FCDEV3B update

Mychaela Falconia mychaela.falconia at gmail.com
Mon Jan 23 16:43:30 UTC 2017


Hi DS,

> Thanks for the update! An unralated question: will it be possible
> to use the board with a battery for on the go operations? In
> particular it'd be useful for testing mobility scenarios such
> as handovers and the like.

Yes, it will certainly be possible to wire up a battery to the power
input connector on the FCDEV3B - a single Li-ion cell or a 3-cell NiMN
(or NiCd) pack would be the safest, as that is what the GSM chipset is
designed to be powered with, but really any battery type that puts out
a voltage between 3.5 and 4.2 V should work fine.  However, there are
no battery charger circuits (in particular, no USB or other charging
power source connection) on the FCDEV3B, hence the board will only
draw power from the battery and not recharge it.

It should be possible to connect the FCDEV3B (a power consumer) and an
external charging circuit to the same battery in parallel (this is
what happens inside Openmoko devices: the Calypso modem is strictly a
power consumer, while the AP subsystem's independent PMIC implements
the battery charging function), to allow the battery to be recharged
while the modem is on, but given the "toy" nature of the FCDEV3B, it
will probably be easier to go out for mobility field tests with a
fully charged battery, then after the test is over, disconnect the
battery from the test MS and recharge it standalone.

M~


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