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I want my 9vdc

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10/12/1999 5:15 PM

I want my 9vdc

Is it just me, or anybody else notice that rectangular 9v batteries are 1)less easy to find, and 2)way more expensive than they used to be?

AC-powered pedalboards are cool, but sometimes I prefer to just throw the Rat into a bag and go play the job; it'll be hard to do this w/o 9v batteries.

Effects mfrs/designers: any way we can have stompboxes powered by AA, C or D cells? Maybe 1.5v or 3v or 6v effects don't work so well... ??

10/12/1999 7:13 PM
Aron	We talked about this on my stompbox forum: D,C batteries or even Radio Controlled battery packs can be used! I plan to get those Radio Controlled battery packs soon - as soon as I see one on sale at Radio Shack. Aron

10/12/1999 8:37 PM

The D-cell approach is the better choice here.

Consider - an alkaline D-cell is a 14Amp/hour source, compared with 1800mAh for the typical RC NiCd pack (which self-discharges quicker, too) and 580mAh for a Duracell alkaline 9V (according to thier website)

Ignoring self-discharge, a pack of 6 series-connected D-cells would last (14000/1800) = 7.78 times longer than the NiCd pack and (14000/0.580) = 24000 times longer than the 9V cell.

A stack of 6 D-cells in a plastic holder IS an ugly wart, but it should keep your whole pedal board alive a whole lot longer than a single 9V in each pedal (especially if you include an OFF switch).

Just a thought.

10/12/1999 11:16 PM

quote:
"Ignoring self-discharge, a pack of 6 series-connected D-cells would last ... (14000/0.580) = 24000 times longer than the 9V cell."

Uhhh, no. The equation is either (14000/580) or (14/.580).
Either way it works out to 24 times longer. Still significantly longer, but not car battery-type longer.

Also, looking at the discharge curves, if you pull 25 mA from a 9V battery, you'll reach 1/2 power (4.5V) in ~25 hours. However, you can pull 475 mA from a 1.5V D cell battery, and you'll reach half power (~.75V) after ~20 hours. This works out to the D cells being approximately 20 times more powerful. Essentially the same result as above.

In other words, 6 D cells in series (as you recommend) can power 1 effect pedal 20 times longer than a 9V battery could. Two effect pedals would have power 10 times as long as a 2 9V batteries (one in each pedal) could provide. Three pedals would have power 6 times longer than three 9 V batteries could provide. And so on.

So, bottom line, I agree with you, Don. This'd be how I'd do it. (Plus, you didn't mention the NiCd "memory" effect and that hassle...)

BTW: if you want to see the data sheets we're talking about, here's the link:

Alkaline Data Sheets

10/13/1999 2:29 PM

quote:
"(Plus, you didn't mention the NiCd "memory" effect and that hassle...)"

Nicad memory only takes place when a battery is charged and recharged repeatedly to the same voltage levels - as in uses where an automatic charging system kicks in when the battery reaches a certain level and then charges back to a preset voltage. In normal everyday use this does not occur. Several years ago, one of the video magazines did a study on nicad batteries in camcorders and could find no evidence of the memory effect. Nicads do gradually lose charge just from layng on the shelf.

J2K

10/13/1999 1:30 PM
fet	Battery idea 1) Thanks for response. 2) It occurs to me that a quick, secure holder for six D-cells could consist of three 99-cent plastic flashlights, minus bulbs, wired in series and velcroed down onto the pedal board; built-in power switches are a bonus.

10/13/1999 2:52 PM

The thing I have espoused for several years is to order a six-D-Cell battery holder from Radio Shack or Mouser. These things securely hold the D-cells and let you solder leads out to whatever distribution wiring you have. They make specific holders for them.

Mouser makes a 2-row, 3 battery holder for six D-cells as part number 12BH161 for $3.85, and a 3-row, 2 battery holder for six D-Cells as part number 12BH162 for $4.45.

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