VisorCentral.com (http://discussion.visorcentral.com/vcforum/index.php)
- Accessories (http://discussion.visorcentral.com/vcforum/forumdisplay.php?forumid=3)
-- Prism Battery Extender (http://discussion.visorcentral.com/vcforum/showthread.php?threadid=8976)

My two biggest concerns with the Prism were the display quality and the non-replaceable lithium battery. My display concerns went away as soon as I started using it, but that battery thing really bothered me. One of the things that I love about the Visor is that I can throw my keyboard and a pack of AAA batteries in my bag and be set for a couple full days of continuous use. Very handy for my occasional trips to Sweden.

The Prism, even if Handspring's 6 hour continuous use number is accurate, isn't going to survive a transatlantic flight (not to mention the domestic connections, bus rides, etc. at either end). And since you can't just pop the battery off and replace it with a fully charged unit like you can with a cell phone, I decided I needed a creative solution.

Fortunately I found one (and in the world of Windows CE of all places!). The Build a Battery Extender web page describes how to build a battery pack that uses ordinary alkaline batteries to power (or recharge) a Casio or iPaq PDA. The good news is that I just built one and it works great for the Prism too!

You'll need a hotsync connector (which I've seen folks selling here on VisorCentral) and less than $10 worth of parts from your local RadioShack. The instructions on the web site are very good. The only thing you should do differently when building one of these is leave out the diode (the Prism's internal charging circuit can easily handle the full 7 volts you'll get from a fresh set of alkaline batteries). When wiring to the hotsync connector connect the positive wire to pin 7 and the negative wire to pin 4. The only other change I made to the design was to put a connector on the other end of the cable so that I can plug in different types of battery packs depending on my needs (I'll carry a AA pack all the time for emergency charging and I'll carry a C or D cell pack when traveling).

Now that I know I can run my Prism anywhere in the world for as long as I want off easily obtainable batteries, I think it is here to stay

__________________
<ul><li>Dave Kessler<br>President - Kopsis, Inc.</li></ul>

Mr. Kessler to the rescue again!

Thanks!

I had seen similar contraption for the Palm V, and I was about to go buy a cable and begin "experimenting." Thanks for saving me the trouble. (This issue of short battery life was/is a big concern for me as well.)

How fast does a battery recharge the Prism? Does the battery provide enough amps to recharge AND use the Prism at the same time?

Thanks again,

tyler

The battery pack with fresh batteries should recharge the Prism just as quickly as the cradle. As the battery pack voltage drops, I'd expect the charging time to increase but I really can't predict how much.

The good news is that you can use the Prism and charge the battery at the same time (just as you can with the cradle) so charging time really isn't much of an issue

__________________
<ul><li>Dave Kessler<br>President - Kopsis, Inc.</li></ul>

quote:

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Originally posted by dkessler
The only thing you should do differently when building one of these is leave out the diode (the Prism's internal charging circuit can easily handle the full 7 volts you'll get from a fresh set of alkaline batteries).

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__________________
<ul><li>Dave Kessler<br>President - Kopsis, Inc.</li></ul>

Hopefully Tech Center Labs will make an emergency recharger for the Prism. They're looking into it, but no final word yet.

__________________
James Hromadka
Old Friend

quote:

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Originally posted by dkessler
...I can throw my keyboard... ...for my occasional trips to Sweden.

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God bless America, my home sweet home...

Kessler's sharing his wonderful work again...thanks a million!
My question: could you use a 9 volt battery (w/ a diode) instead of AA, C or D?
Seems to me you'd get more out of your battery and have a heckuva lot less bulk to mess with.

'Course, I'm an electro-newbie, so I may be way off base... just trying to "think compact," as it were.
What do you think?

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<br><img src="http://brian.covert.net/pix/sitepix/sig.jpg" border="0">

Kessler.. you are da man! another cool thing to have, that should already have been marketed....

Be very careful at the airport xray machine though.. Unless the operator is a VC'er, you may get taken into the back room for some questioning

quote:

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Originally posted by brijoco
My question: could you use a 9 volt battery (w/ a diode) instead of AA, C or D?

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__________________
<ul><li>Dave Kessler<br>President - Kopsis, Inc.</li></ul>

quote:

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Originally posted by MarkEagle
Sweden??? You have CF software to write!!! Sweden can wait! (just kidding, of course)

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<ul><li>Dave Kessler<br>President - Kopsis, Inc.</li></ul>

How about a solar recharger?

Following James' link to Tech Center Labs I ran across a comment by a fellow who used a solar battery charger to recharge his Palm V. Here's a link to a list of solar chargers from Edmunds Scientific: http://www.edmundscientific.com/Pro...s.cfm?catid=125 . The web page does not list any specifics on the performance of the solar panel other than to say that it will recharge two NiCad D cells in 48 hrs. That sounds a little slow, but it might work in a pinch.

Interesting if nothing else.

tyler

Wrong Business

Dkessler:

I think you in the wrong business! You should be in the Visor hardware business not the software business. I can see some practical uses for a battery pack and a CF Module. I am sure that they would be best sellers if they were deleveloped as commercial products.

quote:

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Originally posted by tyler
How about a solar recharger?

Following James' link to Tech Center Labs I ran across a comment by a fellow who used a solar battery charger to recharge his Palm V. Here's a link to a list of solar chargers from Edmunds Scientific:

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__________________
<ul><li>Dave Kessler<br>President - Kopsis, Inc.</li></ul>

Plus the fact that the Prism isn't easy to read in the outdoors anyway makes a solar charger less desireable.

__________________
James Hromadka
Old Friend

quote:

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Originally posted by dkessler
By my calculations that means an array of about 12 4" x 2" crystalline cells. So you're looking at about an 8" x 12" panel. And of course you also need a source of direct sunlight (crystalline solar cells usually won't operate under indoor lighting).

It's an intriguing idea for people who might find themselves in remote sunny areas for extended periods of time, but I think most people would find it more convenient to just carry a few extra sets of batteries [/B]

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quote:

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Originally posted by tyler
[QUOTE][i]I am looking at a trip to Peru in about a year that would have me out in the bush for a few weeks in a tent with no power available. This is what was driving my thinking. (Because, of course, there is NO way I wouldn't have my Prism qwith me! )

tyler

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quote:

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Originally posted by reconnect
[QUOTE]By the way, there are other advantages to having solar charging -- particularly environmental.

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__________________
<ul><li>Dave Kessler<br>President - Kopsis, Inc.</li></ul>

here's another possibility for recharging one's Visor Prism

I wonder if this hand-powered recharger could be modified to work on a Visor Prism


Here's the blurb from the website:
It happens to us all. We reach the end of our talk time before we're ready! And how do we recharge when we're far from a power source? With this innovative new hand-powered generator, you don't need any power source other than your hand! Just squeeze Aladdinpower(r) for a few minutes and your cell phone (or radio, GPS unit, or CD player) is fully recharged--anytime, anywhere! Requires DC power cord (the one you probably already have that plugs into your car's cigarette lighter socket). Just 5-1/4 long. Includes genuine leather carrying case with three compartments and belt loop. (4 oz)

http://shop.gorp.com/magellans/prod...9&sku=ET250


Alladdinpower Hand-Powered Generator with Case
ET250 $75.00

A little pricy but it's an option unless of course someone decides to manufacture and market the D Cell solution created by this thread's originator.

I love this barrery extender idea and i was just going through my junk box and have all the parts but the hotsync connector anyone know where i can get one without ordering 50 or screwing up a $30.00 cradle?

How about "screwing up" a $20 hotsync cable?

tyler