[pct-l] nPower PEG -- some unfortunate numbers

Kevin Cook hikelite at gmail.com
Sat Mar 26 04:01:22 CDT 2011 

So I need to use 2 batteries everyday? The PEG will save me sooo many
batteries.:)

On Sat, Mar 26, 2011 at 1:57 AM, John Abela <pacificcresttrail2011 at gmail.com
> wrote:

> You guys use the Mophie Juice Pack Air Case?? I have one and freaking
> love the thing. It can give me an additional full day of GPS usage
> from a full charge.
>
>
> On Sat, Mar 26, 2011 at 1:44 AM, Kevin Cook <hikelite at gmail.com> wrote:
> > Thanks David
> >
> > Your numbers don't match mine. First, I'm not planning to be talking on
> the
> > phone! That said, here is my math...
> >
> > I've done some field testing of battery life in the type of use I want
> from
> > the phone. First, I want to run the GPS all day. I'd like to occasionally
> > take photos or video with the phone (this use may go away completely if
> > needed). I want to type a journal using the phone as well. Some iPod use,
> > but also willing to give this up.
> >
> > My biggest test was on a two day mountain bike ride from Flagstaff to the
> > Grand Canyon following part of the old Moqui Stage route. Anyway... I ran
> > the GPS all day, took some pictures and video, listened to music a fair
> > amount of the time actually, and sent some email and a FB post when I had
> > signal along the way. This level us use consumed 55-60% of the battery.
> I'll
> > assume I need at least a 75% charge everyday. It would be nice to have a
> > 100% charge each day.
> >
> > The iPhone 4's battery is rated at 3.7V 1420mAh. The PEG is rated at 5V
> DC,
> > 500mA or 2.5W with a 1000mAh battery. I'm not exactly sure how to convert
> > nPowers specs about xx minutes is xx talk time. I'm assuming that I am
> only
> > getting 1.5W from the device while hiking. The PEG will full it's battery
> > completely in less than 4 hours. This means I should get 2 charges a day,
> > perhaps 3 on longer days. Let's make a pessimistic estimate of 75%
> > efficiency in the battery transfers.
> >
> > The PEG's battery has 3.7Wh at the iPhone's voltage (1.0Ah x 3.7V). The
> > iPhone's battery contains 5.3Wh (1420 x 3.7). Accounting for the
> > inefficiency of the transfer, the PEG can provide 2.78 Wh(3.7 x .75) of
> > power to the iPhone's battery. It seems to me that the PEG should be able
> to
> > provide about a half charge for each charge of it's internal battery. If
> the
> > PEG charges twice a day, then it should provide what I'm hoping for.
> >
> > Obviously I've made a LOT of estimates and assumptions. Only time will
> tell.
> > I'm not willing to use all the batteries needed to recharge the phone
> > everyday with one of those AA chargers. If I can't get the PEG to work, I
> > will just alter my use of the phone.
> >
> > On Fri, Mar 25, 2011 at 8:16 PM, David Lippke <lippke.list at gmail.com>
> wrote:
> >>
> >> Kevin, as much as I love alternative energy, I'm afraid the numbers just
> >> don't work on any level for the nPower PEG.
> >>
> >> I've compared the power requirements per talk minute, battery
> capacities,
> >> conversion efficiencies, etc, of the various iPhones and have mapped
> those
> >> into nPower's stated specifications.   Those tell me that the PEG
> generates
> >> less than 0.1 mwh per minute of walking.   I'd be happy to lay all the
> >> calculations out but, at the end of the day, it only takes nPower's own
> >> numbers to convict it --
> >>
> >> nPower states that it takes 26 minutes of walking to obtain 1 minute of
> >> talking on a 3G call using an iPhone 3G.  Since a new iPhone 3G will do
> >> about 340 minutes of 3G talking, give or take, that means that you would
> >> have to walk for 147 hours to charge the phone (26 * 340) / 60.   So
> that
> >> means that you would have hiked for 15(?) days carrying 11-12oz when you
> >> could have gotten the same charge for less than 3 oz (iGo powerXtender +
> 2
> >> lithium AAs).
> >>
> >> Looking at it economically, if a PEG costs $160 and an iGo costs < $20
> and
> >> two lithium AAs cost $5, this means that you could charge the iPhone 28
> >> times (140 / 5) at the same price of of AA charging.    And to charge
> the
> >> iPhone 28 times with the PEG means that you'd have to walk for 4125
> hours(!)
> >> or 412(?) days -- and of course the recharging efficiency will be
> dropping
> >> all the time and so even this extreme number would fall short.
> >>
> >> I didn't look at the personal energy cost of carting the extra 8oz all
> >> that ways but of course a "Ray-sian" calculation would do its own
> frowning
> >> on the solution as well.
> >>
> >> The net for me is that the nPower PEG is a very neat idea but it just is
> >> not efficient or powerful enough to warrant carriage on the basis of
> cost
> >> effectiveness (or convenience).
> >>
> >> On the other hand, maybe (maybe) using it cuts landfill and pollution
> >> loads and that or other reasons might make it worth it for some.  My
> wife
> >> thinks it looks like it might be the perfect instrument -- when applied
> to
> >> my head -- for adjusting my behavior!   :-}
> >>
> >> /David
> >>
> >> On Fri, Mar 25, 2011 at 9:05 PM, Kevin Cook <hikelite at gmail.com> wrote:
> >>>
> >>> I hear you John. If it doesn't work, then I'm no worse off than I am if
> I
> >>> can't get it. Having it lets me use my iPhone for more things is all.
> If
> >>> the
> >>> PEG fails, I'll probably use one of those devices that lets you charge
> it
> >>> from AAs. I've pretty much ruled out solar.
> >>>
> >>> The iPhone isn't critical. My safety won't be at risk or anything. My
> >>> wife
> >>> is also going, so between us, we have 2 iPhones. If we are conscious
> >>> about
> >>> conserving battery, we should always have one available for things like
> >>> being a GPS.
> >>>
> >>> I mostly want the PEG so I can create a GPS trace of the whole trail. I
> >>> know
> >>> several hikers have already done this, but the more data we collect,
> the
> >>> more accurately we have the trail mapped.
> >>>
> >>> On Fri, Mar 25, 2011 at 5:55 PM, John Abela
> >>> <pacificcresttrail2011 at gmail.com
> >>> > wrote:
> >>>
> >>> > I am still going to question the viability and reliability of this
> >>> > product to keep an iPhone powered.
> >>> >
> >>> > Do I love the concept - heck yeah. I would even buy one IF it proved
> >>> > to actually provide enough power to recharge the power-hungry iPhone.
> >>> >
> >>> > But, I just don't know Kevin... seems like a huge risk at this point.
> >>> > You've got what... 20-25 days left to get your gear in order... and
> >>> > you want to go out on the PCT with something that will have very very
> >>> > little trail proveness (guess I have to make up that word).
> >>> >
> >>> > While I am a huge fan of solar systems, even the high dollar ones are
> >>> > still risky.
> >>> >
> >>> > If you are planning to use your iPhone for everything you have said
> >>> > you are going to use it for Kevin, it will be a primary piece of
> >>> > equipment for you. Why put yourself at risk with some product that
> >>> > just had a circuit board issue. We both know what that means... and
> we
> >>> > both should know that is not something that should be screaming red
> >>> > flags - considering your time line, considering the inability for
> >>> > anybody to get this product under review and actual on-trail miles.
> >>> > Sigh, a whole host of red flags here Kevin...
> >>> >
> >>> > As much as I may not like them, nor you like them, maybe those things
> >>> > you throw batteries into and plug it into your device is the better
> >>> > way to go at this point in time.
> >>> >
> >>> > Just some things to consider.
> >>> >
> >>> > John
> >>> >
> >>> >
> >>> > On Fri, Mar 25, 2011 at 4:14 PM, Kevin Cook <hikelite at gmail.com>
> wrote:
> >>> > > When I spoke with Ann this morning, she said they had a problem
> with
> >>> > > the
> >>> > > circuit boards and had to change suppliers. She said all backorders
> >>> > > would
> >>> > be
> >>> > > out next week and that I should also be able to get one shipped
> next
> >>> > week. I
> >>> > > bet you get yours sooner than you think!
> >>> > >
> >>> > > I was getting pretty worried about how to power my iPhone. It was
> >>> > probably
> >>> > > my biggest gear concern that was still unresolved. So relieved to
> >>> > > have
> >>> > that
> >>> > > taken care of!
> >>> > >
> >>> > > On Fri, Mar 25, 2011 at 12:57 PM, Halfmile <list at lon.net> wrote:
> >>> > >
> >>> > >> Kevin,
> >>> > >> I ordered one on 9/13/10, so far it has not shipped. Your post
> >>> > >> prompted me to call for an update as I have not heard about my
> order
> >>> > >> since a 1/4/11 email. They said they had a parts problems and had
> to
> >>> > >> change a supplier. It's suppose to ship in a few weeks.
> >>> > >> -Halfmile
> >>> > >>
> >>> > >> On Fri, Mar 25, 2011 at 11:55 AM, Kevin <hikelite at gmail.com>
> wrote:
> >>> > >> > Did anyone get their hands on an nPower PEG yet?
> >>> > >> >
> >>> > >> > Finally spoke to someone there and they said they are shipping
> >>> > >> > this
> >>> > week.
> >>> > >> I think Halfmile had one ordered.
> >>> > >> >
> >>> > >> > Misspellings and typos brought to you by iPhone.
> >>> > >> > _______________________________________________
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> >>> > >>
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>
>
>
> --
> John B. Abela
> www.RedwoodOutdoors.Com
>
> In God's wildness lies the hope of the world - the great fresh
> unblighted, unredeemed wilderness. The galling harness of civilization
> drops off, and wounds heal ere we are aware. ~ John Muir
>

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