see how far it goes on the next charge. What I'll get is the performance of both powerbanks that came in the package (i.e. "8000 mAh") and see what the total number of times I can charge my phone is going to be using both powerbanks sequentially, and then average it out.Based on the 1st powerbank, if it went from 0-100% first round, then 0-22% second round, the 2nd powerbank should theoretically charge it up from 22-100% for the 3rd round, and then probably up to about 45-50% on the fourth round. But since I am going to sleep once again with the phone charged on the powerbank, it may hit 100% and the powerbank still be connected and staying on. I need to test when I can monitor the charge on the phone and disconnect them as soon as it hits 100%.Also... I am charging from a completely powered down phone at 0% state, watching it boot while charging, and noticing that it gets up to 70-80% within a reasonable time but then the last few % are really slow. The phone will sit at 99% for a while. So because it is not linear and I am not sure what effect it has on the measurements, and whether I should just unplug it when it hits 99% or wait until it finally hits 100% (which could take a while)... that time the powerbank is still likely depleting at a decent rate and therefore may also not be a good indication of the charge capability.Perhaps I should charge my phone when it hits 10-15% and only up to about 85-90% charge, and see how long it will run for in that range? By the way, it takes about 3 hours to charge my 1800 mAh phone battery using the 5v 1000 mA output for the powerbank from 0-100% this way.

author: dannyf
author_rank: Super Contributor
timestamp: October 18, 2016, 10:16:42 am
content: QuotePerhaps you should just be happy that it works reasonably well and be done with that? I haven't seen anyone putting that much thought into an el cheapo charger / battery pack / phone charging exercise. ever.not that it is a bad thing every once in a while but...

author: edy
author_rank: Super Contributor
timestamp: October 19, 2016, 01:36:14 am
content: Quote from: dannyf on October 18, 2016, 10:16:42 amYes, you're right.... I got carried away...It's called...

author: edy
author_rank: Super Contributor
timestamp: October 19, 2016, 10:36:20 pm
content: Oh by the way, after the power bank totally was "depleted" yesterday and couldn't charge my phone any more (showed zero LED lights), I decided to give it a rest for the day. Today I turned it on and it showed 2 bars, so I plugged it in again and I was able to reboot my phone (which powered off) and charge it up to about 4%. Not much... but still. I guess batteries under drain will "rebound" after some time, after the chemistry has time to diffuse inside the battery and ready to release more charge? Any idea why it would have worked after some "rest"?

author: edy
author_rank: Super Contributor
timestamp: October 26, 2016, 01:19:15 am
content: Ok, so I've been testing out the dual powerbank product and have some questions!I decided to tape the 2 powerbanks together so I carry around 8000 mAh (2 x 4000 mAh). When I deplete one pack, I switch the USB to the other and keep going. My experiment has been to let the phone deplete completely to 0%, then plug in until it reaches 100%. Then I let my phone drain again to 0%, and charge again to 100%, and so on....However...That got me thinking...Would I get better efficiency/performance/duration of usage on my phone if I start charging when it drops to 20% (not wait until 0%) and stop charging when it hits 80% rather than try to get all the way to 100%? I know on certain laptops when you have them plugged in they cycle between some values so it is not constantly charging the battery.One question is, the % indicator on the phone, how linear is it? How closely does it equate to "x percentage = x minutes of usage" on average. Does that approximation change drastically at either end of the curve (near 0% and 100%)? For example, let's suppose in the middle range (say 55% to 45% drop, 10% usage of battery) we get 1 hour. Well, at the bottom end... from 15% to 5%, are we getting another 1 hour? Or maybe only 30 minutes? And similarly, at the top end, from 100% to 90%, are we getting 1 hour? All show a drop of 10%.Conversely, when we charge up the phone, does the charge % indicator on the phone give a good approximation of the duration of use? So if I charge my phone at the bottom end from 20% to 30% (10% increase), will I get say 1 more hour of usage before it crops back down to 20%, versus me cycling the phone from 90% to 100%.... (also a 10% increase)... do I get 1 hour of usage before it drops back to 90% and I repeat the cycle?Any thoughts?SCENARIO 1:Start off at 100% (wall plugged in)... UNPLUG! Start timer..... then let it drop to 20%, charge it up to 80%, let it drop to 20%, charge up to 80%, and so on.... until I completely deplete my powerbanks and then I let it drop completely to 0%. STOP TIMER.SCENARIO 2:Start off at 100% (wall plugged in)... UNPLUG! Start timer.... let it drop to 0%, charge it up to 100%, drop down to 0%, charge up to 100%, repeat... until both powerbanks depleted, then let drop back to 0%. STOP TIMER.You can imagine various other scenarios using different "max" and "min" thresholds for when to charge and stop charging with the powerbanks. Like 30% to 70% and so on. Each time you measure how long you can go for on the powerbanks after unplugging from the wall and starting at 100%. Any idea if this will make a difference? If so, what is the rationale?

author: rs20
author_rank: Super Contributor
timestamp: October 26, 2016, 01:28:23 am
content: It's certainly feasible that charging to only 80% might give better results in the long run. After all, the design of the charging circuitry is optimized under the assumption that input power is infinitely plentiful, and assumption clearly violated by the use of an external battery.I'd be wanting to automate the logging of phone battery level and current consumption, and automating the switching on and off as well. The effects you're trying to measure are so small, and the process of staring at a phone waiting for the battery to drop below a certain level* so boring, that'd I'd not want to do it manually.* And you had better not betouchingthe phone at all, lest your inputs cause variations in current consumption.* And the phone should be on airplane mode, lest random signal variations spoil your results.* And the phone better have its ambient light sensor covered up, lest ambient light level variations spoil your results.

author: edy
author_rank: Super Contributor
timestamp: October 30, 2016, 03:57:34 am
content: I have 2 Li-Ion powerpacks... one with 2600 mAh rating, and one with a 4000 mAh rating. The one that is 4000 mAh has a bad charging circuit. Battery is still good, but the PCB with all the USB plugs is damaged.My question is, is it possible to use the same charging circuit to charge either battery?For example, if I strip the batteries out and just have them connect to raw "plugs" (polarized of course) and just add the corresponding plug to my charge circuit (from the 2600 mAh battery pack which still works) can I just swap out batteries when one gets full, and charge the other one?

author: edy
author_rank: Super Contributor
timestamp: October 30, 2016, 12:11:58 pm
content: Thanks, so it will be ok just slower. What about then discharging the battery when I plug in the device I want to recharge. Will the PCB from the 2600 mAh power bank be fine just slower? Or will the larger battery cause it problems?The idea is, if I have several good batteries but only one charge circuit PCB, I could use a quick-connector like in model RC planes/cars and just switch out the batteries as they charge from the one good power bank charge circuit, and when I go to use these batteries to charge my phone I could also use each battery sequentially by swapping them in and out from the charge circuit as I use them up.I find usually the PCB goes first on a portable power bank and I'm stuck with some good batteries. If I can do this, as long as I use the lower-mAH rated powerbank circuit for batteries of the least 2600 or more I should be ok?

author: tooki
author_rank: Super Contributor
timestamp: November 08, 2016, 06:17:46 am
content: Quote from: edavid on October 16, 2016, 04:42:14 amAs with all iPhones ever made.

author: IanB
author_rank: Super Contributor
timestamp: November 09, 2016, 07:26:42 pm
content: Quote from: tooki on November 08, 2016, 06:17:46 amAnd my 1 A iPhone charger also works perfectly well with my iPad, which has a huge battery.

author: rrinker
author_rank: Super Contributor
timestamp: November 09, 2016, 07:44:48 pm
content: It just takes forever. Which is why on my desk I have an iPad charger hooked up that I can plug my phone or ipad into - the larger ipad charger does charge the phone faster. The one I carry in my laptop bag is also an ipad charger. I must have 4 or 5 iphone blocks in my drawer. (latecomer to ipads - I didn't buy one until the 4th gen ones, the first ones with the lightning connector since I already had a phone with lightning)

author: IanB
author_rank: Super Contributor
timestamp: November 09, 2016, 08:55:00 pm
content: I don't mind how long it takes to charge since my phone only needs charging every few days and my iPad far less frequently than that. So all my charging is done overnight.

author: PedroDaGr8
author_rank: Super Contributor
timestamp: November 09, 2016, 09:20:34 pm
content: Quote from: edy on October 16, 2016, 02:12:20 amI think you should most definitely return them. When they ask you why? Let them know the packaging is misleading. Costco VERY VERY much listens to the reasons why customers return goods. In fact, this is the main reason they have such a generous return policy. They want their customers to be happy with their purchases. If you are buying crap that you don't like, you won't renew your membership (most of costco's profit comes from the membership fees).