Note: These test were done before the release
of the latest iPad in March 2012, with it's
larger battery. Our devices still provide the
optimum charging for the newest iPads but the
charge time may be longer because of the larger
battery (42 watt hours vs 25).
Charging speeds for iPads: We ran some tests, charging
iPads that had been completely depleted, to see how long
various methods took to re-charge them from 100% empty to
We found the following:
USB port 2.0: On a desktop PC, it took 13 hours 30 minutes
to charge a single iPad through the trickle charge on the
USB port. The iPad does not display that the unit is charging.
We have heard that this can take longer if it is done on
a computer or notebook that goes into sleep mode.
On some multi-USB hubs (even powered hubs), the
USB charge shares the available power supply and would take
even longer. On one 24-port hub we reviewed, the unit had
a 22.5W power supply which gives less than 200mA per port
so trickle charging would take more than twice as long as
even the worst PC port. If the iPad is used daily for a
few hours, the net charge in the iPad (if charged on this
hub each evening) would go down.
Plugged into the Cambrionix C3 USB board used in the
DS-IP-SYNCCHARGE: A complete empty-to-charged cycle took
4 hours, 35 minutes. According to Cambrionix, this charging
time is the same as would be using the charging block supplied
with the iPad itself. This would be the time required whether
you are re-charging one or 16 iPads, as each port is provided
with the full power required.
If the charge status of the iPads is not 100% empty,
the time would be less.