I grab any and all of the Ryobi 40V and packs greater than 20V. I figure it out later.
That 56V 4Ah Echo looks new and 3 of 4 status lights are lit.
The Makita 4Ah pack is absolutely unused and all cells are in like new condition. I have no way to test if either pack will charge or discharge through a tool though. All I know is that the cells are in perfect condition.
This can be dangerous because sometimes people throw CFL’s in the battery bin. At this point I can pretty much tell the brand of battery by feel, just reaching in with my hand. I don’t even need to be able to see it.
Of course physical condition requires eyes on.
Sadly I don’t find anything super awesome in any of the bins in my area so I’ve not gotten picky. I’m grabbing what Li-ion packs there are.
You can get 6 of the OP4026 1300 mAh packs “broken” for $80 shipped on ebay as well. It’s not bad at $0.67 a cell if you have a use for the 1300 mAh cells. Of course I’d prefer they were free and found in a recycle bin but that’s a good cost per cell. Since the batteries carry a 3yr warranty I wonder if it’d also be possible to get a warranty swap on them without a proof of purchase just going by the mfg date on the pack and by calling customer service.
Well I found a 3rd 40V 4Ah pack in the bin in a store in Canada. It too had been used only a few times and was tossed. When I opened it up, it also had signs of water damage?
This is 3 of 3, 4Ah packs with the same cause of failure. Could these come from the Ryobi lawn mowers and somehow get wet with use?
All cells are sitting at 3.57V, so I am hopeful that the cells are OK
It would appear the water enters via some vent holes for the FET’s
And the angle the battery sits in it’s cradle could provide an easy entry point should any moisture pool in the bottom!
Maybe a really, really dumb design.
It seems like they advertise them as being waterproof or something—i had noticed that dumb design also, and if the FETs get wet, short and fuse out, then they will open the low side of the pack and brick it—no way to charge or discharge after that. The average person has no choice but to just pitch it in the bin.
It looks like Ryobi realized there is a problem with moisture getting inside their 40V packs.They have come out with a newly designed pack, the “OP40261”
Here is the old number next to the new.
Here are some pics of the FET-Heatsink area. There is a more massive, material wise, heatsink and NO ventilation holes.
Perhaps because battery packs have a limited run time, a more massive sink can be used in lieu of ventilation.
Note the insulated heat shield to protect the end caps of the cells. This sink must get very hot!
This is where vent holes used to exist.
The rest of the pack has been redesigned too.
I found this particular pack fully charged, but drawing more than 10A shuts it down. The “fuel” gauge doesn’t work but it will charge back up once it is depleted. Ordinarily I would think it has 1 weak cell pair that falls below the low cutoff voltage when there is a heavy draw, but that seems not to be the case here. I’ll try a heat gun on the circuit board and see if that repairs a poor solder joint somewhere.
thanks for posting the new pack—i had noticed the part number on the new packs for sale in the store and wondered what was the difference. Wonder why they didn’t go with the 5Ahr pack with the new design?
i had nearly finished tracing the circuits of the older design, and now they go and change. Probably a good thing since so many packs were “failing” with good cells.
i doubt they left the part numbers intact on the microcontroller and cell monitoring chips—the two quad flat pack chips. i’ll try to look them up if you can get the part numbers.
There appears to be 2 current sense locations: the central trace with the necked down section looks like a custom current sense resistor on the high side of the pack, and the fat trace at the bottom left is the current sense for the FETs at the low side.
You could try soldering some wire across the necked-down section to lower the resistance and see if the “10 amp” current limit changes.
Aaron, if you have one dismantled can you post a photo of the bottom of the board?
I believe that top section you made note of is a fuse.
The fact that the fuel gauge doesn’t work to me means that it is not as simple as a poor solder joint in the high current path. I will fully discharge this pack, determine it’s capacity and then recharge it to see if anything is “reset”
Here are the numbers after cleaning the gunk off the 2 microcontrollers.
Thanks for the excellent photos. Unfortunately these tool packs are kept under wraps.
The O2 Micro, ic U3, is the BMU chip to monitor the cells. i haven’t been able to get any information or datasheets on their devices, even with an email request. There is no info on the www, they are a secretive company with HQ in the Cayman Islands—great place for a semiconductor company…
The other device, ic U1, will be the microcontroller with firmware to run the board. The chip id has been hidden behind proprietary numbers. If we ever get the devices identified and pull the firmware then we will see the stupidity that they are forcing on us and bricking packs with good cells.
Check the condition of the electrolytic caps C1 and C6, that would be my first guess of leaky caps causing it to not work. i see a solder joint labelled “power”—it might be that you could remove that big glob of solder to take power off the controller, then solder it back to turn it on. Don’t know why they put so much solder on the cell voltage monitoring points—there is no significant current in those circuits.
i thought about the necked-down section being a fuse, but only if there is a mechanism to blow the fuse if the controller commands it to disable the pack. Otherwise i’m guessing it is a new current sense that is disabling your pack and the fuel gauge.
Those 40V Kobalt packs look very similar to the Ryobis—has anyone taken photos of the insides? i’m sure they will have the same patent number.
It’s unlike any other pack Ive taken apart or the Ryobi 40V packs. It appears the board is split into two and the front board with the battery gauge also has the main BMS stuff but it’s covered under a ton of goop.
The pack has space for 20 cells but only 10 are populated. It’d be trivial from the looks of it to double the pack capacity.
Small potatoes compared to what I am seeing above, but today I pulled 12 AAA eneloop cells from the bin at work. They all light my Maratac copper AAA on high, so it seems like a good start. Not sure what to do with 12 more backup batteries yet . . .
and now I see why they were in the recycle bin. Not charging immediately with my BQ-cc17, but hoping with my RC battery charger and some power cycles I may nurse them back to some health. All I have all my AAA lights full of these batteries and they have been running for 2 hours now. Should get 4-10 hours with fresh eneloops, depending on the light. Still seeming promising. These are 2nd gen eneloops, so they could be 8 or so years old. Looked like new from the outside, no obvious wear or damage. They are marked made in Japan, and PN HR4UTGA
Not small potatos, I found some less desirable Duracells in post 173
I had fun bringing back 4 of the 8 “exercising” the cells just as you plan on doing. I didn’t need them, but I still had fun doing it.
And it’s a learning experience.
I tried to charge all 12 cells in my BQ CC17, and most just gave the blinking light, the others charged for 30 minutes or less. The blinkers I put a constant 0.1A for 15-30 minutes. Now I am running them. First set of 4 ran for 2:55 in lights that would discharge them in 4-10 hours. Not bad. I charged those 4 up overnight and am running them again for 3 hours. I don’t have a nice charger like you, but so this will take a bit more time . . . but interesting for me
Today I found one of those Kobalt 40V packs in the bin. How did you get yours open. I find 4 screws on the corners. Are there others hidden under the labels?
There’s just the 4 screws and then pressure clips along the sides. I wedged a small flat blade in the top/bottom seam along the front panel (with the battery indicator). Then while putting some pressure to open the seam I ran another small screw driver along the seam until the clips popped on one side. Then just pull it the rest of the way open.
