Re: Quest 2 charger/USB wil not work

Jack Erbes schrieb:

In theory, your USB bus voltage and the device battery will eventually stabilize at the bus voltage which is normally very close to 5V. A fully charged 5V battery will have up around 5.6V.

There is no such thing as a 5V battery. These devices now all use Li cells of a few types, and the chargers use PWM schemes and DC/DC circuits. As such, 5V is completely sufficient to charge such a battery. The average current may vary due to the PWM scheme, but the battery get's a full charge. Only very few devices are spec'd with more than 5V, but not because of the battery voltage, but the power conversion electronics involved (e.g. some Casio PDAs are spec'd at 5.9 volts).


Devices with 4 NiCD/NiMH cells are a different story. Most of these cells are charged externally anyway. I know only some outdated cellphones that use 4 NiMH cell packs for supply. But these are charged constant current, not constant voltage.


- Carsten
.

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