Author Topic: Battery bank for mobile  (Read 937 times)

Nomad32

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Battery bank for mobile
« on: 18:03:27, 05/07/18 »
What's the best battery bank for 3 charges on a smart phone?

gunwharfman

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Re: Battery bank for mobile
« Reply #1 on: 18:14:31, 05/07/18 »
Mine is made by Anker, I bought it from Amazon. Mine charges my smartphone up to four times before it itself needs charging. The only downside is that it weighs 12oz. I don't mind, I think its great!

NeilC

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Re: Battery bank for mobile
« Reply #2 on: 19:03:08, 05/07/18 »
What's the best battery bank for 3 charges on a smart phone?


Depends on the battery capacity of the phone. Find out what that is, multiply it by 3. Could be anything from c.4500 - 15000 mAh.


The Anker ones I've owned seem sold items.

Hillhiker1

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Re: Battery bank for mobile
« Reply #3 on: 21:08:55, 05/07/18 »

Another shout for the Anker here O0 
I've a 20000mAh one and it can charge my camera in around an hour and still have plenty for a few does at my mobile and GPS.. Love it.!

alan de enfield

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Re: Battery bank for mobile
« Reply #4 on: 22:48:21, 05/07/18 »

Depends on the battery capacity of the phone. Find out what that is, multiply it by 3. Could be anything from c.4500 - 15000 mAh.


The Anker ones I've owned seem sold items.



Its amazing what Ah ratings some sellers put on their battery packs (particularly ebay Chinese sellers)


My business background is 'electrical' and I have a fair bit of knowledge in low voltage (battery) applications.


A bit of background :


1Ah is (basically) the ability to run an item at 1 amp for 1 hour, or 2 amps for 30 minutes, or 4 amps for 15 minutes etc etc.


 1mA (mille amp) is 1/1000th of an amp, so 1000mAh is 1Ah, 10,000 mAh is 10Ah etc.


A typical car 'starter battery' will be in the order of 80Ah






Knowing all of this I purchased a 30,000mAh (30Ah) 5v Solar panel & battery power pack off ebay for about 12
Remember the 80Ah car battery - and the size and imagine the weight that would be ?
How big is a 30Ah battery power pack + Solar recharging panel ?


Answer - about the size of a packet of cigarettes and total weight of about 230g.


It is physically impossible (and contravenes all known science) for that battery power pack to be 30Ah (30,000mAh)


I undertook some tests and to cut a long story short it was actually just about 4Ah


My phone battery is rated at 1400mAh so I can get just under 3x recharges on my phone.
My GPS battery is 2700mAh so I get 1 & 1/3 recharges
My Headlight is 1200mAh so I get just over 3x recharges.


I then purchased (again off ebay) a 2600mA 5v power bank, did all the testing again and it actually turned out to almost exactly 1Ah (1000mAh)


Do not be fooled by the quoted ratings - I don't know how they measure them, or how they get away with such claims.

The 30,000mAh solar charging battery bank
« Last Edit: 22:57:46, 05/07/18 by alan de enfield »

NeilC

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Re: Battery bank for mobile
« Reply #5 on: 11:03:51, 06/07/18 »

Its amazing what Ah ratings some sellers put on their battery packs (particularly ebay Chinese sellers)



Yeah you're right of course, it's not that simple.


You have to bear in mind that amp-hour ratings are done at specific vltages - 12V for car battery but more like 3.6V for lithium cells so big difference there. So to compare apples to apples you need to be talking watt hours rather than amp hours. A 40AH car battery is 480 watt hours whereas a 40,000 mah bank at 3.6V is only 144 watt hours


They're generally quoting the cell capacities not the output capacity (which may be delivering a higher voltage, like 5V not, the cells' 3.6V) so there is a conversion factor and, in addition, an efficiency % loss during that conversion by the circuit in it. So all of that knocks it down a fair old amount. However plenty of  mobile phone battery figures are also skewed unrealistically themsevles so it's not as far off as you might think. E.g. my phone is 3600mah and my 5000mah bank does charge it fully once.


And as you point it, if you're buying some cheap non-branded bank then all bets are off. They just make [censored] up like they do on so many products - like my 0C degree rated cheap down bag that is really only good to about 10C or 8C with baselayers.


My post was sloppy and you have to upgrade the figures accordingly, but the point stands that nobody can tell you what will charge a phone 3x without knowing the capacity of the phone. Some of the newer smartphones have really large capacities now, requiring like double the energy to recharge compared to an older phone.
« Last Edit: 11:08:24, 06/07/18 by NeilC »

alan de enfield

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Re: Battery bank for mobile
« Reply #6 on: 11:11:29, 06/07/18 »

Yeah you're right of course, it's not that simple.


You have to bear in mind that amp-hour ratings are done at specific vltages - 12V for car battery but more like 3.6V for lithium cells so big difference there. So to compare apples to apples you need to be talking watt hours rather than amp hours. A 40AH car battery is 480 watt hours whereas a 40,000 mah bank at 3.6V is only 144 watt hours


They're generally quoting the cell capacities not the output capacity (which may be delivering a higher voltage, like 5V not, the cells' 3.6V) so there is a conversion factor and, in addition, an efficiency % loss during that conversion by the circuit in it. So all of that knocks it down a fair old amount. However plenty of  mobile phone battery figures are also skewed unrealistically themsevles so it's not as far off as you might think. E.g. my phone is 3600mah and my 5000mah bank does charge it fully once.


And as you point it, if you're buying some cheap non-branded bank then all bets are off. They just make [censored] up like they do on so many products - like my 0C degree rated cheap down bag that is really only good to about 10C or 8C with baselayers.


My post was sloppy and you have to upgrade the figures by I reckon but the point stands that nobody can tell you what will charge a phone 3x without knowing the capacity of the phone. Some of the newer smartphones have really large capacities compared older ones.



All very true and quite confusing for a non-electrical-technical person.


The newer smartphones not only have larger capacity batteries (which as technology continues to improve will not doubt increase further) but all of the additional features that are 'running in the background' mean that their consumption is also greater.


But your answer "no one can tell you with the information provided" is spot-on.

Nomad32

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Re: Battery bank for mobile
« Reply #7 on: 12:38:30, 06/07/18 »
Ok my apologies. It's a Samsung s7 with a 3000mah battery. I was looking at a 50000mah solar bat bank my reckoning based on the info and a guess is it will get me 2.5 charges. Should be ample for my hiking. Hopefully I get a bank that does what it claimes it can do.

alan de enfield

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Re: Battery bank for mobile
« Reply #8 on: 13:00:17, 06/07/18 »
Ok my apologies. It's a Samsung s7 with a 3000mah battery. I was looking at a 50000mah solar bat bank my reckoning based on the info and a guess is it will get me 2.5 charges. Should be ample for my hiking. Hopefully I get a bank that does what it claimes it can do.



The battery bank I pictured above is rated by some suppliers as 50,000mAh but is in reality on 4Ah on test. It will give you approximately 1 full recharge (and a little bit).
The Solar recharging is almost worthless as it is only about 1watt (1.5 watts claimed) and takes getting on for 30 hours of direct sunlight to recharge.
The 'lights' (LEDs) on the unit flash if you put it in the daylight and you assume it is charging, however the charge rate is lower than the discharge rate to power the LEDs so it actually discharges the battery bank - the only time it is actually charging is in direct, strong Sunlight.


If you use a mains charging unit, it takes about 12 hours to recharge at 0.4amps (irrespective of what your charger is rated at) so it can only be about a 4Ah capacity - you cannot get more out than you put in.


If you do a You-tube search for these solar power banks there are some interesting tests undertaken.
« Last Edit: 13:03:23, 06/07/18 by alan de enfield »

Nomad32

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Re: Battery bank for mobile
« Reply #9 on: 13:03:24, 06/07/18 »
Ok so solar is rubbish is what you are saying and I should just get a mains one.

alan de enfield

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Re: Battery bank for mobile
« Reply #10 on: 13:07:20, 06/07/18 »
Ok so solar is rubbish is what you are saying and I should just get a mains one.



NO NO NO - solar is not rubbish, its just useless on that particular unit.


I invested in a 7w Folding Solar Panel which can be used (open) on the back of your pack - in good Sunshine it will give a steady 1amp (at 5v) and recharge your phone / GPS / headlight / etc in a matter of a couple hours.






« Last Edit: 13:12:15, 06/07/18 by alan de enfield »

Dyffryn Ardudwy

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Re: Battery bank for mobile
« Reply #11 on: 13:53:18, 06/07/18 »
Anker are one of the best manufacturers of portable battery packs, i bought one two years ago, and they hold their charge extremely well.
They come in various capacity sizes, and are very well made, and are very portable, and are excellent value for money.
If you know you might require a small high quality power reserve, check out Ankers website.

jimbob

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Re: Battery bank for mobile
« Reply #12 on: 13:58:22, 06/07/18 »
I have a phone sized solar charger /battery bank which charges my phoneS ok. On day walks.

On very long walks I carry a 7W folding charger which works great to the extent that I never mains charge phone or solar battery bank over a multi day walk.
I learnt my lesson earlier this year, being phone dependant on maps etc and realising I had run out of battery with no means of recharge. My everyday phone, etrex, solar pack and cables were all sitting nicely in my cubby hole when I got back home. ( I normally use a large screen cheap smartphone with viewranger as my primary gps, no sim so couldn't ring home for backup supplies, which would have been popular).
Too little, too late, too bad......

BuzyG

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Re: Battery bank for mobile
« Reply #13 on: 20:11:13, 08/07/18 »
Another who uses Anker here.  Not sure how many charges I could get as I only do day walks and carry one of their smallest packs, just to be sure not out of necessity.  Generally my phone goes all day on one charge.

Mel

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Re: Battery bank for mobile
« Reply #14 on: 21:23:19, 08/07/18 »
I have a Kodak one.  I get 2.5 charges out of it on my old, crappy samsung battery but only 1 charge from flat on my larger but newer Alcatel "GPS" phone.  Granted, once charged, the phone does last 3 days though  :)
No expense spared in pursuit of a bargain ;)
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