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Gear / Technical Help => Remote Power => Topic started by: bagtagsell on November 25, 2003, 05:01:54 AM
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Does anyone know how to build a rechargeable power supply for the JB3. I know I should buy the extra battery, but I need the power for this weekend and the battery wont get here in time. Rat Shack parts would be best since it is close to my house. Thanks. Mark
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Look for Dail Reed's solution... Do a search, his name is more than likely DATGeek. He has figured out the mobile power for JB3...
Terry
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I don't have mine handy to check, but...you could remove the internal batteries outright and power it from an external SLA or RC pack with a voltage regulator to drop down to 5v, which I believe is what the JB3 takes.
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The one thing you will want to be careful of when using external power, is if your power supply dies, you lose the entire recording!!! Make sure you test the battery life before you record your show so you know what to expect.
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So I could get 4 AA rechargeable batteries (build something so it plugs in the dc jack) and that would work? Ive been searching NJB3 tapers group on yahoo and havent found a good answer yet. Anyone out there who has done this help me out please
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You will need to use rechargeable AA batteries. That way your voltage will be 4.8 volts. The JB3 is really picky about the voltage. It won't work with volts above about 5.3 and won't work below 4.3 I believe. So if you try to use 4 AAs they won't work until you drain the batteries some. But yes it will work, just don't let them die on you while recording.
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You will need to use rechargeable AA batteries. That way your voltage will be 4.8 volts. The JB3 is really picky about the voltage. It won't work with volts above about 5.3 and won't work below 4.3 I believe. So if you try to use 4 AAs they won't work until you drain the batteries some. But yes it will work, just don't let them die on you while recording.
you can use a 12V SLA pr 9.6V batt. along with a +5V voltage regulator IC. NTE makes wide variety of VRs. they are pretty easy to wire up. Vin, Vout, Gnd.
it's not too hard to wire these up in a small craft box in your wiring. hell, you could even use some shrink tubing to protect the IC in your line.
http://www.nteinc.com/specs/900to999/pdf/nte960.pdf
marc
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I found this on yahoo groups:
I have a simple 4-D cell (Radio Shack) battery pack that I built to power my Sony TCD-D7 DAT deck. I use 4 x 7500 mAh Powerex NiMH D cell's. The D7 power plug is an EIAJ-4 (4.0mm OD x 1.7mm ID). I measured the JB3 plug OD and it was the same as the D7's. All looked promising. I had charged the D cells the day before, but not used them. I measured them and they were at 5.52v (1.38v x 4 unloaded). I figured a half volt shouldn't hurt this thing.
Does anyone know how exactly to make this (step by step Im retarded)
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If you're asking how to, I'd recommend the second battery from Creative.
While NiMh cells are rated at 1.2v, they can creep up over 1.4 on a full charge so 4 cells can actually deliver too high a voltage for the JB3 - causing it to not operate. You may have to pre-drain slightly. Test it first - if it doesn't power up that's the problem. I ran a halogen bulb on it for a minute and all was good. BTW, 3 cells is not enough voltage (tried it).
Others (Dale I think) tried just adding a diode to a 6V (to cut the voltage a bit) is the huge intermittent power draw the JB3 needs. Tends to overload the diode(s).
Using regulators is great - but they generate heat and need ~1.7 v of overhead to operate. A 7805 regulator will do (cost <$1), but you'll need at least 6.7v source (i.e. a 6v SLA won't do it). Run a regulator straight off a 12v without a heatsink and you'll burn yourself if you touch it, and it will probably shut down after a few minutes anyways (built in thermal protection). With a 9.6v battery, it's not quite so dramatic. Haven't tried with 7.2 but that's where you probably want to be if you go this way.
The easiest DIY is to buy any old 'car adaptor', set it to 4.5v output and cut off the lighter adapter and power if from a 7.2, 9.6v NiMh or 12 v SLA. It has the regulator already heat sinked.
Also, anytime you hook up an external source, the JB3 will attempt to recharge the internal battery, so there's some strategy to the order that you use power. Because any interruptions in the voltage level of the external source will screw up your recordings, I'd recommend starting with external and yanking it at a known safe point, allowing the internal to take over. If you run out of juice then, the internal shuts down safely and saves your recording.
If you're looking for the JB3 connector, I had luck with a 1.75 X 4.0, wired centre positive. Even the Creative connector is kind of a sloppy fit due to the angle of the case.
So while I've had success with several methods, if not for my fondness for DIY'g, I'd just go for the official battery.
Understood - you have special rush needs so good luck!