informed opinions/educated guesses sought - external HD po..

Archived from groups: comp.sys.laptops (More info?)

.... as above ....

I have a USB2 external HD enclosure - and a cardbus -> USB2 adapter.
The cardbus -> USB adapter has a PS/2 pass thru thang to supply 5V to
the adapter - this works OK for USB periphs requiring very low power,
but doesn't cut it for the ext. HD - I have to use a AC adapter for
that, which is a bit tedious. So I'm thinking of DIY'ing a rechargeable
battery pack (4 x NiMH batteries in a generic holder). For me this makes
sense as I usually carry a NiMH charger with me for the digital camera.

Question is this :-

On a full charge, 4 of those cells (in series) measures about 6V. The
USB2 enclosure expects 5V .... is there any possibilty/likelihood of 6V
being too high or causing any damage to the enclosure electronics or the
HD itself ?

TIA.

Archived from groups: comp.sys.laptops (More info?)

Martin Slaney wrote:
> ... as above ....
>
> I have a USB2 external HD enclosure - and a cardbus -> USB2 adapter.
> The cardbus -> USB adapter has a PS/2 pass thru thang to supply 5V to
> the adapter - this works OK for USB periphs requiring very low power,
> but doesn't cut it for the ext. HD - I have to use a AC adapter for
> that, which is a bit tedious. So I'm thinking of DIY'ing a
> rechargeable battery pack (4 x NiMH batteries in a generic holder).
> For me this makes sense as I usually carry a NiMH charger with me for
> the digital camera.
>
> Question is this :-
>
> On a full charge, 4 of those cells (in series) measures about 6V. The
> USB2 enclosure expects 5V .... is there any possibilty/likelihood of
> 6V being too high or causing any damage to the enclosure electronics
> or the HD itself ?
>
> TIA.

Not really. The real "danger" is that the drive suddenly loses power
when the batteries crest over the voltage curve - the drive will have no
ability to monitor the voltage and only one time will likely corrupt the
contents. If I were seriously going to power with 6 volts, I'd use a
sealed 6V lead-acid battery as I do on an older digital camera for
telescope use. Far greater amp-hour capacity, its portable, and easily
patched into the correct adapter plug.

Q