Preamble

This mod uses Panasonic cells CGP345010 for only 2€ each!

Here you can read a descripion written by philib10 on this forum. Thx for that great work! He mentioned to name him, philib10 and his webpage.

Also thx to [IDC]Dragon who hinted here about the oem cells for SIMpads.

Philib10s mod

Last year I (philb10) asked on the forums about replacing the battery in my Simpad as the current one was not holding charge.

Main Page had a posting that the battery could be replaced using cheap Panasonic CGP345010 cells. Armed with the information, I purchased 4 from ebay to replace the worn ones in my simpad.

This page shows the different stages of the process.

The stock Simpad battery that comes in the unit. It’s actually made up of 4 cells, some wiring, a plastic holder and a circuit board.

These are the replacement cells that I purchased from ebay. They look to have been pulled from a working battery rather than being brand new, but I’m not too sure. Once I’ve tried them for a while I’ll make my mind up. The main thing to note is that they came pre-configured with connections that have been spot welded onto the terminals. This caused some minor problems when taking them apart as the welds adhered to the terminals and had to be filed off.

These are the cells from the Simpad battery, once the black plastic wrapper has been removed. The interesting thing is that the terminals are not marked with +ve or -ve, but can be distinguished by the shape of the plastic sheath at the ends. I’m assuming -ve is where the sheath totally covers the end of the cell and +ve is where the sheath is cutaway. The two pictures above show each side of the cells, including the wiring layout that I had to hookup with my replacement cells.

A closeup of the connections showing how the cells are taped together.

This shows the original Simpad cells behind the replacement ones. Fortunately, two of the cells were already wired up the same as two the Simpad ones. This saved some soldering later on.

This is the circuit board and plastic holder into which it sits on the edge of the batteries.

I noticed that there was a small fuse one of the connections. I didn’t take it off and re-use it on the replacements.

This next photo shows the first two replacement cells being wired up. I couldn’t work out a way to guarantee a connection between each cell and decided to solder them together using wire.

I then used electrical tape to ensure that the two cells stayed together and to cover the wiring.

The other two cells were joined in a similar way. I then attached the circuit board and holder, again using tape.

The final picture shows the new cells in the simpad, connected to the main circuit board. I taped up all the exposed connections in a similar manner to the original cells to ensure that nothing would short circuit.

The new cells were then charged overnight. I've not yet done much testing, but the Simpad now works for far longer than when the original cells were used.

To do

• resize the pictures

Additional notes

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not really sure if I should put this here or on a forum :

I can confirm that this tutorial is 100% foolproof. Since I'm not familiar with voltage/amperes & soldering, I decided to give this a try. This is what I did :

After ordering cheap 3.7V cells at www.dealextreme.com. (btw. 'maH' is how long the battery lasts), I was ready...for victory or total destruction :) Btw. my batteries were very cheap..like 2 dollars each.

Since I didn't wanted to blow up my simpad, I also bought an multimeter to measure the voltage after every action. I also needed the multimeter to discover the + and - of the battery (since it wasn't described on the sticker) How 2x 3.7v batteries could double the voltage was a bit of a mystery to me, so if you wanna know how its works just google on 'battery serial parallel'.

you can do it!