Comments on Brad Linder's blog: Building an external battery pack for portable ele...

The thing is, the AC adapter that came with MY Zoo...

2011-02-20T11:14:03.420-05:00

The thing is, the AC adapter that came with MY Zoom H4 says that it has an output of 9V at 300mA. The same is said on my Zoom H4... and most times I don't hear that whining noise when on batteries.

@ Josephers YOUR MODEL IS NEWER IT MAY NOT GENERAT...

2011-02-20T11:14:03.093-05:00

@ Josephers YOUR MODEL IS NEWER IT MAY NOT GENERATE THAT PULSE NOISE BUT BY BUILDING BATTERY PACK WILL GIVE YOU LONGER RECORDING HOURS - TRY 7.2 VOLT AND THAT SHOULD BE FINE.

@ Brad..This is a better solution, you can use st...

2011-01-29T08:10:27.146-05:00

@ Brad..This is a better solution, you can use standard batteries as well as Rechargeble. check this link:

http://www.jprelec.co.uk/store.asp/c=361/Battery-Box-6-x-AA-size

Graham

@ Josephers YOUR MODEL IS NEWER IT MAY NOT GENERAT...

2011-01-27T18:28:49.802-05:00

@ Josephers YOUR MODEL IS NEWER IT MAY NOT GENERATE THAT PULSE NOISE BUT BY BUILDING BATTERY PACK WILL GIVE YOU LONGER RECORDING HOURS - TRY 7.2 VOLT AND THAT SHOULD BE FINE.

You legend! I've been fumbling around with rec...

2010-11-03T11:28:18.865-04:00

You legend! I've been fumbling around with rechargeable NiMH AA's for ages; they wouldn't last long at all recording on location, and I had to carry a bag-full to share with my lectro radio mics.

A 9.6v 2000mAh batt took 2 hours to charge with a 1A delta charger and took approx 24hrs to drain fully. That's with normal everyday use: switching on/ off, recording at 48khz, but the rest of the time leaving on/rec armed. Plus that high pitched noise is now not present in my recordings. Extremely happy all round!!!

Thinking of making an external battery pack myself...

2009-11-19T11:41:08.419-05:00

Thinking of making an external battery pack myself. My AC Adapter also says it has an output of 9V at 300mA.

I have measured the actual voltage and current from the adapter with a multimeter. I notice that the numbers are almost identical to those that I get when I measure a standard PP3 (AKA "transistor") 9V battery.

I'm no electronics expert, but what would be wrong with simply hooking up a PP3 battery to a standard PP3 snap that is wired to the proper size DC connector?

Of course, I don't want to blow up my recorder. Any thoughts would be appreciated.

Well Josephers, It could be that Zoom decided to ...

2009-06-10T22:21:27.569-04:00

Well Josephers, It could be that Zoom decided to change some things about the H-4 and one of them was to change the output voltage of the AC Adapter.

I assembled a battery pack as Brad suggested and it works great.. I can turn the recorder on while my band is playing and just let it go.. I have never run out of battery power.. and I do not recharge between every use either.,

The thing is, the AC adapter that came with MY Zoo...

2009-06-10T16:58:21.076-04:00

The thing is, the AC adapter that came with MY Zoom H4 says that it has an output of 9V at 300mA. The same is said on my Zoom H4... and most times I don't hear that whining noise when on batteries.

The AC Adapter that came with my H-4 said it had a...

2009-06-03T21:53:15.858-04:00

The AC Adapter that came with my H-4 said it had an output of 12 volts.
The original idea of the Radio Shack kit and adaptor is the best idea put forth. I put together a battery pack as Brad recommended. It has worked flawlessly for many months now. Why try another route?

When I checked my Zoom H4 Unit, it said it took a ...

2009-06-03T21:22:29.059-04:00

When I checked my Zoom H4 Unit, it said it took a 9V power source. Are you absolutely sure that yours uses a 12V pack? Because I think what's happening is that you're overfeeding your Zoom H4's by 0.6 volts.

we have 3v-24v external Lithium battery pack.Capci...

2008-11-28T04:23:00.000-05:00

we have 3v-24v external Lithium battery pack.Capcity from 7Wh to 266Wh.

We are looking to cooperate with ebay sellers.

my contact E-mail kathy@owellpower.com
skype:kathy_yuan80

I'm ready to do this. I found a pack with 2 batter...

2008-11-22T14:08:00.000-05:00

I'm ready to do this. I found a pack with 2 battery packs (9.6 V and 2300 mAh) and a charge for $34 on Amazon. The thing should last forever. Toobad there isn't a good way to meter the power left in the battery packs.

It cracks me up that the unit runs off 2 AA's (3 volts) internal but 12 volts external. No wonder it has issues.

Perhaps a RE50N/D would be a little better with these mic preamps. Now we need a portable mic pre that doesn't suck.

Would something like the following work as a power...

2008-10-09T20:27:00.000-04:00

Would something like the following work as a power-source??

http://cgi.ebay.co.uk/Portable-12V-li-ion-rechargeable-battery-pack-1800-mAH_W0QQitemZ290265454760QQcmdZViewItem?hash=item290265454760&_trkparms=72%3A1301%7C39%3A1%7C66%3A2%7C65%3A12%7C240%3A1318&_trksid=p3286.c0.m14

???? or is there a reason for using 9.whatever volts battery, rather than a 12v to match the mains adapter supplied with the H4? what is the actual input operating voltage?

I decided I really liked the battery pack idea.. b...

2008-04-29T17:31:00.000-04:00

I decided I really liked the battery pack idea.. but instead of ruining my AC adapter I looked around through my old AC adapters from cordless phones etc. I found one that had a matching plug. The polarity is different but that is not a problem. I sorted out the polarity with a meter. Thanks for a great idea.. on more than one occasion the AA NMH batteries gave out too soon. Oh, and the battery pack I got at Radio Shack is 1600 MAH

Thanks a mil Brad for the instructions... how dari...

2008-03-26T15:25:00.000-04:00

Thanks a mil Brad for the instructions... how daring to try this batt on yer unit. Question - why cut the barrel connectors off of the doohickey? They let you crimp the bare stripped wires together without twisting, exposed wires, or soldering. Perfect as is.

If you compare volts to the octane of gasoline, mA...

2007-10-07T12:11:00.000-04:00

If you compare volts to the octane of gasoline, mAh would be how many gallons your gas tank holds.

If you know the wattage of your device you can figure out how long your batteries would last.

With Brad's pack: 9.6 volts x 1000 mAh = 9600 watt hours. Take the wattage of the H4 and divide it by 9600 and you get a rough run-time.

My understanding is that the voltage matters more ...

2007-08-27T08:58:00.000-04:00

My understanding is that the voltage matters more than the mAh. Too many volts and you'll fry your unit.

FYI, my battery pack is 9.6 volts and 1000 mAh.

hi brad, great job here! do you know if there are...

2007-08-27T07:35:00.000-04:00

hi brad, great job here! do you know if there are any other things to take note of when purchasing a battery... ie. keep it under 12v and what about the mAh rating? does it matter what its rated at?

your help would be appreciated.

cheers

dan