Ryobi battery pack disassembly?

I have several 18v Ryobi tools and battery packs, including one of the lower-capacity Li-Ion ones that shows as fully charged in the charger but will not operate a tool and shows no voltage across the "supply terminals" (there are separate charging contacts). It seems likely that there is an internal broken connection between the battery and the "supply terminals" that should be easy to fix if I can get the case apart.
But that is the problem: I have removed 4 Security-Torx screws in the bottom and one in the "plug" part that goes up into the handle of the tool, but the case still will not come apart. I can pry the halves apart a small amount at either end, but they seem to be held firmly together in the middle. There do not seem to be any screws hidden by the label on the bottom
Has anyone managed to take one of these things apart? If so, how?
Perce
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wrote:

i get primecell.com to rebuild them, they work great after rebuild, cost little more than buying the cells alone, one had paint smerared on the battery case, it came back looking brand new, they must of cleaned and buffed it too.
its very likely you have a bad cell or many bad cells in those packs..
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http://primecell.com/pctools.htm
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On 12/14/10 11:23 am, snipped-for-privacy@aol.com wrote:

I saw no mention of LI-Ion batteries -- only NiCd and NiMH. And their price to rebuild an 18V NiCd pack ($48) is more than the cost of a new Ryobi NiCd pack ($40) -- and shipping both ways would be extra.
I can see using PrimeCell (maybe) where a new battery pack is no longer available from the manufacturer of the tool, but only then.
Perce
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On 12/14/10 11:13 am, snipped-for-privacy@aol.com wrote:

But why does it show fully charged? The charger does have an indicator-light pattern for "battery defective", which I assume (I know, I know) would be triggered by the presence of a dead cell. As I wrote originally, there are separate charging terminals, and the charge state must be getting measured there.
Perce
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wrote:

Can't help you with how that specific battery comes apart. But I reached the same conclusion that you did. It's not worth sending them out to rebuild. Between the cost, the shipping, etc, you can usually buy a new battery pack on Ebay for maybe $10 more.
If you can DIY, then it's an option. I recently rebuilt an old Milwaukee. Cost me about $22 on Ebay for the new NiCads.
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On Dec 14, 2:07pm, snipped-for-privacy@optonline.net wrote:

new battery packs for older tools were likely assembled years ago when the tools were first produced, so they arent really new they are new old stock and their cells will already be aged.
if your rebuilding packs yourself buy cells with tabs welded on, soldering on batteries can damage them
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It would be one hell of an inventory if vendors were keeping stock of battery packs from 15 years ago, don't you think?

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Probably one-way interlocking tabs that snap together. Sometimes, with a helper you can pry from both ends and pop them without breaking anything but I've had to glue them back together too many times to bother with it anymore. You might try pushing very hard along the length of the seam. If there's a tab along that seam, there will be a greater resistance. Sometimes you have to squeeze it in a vise to see where the connecting tab is along the seam. Sometimes the seam is heat welded, though, and you'll find no weak/strong spots.
I've recall having to use a Dremel with a cutoff wheel to get into some packs. Be aware that newer lithium packs often have charging "chips" built into them that go bad - all your cells can be good but the chip is either bad or isn't resetting and allowing a full charge. I empathize with your desire to salvage it, but it could be a lost cause, especially if you snap a tab that's structurally required to keep the pack attached to the drill.
I do, however, find it odd that is shows "fully charged" when there's no voltage across the terminals. My charger flashes rapidly in such cases to tell me it's a bad pack. I assume it charges your other batteries without issue. Is there any voltage present on any of the contacts?
-- Bobby G.
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Percival P. Cassidy wrote:

If you want to rebuild your own battery pack, here's a CD (capacitive discharge) welder you can build yourself. It's used for welding the individual cells together.
http://ledhacks.com/power/battery_tab_welder.htm
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All of these issues could be forever ended just by a federal law, all battery packs MUST have easily replaceabe cells....
Its sensibile, good for the environment, decreases trash, and would save the owner money...
a win win for everyone
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On 12/14/2010 8:55 PM, snipped-for-privacy@aol.com wrote:

DON"T EVER SAY THERE OUGHT TO BE A LAW! Do you have any idea of the horrors that such a law could bring to this country? Some Republicrat or Demican will add some weird crap to the bill requiring stool samples before you can board a plane or all home appliances must be 100% efficient within a few years or you will have to fill out reams of paperwork in order to buy batteries for your flashlight because the batteries which will be required to have serial numbers for tracking purposes due to a possible hazard to the environment. The end is near!
TDD
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On Tue, 14 Dec 2010 21:54:24 -0600, The Daring Dufas

Some laws make sense though. I have a few Roomba batteries that likely only have one bad cell, but taking them apart is such a PITA that it's just easier to get a new one. That is a huge waste of resources. It also shouldn't cost as much to replace a batterry pack as to buy a whole new drill set, as is the case with some of my old Dewalt stuff.
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its all carefully calculated before designs are complete, how do we assure the next sale?
just pulling a flashlight type cover and swapping cells would be so easy.....
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Just send it to Primecell.com and have it repaired. They do an excellent job. There are many other rebuilders that can fix it equal or better than news.
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On Wed, 15 Dec 2010 22:22:45 -0500, "Ed Pawlowski"

Thanks, this looks like a good place. I have many things that might benefit from them.
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