How long do powerbanks keep their charge?

[MRrainer]

Hi,

I'm contemplating going on a sort of off-line holiday, where I might not have access to a charging outlet for days - or even a week.
I'd take an iPhone (SE probably) as camera and use that to take pictures.
I was wondering if that was a sane idea to begin with (I don't own a DSLR and my compact camera from 2007/2008-ish has probably long been surpassed in picture quality by a previous iPhone generation. Plus the battery in that isn't that great, either.
How long do powerbanks keep their charge? Has anybody done any research/tests about that?

 

[kapolani]

With a good brand of battery in it the bank can hold up to 85% charge over a year of no use.

Depending on how many charges you want and how long you will be without power you could get a 20,000 ma battery that would give 15+ charges during your trip.

For the times when I go camping off grid and need power I use my fold up solar panel and any one of my many battery banks.

Something like this would do:

http://www.amazon.com/15000mAh-External-Battery-Portable-Charger/dp/B00D5T3QK4

Do your own shopping though because I'm sure you can find a better deal. That was a quick search.

 

[MRrainer]

Thanks. I plan to do a biking trip (MTB). So, it's not realistic to charge during the day via solar.
But it's relieving to know the banks can hold their capacity for a while.

 

[dictoresno]

I keep a fully charged one in my work bag and never really use it. I've gone months without touching it and when I power it up, it still shows full charge.

 

[Richdmoore]

One caveat to the larger battery power banks, they can take a long time to charge up. I have owned a couple of anker brand power cases over the years, and they do take hours to charge up (from empty). I have had them not charge completely up after a short 4 to 5 hour overnight, they simply needed more time to fill.

I believe anker and others do now have a couple models that charge using a special qualcom quick charger, that may help charge the battery pack faster than using an iPad 12w charger.

I do agree that the power loss just sitting in a bag is almost zero, I have had some sit for months without use and still indicate between 75 to 100% charge when I checked them months later.
[doublepost=1462516951][/doublepost]I was looking at the anker web site. Their powercore 20100 charger takes 11-12 hours to charge from dead using a 2amp charger (iPad for example)
https://www.anker.com/products/A1271011

Their powercore+ 26800 with a qualcomm 2.0 charger (included in the package, but twice as expensive) lists a 8 to 9 hour charge from dead.
https://www.anker.com/products/B1372014

Anyway, it's another consideration. The other powercore+ products appear to charge slightly faster with the 2.4 amp (12w) charger than the 2.1 (10w) charger, but it's the only one I see with the qualcomm 2 charging spec.

 

[MRrainer]

Thanks all.
Charge-time is currently not a consideration, as I assume to be off-grid for a week. All power I need will have to come from power-banks.
I had already assumed anyway that these large power-banks take ages to fully charge.
I'm old-school, so if something claims to charge very quickly, I automatically assume "that cannot be too good for the batteries in the long run" ;-)