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-- Battery charger modification (http://discussion.visorcentral.com/vcforum/showthread.php?threadid=13372)

Hi,
I am currently using NiMH batteries in my Platinum. I'm looking for a way to charge the batteries without having to take them out of the Visor.

I have found that there are basically 2 ways of doing this:

(1) modify the cradle to supply constant +5V on the Vdock pin (as per Handspring specification), and add a rough voltage regulator inside the Visor

(2) connect a full blown charge controller to the Vdock pin, connect the battery directly to the Vdock pin.

There is an example of (1) at http://www.maksystems.com/visor/ and an example of (2) at http://ueno.cool.ne.jp/molly/Palm/c.../c_visor_e.html

(1) is simple requires only a few components, and is compatible with handspring specs for the Vdock pin. The Vdock pin is connected direclty to the springboard connector, it is intended to allow springboards with rechargeable batteries to charge (!). On the other hand, this solution does not include a charge controller, so you have to be very careful about how long you leave it charging, etc. I wouldn't feel very confident about using this solution

(2) is more costly (requires to buy or build a charge controller), and it does not provide the required voltage on Vdock; hence it will (probably) not allow charging springboards to charge, and could possibly cause problems. The example of (2) says that they have not encountered any problems with springboards, but they advise to cut the connection between the Vdock pin and the springboard conector.

So, finally, my question is: has anyone done one of those modifications on their Visor? Are you happy with it? What is your advice?

TIA

For over a year I've been using a charger based on these instructions.
http://bodotill.suburbia.com.au/cradle/cradle.html
However, when I upgraded to a Visor Platinum I decided that I no longer wanted to use VDOCK. Now that the Prism and some Springboards can receive external power from VDOCK (such as the Geode GPS), you must either obey the standard voltages or risk frying your batteries or do with out external power for the springboard.
Instead of VDOCK I added my own contact to the back of the Platinum, beside the batter compartment. Just a loop of wire, but it matchs a corrisponding loop on my cradels. Works perfectly.

In all, the modification is probably a little costly in parts, circuit board, and construction when compared to an equivalent dollar amount of disposable batteries, but the convienence of not requiring replacement batteries make it worth while for me.

Explorer1

Thanks for the link; it's very interesting, yet I don't have the tools to build my own PCB, so it's not for me.

I'm still undecided as to whether to sacrifice the Vdock or not... The best choice might be to add an extra contact, like you did. Could you send me some details on your modification?

IT might be a little procey but it pays off in the end. The ICU digital charger, comes with a charger and a battery cover, and 2 standtered NIMH batteries. $49.95, at CompUSA. IT works great

The Full charger, uses a priporitory battery, and costs $49.95 for all the acceroies that you get with the ICU. Both work wonderfly, but the ICU includes open conatacs, so you can modify things to fit onto those contacts, to eith draw power, or to charger it.

-Ra the sun God
ra! ra! RARARA!