Re: Magellan eXplorist 400, 500 and 600

From: Peter (prathman_at_comcast.net)
Date: 01/07/05 

Date: Fri, 07 Jan 2005 00:19:27 -0800

Tony Clark wrote:

> "Peter" <prathman@comcast.net> wrote in message
> news:79udnWuJSpjPY0DcRVn-uQ@comcast.com...
>
>>Tony Clark wrote:
>>
>
> SNIP
>
>
>>Even when backpacking on extended trails like the Appalachian, there are
>>sometimes road crossings where one comes near convenience stores. And
>>another use for my GPS is during bicycle tours where stores are found
>>frequently but finding an available electrical outlet while camping can
>>be a problem.
>
> True, but a portable charger could be an option. Or if you're on a bike why
> not get one of those generator gizmos to supply recharging power while you
> ride?

Even on sunny days you need a decent size solar panel to do much
recharging - and I haven't found any guarantees of sunny days.
Using a bike generator is a possibility but requires some modifications
since they inherently put out AC and use the bike frame as part
of the current path. That makes it harder to insert the rectifier
and voltage regulator circuits to let it act as a charger. One can
electrically isolate the generator from the bike frame and run
extra wires, but it does add to the complexity and possibility of
bad connections. There's also the fact that I'm very stingy with
my personal mechanical energy and hate to have some of it running
a rather inefficient dynamo/charging system.

But both the solar and generator approaches work much better for
devices that run off standard NiMH AAs. That way you just keep
rotating the AA cells through the charger as needed. But if
each device has its own built-in rechargeable battery then you
need to run wires from the charger to all those devices - the GPS
on my handlebars, the camera in my jersey pocket, the radio in my
pannier bag, etc. And then try to keep everything waterproof
when the rain comes and water follows the wires down into the
various bags.
>
>
>>Furthermore, this is only one of the arguments in favor of the standard
>>AA cells format. More significant to me is that it's standard and used
>>by many of my electrical devices. So if the batteries in my GPS die and
>>I really need to figure out where I am then the cells from my digital
>>camera can be substituted. ...
>
> I agree on the form factor argument. Between my cellular phone, digital
> camera and bluetooth GPS none of them use the same form factor although they
> are very very similar.

>>The information I saw was that replacement packs would be available, but
>>at the typical high price of proprietary form factors (~$50).
...
> Agreed that cost can be an issue, although I wonder over the life time of
> the unit how much will be spent on disposables?

I once estimated this and determined that I would have spent well over
$1000 on alkalines over the life of my last GPS receiver. But as I said
before, I use NiMH AA cells and therefore have only spent $2 total on
alkalines on the one trip where I underestimated the number of spares
needed.

> As I mentioned above a
> portable charger could be an option. They make these little devices that use
> alkaline batteries to recharge devices like PDAs so I am sure something like
> that could be done for the GPS. Other than the small cable with battery
> connectors you can achieve virtually the same thing as carrying extra AAs.

Yes, that's probably the best work-around and it's what I'll be forced
to do if the trend toward separate proprietary batteries for each device
continues. Some of these designs are made to be recharged by the 5V
available from USB ports, so a 4-pack of NiMH AA cells should work
as an external power source.
But I'd still prefer to be able to just run directly off the AAs
rather than have to use them to recharge the internal lithium cell.
>
>
>>Note to any manufacturers: The CR3V-type form factor can give us the
>>best of both options. Make your lithium battery pack in this form
>>factor and include some special contacts so the device will know that
>>the pack can be recharged safely. That lets us have convenient
>>recharging without removal of the batteries when using your standard
>>pack. But if we find ourselves ever needing to substitute AA cells then
>>those will fit as well (and without those special contacts so the device
>>will know not to attempt recharging such substitute cells).
>>
> Standardization is a good thing in my opinion. I have a video camera that
> uses a larger rechargeable but the battery compartment is designed to also
> accomodate 4 AAs. They won't last but about 20 mins but as you say they're
> good in a pinch. I guess what I am trying to say is that the rechargeables
> in a GPS are not a show stopper for me. Common form factors would make it
> even better and more convenient too.

Yes, the AA cell has been a triumph of standardization. They're readily
available worldwide and interchangeable in a vast array of devices.

The rechargeable Li+ cells certainly have advantages and I'm hoping
that there will be some standardization around the CR3V form so
we can get those advantages without resorting to separate proprietary
designs for each device.
But it won't happen unless more consumers start considering the
battery form factor when making their purchasing decisions.

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