Comments on: Review: Minty Boost iPod Charger Kit

By: joel shay

joel shay — Sun, 02 Aug 2009 22:48:07 +0000

yeah it will charge a nano about 5 times. ipod touch, 1 full charge

By: josephine Yau

josephine Yau — Sun, 07 Sep 2008 05:40:48 +0000

I am wondering if the pin 2 and 3 are signalled, cos I learnt that for some ipod and i phone, if the pin 2 and 3 are not signalle, the phone of ipod wont be charged even though Pin1 and 4 got 5 volt potential difference.

thx

By: Mike

Mike — Wed, 10 Oct 2007 07:57:18 +0000

Can anyone advise me if Minty Boost will do the job for a Nokia 6110 which is equipped with a great (but power-hungry) GPS. the OEM wall charger for this cellphone is rated 5VDC / 650mA.

By: Jamie

Jamie — Mon, 24 Sep 2007 21:58:30 +0000

If you will build it I will buy it. Let me know if you are interested and how much.

By: DaveC

DaveC — Wed, 27 Jun 2007 20:03:26 +0000

The actual voltage of a fully charged NiMH battery is much higher than the nominal 1.2V. In practice, 4 AA batteries come up to about 5.2 volts. I believe that’s where Stefan’s numbers came from.

As for Stefan’s comments, I am sorry it took me this long to address it. I had forgotten about my post here. Basically, I made a major assumption that the Nano must have a cut-off operating voltage. I assumed that the operating energy consumption is NOT 3.7V*400mAH*t but is something much less based on the voltage drop of V delta = 3.7 V – V cut-off. Therefore the additional energy consumption would be based on (5.2 – 3.7) V. This assumption, a pure conjecture on my part, could be completely wrong.

One thing is certain, if one takes into the conversion loss and the NiMH degradation over time, the actual additional time would be much less. But no matter what, the solution works like a charm. I have no idea how long the actual play time extension is because I have always recharged the NiMH batteries long before they ran out of juice.

By: Anonymous

Anonymous — Tue, 26 Jun 2007 00:24:45 +0000

@Stefan:
Where is the “5V x 2500mAh” coming from?

2 NiMH cells are 2.4V. 2.4V x 2500mAh = 6,000 mWh, which is 4 times as long.

By: Stefan Vorkoetter

Stefan Vorkoetter — Sun, 21 Jan 2007 14:40:35 +0000

Actually, it’s more like 6 or 7 times the Nano battery capacity. The Nano has a 3.7V 400mAh battery, which is 1480mWh. On the other hand, 5V x 2500mAh is 12500mWh.
Then, 12500 / 1480 = 8.4 times as long, but since the internal regulator is maybe 85% efficient, you have to reduce that to about 7 times.

By: DaveC

DaveC — Fri, 25 Aug 2006 14:52:20 +0000

You will find a home-brewed, simpler and cheaper DIY solution at http://knowledgeaction.blogspot.com/2006/08/tech-tip-cheap-charger-for-ipod.ht . A trip to the local RadioShack and a few dollar bills will get you 4×2500 mAh (25 times Nano battery capacity). All iPods have an internal voltage regulator so this simple, batteries only arrangement will work. It can be used to recharge cell phones and other devices.

By: Calvin

Calvin — Sat, 08 Jul 2006 21:39:07 +0000

Can i buy one?

By: Paul Stamatiou

Paul Stamatiou — Thu, 08 Jun 2006 02:43:50 +0000

If you are thinking about ordering this, wait until the next version. The creator has contacted me saying that it might not work on all devices just yet due to the lack of down pull on the USB D+ line. A newer version will be out sometime in the near future.

By: Jeff

Jeff — Wed, 07 Jun 2006 22:34:05 +0000

Hey Chris

That’s exactly what I am interested in this for, so I can use my Treo on the plane for longer.

You can use a USB charger cable for your phone. I have one for my Treo, and recharge from my laptop on the plane, but this minty boost would be a whole lot more convenient.

Being that I have never done any soldering, I am also considering one of these

By: Chris Morrell

Chris Morrell — Wed, 07 Jun 2006 15:50:55 +0000

I would love to find a way to make this charge a cell phone, perhaps that will be my next project once my current project is completed. Awesome project Paul.

By: Cory

Cory — Wed, 07 Jun 2006 14:08:40 +0000

thats awesome, ive been meaning to try it, it will work with any usb device

By: Jeff

Jeff — Wed, 07 Jun 2006 08:09:16 +0000

D’Oh! There it is, right in the article. Hmm, will have to do some of my own capacity testing.

Yes, each battery technology has a different capacity for the same sized cell. Most photograhy guys are using NiMH over Alcalines for value and high capacity reasons. The NiCD technology has been left behind. The Energizer Lithiums have the most juice of any battery at the moment, but are only a one-time use.

Dude, it’s late there! Get some ZZZ!

By: Paul Stamatiou

Paul Stamatiou — Wed, 07 Jun 2006 07:26:57 +0000

It was mentioned on the instructables page, but yes I do know that it varies by type – alkalines, nicads, nihms, lithiums, etc.

By: Jeff

Jeff — Wed, 07 Jun 2006 07:23:46 +0000

Hi Paul

Where do you get the battery capacity figures of 500mAh for the 9V and 3000mAh for the AA?

The reason I ask is that rechargable batteries have a higher capacity than alkaline (disposable) batteries, yet the latest 9V NiMH capacity is 200mAh, and AA NiMH are 2700mAh, which is quite different to the figures in your article.

I would expect alkaline AA batteries to be 1500-2000mAh, though their capacity it typically not printed on the side like NiMH and NiCD’s.

Cheers

Jeff

By: Paul Stamatiou

Paul Stamatiou — Wed, 07 Jun 2006 05:03:06 +0000

I haven’t had the chance to charge it from a complete drain, but I think it can do a full charge on a Nano and a bit more.

By: Zach Hale

Zach Hale — Wed, 07 Jun 2006 05:02:04 +0000

How much power does the Minty Boost provide? Will 2 AA’s fully charge the Nano? How long will the Nano run using Minty Boost power? Stats!