I recently purchased the Goal Zero Guide 10 Plus Battery Pack to recharge my cellphone, which it does well. I was surprised to find that despite using four 1,900 mAh Eneloop batteries the charger will only charge my iPhone 5 (1440 mAh battery) once from zero to full before exhausting the battery pack.

Now I know just about nothing about electricity, as if that was not already clear, and I was wondering why the charger would not be able to charge the phone more than once before exhausting the batteries?

Please school me on electricity, batteries, and charging.

Here is the battery pack.
http://www.goalzero.com/shop/p/133/Guide-10-Plus-Battery-Pack/2:8/

Losses through circuity and wiring.

Posted Via AR15.Com Mobile

I was imaging there would be loss through insufficiency but seriously that much loss? Is that typical for battery packs?

It appears that the iPhone 5 requires 5 volts charging voltage. The eneloops each provide around 1.4 v (i think) so if they run them in series to get 5.6 volts then the 1900mah is probably about right for one charge. Sorry. With electricity you need both the voltage AND current.

If it helps my Mophie battery pack/case is good for 2 full recharges of my iPhone 4s.

Charge/discharge losses on batteries are higher than you might think.