[pct-l] external battery

[enyapjr at comcast.net]

> Thanks for sharing this Jim!

You're welcome!  New Trent has been used & recommended by quite a few hikers (including Halfmile - using 
an 'older' model 5000 mAh New Trent charger with his iPhone 4S)...

I do have to mention & correct your calculations, however - you show "xx grams per mAh", whereas it should be
"xx mAh per gram"...
Using 'some' of your input data for the New Trent iTorch & Duracell Instant (didn't look up the other two specs):
iTorch - 5200 mAh, 124 grams > = 41.94 mAh per gram; Instant - 1150 mAh, 91 grams > = 12.64 mAh per gram...
Calculating for grams per mAh: iTorch = 0.024 grams per mAh; Instant = 0.079 grams per mAh...
For 1.2 oz. more weight, you get 4.52 times the 'power' from an iTorch than the Instant...

Does one really 'need' 5000+ mAh backup?  Not always - that's dependent on how often you will need to recharge
your 'backup' power (and 'top off' your device) when in a 'town' and also how you 'use' your device (smartphone
in my case, in the 'future')...  Since I've mostly made up my mind on getting an iPhone 5, another factor is which
carrier one uses (I'll be staying with Verizon)...  To check GPS location, an AT&T iPhone can stay in 'airplane' 
mode (not activating other 'services' such as Bluetooth or searching for cell towers, etc.), whereas a Verizon iPhone 
comes out of 'airplane' mode - so one must remember to shut down all the power hogging 'services' on a Verizon 
iPhone (before shutting it off entirely to save the most power!)...
So, for long stretches of trail and for much less frequent 'hassle' of recharging 'everything' when an AC outlet is 
available - an additional 1.2 ounces for 4.52 times more power is well worth it for me while on a thru-hike...
As I suggested before, the iTorch has both the best power to weight and weight to power ratios at a relatively low
weight penalty...
As always, YMMV, HYOH, etc. ...   ;-)    Gotta get back to work now...  :-/

Happy trails!!!
Jim (PITA)