How to fix a Ryobi 40V6ah battery

I was given a 40V6ah ryobi battery and I was able to bring it back from the recycle bin!
Also it is a T10 security bit, not a T15.

[@mahatmaabba4113]

The battery has a controller, the BMS (Battery Management System). This BMS has a low voltage fault to “protect” the cells. The person in this video bypassed the BMS and raised the voltage in the cells (hooking up a controlled current directly to the cells at main positive contact and b- “ground”). They then reset the BMS (shorting the 3.3v reset) to clear the fault. Because the cells are now charged above the low voltage fault the BMS realizes the cells are good and allows charging.

[@arikofoz]

I did the reset with a wire between ground and reset, but it still does not charge. Only the LED1 and LED3 are lit up when i press the button on the battery. Anyone else having this LED1 and LED3 lit up?

[@jonathanjijon626]

Did you ever figure out? I have the same issue

[@IZZYICE93]

Same issue? Any answers

[@andremadeira6916]

Same here . Help😮

[@gabrieldeslauries9737]

@@andremadeira6916did you ever figure it out??

[@loberant]

You guys have a bad cell.

[@danbo98042]

Thank you for sharing this! I have been watching many videos about restoring a Ryobi 40V battery - this is the only one that has the same circuit board as mine! Thanks!

[@brycethoreson9216]

I had first and 3rd light on. After shorting ground and reset, no lights. Getting 3.3v on each cell. 15v at main positive and negative terminal of the charging tabs but wont take a charge, still shows defective plus no test lights

[@maxupole]

Thanks a ton for sharing this! Spent 700 bucks on the mower set only one season later both batteries wouldn’t charge! This fixed my issue! I used a 12v small battery car charger and just clipped onto the plastic // metal of the negative side I had larger alligator clips

[@christianmastache8052]

I almost killed myself trying to fix it long story short it sparked and caught fire and I almost died I now nothing about voltage ty for sharing tho 😅

[@EMCRen]

Mine lit up and started to smoke too when I touched the rear positive terminal by mistake. I immediately removed the jumper and it stopped smoking. Let it sit for a bit and cleaned everything with a alcohol swab afterward. I need a charger like his if I'm going to charge it long enough to get rid of the low voltage fault, bypass the BMS, and reset it correctly.

[@maukaman]

Did the parasitic draw continue? I’ve had 2 of these newer 40v batteries that started to “self discharge” for an unknown reason. There are two relatively large smd resistors that it shorted in a sort of “self destruct” discharge process. Those 2 resistors were very hot to the touch which is how I found them. I removed them from the pcb and was able to charge both packs back up with a power supply. One pack I caught before it dropped below probably 20v and that one is still working and charging normally with its “self destruct ” resistors removed. The other pack had already drained itself down to 5v or so when I caught it and would not charge normally (with original charger) ever again. It actually worked to power a Ryobi tool for a time, but not long after the cells fell out of balance and it wouldn’t take a full charge ever again through the main terminals using a power supply. I was not aware of this reset function at the time. It would have been interesting to see if that pack could have been restored with a reset, but since I typically don’t like to use cells that have dropped below 1v for any high current applications anyways I ended up tearing it apart to reuse the cells elsewhere. Im looking forward to testing this reset method sometime in the future. Im sure I’ll have a need for it before too long, I come across failed Ryobi batteries quite often unfortunately. Anyways, Thanks for sharing! 🤙

[@ericensley2427]

no clue. but it does drain over time. I have seen it lose a bar in a week or 2.

[@WIZEMART]

What a coincidence RYOBI? Love all my Milwaukee. Never ever discharges even within a years. We are not that rich to buy cheap stuff - dutch proverb

[@jonsoldinindy]

What is the box that is showing you voltage? do you have a part number or amazon link?

[@toan3000]

Thank you so much, I was short the reset jump and it work again.

[@kerryd4696]

worked 100% jumping the reset on the board - went from DOA with all four lights flashing to Please recharge me [1 flashing green light] which I did -- Thank YOU

[@hunterhryciuk3964]

When these batterys get to low they become unsafe to use so jumpstarting is necessary but it will take a while

[@gavinmcclure8047]

Where did you get your power supply? Btw I got one battery to work but I have one that's giving me a fit. Two of the LEDs flash after I get the voltage up to 35 on my dc to dc charger. Number 2 and 4 led

[@ericensley2427]

Aliexpress... aka china

[@WIZEMART]

LOL Look how many people saw this video and how many thumbs up - it’s a ratio between people who said WTF and who understood and appreciate what he’s doing. It’s so funny. As I’m writing it’s 32K views and only 195 thumbs up.

[@ericensley2427]

Lol. Yeah probably true

[@rbrock00]

It was impossible to follow your method.

[@SilverTreasures]

Lol right.

[@walteraustinr102]

Definitely big thank you for tearing it down 👍

[@bertdunn8755]

I watched this and figured out one big thing. You are way way smarter than I am. I’ve watched other videos on this subject and it seems if I can figure out where the ground is I have a chance of fixing my batteries. I have like four batteries and after taking them apart, they are all different. So is there a way to explain to a retired truck driver with very little electrical knowledge how to determine where the negative (ground) is.

[@ericensley2427]

There may be labels on the board. Look for GND and rst or reset. Also call ryobi and complain u may get a new battery if less than a yr old

[@user-vl1bo6pf7g]

"Hit the reset', do you need to put the clip inside the hole and "hit" or depress anything ? or just touching the ring around the hole ? For how long ?

[@josephp.3149]

I have a 40v Ryobi battery that shows 35 volts on my meter but refuses to work on any of my tools or take a charge. I tried the reset to no avail I really don't know what else I could try. Any suggestions?

[@kevinjackson4464]

Cool. Dropped mine in the creek. All lights flash, guess this won't help me, LOL.

[@walteraustinr102]

10S3P to power 40V 6AH I can’t believe their using 18650 Li-ion 2000mh batteries. 21700 Li-ion batteries @ 5,000mh would kick ass!!!

[@scottbaker9066]

You could switch all the cells, but the 3500 mAh cells are 2x the cost of the 2000 mAh cells.

[@michaelmendez8516]

I have two of them. They went bad I push the button and out of the four lights only the first one and the last one turns. I took it apart out of the 20 cells only three had a voltage of 3.5v the rest had .47v or less.

[@ericensley2427]

U can try charging the low cells up, but I would guess some cells are shorted/bad and the pack is bad.

[@robertzacharias5460]

How many batteries are in there?

[@grandpaworks8632]

morning sir now yours seems to be a easy fix but my issue is after it is charged and wire the ground with reset i press the fuel button for a second. then after taking the short wire off the fuel lights flash one at a time moving from left to right. will not reset. i usually charge the pack at the battery b+ which is 10 positive and the b- which is the 1 negative. now i haven't try charging your way but i might try for the heck of it. but there are issue with that. thank you for your post

[@weizhao8743]

Hi, i have the exact same issue" wire the ground with reset , the fuel lights flash one at a time moving from left to right. will not reset " have you got any solution ? thanks!

[@ericensley2427]

Check the volts of each of the 10 cells, makes sure it is not out of balance

[@lifehackertips]

What’s that little black power adaptor called?

[@spodee55]

How old was this battery before you had issues with it?

[@jamespeek]

Can I just wire my charger to it like that or do I have to have that device

[@ericensley2427]

No idea what u are asking

[@mikemazzoli1990]

Are they 18650 Samsung cells?

[@ericensley2427]

I don't know, I did not look that close at them when I took it apart

[@manuelruiz1854]

All I see is not enough knowledge in the matter...... I am only waisting my time!

[@thanhpham1320]

Bạn có thể chỉ giúp tôi cách reset.vào chân nào

[@ericensley2427]

Take a wire and hook the wire to GND and RESET. this will reset the BMS and SHOULD make it come back to life.

[@thanhpham1320]

cảm ơn bạn rất nhiều.

[@thanhpham1320]

Chào bạn.1 dây móc vào GND và kết nối tới chân reset phải không bạn ?

[@gavinmcclure8047]

Do you just slide the wire in or are you soldering it to the board

[@ericensley2427]

@@gavinmcclure8047 Just short it for a second or two. DO NOT SOLDER A WIRE IN!.

[@imanoleonardo6902]

I could not see where you attached the lead on the battery side Camara moved too quick for me

[@ericensley2427]

I connected a wire from GND to RST. That shorted the rest and allowed the BMS to start working.

[@imanoleonardo6902]

@@ericensley2427 not the reset but when you added the tab to charge

[@manuelruiz1854]

😁

[@BLASTIC0]

You are mixing cells in the dewalt pack? Any reason?

[@ericensley2427]

I had tesla cells laying around. Just what I had on hand

[@bonnietech5433]

So… you don’t know what you’re doing….cool thanks.

[@wo0416]

Where I bought you charger?

[@loiswallace3334]

I have a 36V (aka 40V) Ryobi 6Ah battery pack that was found to self discharge very rapidly. The battery pack charge status LED's didn't light up when testing the pack charge level by pressing the pack test button. I opened up the battery pack and measured the pack voltage, it was only about 2 volts! Using a small bench power supply, I tried charging the battery pack by placing the power supply negative lead clip on the negative solder pad on the pack circuit board. The power supply positive lead clip was attached to the pack main positive terminal. The battery pack was charged up to around 34.5 volts before I stopped the charging process. The battery pack charge status LED's still didn't light up when pressing the charge test button on the pack circuit board!? So I tried "jumping" the RESET and GND holes on the pack circuit board with a metal conductor, but that didn't seem to do anything. The charge status LED's still wouldn't light up!? I then left the pack overnight and then measured the battery pack voltage again, and the pack had self discharged overnight down to around 2 volts again!!?? So something was seriously discharging the pack probably due to some component(s) on the battery pack circuit board. In the end I scrapped this battery pack as it seemed there was some (serious) issue with the battery pack circuit board which could not be fixed just by jumping the RESET hole. What is particularly annoying is the pack is only around a year old and had only been used on about 4 occasions! The cells used within the pack are - EVE brand, rated at 2Ah, and there are thirty cells in total. I removed the cells and measured their voltage. The voltages ranged from 0.3 to 0.9 volts.

[@ericensley2427]

Send a msg to ryobi, they may warranty the battery.

[@chowerter]

I'm getting the same thing with mine. Very frustrating. I charge the pack up to about 35V and can watch it drop voltage about 5mV/sec just sitting on the table. When I measure across all the cell test points they are generally the same except one set does not get more than 0.9V. So I'm assuming there's a bad cell pair in the pack? It's two+ years old so Ryobi says sorry buy another....

[@ericensley2427]

@@chowerter Yes, sounds like u have a bad cell killing that set. sounds like it is internally shorted. You can try to take the battery apart, and cut those cells out and replace them. just try to get a cell that is about the same capacity.

[@loiswallace3334]

@@chowerter Three possibilities as I understand it. One or more cells might be faulty, or, one or more components on the BMS circuit board may be faulty, or, maybe both cell(s) and component(s) faulty. Based on my faulty 6 Ah battery pack, you may find it extremely difficult to access the cells as the cells have spot welded metal plates and spot welded wires attached to them. And some parts are soldered in also. I believe it would be near impossible to remove the spot welded and soldered connections and some associated parts without causing permanent damage! But you can try and see how things go. If the problem is due to faulty BMS component(s) (also), then trying to find the faulty component(s) would be extremely difficult as there are heaps of very small (SMD) components to check. Even if the faulty components are found, replacing them could be difficult as it would require excellent de-soldering and soldering skills and appropriate tools to work on the (very) small SMD components and without damaging other components in the process. Again you can try, or maybe someone else could try who is experienced in working with small SMD components? Good luck.