Friends:
I'm very interested in this topic too, but would be happy to find a
quick, moderately priced fix rather than understand the problem
completely. But to tell the truth, I've never had a problem ---
sometimes the recorder shuts down as it should when the Li-ion supply
is gone, but I've never lost data. (And never recorded more than 3 GB
(.flac) of data in one take).
But, as Rob suggested, I'm contemplating as mid-sized Pb-acid battery
as well as a NiMH battery of 10-12 cells. And, the SD website talks
about NP-type batteries. Has anybody used these?
I hope others will post about their wisdom about powering these
recorders and eventually solve my quandry with their experience.
Cheers!
Steve P
--- In Rob Danielson <> wrote:
>
> Hi John--
> Seems like SD would have provided more insight doesn't it,..
> especially if switch-over problems turn out to be more frequent with
> CF media? Perhaps some other 702 users can chime in with supporting
> or contrary experiences. The 702's external power requirement is 1000
> ma minimum, 10-16 volts. It seems like your 10- ~2000ma AA cells
> would provide enough power to operate the recorder, at least for a
> while. Perhaps the combined load of "topping-off" the internal
> battery while powering the deck is part of the problem.
>
> If the source of the switch-over problem is insufficient amperage
> from your current external battery pack, maybe you could confirm this
> by running it from an old car battery until its voltage drops below 9
> volts and the recorder attempts the switch-over. You should also be
> able to initiate a switch-over by disconnecting the external battery
> while its recording. If you can get the 702 to switch-over reliably
> and use the internal battery to close-out and save the files, your
> external battery can be sized fairly conservatively. If not, you
> might need a much larger external battery pack to insure you'll have
> plenty of time to get there and manually close out the files. I'd
> hate for you to invest in the pricey NiMH batteries and find out they
> don't solve the switch-over problem. If you do need the assurance it
> won't run out of power under any circumstances, a $25 lawn tractor
> battery might be a better solution. Rob D.
>
> =3D =3D =3D
>
> At 5:58 AM +0000 5/27/08, John Hartog wrote:
> >Hi Rob,
> >My adapter is wired pin-1 to negative, pin-4 to positive as the 702
> >manual recommends for use with an external battery pack. Wired that
> >way, it does nothing until the recorder is turned on, at which point
> >the external battery pack both charges (tops up)the attached Lion
> >battery and runs the recorder until the external battery reaches about
> >8.5V at which point a little roulette wheel spins inside the recorder
> >deciding the fate of the file in progress.
> >
> >Replies from SD to my inquires suggest not using NiMH battery packs
> >but Lion instead. They did not suggest that anything might be wrong
> >with my recorder, which leaves me to assume it is normal for the
> >battery switch-over circuitry (at least in 702 recorders) to be far
> >from fail safe. I have not yet tried the SD users forum - but will
soon.
> >
> >I have been using AA NiMH because that's what I have around, and did
> >not want to spend money on a new battery/charger system. I liked the
> >idea of keeping my external battery pack fairly small, providing just
> >enough extra to get a full night of recording when combined with the
> >attached Sony NP-F970 battery. I have tried several AA pack schemes
> >now, and all have proven unreliable.
> >
> >For now I just need to put together a bigger battery pack - enough
> >power to fill an 8GB card without needing the internal battery at all.
> >I like your D-cell pack, so I'll probably give that a try.
> >
> >John Hartog
> >
> >--- In
>
><naturerecordists%40yahoogroups.com>=
m,
> >Rob Danielson <type@> wrote:
> >>
> >> At 6:19 AM +0000 5/19/08, John Hartog wrote:
> >> >Hi Rob, you say, "You can also set the "shut-off" voltage
lower, like
> >> >10 volts when you use the external DC input."
> >> >
> >> >Though I have not tried using an external pack without an attached
> >> >battery also installed, at least on the 702 I think that
setting you
> >> >mention only changes the the low voltage indicator and warning
alarm,
> >> >but the switch over voltage (if I remember correctly, ~7 volts
)is not
> >> >changeable.
> >>
> >> I believe you are correct, John. The manual says the 744T
> >> automatically switches to the internal battery at 9 volts. Starting
> >> with a 14.4 - 18 volt battery pack extends the operation time
> >> considerably over that of a 12 volt pack. The factory alarm setting
> >> of 11 volts seems too high for my higher voltage/higher amperage
> >> battery packs.
> >>
> >> >I still have not solved my battery switch-over problem that
results in
> > > >corrupted files.
> >>
> >> I've never had this happen-- no matter the powering situation as
long
> >> as I have a charged Lion battery installed. My 744T always closes
> >> out the files on the HD and also tells me upon re-powering that it
> > > powered down early and asks if I want to check for lost files
on the
> >> HD.
> >>
> >> How is your Hirose external battery connecter wired? Pin 1(-) and
> >> 4(+) should provide power without charging the removable 7.2 volt
> >> battery and the configuration of pin 1(-) and pin 3 (+) should
> >> provide power and charge the removable 7.2 volt battery. I use the
> >> later wiring on my primary Hirose cables because it encourages me to
> >> start off both batteries fully-charged. The wiring shouldn't make a
> >> difference but its the only thing I can think of that is not
> >> programming related,.. Did you check the SD users forum? Rob D.
> >>
> >> >I set the file size limit to around <2GB to allow for
> >> >easier DVD archiving: this has turned out to save me some important
> >> >recordings as it is only the last file being written when the
failure
> >> >occurs that gets corrupted.
> >> >
> >> >John Hartog
> >> >
> >> >
> >>
> >>
> >> --
> >>
> >>
> >>
> >
> >
>
>
> --
>
>
>
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