Having seen Julian Ilett dismember a larger version of the lithium battery pack used with the Ryobi one-plus power tool range, I decided to have a look inside one of my own. Especially when I'd just bought a cordless circular saw and wanted to see how the battery pack could handle the power requirements of a fairly high current tool. It's worth noting that the cordless circular saw is designed for simple cuts of sheet wood and not for full-on continuous industrial use.
Inside is a surprisingly simple array of just five 18650 style cells with beefy interconnects and a control PCB for handling the charge/discharge requirements of lithium cells.
If you could source decent known-quality cells capable of super high current then there's no obvious reason you couldn't fit an old or faulty battery pack with a set of new cells.
Julian's teardown of a higher capacity pack differs from this one in that it uses five clusters of two paralleled cells to give a higher capacity, but just treats each pair of cells as a single cell.
Inside is a surprisingly simple array of just five 18650 style cells with beefy interconnects and a control PCB for handling the charge/discharge requirements of lithium cells.
If you could source decent known-quality cells capable of super high current then there's no obvious reason you couldn't fit an old or faulty battery pack with a set of new cells.
Julian's teardown of a higher capacity pack differs from this one in that it uses five clusters of two paralleled cells to give a higher capacity, but just treats each pair of cells as a single cell.
I love my Ryobi tools. I have several that used the NiCAD/NiMH cells that the One+ lithiums can replace and it's really nice. Plus they seem to do a good job maintaining the cells — mine are several years old and all the lithium batteries still hold a significant charge
What's the second red wire going down the middle for?
Next time use electric screw driver, or power drill to remove screws, it can save you a lot of time.
No closedcaptions…. ๐
Hey Clive, love your content. Any chance you could go into more detail about how the 2 mosfets work in this circuit? I've opened a pack and am troubleshooting why the 5s batteries show 21v but the pack terminals show 9.6v. It seems related to the mosfets. I would love to be able to repair the pack but at this point am more concerned with just understanding how it works.
I actually use a pile of different tools all purchased or received second hand without batteries.
I did make sure all were between 18-21V.
Ended up hacking connectors off of all of them, tacking on a standard hobby plug (deans), and using my ample supply of 5 cell 90C batteries my drones run off of.
Works incredibly well and you don't need to buy the overpriced $150 batteries for each tool. I also use a $25 charger from Aliexpress in balance mode.
…thanks for not trying to see if the cells are removable, so that I could recharge them in a pinch with a solar charger using a rechargeable head lamp…
I just drilled the nub down in the non tamper screws. Regular torx bit went in fine after that
I had one recently lose the control board. Batteries charge and test fine. Need to find a 5s board. If I can find one I might build my own 10 cell packs out of some old dead Ryobi ni cd packs.
A bit late to this party, but I've been doing a sort of CPR on these. Seems if one or more cells drops below @10 volts, the charger/charging circuit will refuse to charge the battery. If I remove the pack from the case and charge the cell array directly, by-passing the circuitry (from a fully-charged battery), and get the total voltage above 12-14 volts, the charging system will allow the pack to be fully charged. It just takes a minute or two. Once fully charged, I test each cell for reasonable voltage.
I took four batteries from the recycle bin at the big box store and all were fine after this procedure (two were the big 10 cell packs). They've been working fine for months now.
Moral of this story? Don't let these battery packs self-discharge below 10-12 volts or the charging system will reject them, even if they are perfectly good.
does anybody know where you can buy that chip (circuit board)
Who knows where to purchase the protection circuit boards. Can't find them anywhere
Clive, you really need a cordless power screwdriver! It will avoid rsi of the wrist too.
anyone found decent price an supplier for these battery cells?
These are the same batteries used in Alien and other vape mods.
what ya do is wait to you have 2 bad packs.Chances are between the 2 bad backs you'll have enough good cells to make one good pack.
Can't we edit repetitive screw removal process nowadays?