Powerbank for phone charging

Discussion in 'Gadgets & Tech' started by syd_away, May 12, 2021.

  1. syd_away

    syd_away Backpacker

    Just wondering if I could pick folk's brains about the most appropriate power source for a two-ish week trek?

    I just need something to keep an Android smartphone running (no other devices). I plan to put it in "ultra battery saving" mode, switch off wifi, bluetooth and mobile data etc. I'd be using it for the odd text, phone call and photo, to check the weather forecast (temporarily re-enabling mobile data), and using the Kindle app in the evenings. (I had planned on taking my Kindle Paperwhite but saw on a different thread here that that isn't the most weight-efficient option).

    At the moment I only have a 2000mAh powerbank (weight ~ 80g), of the type given out as marketing freebies at business conferences. I'm worried about relying on this though. Do I need something better?

    Sorry for the basic question - I've never used anything like this before!
    Last edited: May 12, 2021
  2. Chiseller

    Chiseller Thru Hiker

    Hi Syd, sadly that little thing you've got is best kept in a car glove box for emergency use. As light as it is, it's not worth it's weight for the hills.

    2 week ish? Any chance of topping up power during those two weeks? That could help advise on the size of powerbank you might need.

    Running your phone on ultramode etc is a good choice and you shouldn't need much juice.
    I've little experience on two week trips without having an option to recharge either my phone or my powerbank. I know I can manage a week with my Huawei and its huawei charger 12k mah 40w.
  3. WilliamC

    WilliamC Thru Hiker

    It's hard to answer your question as it partly depends on your phone and how power hungry it is. Many phones will go for a week in power saving mode and used only occasional use, but I suspect Kindle in the evenings will use a fair bit of battery. When I look at the battery use of my phone at the end of the trip, the screen has always been the biggest user (dark mode can help if it's an AMOLED screen).
    Personally, I reckon on a 10,000mAh power bank if I'm away for a week and I haven't run out yet. If you can, try to use your phone in a similar way at home and see how quickly the battery is draining. Then you can calculate roughly how big a power bank you need. But remember, a power bank's capacity needs to be multiplied by 3.7/5 due to the different voltages and that efficiency is about 85%. So a 10,000mAh power bank will charge a 6,290mAh phone battery once (10,000x.85x3.7/5), 2 or fewer charges for most modern phones.
    Chiseller and markgoodlad like this.
  4. dovidola

    dovidola Thru Hiker

    You'll be wise to also disable the telephone signal - i.e. use Airplane Mode at all times other than when you specifically need to access a specific function outside airplane mode. The greatest drain of a smartphone's battery in remote areas is continually searching for a non-existent/weak signal, which it is programmed to do by default unless you disable it.

    I don't know the exact model of phone you're using, and I don't know how much power Kindle uses, and I don't know if there's a relevant significant difference between Android and iOS, so can only advise based on my experience with my iPhone 11 (and iPhone 6 before that).

    Based on my usage (similar to yours apart from Kindle, but also allowing moderate recharging of headtorch), I would take a 10,000 mAh unit if I were anticipating being away from a power source for 2 weeks.

    Your 2,000 mAh is inadequate. I take an 'emergency backup' 3350 mAh (68g) powerbank on 2-3 nighters, and a 5000 mAh (105g) for 3-5 nighters.

    There are plenty of options out there, but this Anker Power Core 10,000 mAh (180g) is a solid choice:
    https://www.amazon.co.uk/Anker-PowerCore-Ultra-Compact-Fast-Charging-Technology/dp/B019GJLER8/ref=sr_1_3?crid=39OTARDJD2SP2&dchild=1&keywords=anker power bank 10000mah&qid=1620810939&sprefix=anker power bank 10000,aps,161&sr=8-3
    markgoodlad, WilliamC and Chiseller like this.
  5. Lempo

    Lempo Thru Hiker

    markgoodlad likes this.
  6. markgoodlad

    markgoodlad Trail Blazer

    The Anker is a good /popular choice.

    The NightCore NB10000 10k mAH at 150g is the lightest power bank that I found. I have a couple of them to charge phone, gps, watch, headlamp, …. They have fast charging through the USB-C port and output both -A and -C.


    Yes switch off absolutely all signals and activate battery saver modes. 2 weeks is a long time without recharging. Also depends on temperature. If it is cold, then the batteries will not last as long. Make sure to put them in your sleeping bag at night.

    As per Williams mail add up the power requirement and compare to battery capacity. If you will use your phone as a gps as well then I suspect you may need to be in the 20-30k mAh range for safety.
    Last edited: May 12, 2021
    WilliamC likes this.
  7. Taz38

    Taz38 Thru Hiker

    I got an anker 20000mah for longer trips, lasts at least a week with my usage. I use my phone for navigation, keeping in touch, checking weather, train travel, taking a few pics, charging mp3, so need some juice. It weighs a fair bit but for me its worth it. The phone is usually on airplane mode and battery safe mode, but its a thirsty one. I really should look at a better one.
    markgoodlad likes this.
  8. markgoodlad

    markgoodlad Trail Blazer

    I tested my set-up a few weeks ago. The NB10k will recharge my iPhone 11 Pro (3046mAh) 2.25 - 2.5 times.
    I use my phone for connecting to my inreach for route tracking and messaging, taking photos (lots), some filming (filmic pro - chews up the battery) and reading books.

    I can just about manage to last 2 days if I am careful, but I would classify my phone usage as heavy, even though everything that’s can be switched off is. So with 2 batteries that’s is approx 8 days (max) with the other devices.

    If possible test your phone for a few days on a shorter trip or at home to estimate your usage. It can be very surprising how much battery you use if you are not careful.
  9. Chiseller

    Chiseller Thru Hiker


    Tartanferret and Lempo like this.
  10. Whiteburn

    Whiteburn Thru Hiker

    In addition, the best battery saving tip is don't use the phone :) (or minimize it).
    I suspect that having everything switched off 95% of the time (only occasional camera use, no GPS tracking, etc) that your largest power use will be the Kindle App (screen time eats power) & eliminating that will markedly improve the overall phones battery life....switch to music or podcasts with plug-in earphones.
    I regularly got over a week out of my old Samsung Galaxy 5 (occasional GPS, camera & an hours' podcast everyday) but then I can just replace the battery when I need to (45g) for a full charge.
  11. markgoodlad

    markgoodlad Trail Blazer

    Great list. The thing that I found was killing my phone and watch batteries was the “Raise to wake”, “Tap to wake” and “Shake to undo” features. Every time I moved the phone in my pocket, the screen came on for 30secs and drained the power.
    Lempo likes this.
  12. Lempo

    Lempo Thru Hiker

    Changing the Kindle app to use dark mode, black background will reduce the energy consumption also.
  13. syd_away

    syd_away Backpacker

    Thank you everyone for the advice. I'm glad I asked :)

    My local PC World has the Anker so think I will get one.

    I have a Hwawei PSmart. It's usual battery life isn't bad, but it is quite old now (> 2yrs) so probably not as good as it used to be. It has this "ultra power saving mode" which (allegedly) switches off all background apps. So maybe if I do that, plus "airplane mode", all data off, screen as dim as possible, black screen background... So main worry is the Kindle app. Taking my Paperwhite as well would add 200g - but I don't want to be without books! I'll give it a go tonight, read a few chapters on my phone in that mode and see how power hungry it is.

    Another question - is it better to do daily "top-up" phone recharges from the powerbank, or is it better to leave it until the phone's at about 20% and do a big recharge?
  14. Lempo

    Lempo Thru Hiker

    I haven't come across any information which is better regarding the efficiency, only how these affect the battery longevity, which is to keep the battery charged between 20-80% is most optimal way to improve the longevity.

    However, I'd hazard a guess that every time you're connecting a cable, there might a little extra being used, but I could be completely off.
  15. WilliamC

    WilliamC Thru Hiker

    I've read that it's more efficient to only charge to somewhere between 80 and 90%.
    Patrick likes this.
  16. Diddi

    Diddi Thru Hiker

    Whatever you go for try it out for two weeks before you go :thumbsup:....
  17. Foxster

    Foxster Section Hiker

    The charge-to-only-a-certain-amount and only-charge-when-near-empty is kinda old advice now, batteries being more forgiving. What is still pertinent is the number of charge cycles. You can reduce the life of your battery if you have a habit of always charging whether it needs it or not, particularly common with wireless charging stands.

    Having said that, if you are the sort to swap out you phone every couple of years then it's hardly worth worrying about.

    I read using the Kindle app pretty much every workday and I've not found the Kindle app to be power hungry. Its what else is running while you have the phone on that sucks up the power. If you put the phone in airplane mode, select dark mode and white-on-black in the Kindle app, and close all the other background apps then reading will suck up very little power.

    For two weeks with no access to any kind of recharge I'd be taking a 20Ah brick.
  18. turkeyphant

    turkeyphant Trail Blazer

    Modern PD and fast charge phones/power banks use high voltages for the first ~40% or so which will probably be less efficient than the slow-and-steady 60%-80%. But I suspect you also don't want to be topping up several times a day.
  19. Teepee

    Teepee Thru Hiker

    For a week out, I carry a 26500 anker and use it like normal

    I can't be bothered with farting about with trying not to use it much, it kind of defeats the purpose of taking a smartphone.
    edh and gixer like this.
  20. Cranston

    Cranston Thru Hiker

    I hope you're paying your sherpa well.
    Last edited: May 14, 2021
  21. syd_away

    syd_away Backpacker

    Thanks all for the advice. I've gone for the Anker 10,000, and I'll use my phone sparingly. Might even take the Kindle Paperwhite for reading, use on lowest backlight setting and put it in airplane mode as well - see how long it lasts. I won't try and recharge it - having a workable phone is more important. (And if I take it to the pub for the odd meal I'll look more like a bookworm than a ditzy social media addict! :) )

    My question about the best recharging schedule was about getting the most out of the powerbank before it runs out. Sounds like it's best to make sure the phone doesn't go below about 50% and recharge up to about 80%.

    Hopefully I will find a place to recharge, this was just a "worst case" really :)
    dovidola likes this.
  22. Bmblbzzz

    Bmblbzzz Ultralighter

    Call that old?!!! Mine's from 2013!

    Sorry, can't answer any of your questions – have found 10,000mAh fine for a week, can't speak about two weeks – more interested in some of the answers. But a completely OT question: What is that photo in your avatar? Thought for a second it was a decorated bus stop of the sort you see in some out of the way places, but looks more like some sort of trophy cabinet on public display????? Perhaps a shrine of some sort????
  23. syd_away

    syd_away Backpacker

    You were right first time - it is actually a decorated bus stop!

    It's the famous fully-furnished bus stop of Unst, Shetland. Every so often it has a makeover, each one having a particular theme. The first time I went the theme was "Africa", so all the decor was leopard and zebra prints. The second time (this photo) is was Vincent van Gogh's Sunflowers :)
    cathyjc, dovidola and Bmblbzzz like this.
  24. dovidola

    dovidola Thru Hiker

    As is oft and correctly observed on this forum, what one chooses to carry on one's back on a pleasure trip into the wilderness and back again is an individual matter; our requirements vary, our objectives vary, we enjoy different things, our capabilities differ, our pockets differ, plus all the other current obligatory platitudinous preamble stuff.


    When the accumulated weight of carried electricals exceeds the combined weight of the 'Big Three', it does prompt one to question the point of the incredible advances made in recent decades in reducing the weight of essential equipment if all that saving is then squandered on gadgets.

    Smartphone, Sat-Nav, Flashlight, Backup Flashlight, Kindle, Drone, PLB, Cameras, Music Systems, Powerbank, Cables...Of course it's not a crime to tote the contents of a small sub-branch of Dixons in your rucksack, but, to this dinosaur at least, it seems to defeat the purpose.
    cathyjc, turkeyphant and markgoodlad like this.
  25. dovidola

    dovidola Thru Hiker

    I should have recognised it - I spent a great week on Unst some years back and saw it then. Shetland seldom features on this forum, and I'm not sure why?

Share This Page