Failing to repair a Ryobi One+ 18V 1.5Ah Rechargeable Battery

[@test-193]

I've rebuilt about 75 of these Ryobi batteries. Some Advice: 1. You incorrectly replaced the 30Amp, high current cells (LG HB2) with low current cells. (LG ME1 are only 4.2Amps) This will not be able to supply the high current needed in cordless Ryobi tools. (except perhaps the Ryobi flashlight). 2. You need to match the capacities (mAh) of the five cells reasonably well for best results. Otherwise the lowest capacity cell will drain the fastest and will trip the under voltage monitoring of the BMS board. This safety function will shutoff the MosFets and thus the output terminals wil not show the true voltage. This error flag will typically not let the Ryobi charger charge the battery. 3. Not only MUST you use the same capacity cells, it is imperative the voltages must be within 0.2 Volts of each other or the BMS will flag a mismatched cell...... and disable the MosFets. 4. If you must solder these cells, please sand the top and bottom with some sandpaper or a dremel tool. The nickel coating prevents the solder from flowing/sticking. After sanding a small bit... you'll be shocked at how well the solder now sticks! 5. Once the BMS has tripped an error flag, it will sometimes be necessary to use the reset in order to bring these back to life. It's just a jumper/ paperclip that pulls the reset to ground for about a second. This drops the 3.3Volts on the BMS chip to ground, which clears all flags and initiates a reboot of the BMS software. 6. Connecting the cells in sequential order (0V, 4.2V, 8.4V, 12.6V, 16.8V, 21.0V) gives you the best chance of success with these batteries. The same is true of the "sense" wires that the BMS utilizes for each cell's voltage.

[@PlatimaTinkers]

Hey mate nice work on the comment, thank you kindly! Some feedback from what you said on what I've found with this one; 1. You are absolutely right that I used low current cells. Unfortunately all I had, but I swapped out the little tungsten bulb in my One+ flashlight for an LED one, and this rebuild runs it beut (eventually got it working). The cells I had were old spares from laptops scrapped. 2. The cells were pretty closely matched - I used the Nitecore UMS4 to measure them all - hence @9:20 you can see I've labelled them with capacity and sometimes date. 3. I've no issues with the BMS shutting down the MOSFETs in this. From what I understand, and can see with the multimeter, the BMS just keeps them balanced? 4. Good point re solder. Ended up buying a mini rechargeable spot welder afterwards for this exact purpose! 5. Never had to reset but that is excellent to know! That could have been what ended up happening here for it to work without me even knowing. 6. That makes sense! I had not considered that it is essentially 'live' whilst being assembled. Definitely worth knowing! Thanks again, awesome info for everyone, and I guess I'll have to do another rebuild in the future.

[@КасиоПея-ь7г]

@@test-193 подскажите где находятся на данном акамуляторе сброс, reset?

[@thefleaflop]

Please tell us more about the charger used in video... Features, how well you like it, cost etc. Thanks...

[@PlatimaTinkers]

Wut? 😕 Righto, mr Bot!

[@wrathofsocrus]

Did you manage to get it going? The BMS needs to see power on the output side to turn on, and some smart chargers won't apply power if there isn't sufficient voltage. Apparently the BMS powers itself off of one of the cells, so if it sits too long that cell can drop below safe voltage and the whole thing shuts down. I've had good luck getting cells working again unless they are well under 1V.

[@PlatimaTinkers]

@wrathofsocrus Hey I found a solution but just have not gotten there yet! I thought the BMS may be the issue, but at a lower level. I had charged all those cells up to nominal and confirmed the series and parallel connections were all good before trying to use it. Stay tuned and see my solution in a few weeks when it's not a million degrees in my shed hah. Cheers

[@KSCPMark6742]

@@PlatimaTinkers Thanks, I'm also hoping for an update 👍

[@PlatimaTinkers]

@@KSCPMark6742 Roger that mate, will bump it up the schedule!

[@BajaWam]

Were you able to get it working ? I have the exact same problem and no luck :/

[@TulaLexx]

hi. Did you manage to fix the bms?

[@PlatimaTinkers]

Nah it seemed like the IC was busted. Ended up finding a replacement knockoff one on AliExpress for about $15 though, and just re-built it with the same batteries!

[@TulaLexx]

@@PlatimaTinkers Could you give me a link? I couldn't find something.

[@PlatimaTinkers]

@@TulaLexx Yeah but take it with a grain of salt, as the quality varies and this was a while ago. Plus: CAUTION. The link for the battery pack was www.aliexpress.com/item/1005004639263509.html. My memory issue is that I also got a knockoff 9Ah at the same time from some other shop, and one of them works well, but one of them overheats and cuts off after a minute or so of use... I do not recall which is which, but it could even just be a dicky NTC. Could be worth grabbing an alternative model like www.aliexpress.com/item/1005005219176048.html at the same time. Note that having a mini spot welder for the 18650 attachments (I have this one: amzn.to/49Xvr64 - affiliate link, I should actually make a video on it though as it works well) and some hand soldering is required. If you get the instructions wrong it can also let out the magic smoke. If you don't have electronics experience a genuine replacement is likely the way to go! Good luck

[@TulaLexx]

@@PlatimaTinkers Thank you. I have everything, I am repair batteries. I use SUNKKO 738AL welder.

[@PlatimaTinkers]

@@TulaLexx Absolute ripper, sounds like you're good to go then!