Very weight-efficient power bank

[MuddyWaters]

Anker is pretty much the gold standard when it comes to power packs. They have a well deserved reputation for quality.

There are a couple of things to question with this battery: the true capacity (which would be hard to measure), the efficiency (basically, you lose part of the stated capacity to heat when using the battery to charge another device. Most Anker batteries lose 15-20% when charging, cheaper packs can lose up to 50% and sometimes more), the quality of the circuitry (you risk frying the battery components and even the device you are charging), and the rate of charge.

The only way for you to really tell would be to take a device with a known battery capacity (google is your friend) and after fully charging the battery pack, completely discharge and then recharge that one device from the battery pack until the battery pack is out of juice. You can make an educated guess about capacity and efficiency at that point, and more importantly, tell if this particular battery pack meets your needs for charging on the trail.

I know you think you found a good deal for an ultralight battery pack, but there are a lot of factors stacked against you. eBay is not known for being a place to buy quality electronics. Ultralight and cheap do not go together 99% of the time.

Hopefully it works for your needs. Best of luck!

Its not hard to discharge slowly with essentially constant current and time it. Use simple resistor , current will vary a little as voltage changes , but you can take average. Easy to build current regulator with radio shack chip too.

I used to charge and monitor and chart battery packs for radio control aircraft tx and rx,.

[HooKooDooKu]

From what I can tell, Anker is still using cylindrical cells in their battery packs, whereas newer batteries like the one in my phone are flat. There's more casing overhead (weight) in cylindrical cells.

Perhaps true, but the point is irrelevant.

The bulk of the weight in these battery packs is going to be in the batteries and not the case.

Add to the the fact that my latest comparison to the 20000mAh Malaysian battery was to an Anker 10000mAh battery and the deal still sounds too good to be true.

[Puddlefish]

I'd just wait for some electronics geek to put it on his workbench and do the testing. Yay for geeks!

[cbxx]

One way to answer all these concerns concretely, start using the battery and see what it can do. Use it a couple weeks and report back please because if it does what is advertised, it would be a great improvement, but we would need proof. Anker has a reputation, this is a new deal so please do report back.

[Slo-go'en]

The capacity of a battery is directly related to the surface area of the "plates" which make up the battery. A round battery is simply a flat battery which has been rolled up. The only difference is shape. The volume and capacity stay the same.

Anyway, despite this thing is unlikely to live up to it's spec's, it's still useful and it didn't cost you much. The "how many times can it charge my phone from 10% to 100%" is a good test.

[Another Kevin]

The capacity of a battery is directly related to the surface area of the "plates" which make up the battery. A round battery is simply a flat battery which has been rolled up. The only difference is shape. The volume and capacity stay the same.

Anyway, despite this thing is unlikely to live up to it's spec's, it's still useful and it didn't cost you much. The "how many times can it charge my phone from 10% to 100%" is a good test.

Assuming that they didn't cheap out on the charge controller. The case that scares me is that it's close to being true to rated capacity but has a crap controller and goes up in smoke. 20 Ah of lithium battery makes a LOT of smoke.

[Riocielo]

It's also a generic unit shipped from Malaysia whereas Anker is a US-based company that offers an 18-month warranty and a thousand positive reviews on Amazon. If your unit fails, you're carrying 5.3 ounces of garbage. And 20,000mAh is overkill in my book (actual testing would likely prove this claim to be highly overstated).

I can make it 5 days easily without recharging my iphone (airplane mode with limited picture taking).

The Anker Powercore 5000 charges an iphone twice for 4.8 ounces. I have the 3350 mini, but don't carry it.

And Anker has tremendous customer service, too.


Sent from my iPad using Tapatalk

[Starchild]

Its not hard to discharge slowly with essentially constant current and time it. Use simple resistor , current will vary a little as voltage changes , but you can take average. Easy to build current regulator with radio shack chip too.

I used to charge and monitor and chart battery packs for radio control aircraft tx and rx,.

Yes but...
Can it deliver time and time again??? Some Li-ion batteries can deliver early in life but only live a quick life.

[scope422]

I'll add my 2 cents on this one. I've been using this battery bank for over a year now. I like it but I usually only do 3-4 day trips at a time. I tested it's capabilities at home and here's what I found. With a Galaxy S5 phone, I let it go till it went dead. Got 1 full charge to 100% and then ran phone dead again and got 70 percent on 2nd charge before battery bank died. This battery bank does take about 6-7 hours to charge back up again from dead. I never run my phone to dead, lots of airplane mode, so it's always had sufficient power to get me through long weekends. Also, you can find US sellers selling this same battery on Ebay for the same price, so you don't need to wait for overseas shipping.

[HooKooDooKu]

I'll add my 2 cents on this one. I've been using this battery bank for over a year now. I like it but I usually only do 3-4 day trips at a time. I tested it's capabilities at home and here's what I found. With a Galaxy S5 phone, I let it go till it went dead. Got 1 full charge to 100% and then ran phone dead again and got 70 percent on 2nd charge before battery bank died. This battery bank does take about 6-7 hours to charge back up again from dead. I never run my phone to dead, lots of airplane mode, so it's always had sufficient power to get me through long weekends. Also, you can find US sellers selling this same battery on Ebay for the same price, so you don't need to wait for overseas shipping.

That sounds about like the performance I would expect from a 6700mAh Anker battery that weighs about 4.5oz.

[Starchild]

The charging time of the battery seems a little slow, and on trail you might have limited access to an outlet and want to cram as much juice in as you can. Other then that it seems like a good value and certainly good enough for weekend warriors and even week long trips with limited use of the phone.

[MuddyWaters]

Yep
Recharge time is issue if use lots of power
Better with two smaller batteries for that

My 10,000 anker can take 8 hrs to charge, overnight badically. Not going to recharge at quick resupplies.

My phone has little battery, but for even 6-7 day stretches taking 20 pics per day, reviewing, airplane mode, etc Ive not used more than half the anker in recharging. Cant umagine needing more. most time i bring my little 4000 3.25 oz battery , it lasts me week basically if careful.

[DownEaster]

The charging time of the battery seems a little slow, and on trail you might have limited access to an outlet and want to cram as much juice in as you can.

I agree completely. That's why I've got a 4 USB port AC adapter so I can charge up the power bank, my phone, and both headlamps simultaneously. With that approach I shouldn't need to draw down the power bank's charge for at least a couple of days. I'd expect to have at least 3 hours connected to power outlets while I'm doing laundry and eating a meal. ("Table by a wall socket, please." ) Or if I don't need to charge up the headlamps, I can gain some hiker goodwill by sharing the outlet.

[Starchild]

I agree completely. That's why I've got a 4 USB port AC adapter so I can charge up the power bank, my phone, and both headlamps simultaneously. With that approach I shouldn't need to draw down the power bank's charge for at least a couple of days. I'd expect to have at least 3 hours connected to power outlets while I'm doing laundry and eating a meal. ("Table by a wall socket, please." ) Or if I don't need to charge up the headlamps, I can gain some hiker goodwill by sharing the outlet.

Having a multiple USB charger is a good thing on trail and I have used that also. But other times when I know I'm going to be in town I will charge my phone and steripen before I get there. This way I only have to leave a battery pack unattended to charge. And that ability to leave it unattended usually results in a longer uninterrupted charge time and perhaps more overall charge. I actually prefer that second option over having to hover over my phone tethered to a wall outlet, which out of boredom I use and thus make charge time longer. But yes restaurants, everything charging at once with the table by the outlet please.


Also I do play the state of charge knowing that the quickest and most efficient charge is apx from 25% to 80%, dip far below 25% and you wait a long time to get back up to it likewise getting that last from 80% to 100% takes longer and is less efficient, so when multi charging I try to keep the items balanced within those limits so they can accept the most charge in the least time (also knowing that using a battery pack to charge another device is about a 20% loss, but that charge is still more efficient in that 25% to 80% range, so not topping off the phone to 100% unless I am using that plan to leave the battery pack unattended to charge).

[Another Kevin]

That sounds about like the performance I would expect from a 6700mAh Anker battery that weighs about 4.5oz.

Yup. No way is that a 20 Ah pack. I get more like 3½ charges on my S7 using a 12 Ah pack (I misremembered yesterday when I quoted '16 Ah'.) It's NewTrent, rather than Anker, because when I got it, it was the only one I could find that was IP68. I'm hard on gear. NewTrent went out of the battery business shortly after I got it. The Anker ones of comparable rating are lighter now, but I don't fix what ain't broke.

[Leo L.]

Just recently there was a good test report about powerbanks in my favorite computer magazine.
While it doesn't cover Anker products, it still unveils some typical, hmmm, misunderstandings, or you may say, ways of cheating around powerbanks.

First, the numbers for mAh on the powerbank are the numbers for the cells itself, and do not count in the voltage (which usually is 3,6 or 3.7V).
The output on the plug is around 5V (and more, if Quickcharge or similar), and to come from 3.7V to 5V (or more) you need a step-up converter amongst others, and this electronics might have an efficiency of 60-70%. By just telling you the cell capacity, the manufacturer keeps the real output a secret.

Second, LI-cells are very sensitive around zero and 100% charge, both states can damage the cells pretty fast.
In high-end products a clever electronics keeps the operating range off these dangerouse states by a certain margin, by this limiting the real-life capacity by a certain percentage, in order to achieve a better life span of the product.
When a manufacturer is boasting very high capacity for low weight and small dimensiones (and still doesn't outright lie about the sheer numbers), most likely no such measures are taken, and the pack might lose a lot of its capacity after a few times of use - given that the operator doesn't keep the pack strictly within a, say, 20-80% charge state.

During my desert hike this spring I carried two powerpacks, my good old Varta 6000, and a borrowed brand-new noname 10.000.
While my Varta, now 3yrs old, still can charge my smartphone 2.5 times, the noname 10.000 could fill it 1 time and after this just gave me blinking LEDs.

BTW, in the above mentioned test report, all 5.000mAh powerbanks weighed in about 150-200grams, the 10.000mAh 250-300grams, and the 20.000 were about 450-500grams.
The difference in weight per category correlates with additional features, like solar cells (which are completely useless BTW, and make a 10.000 pack 300grams instead of typical 250), and sturdy/waterproof case etc.
The weight of the cells itself seems to be quite a fixed number. This mages it pretty much impossible for a 20.000mAh pack to weight in at only 151g.

[Gabigabs]

Sounds like a great deal. We carried the Anker because of its weight and reliability. We were very happy with it.

[Cheyou]

http://charger.nitecore.com/CHARGER/F/F2/
Bring as many batteries as you need
thom

[Crossup]

A LOT of guessing and assumptions in this thread.
I fly R/C model planes and we have been using Lithium ion family cells/batteries as long as they have been used...I literally own hundreds cells of all ages and several (lithium)chemistries and have pushed them to their limits.
NOTE: cells are individual "batteries" which can be added together to make different capacity/voltage batteries. Lithium chemistry cells provide a nominal 3.7volts with 4.2v being fully charged. Cell phones use a single cell, lights and other devices may use several cells to provide either more capacity or voltage or both.

A lot of these power packs use the 18650 cell but there is no hard reason why they should beyond cost as there are several traits which make Lithium Polymer cells a better choice.
The 18650 is one of the oldest cells out there yet somehow is still a favorite...ask Tesla why they use them. There have been no dramatic improvements in these but capacity has crept up continuously...early cells(circa 1995) were pretty low, IRC sub 2000mah...current cells are now topping 3900 mah. They are good cells for many apps but worthless for high discharge compared to current Lithium Polymer cells.

Lithium polymer(LiPo) batteries on the other hand have evolved a good bit faster and while the bulk of the improvement has been toward improved(even monstrous) discharge ratings and faster charging along with longer cycle life, the basic power density has not changed a lot. To me, the big advantage to LiPo cells is they are packaged in a plastic film significantly decreasing weight while also allowing the packaging to be nearly any shape. The down side is they must be protected from physical trauma unlike the fairly robust metal cased 18650 type.

Of course there are a lot of factors involved but first off lets consider this: with 18650s you can only pack round cells so close and with the capacity "fixed" by the standard size of them, overall capacity for a given volume is always going to be a good deal lower than a single cell LiPo.
I'd guess a 20k mah LiPo pack could be 25% smaller compared to 18650s. Weight wise LiPo also trumps the 18650 but bottom line a 20k mahLiPo is going to have a bare cell weight of around 350 grams.

A few facts about Lithium Polymer batteries- they have a life of approximately 1000 cycles but that can be shortened by many factors- I'll list the main ones. When they approach their cycle life they loose capacity increasingly.
1) Deep discharge- you can take them down to 3.0volts without real damage and many applications allow that...stopping early helps cell life but costs you capacity use. Ideally 3.3v is a good lower limit.
2)Storing fully charged- that will cut years off their (including shelf) life which is very long. A very low self discharge rate being a huge benefit of Lithium cell tech. Manufacturers recommend storage voltage of 3.8v versus the 4.2v a full charge provides. Modern high discharge rate cells can be significantly damaged with full charge storage in only a few years.
3)Fast discharge- cells are all rated to be discharged as multiples of the capacity ie: a 20k mah cell maybe rated "10C" which means you can pull current out at 10 x 20k ma(ma=milliamp or 20 amps in this case) or 200 amps total- that will start you car if you series 3 cells to get 12volts. Discharging at the rating will cut life dramatically, going over the rating can cut it down to a handful of cycles. In general for charging other devices this should never be an issue, charging your phone off a 20k mah pack is only 0.1C. Even garbage cells can handle 1C discharges so again, should be no issue for the intended use.
4)Fast charging- most cells are rated 1C charging or put another way, a one hour charge rate. We now have cells that can handle 10C(6 minute charge) but obviously its hard(and dangerous, fire wise) on a cell to push its temps to the limit which fast charging does. Charging and discharging are both limited by the cells internal resistance and the push is to lower that to improve performance and efficiency along with safety.

I'll be glad to answer any questions if any of this is not clear or complete enough.

[Crossup]

Not stated here but the vast majority of power pak manufacturers DO NOT make the cells... my assumption would be if they dont state they do, then they dont. The fact that this useage is very easy on cells means there are a lot of opportunities to cut costs with older, low performance cells and a poor cost-benefit ratio for using premium cells. So researching for test data is not only a good idea but perhaps the only way you can find out ahead of time if a pack will or wont last long term