Thread 2939730

>milwaukee
no cell balancing
>dewalt
no cell balancing
>makita
no cell balancing
>bosch
no cell balancing
>ryobi
no cell balancing

Every 0.1V of imbalance takes away ~10% of the total capacity and eventually the cells are going to die. Surely they dont want the batteries to go bad so you dont need to buy a new one, right? How many normies you see tearing down the packs to balance the cells individually when they wrongfully think that the battery is at the end of its life? No, they throw it away and buy a new one that can costs as much as new tool. And the companies keep getting away with it when simultaneously marketing as how green and caring they are.

>>2939730 (OP)
In their newer packs, almost all of them have at least something resembling balancing. Supposedly Milwaukee and Ryobi are not very good at it, but Bosch, Dewalt and Makita should have balancing in their 18V batteries.

>>2939730 (OP)
Just slap resistors? Duh

>>2939730 (OP)
bullshit: the post

>>2939730 (OP)
im a professional carpenter and have 20 year old makita batteries that get used on a daily basis. I know they get shit on here for their batteries by retards, but i have never had one go bad or any of my makita tools. In fact I regularly interact with old carpenters who still have the the original stick battery tools. Im not a shill. my table and miter saws are dewalt, my sawzall is milwaukee, nail guns hitachi (would like to pick up one of their old 8 1/2" sliding miter saws), rotary hammer bosch, etc. drills/drivers/battery skillsaws/corded skilsaws all makita.

>>2939730 (OP)
>makita
>no cell balancing
wrong

>>2939763
He might be correct. I think a lot of chargers just shut off when the highest cell hits 4.20V or whatever.

I’ll admit OP and myself are wrong and I see a video of balancing wires in packs sending current to each set of parallel cells rather than just monitoring voltage to tell the charger when to stop. I think that’s why the 3P packs like the 12.0s always get messed up and only charge to 3 bars, especially if you don’t run them flat from time to time.

>>2939787
makita is absolutely one of the batteries that does cell balancing, it's what that yellow thing with all the connectors on it are for.

hell even some of the knockoff batteries have cell balancing.

>>2939789
Ok. Show me somebody measuring extra juice flowing through the low cells rather than the 1 balancing wire to each set of cells simply watching for the highest cell to get to 4.20V.

>>2939792
the cell balancing is in the charger, that's why the yellow connector is there.

>>2939795
Yup, and lots of chargers “balance” by knowing to stop when the highest cell hits 4.2V rather than when they’re all even.

Show me somebody measuring it,

>>2939792
also that is not an oem makita battery.

>>2939797
Ok now show me those connections bringing every cell to max instead of monitoring for the first one to hit max.

I’m willing to concede you’re right when I see evidence

>>2939796
>>2939798

oh for fucks sake, test it yourself.

I've checked my batteries cells. and they all had the same voltage when charging completed.

>>2939786
>>2939789
>>2939795
>>2939800
According to this video makita does not balance. 40V models might be different, who knows.

>>2939800
I don’t have Makita.

And I’ve seen a handful of unbalanced packs because one cell is low and you can charge them a million times and they will never balance unless you hit the low one(s) with a power supply and bring them up to the highest cell’s voltage.

>>2939769
>t.

>>2939798
You don't actually know how balancing works do you?
It's only one wire connection and a set of relays.
Cheap balancers don't charge or transfer power, they send the highest charged batteries through a resistor to burn off power until it matches the other batteries.
More expensive ones will take power from the highest charged battery and send it to a lower charged one.
In both cases balancers are not designed to handle large imbalances like with a failing battery, only nominally small ones seen in a healthy pack.

>>2939918
>More expensive ones will take power from the highest charged battery and send it to a lower charged one.
The only active balancers I've seen are the ones sold as placebo for fixed battery storage applications

>>2939789
I don't think the Makita yellow thing is for balancing just on the basis that it predates PCB-to-18650 connections. Old Makita batteries (5 years ago or so) only had 3 connections to the battery pack, positive, negative and one extra, 3.6V connection. If you do not have a physical connection to every series connection point, it's literally impossible to balance charge.
Second argument is that I have 2 disassembled Makita packs, one with actual balancing, and none of the yellow terminals have voltage on them. You'd normally directly expose the cells to the yellow connector if the charger was handling the balancing, and yet the balancing traces from cells on the pcb all go through transistors and sure don't go to the yellow thing.
Third argument is that someone else has already decoded the yellow connector and it's clearly for comms https://www.laptopu.ro/community/power-tools-battery-pinout/makita/paged/2/

Makita 18V batteries that have balancing handle it on board.

>ITT: I know literally nothing about this topic and don't have the battery, but let me tell you how it works

>>2939918
So power tool batteries don’t really have balancing, simply protection to stop it from charging when the highest cell hits 4.2V?

>>2939730 (OP)
never had a battery die on me
makita, dewalt, bosch, milwaukkee, b&d, ryobi
>t. tradie since 2003
skill issue.

>>2940028
But you throw away old batteries too early because you think they are losing capacity when actually just one or few cells are low on voltage. I hope thats your employers money and not your own money.

>>2939730 (OP)
im throwing poop at your post

>>2940067
what part of
>never had a battery die on me
did you not understand? why would i throw away batteries thats not dead?

>>2939769
buy an ad

>>2940170
Hard to believe that you have 22 years old batteries that still work fine. I bet you dont have a single of those early tools anymore. The changes are that you switched companies and tools many times so you dont even know what we are talking about here.

>>2940022
Did you even read? They do balance, but balancing is done by matching to the lowest voltage cell by draining off power from higher charged cells. It's one of the most common forms of balancing due to cost, speed, and safety. It's a lot easier and quicker to take 2 mismatched batteries and burn off say 4.2v to 4.1v then to try and shove more power into a 4.1v battery and pray it's going to take the charge well. It also gives the most reliable charge estimates as all batteries will be at a known charge level. This Balancing happens after charging.
Balancing the other way, trying to force lower voltage batteries up to higher voltages while charging, leads to the weaker batteries draining faster and the battery cutting out early from a weak battery going low while others are still good.
They do also have under and over charge protection, the "Stop at 4.2V" (or whatever the flavor of lithium they use has for its max charge voltage) being over charge protection, not balancing.

>>2940192
Strange how they end up unbalanced then!

Still waiting to see that bleeding off of a high cell with some actual testing in a power tool pack. I’ve seen a lot of evidence that it’s mostly just monitoring to stop charging when the highest cell hits an upper limit, no matter where the other cells are. That’s why people get issues where packs only charge to 3 out of 4 bars.

The only evidence of bleed off resistors on power tool boards I’ve seen is “Anon said so” and I’m not so convinced.

>>2939730 (OP)
Cell balancing is required for safety reasons. They.must have it.

>>2939884
how are you even supposed to do this correctly though

>>2940333
Holy Christ you are dumb. The only charges to 3 of 4 bars issue is due to balancing. On the charger it will try to go to max voltage allowed. Once you take it off the balancing occurs and now you quickly have 3 bars. The still good batteries were drained down to the lowest voltage in the pack, giving you three bars. Balancing doesn't bring bad batteries up to match good battery levels, that's dangerous, it brings good batteries down to bad battery levels. Power tools also have aggressive low voltage cutoffs, so once you get that one bad battery in the pack that drags it down the entire pack will be shot without repair or replacement.

Image related, BMS board from a DeWalt pack. Note the resistors and 4 bare balance legs. The balancing happens to groups of batteries, not each individual battery. In this case it's completely passive, the batteries balance against each other through the resistors. Some larger packs use active components and microcontrollers.

>>2940437
Continued...

Pic related, Ryobi and rigid BMS boards. They have a bit more to them, with a microcontroller to assist in balancing.

>>2940437
>quickly
Milwaukee batteries have 1kΩ resistors so they are capable of discharging 4mA per hour. Discharging 25% of a 5Ah battery (1,25Ah) would take 13 days. What is even more funny is that the chips are not programmed to do so. So there is no balancing even when they have the hardware to do so. How do you explain the 3 bar problems straight outta charger with these?

>>2940459
I messed that up. They are 5s2p packs so single cells are 2.5Ah. Balancing them down 25% would take only one week kek.

>>2940467
>>2940439
>>2940437
Show me on the meter or thermal cam where that resistor is burning off energy from the high cell!

Because the people with the 3/4 bar issue don’t seem to get it resolved in a week. Only thing that ever fixes it is a warranty replacement or hitting the low cell(s) with a power supply and bringing them up.

Also nobody complains that it charges to 4 bars and then quickly drops to 3.

I still think Anon is incorrect until I see proof and testing beyond “Anon saw some resistors on a board”

>>2940615
Its pretty hard to show it because they dont do it. As i said the controller chip is not programmed to discharge them dispite that they have all the hardware to do it. Its been like this since the beginning and they chose not to impliment or fix it for what ever reason.

>>2940621
Oh, so I was right when I said the BMS simply stops charging when the highest cell hits the limit and doesn’t truly balance?

>>2940660
Yes.

https://www.reddit.com/r/Dewalt/comments/1e0gbn8/do_dewalt_chargers_balance_the_cells/

https://www.reddit.com/r/Dewalt/comments/1k6asnr/does_this_guy_balance_the_battery_cells/

https://badar.tech/2025/08/24/ryobi-battery-repair-guide/comment-page-1/

>>2939730 (OP)
That's why I shill for Metabo, they actually have properly engineered packs with build-in balancing.
There is no connector for each cell to the charger, the balancing is done internally with a transistor on each cell connecting it to a small capacitor. The capacitor is charged/decharged into/from cells, the pack balances itself even when not connected to a charger.
On a new pack it takes a handful of cycles on the charger and then all cells are synced.
Since the transistor and capacitor are very small, it is very cheap to do, and there is no connector with a lot of small fiddly contacts that can break.

>>2940621
A majority of the DeWalt BMS system resides in the tool, only the resistor balance board is in the battery. Do you guys even know anything about power tools?

>>2940615
No wonder you are a trip fag, you are too dumb to remember to breathe with out someone reminding you.