Topic: jb3 external power II...

[Todd R]

I don't know if anyone talked about it before but I've just found this.
It looks like small, not too expensive, usable for powering a single JB3 but I wondered how long... 4200mAh is good isn't it?

according to my calculations about 6 hours

I think you're off in your calculations.  IIRC, the JB3 draws about 300ma on average, so this should be good for 12-14 hours.  Thanks for that link, Laurent, that looks like a nice little power pack.

[momule]

IMO. I think those calculations are a bit on the low side as the jb3 can pull an amp during disc spin up and then around 350ma during playback and around 500ma during recording.  Hense why I decided to go with 700ma as a average.

you gonna make it to waka again this year Todd?  Hope to see ya there.
Nick

[Todd R]

Yep, Nick, I'll see you there!  Doing it in style this year -- driving an RV out from Denver.  Bringing the wife too, so I'll probably be a bit more low key.  Of course, the late night sets once she's in bed might be a different story.


As to the JB3 power, this thread shows measurements for about 300ma current draw:

http://taperssection.com/index.php?topic=41007.0


300-350 seems to be about my experience from what I can tell.  Plus, I really thought the internal batteries were 1100ma ea.  So using two of them to get 6 to 6.5 hours seems to be consistent with a 300-350ma draw.  I'm still thinking a 4200mahr battery should get you 10 hours or more.

I've got a 3000mahr battery, maybe I'll try converting some DATs with my JB3 and do some power/time calculations at the same time.

[Laurent]

I think you're off in your calculations.  IIRC, the JB3 draws about 300ma on average, so this should be good for 12-14 hours.  Thanks for that link, Laurent, that looks like a nice little power pack.

They are 1£ less if ordered from here:
http://www.portablepowersupplies.co.uk
I've already ordered one! I might test it to record some class at university and a jazz fest this summer.

[setboy]

hey rowjimmy

this thing still working for you?

I just picked up this : http://www.bixnet.com/hicamiexbapa.html

Has pretty much everything that the Digital concepts product has plus more power (4400mAh @ 5v).

The thing that sold me over the Digital Concepts product is that it was actually instock (i looked everywhere for the other) and i could get it before leaving for vegas.

[Jammin72]

Anything to report on this...


Mine arrived today.

here is Another one I just purchesed.  I hope to get a chance to try it out before wakarusa.  I have confirmed that the Jb3 will power up and so on with it but need to see how it does in the field.

Should be nice for thoise folks who dont know how to solder and just need something they can throw some AA's in and go.

edit to add It runs on 4 AA's.

[Jammin72]

OK... This thing didn't work at ALL... Is there something special I'm missing or did I just get a bad one?!?

Anything to report on this...


Mine arrived today.

here is Another one I just purchesed.  I hope to get a chance to try it out before wakarusa.  I have confirmed that the Jb3 will power up and so on with it but need to see how it does in the field.

Should be nice for thoise folks who dont know how to solder and just need something they can throw some AA's in and go.

edit to add It runs on 4 AA's.

[kskreider]

Try draining the capacity just a bit first.  If it is just straight AA's then it is outputting more than the 5V that the JB3 needs.  Hit it with a volt meter and confirm.

OK... This thing didn't work at ALL... Is there something special I'm missing or did I just get a bad one?!?

Anything to report on this...


Mine arrived today.

here is Another one I just purchesed.  I hope to get a chance to try it out before wakarusa.  I have confirmed that the Jb3 will power up and so on with it but need to see how it does in the field.

Should be nice for thoise folks who dont know how to solder and just need something they can throw some AA's in and go.

edit to add It runs on 4 AA's.

[Jammin72]

I appreciate the tip.. however isn't the thing designed to output 5V which is the PSP spec?

Try draining the capacity just a bit first.  If it is just straight AA's then it is outputting more than the 5V that the JB3 needs.  Hit it with a volt meter and confirm.

OK... This thing didn't work at ALL... Is there something special I'm missing or did I just get a bad one?!?

Anything to report on this...


Mine arrived today.

here is Another one I just purchesed.  I hope to get a chance to try it out before wakarusa.  I have confirmed that the Jb3 will power up and so on with it but need to see how it does in the field.

Should be nice for thoise folks who dont know how to solder and just need something they can throw some AA's in and go.

edit to add It runs on 4 AA's.

[dnsacks]

I suspect it's designed to output whatever voltage range the PSP will accept.  Sounds like it could be too much for the jb3.  Are you running alkaline aa batteries (1.5 volts each, or 6 volts total from 4) or nimh aa batteries (1.2 volts each or 4.8 volts total from 4)?

[Jammin72]

I'll go home and measure.  I was hoping to have a "AA" Solution. I've got plenty of NiMH "AA" Cells I'll try with those.  The heat shut down the JB-3 anyway during the Donna Set anyway... D8 next to me ran just fine.

It may be time for a 660!

[tms]

I'll go home and measure.  I was hoping to have a "AA" Solution. I've got plenty of NiMH "AA" Cells I'll try with those.  The heat shut down the JB-3 anyway during the Donna Set anyway... D8 next to me ran just fine.

It may be time for a 660!

Anything trying to power a JB3 through the 5V port using 4 AA batteries is doomed to failure.  Even if they're alkaline batteries and start out at 6V total, that's not enough over voltage to drive a power regulator (if that unit has one inside it). 

The JB3 needs a steady 5V supply and it's pretty fickle about the voltage range it can accept. 

If you use something with a regulator like a 7805 it needs some headspace on the voltage, like 1.5V.  So if you started with a sled of 6 NiMH AA batteries that will give you about 7.2V going to the regulator which would then knock it down to 5V and you'd be good until the AA's drain from 1.2V each to 1.1 V each.  Which would take how long? Probably not very long.  I think if it were me I'd get a sled of 8 AA's and run that to the regulator.  That would give you a lot more headroom b/c you could drain it from 9.6 down to 6.5V and you'd get the full capacity of the batteries that way.

[j.mart]

http://cgi.ebay.com/Creative-Nomad-Jukebox-2-3-External-Battery-25-50-hours_W0QQitemZ320003053525QQihZ011QQcategoryZ86541QQcmdZViewItem

Just got one on the mail today. It's really small and looks awesome.

[poorlyconditioned]

I'll go home and measure.  I was hoping to have a "AA" Solution. I've got plenty of NiMH "AA" Cells I'll try with those.  The heat shut down the JB-3 anyway during the Donna Set anyway... D8 next to me ran just fine.

It may be time for a 660!

Anything trying to power a JB3 through the 5V port using 4 AA batteries is doomed to failure.  Even if they're alkaline batteries and start out at 6V total, that's not enough over voltage to drive a power regulator (if that unit has one inside it). 

The JB3 needs a steady 5V supply and it's pretty fickle about the voltage range it can accept. 

If you use something with a regulator like a 7805 it needs some headspace on the voltage, like 1.5V.  So if you started with a sled of 6 NiMH AA batteries that will give you about 7.2V going to the regulator which would then knock it down to 5V and you'd be good until the AA's drain from 1.2V each to 1.1 V each.  Which would take how long? Probably not very long.  I think if it were me I'd get a sled of 8 AA's and run that to the regulator.  That would give you a lot more headroom b/c you could drain it from 9.6 down to 6.5V and you'd get the full capacity of the batteries that way.

Six batteries (7.2V) through a regulator should do it.  I'm running two LiIon cells (3.6V each, total 7.2V) through a standard 7805 and that works fine.

Don't put too much input voltage in because you'll be: 1) wasting battery, 2) heating the regulator (need a bigger heatsink).  Also, you can get "low drop out" regulators that will work with lower headroom, maybe down to 0.5V.  (So, five cells might even work.)  But I have not tried these yet.

  Richard

[dnsacks]

fyi, built a voltage regulator out of a 7805 (purchased at my friendly neighborhood radio shack and mounted into an empty altoids box) for my jb3.  I'm using it with 9 volt 5400mah wallmart-style Lithium Ion Batteries (purchased direct from an ebay seller for $25 apiece shipped).

the wallmart-style battery will power the jb3 and my t+mod ua5 for a HAIR under 6 hours, with the ua5 providing phantom power to a relatively power-hungry studio projects lsd2.

The altoids box vr does get a bit warm, but ran this rig throughout the telluride bluegrass festival without any problem.

A few observations:

1) critical that you remove the batteries from the jb3 when using this external powering scheme as the jb3 appears to pull a LOT more power with the batteries in.

2) the external battery pack will not reliably power the jb3 when transferring wavs to the pc (likely too much power drain).

3) the external battery pack will reliably charge the jb3's internal batteries.