I have an HP 8430 15 inch laptop running Ubuntu 12.10. Ubuntu gives this old war horse new legs, but the battery pack is shot. It will only hold a charge for about 30 minutes.
I have three of these battery packs… none work more than a few minutes.
My question is how can I repair this battery pack? I’m concerned about mixing batteries of different brands. Are there any rookie mistakes I should avoid? I assume I just crack it open. Snip out the old batteries. Test them one by one to see which ones are bad. Replace them. Do I replace just the bad ones, or should I replace all of them? These battery packs are probably 7 years old. I don’t need all three battery packs to work. One would be fine.
You should replace all cells, not just the bad ones.
I’d recommend tabbed cells for replacement, they’re much easier and safer to solder - such as Page Not Found - Aliexpress.com
1. Get some new decent quality cells (Samsung, Panasonic, Sanyo, LG, ….)
2. Open up one of the packs, but be careful not to break any connections
3. Measure all of the individual cells in the pack so you can find the one that is bad
4. Measure the voltage of the entire pack and divide it by the number of cells wired in series
5. Now that you know the voltage of each individual cell, charge/discharge your new cells to the same level
6. Once you’ve got the idea of how the cells are wired, wire your new cells the same way
7. Connect those new cells parallel with the old ones
8. Disconnect the old ones and assemble the battery pack
9. Use all the old cells that are good to run your flashlights
s.: Under no circumstances don’t disconnect your old cells from the packs PCB so it will see 0V, or you’ll have one dead battery pack
It’s easier to just buy a new pack. By the time you buy all new cells and do the work, you are not saving much money. You will most likely damage something since you have never done it before. Just not worth it on a laptop pack. They are too cheap to mess with. If it was cordless drill pack that they sell for $100 and you could drop in 4 cells, then it would make sense.
I’ll go along with what he said^.
I have taken a few packs apart to salvage the cells. And the packs I have fouled with were very difficult to get apart without damage to the case. I don’t think replacing the cells was on the engineers to do list.
I’ve opened bad packs where all of the cells appeared good and the pack pcb was suspect, but that seems less likely with 3 packs.
I’d probably try replacing bad cells with similar good cells from another pack if you find some are bad (sometimes it is all the cells wired in parallel). Make sure all of the cells are at least 3v to start, and ultimately within .1v of each other as you reassemble. That is free, assuming you don’t count your time.
Some packs open easy, others are much more difficult. Some packs are easy to get to the cells by peeling the label off (just did a Dell that way) and then cutting strips visible under the label. Otherwise, I start along a glued seam. On machines where the pack is needed for the laptop to sit level, I gut the pack so as to only open the top inside of the pack (if the latch doesn’t engage that surface) so that the empty pack (pcb removed) fits back into its slot.
Normally I start by cutting and isolating individual wires and tabs to avoid shorts. You’ll have to be much more careful at documenting if you are going to rebuild. Since none of the packs are functional, there’s not much to be lost by opening a couple of them to see what you find and whether it is worth the rebuild effort. Worst case you’ll have a few free unprotected cells for single cell lights.
