Bosch 509e battery pack rebuild
Because everyone needs a hobby ...
Hi folks. While I am willing to accept that I'm the only person here who's bothered about rebuilding a Bosch 509e battery pack, the basic principles should apply to all the old-school phones with NiMH batteries.
So, without further ado, let's get our hands dirty.
1. Duff Bosch 509e battery pack.
2. Replacement 3xAAA battery pack. Mine came from eBay, was meant for a cordless phone and cost £1.08 delivered from China.
3. Soldering iron and solder.
4. Sharp knife and small screwdriver (I used a Swiss Army Knife for both).
5. The rest of the Bosch 509e
6. Sticky stuff remover
7. Copious quantities of tea ...
Here's my beautiful Bosch 509e.
Remove the battery pack. You can see the 3 600mAh NiMH AAA cells within.
Carefully, using a pocket knife or a flat-bladed screwdriver, prise loose the plastic cover to reveal the cells and the little PCB with the contacts.
Run a knife blade behind the cells to separate them from the case (they're stuck in with some adhesive foam) and lift them out. Clean up the case to your own standards (this is where the sticky stuff remover comes in handy).
Here is my replacement 3.6V 800mAh cordless phone battery pack, bought off eBay from China for £1.08. Usefully it's got 33% more capacity than the original 600mAh cells.
Remove the outer heatshrink from the battery pack (being careful not to damage the insulation on the cells), trim the leads to length and solder on the little PCB with the battery pack contacts. Make sure you get the polarity of the connections right, or it could all go horribly wrong later!
In the immortal words of the Haynes manuals, reassembly is the reverse of removal.
Put the battery (centre) into the case (left) then refit the cover (right). I suggest you try it like this before you break out the glue, just in case you've got something wrong somewhere.
It should now look like this.
You'd never know it has been apart, would you?
My creature, it lives!
Sorry for running an Orange SIM in the photo, I'll try to get another shot with a giffgaff one
Thanks for the positive feedback
It all started with me being too cheap to spend £7+ on a replacement battery for a phone that's worth less than a fiver. Being able to see the NiMH cells through the battery case simply encouraged me.
I don't often have to fix phones, usually it's children's toys. Or cars. Or the washing machine. But next time there's a phone to fix, I'll be sure to take photos and share them here!
I did a similar battery pack rebuild on the 509e, although the batteries I used came individually, with solderable tags welded on at each end. The idea of using a shrinkwrapped triple battery is much more elegant.
Compared to the original battery ratings, which were only 500 maH types, I improved the battery life to about a week... although that's all ancient history now. I use an iPhone nowadays, so it's a nightly recharge for me.