So it sounds like there is a good reason to hang on to my first generation iPads.  I maintain charge in-flight with a small automotive 1A charger.  I went small on the charger simply to hold state of charge constant.  At full brightness it balances out just about right, maybe a slightly positive charge rate. 

Chris Zavatson

N91CZ

360std

www.N91Z.net

>
> I am another Ipad in-flight user and am very happy with it. As others
> have said, keep it out of DIRECT sunlight. With the WIFI turned on
> (required for my ADS-B receiver) it does drain the battery faster.
>
> I researched the literature quite a lot about re-charging and there was
> a lot of grumbling from non-aviation users of IPad 3 (and newer) when
> they first came out. Those people complained that the IPad would no
> longer charge from a wall charger while being used heavily, and it would
> never re-charge if plugged into a computer's USB port. The complainers
> were correct. BTW a computer's USB port is limited to .5 amp by the
> USB standard. The response from Apple was that the newer models use
> significantly more power than prior versions. So much more that the
> Apple standard 10 Watt (~2.1 amps at ~5 volts) wall chargers deliver
> about the same power back to the unit for re-charge as it is consuming
> when WIFI is on and the screen is bright etc, etc. Apple technical
> people said that a unit with a low state of charge will not re-charge
> while in heavy use from a wall charger or auto charger. In order to
> recharge, the heavy consumption of power must be removed until re-charge
> is complete. Just closing the lid does that, or the short push of the
> power button.
>
> So, the upshot for us is, IPad 3 and newer won't really re-charge at all
> in-flight, but consumption of the battery should be greatly reduced if
> we use the right charger.
>
> All in all, I can fly two four hour legs and the battery is not
> excessively drained, if I plug it into the cigarette lighter with a
> quality 10 Watt auto charger. These are 2.1 amp at 5 Volt output. There
> are dual chargers out there advertising 15 Watts but most are one outlet
> at 2.1 amps and one at 1.1 amps. The lower output connection is
> appropriate for phones or other small devices. The IPad 3 itself won't
> consume more than 2.1 amps anyway, so more would not help.