I emailed Grace asking about the Walmart battery question. Here was my reply....
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I just received my new 6volt V3 from Colorado. thanks.
I see some folks using a WalMart DVD rechargable 5400mAh/9v battery with their V3's. Is this safe to use with my 6volt V3?
thanks,
Tim
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Hi Tim-
Glad to hear you received your V3! As you probably know, the V3 has two
settings that can be calibrated based on DC operating voltage.
The first of which is the low battery indicator. This is set to engage
at 5.75V for 6V operation or 11.5V for 12V. These voltage thresholds
provide an indicator that will engage with approx. 45 minutes to 1 hour
of runtime remaining and are based on sealed lead-acid discharge
characteristics.
The second adjustable DC parameter is the auto-shutdown circuitry
threshold. Over-discharge of a sealed lead-acid battery will
permanently damage the cells. To prevent this, the V3 will turn off at
the given threshold and will not turn back on until the battery has been
disconnected and reconnected. For 6V operation this voltage is set to
5.0V and for 12V it is placed at 10.0V. Again these values are based on
the sealed lead-acid discharge curve.
Now to address your questions directly:
> Is there any problem running the V3 with a 9.0V source?
There is no problem running the V3 from 9.0VDC. The higher the voltage
you run the preamp on, the warmer it will run. Given the calibration
settings of your V3 (6V) you can run it as-is. If your unit was set for
12V you would not be able to run it off this battery - the DC input
voltage would never exceed the auto-shutdown voltage and the preamp
would not power up (or would power on momentarily and then shutoff).
With this setting however, you will not have low battery indication or
auto-shutdown facilities available.
Depending on the type of cells this 'dvd' battery utilizes, you may be
able to recalibrate the V3's low-batt and auto-shutdown voltages to
match its discharge characteristics. To do so you will need an accurate
voltmeter and variable DC power supply would make it easier. To
reiterate, you do not need to recalibrate the V3, you just won't be able
to use these functions.
It is critical if you wire your own battery to connect the positive to
be to the internal opening and the negative to the external outer shroud
of the DC barrel connector the plugs into the V3. Failure to observe
this proper polarity will cause damage to the V3.
--
Jamie Krapohl
Assistant Design Engineer
Grace Design & Lunatec LLC
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Hi Tim-
Thanks for sending us the link. Looks like a nice power option, and
convenient form-factor. Nice work!
Tim Younkin wrote:
> thought you might like to see this image
>
>
http://www.seaofsouls.net/mbp/V3wire.jpg>
> thanks for your prior input
>
> Tim
>
--
Jamie Krapohl
Assistant Design Engineer
Grace Design & Lunatec LLC