I'm pretty new at posting, but have been a long time lurker.
After much research into extending the battery life of the clip +, it became evident that there was no elegant and simple solution. I flirted with the idea of purchasing a portable battery charger. I also considered modifying a portable amp so it would serve as a large external battery for the clip +.
Anyway, I got restless and had 2 Sansa clips so I experimented. ----This is the result.
Essentially I have soldered another lithium polymer cell in parallel with the existing one. This effectively increases the net capacity, though in the interest of full disclosure it isn't necessarily that simple.
The additional battery was sourced from a dead Iriver s10. Its capacity is somewhere around 300 mah despite being smaller than the original clip + battery.
Recommended Tools + Parts
§ Sansa Clip +
§ small flat head screw driver (for prying open case)
§ Soldering Iron + Solder/Flux/Sponge for tip cleaning
§ 200-400 mah lithium polymer single cell 3.7v battery ( from Iriver s10, toy rc helicopter, or many other small electronic devices)
§ Heat Gun/ Butane jet lighter (for warping the enclosure slightly)
§ Copper wire 20 guage ( larger the guage/smaller the wire - the better)
Disclaimer: Basic knowledge of electronics is a prerequisite for this modification. By no means attempt this if you do not want to run the risk of damaging your player!
1. Disassemble the clip +
There are many clips located around the enclosure. You can carefully prying them undone with a small flathead screwdriver. If unsure about this step, there are guides on youtube.
You will notice the 290mah lipo secured by double sided adhesive foam. Remove it, as it takes up precious space.
2. Solder the additional Li Po battery in parallel.
Here you see the smaller silver S10 battery soldered via incredibly thin copper wires. These very thin and flexible wires are do not take up any needless space and are very easy to work with, provided you have a steady hand. So batteries wired in parallel add capacity and hence run time. For example battery1 black to b2 black, b1 red to b2 red, or respectively negative to negative and positive to positive. Be careful whilst soldering, the board is packed with tiny surface mount components.
(excuse the abhorrent picture quality, recently lost my camera)
Here you can see the new lipo piggy backing on top of the original. Now we encounter the problem of fit. With the Iriver S10 battery measuring at 4mm high it won't fit. So what to do!
Well you have 2 options;
First you dont use an Iriver s10 battery. There are many similar lipo batteries out there that will fit without case modification. However the bigger the better in the game of batteries.
Secondly you can alter the back part of the enclosure, like I had to.
4. Enclosure modification to allow for battery height.
Despite how horrible this looks. From the outside it is almost insignificant.
I used a butane heat gun and a jet lighter in an attempt to head the plastic to a point where it would soften. While it is hot and soft, use a tool to depress the molten plastic. Only push down the plastic that is hidden by the clip. This way it doesn't have to look ugly.
This after a few attempts should allow for the extra several mm of the additional battery.
5. I had to use epoxy to get the enclosure to keep together flush after the battery installation. This is a consequence of my carelessness and impatience. This mod can be done a lot better than i have showcased.
The player has been knocked around a bit, which made it easier to justify modding. But it is fully functional and reliable. I achieve much longer battery life now and the player feels heavier and far more substantial. I would estimate having 1.5 to 2 times longer battery cycles. However more experimentation is needed, I am no electrical engineer. This could potentially break your device.
Also I am not familiar with battery bench in rockbox. could someone explain its usage?
Hope this inspires some hardware mods hahah.
Thanks guys. Feel free to post, ask questions and pose better solutions.