Good day folks. Let's talk about batteries because it's a huge topic which I haven't tackled as well as I would like, so let's put it into practice: my colleague worked on a portable handheld vacuum cleaner which had dead NiMh cells in it. It would charge, run for a few seconds then shut off entirely. Wanting to "upgrade" it, he replaced the NiMh cells with Li Ion ones....directly - no other mods or precautions taken. Ok, he's not as stupid as to substitute a Li Ion cell for EVERY NiMh battery in there, because the voltage wouldn't match for one, so he put in 4 Li Ions, so that would make it a 16v vacuum, which I reckon is a typical voltage for handhelds. The vacuum was functional again and after leaving it for a full charge, he returned it to the chap who brought it in. All was fine and dandy.
Now just the other day, I saw the same vacuum just lying there in the shop again, which, not to be rude, but I kinda saw coming - I warned him but he was rather dismissive to any form of suggestion or criticism, as usual, so I dug no further. I asked Mr. Knowitall what's wrong with it and he said a couple of cells had popped...not sure if literally or otherwise, because I didn't actually see them, but the bottom line is it didn't work - at least not well enough.
I knew it from the start that replacing a NiMh cell with a Li Ion one is not as easy as simply swapping them around directly and hoping for the best - the charge characteristics are different, which is what I believe destroyed the new cells he put in. It's probably down to each individual device and how it implements the actualy charging, but how easy or advisable is it to did what he did and just swap NiMhs or NiCads for Li Ions ?
Now just the other day, I saw the same vacuum just lying there in the shop again, which, not to be rude, but I kinda saw coming - I warned him but he was rather dismissive to any form of suggestion or criticism, as usual, so I dug no further. I asked Mr. Knowitall what's wrong with it and he said a couple of cells had popped...not sure if literally or otherwise, because I didn't actually see them, but the bottom line is it didn't work - at least not well enough.
I knew it from the start that replacing a NiMh cell with a Li Ion one is not as easy as simply swapping them around directly and hoping for the best - the charge characteristics are different, which is what I believe destroyed the new cells he put in. It's probably down to each individual device and how it implements the actualy charging, but how easy or advisable is it to did what he did and just swap NiMhs or NiCads for Li Ions ?
Comment