[HN Gopher] Milwaukee M18 Battery Reverse Engineering
___________________________________________________________________
Milwaukee M18 Battery Reverse Engineering
Author : jakogut
Score : 210 points
Date : 2025-04-17 16:07 UTC (1 days ago)
(HTM) web link (quagmirerepair.com)
(TXT) w3m dump (quagmirerepair.com)
| Liftyee wrote:
| Always love to see an in-depth reverse engineering write-up. This
| one's particularly interesting since I'm currently designing a
| battery pack for my own project.
|
| Interesting to see a microcontroller (and quite a classic one...)
| as well as an ASIC for battery management. I imagine it's for
| communication purposes. The battery management chips I've been
| looking at have built in I2C interfaces to let me avoid firmware.
| alnwlsn wrote:
| I've been down this road before. The ASIC in the Milwaukee pack
| is known as an "analog front end". Since you can't wire cells
| directly up to the pins of your MCU, you have a chip to handle
| that stuff for you. It will let you read the voltage of each
| cell in the stack (some are literally analog, and just provide
| a nicely in-range voltage output for your MCU's ADC to read;
| others have internal ADCs). It might do current sensing. It
| might handle a couple alarms to turn off a mosfet when things
| go wrong. It will have an I2C interface, but the supported
| commands are "tell me voltage of cell #2" or "put shunt
| resistor on cell #1 for balancing". It's still the MCU that
| calls most of the shots here, but the more advanced ASICs can
| do more things autonomously.
| thephyber wrote:
| There was a GitHub project a few years ago to try and RE the
| Milwaukee M18 system. I think it was based around this
| teardown: https://www.allaboutcircuits.com/news/teardown-
| tuesday-batte...
| rapjr9 wrote:
| The MSP430 can be put into an extremely low power sleep mode
| (microAmps I believe, though you have to turn off all it's
| peripherals also) which means the MCU will not draw down the
| battery over time, leaving it fully charged and ready to be
| used even after long storage.
| whalesalad wrote:
| As a heavy user of Milwaukee gear this is a very pertinent and
| interesting analysis.
| gcormier wrote:
| https://www.youtube.com/watch?v=q7spzrIbdKY
|
| This guy has a few videos on his channel dedicated to the
| batteries.
| glitchc wrote:
| I'm not sure I follow. Aren't all lithium charging circuits
| basically the same nowadays, namely an SMC paired with a voltage
| pump or switching power circuit?
| s_tec wrote:
| This isn't the charging circuit - that goes in the charger.
| This circuit is responsible monitoring the state-of-charge (for
| that little LED bar graph on the front), disconnecting the
| cells if something goes wrong, and negotiating available
| current with the tool. It _should_ also be responsible for cell
| balancing, but it looks like Milwaukee forgot to implement that
| feature (oops).
|
| The videos at the bottom of the article have most of the
| details, since those dive into the communications protocols as
| opposed to the raw schematics.
| Saris wrote:
| Their M12 batteries don't have balancing (or a BMS inside),
| so they go out of balance and 'bad' very quickly. I've just
| added a balance plug to the outside of mine that I plug into
| my hobby Li-ion charger.
| nicolaslem wrote:
| Fun fact, DeWalt 18/20V batteries also don't have
| balancing. The batteries have pins going to each cell for
| it but no chargers actually use them.
| Saris wrote:
| It's such a strange thing to do unless they wanted to
| intentionally make them have short lifespans.
|
| The M12s have the pins too for voltage sensing in the
| charger (and tool maybe?), but they have 1 mega ohm
| resistors in line so cannot be used for balancing.
| notjulianjaynes wrote:
| DeWalt also makes a series of batteries that will either
| provide ~20v (5s3p) or ~60v (15s1p) depending on the tool
| you plug it into. I've taken one of these apart before
| and how they implement this is just a mechanical switch
| between the cell groups, which only gets depressed when
| inserted into 60v tools. Not sure if thats why they put
| all the circuitry on the tool side, but I can't think of
| another good way to implement the same. (You'd need a
| pretty beefy boost/buck controller for the amps these
| tools pull )
| zippergz wrote:
| I believe you on the technical details, but as an anecdote,
| I have M12 batteries that are 10 years old and still
| working fine. At least, good enough that I have noticed no
| issues with them and I don't even know off the top of my
| head which of my batteries are newer and which are older. I
| also have a bunch of M18 tools and batteries, and I've
| noticed no particular difference in how they age compared
| to the M12 ones. But I'm just a DIY homeowner, so my usage
| is relatively light.
| Saris wrote:
| Yeah I figure most of them work fine, otherwise I'd find
| more similar stories.
|
| We have about 10 of the M12 batteries, about half are the
| 3 cell ones and half the 6 cell larger capacity ones. And
| every single one has gone completely out of balance
| within 2 years of use.
|
| I plug them into a balancer and they last another solid 6
| months or so.
| glitchc wrote:
| There are always two charging circuits for Li batteries, one
| in the battery and the other in the charger. They pair
| together to negotiate the voltage and current. There's a
| dedicated protocol to do this.
| teraflop wrote:
| This is absolutely not "always" true. There are tons of
| 18650 cells that have no electronics whatsoever, and there
| are tons of dedicated charging ICs that connect directly to
| cells/batteries.
| throwaway48476 wrote:
| The EU is forcing toolmakers to use standard batteries. Hopefully
| we can get them in the US too.
| aequitas wrote:
| Do you have a source for this? Because all I know is that this
| was an April fools joke from last year. I'm curious of the EU
| is now actually doing this.
| toomuchtodo wrote:
| Edit: Bamboozled by the search gods
| kube-system wrote:
| That appears to be the abovementioned April Fools video.
| throwaway48476 wrote:
| https://eur-lex.europa.eu/eli/reg/2023/1542/oj/eng
| AlexandrB wrote:
| This would be painful in the short term because all my current
| tools and batteries would likely become obsolete, but it would
| be cool to see manufacturers more vigorously competing on
| battery specs like power and energy density.
|
| There's also the risk that tool prices could go up as I suspect
| some tools are currently sold as a loss-leader to get you into
| "the system".
| MisterTea wrote:
| > This would be painful in the short term because all my
| current tools and batteries would likely become obsolete
|
| I have seen 3rd party battery accessories so anyone looking
| to make money might wind up making adapters to retrofit
| tools. Good for the environment too.
| fragmede wrote:
| https://powertoolsadapters.com/ specializes in exactly
| this.
| bombela wrote:
| For some reason they insist in shoving some USB PSU in
| many of those adapters.
|
| That will drain the battery by itself over time. So you
| then must make sure to remove the battery from the
| adapter as per instructions.
|
| That is just so dumb, it's beyond my understanding.
| MisterTea wrote:
| Cheap design. You can do a shutdown and then have a
| controller go into deep sleep with picowatts of standby
| power consumption. A load connected wakes it up.
| mkj wrote:
| There's no reason a USB PSU couldn't have such a low
| quiescent current that you wouldn't notice it when
| there's no usb plug. No idea if they've done that there
| though.
| whalesalad wrote:
| We've had universal adapters for ages. You can run a DeWalt
| battery on a Milwaukee, Makita on DeWalt, etc. I even have an
| adapter to run my Milwaukee M18 batteries on my Dyson vacuum.
| You can run a wire to the pos/neg leads on the battery and use
| it standalone. I use it to power temporary reverse off-road
| lights on my truck. I see no reason to do this sort of thing.
| More oppressive regulation from the EU that no one actually
| wants. Fortunately Milwaukee is a US company as well as a
| dominant player in the market and will likely not participate
| in this whatsoever.
| buescher wrote:
| Milwaukee was a US company but has been a brand of Techtronic
| Industries, which is based in Hong Kong, for about 20 years
| now.
| IneffablePigeon wrote:
| You have to be careful with the adapters because some brands
| have the circuitry that stops you running the battery too low
| in the tool and some in the battery. If you end up with a
| combo where that circuitry doesn't exist you can over-deplete
| the battery.
|
| Also: I want that regulation :)
| Panzer04 wrote:
| Agree. The toolmakers don't impose some sort of coding (that
| I know of) so you can just use a 3rd party replacement
| battery too. I don't see a need to regulate this either.
| johnwalkr wrote:
| Too bad this wasn't real, especially since at the end of the
| day, all these things are just using 18560 cells.
|
| I tried to standardize on one system (Hikoki 18/36V). This was
| great as they use the same battery across consumer and pro
| products. But I moved from Japan to Europe and they are far
| less available, and more expensive. Now I buy Parkside stuff
| (Lidl brand) and they are probably a tier lower but better
| value and also use the same battery across consumer and pro
| products.
|
| Anyway I felt lucky that I could buy both low and high(er) end
| cordless tools in two countries/brands and also find adapters
| to use both batteries in both sets of tools. Both systems don't
| have any sort of data handshake between tool and battery. Going
| forward, this will probably increasingly be the case so I would
| love for a standard to be enforced.
| mrheosuper wrote:
| Unrelated, but Makita 18v has been an "unofficial" standard for
| cheap Chinese tool.
| HeyLaughingBoy wrote:
| What do you mean by that? Makita tools are not known for
| being cheap.
| doubled112 wrote:
| There are a ton of tools on AliExpress that will fit Makita
| 18v batteries.
|
| Some listings go so far as to be worded like "electric
| drill for Makita battery".
| tomcam wrote:
| FWIW I find these batteries and the charger to be exceptional.
| You can just leave batteries in and it knows when to stop
| charging. If you get the big charger and put a bunch of batteries
| in it charges them round-robin style. And the batteries
| themselves seem to be sturdy, robust, and high capacity. They're
| also expensive af so you want to wait for a sale if possible. I
| even spent a ridiculous amount of money on the battery-powered
| wet/dry vac and haven't regretted it for a moment.
| bombcar wrote:
| I never buy the batteries - I always look for a tool with the
| battery, as you can almost always score a free tool (or free
| battery depending on how you look at it).
| FlyingBears wrote:
| Drug dealers give out feelers to get customers started.
| wlesieutre wrote:
| The 4x 18V/5Ah batteries that came with my lawnmower (which
| uses them in pairs) are retailing for for $560.
|
| And then not as any sort of special deal, just the standard
| retail bundle, the lawnmower with four batteries included
| costs $700. So that's $560 of batteries and $140 of
| lawnmower.
|
| It's funny how lithium ion cell prices have absolutely
| cratered everywhere else, but the price of tool batteries
| just keeps going up.
|
| I wish there was somebody making reputable quality compatible
| tool batteries instead of mystery brand counterfeit trash.
| terribleperson wrote:
| At this point I suspect the only way we're getting
| compatible tool batteries is if the E.U. comes out with
| regulation.
|
| No company actually wants to make it easier for people to
| buy other tool brands.
| simondotau wrote:
| Before the EU can do that, someone will have to define a
| standard.
| Already__Taken wrote:
| That is how the EU will do that.
| throwaway81523 wrote:
| ceenr.com batteries appear to be ok.
| blagie wrote:
| Curiously, the mystery brand Bosch-compatible batteries on
| I bought on eBay -- literally cheapest seller -- seem to
| work very well even after years.
|
| With brandless batteries, it's luck-of-the-draw, but
| overall, as much as I do wish there were some way to know
| what you're getting, I've had good luck more often than
| not.
|
| What's also been nice is the rise of adapters. My Bosch
| blue batteries now fit many places they didn't used to.
| freedomben wrote:
| I wish these manufacturers wouldn't go brandless, because
| I've found some cheap but great laptop chargers in the
| past that I would buy a ton of if I knew who made them,
| but the brandless nature means that once that seller is
| done or out of stock, it's back to crapshoot.
|
| Some of these brandless Chinese makes are really solid,
| high quality products, but you can't easily tell which
| ones because they're visually indistinguishable from the
| bad ones.
| bsoles wrote:
| > It's funny how lithium ion cell prices have absolutely
| cratered everywhere else, but the price of tool batteries
| just keeps going up.
|
| Seems like the tool batteries might be the new ink
| cartridges.
| eth0up wrote:
| Behold
|
| https://ceenr.com/ !
| Panzer04 wrote:
| You get what you pay for.
|
| Tool batteries as a general rule don't do anything fancy
| internally, so they are easily substituted. I suspect it's
| mostly a matter of the main buyers being tradies/workers
| who use them to make money and thus don't care that much
| about the expense of the batteries - they probably aren't
| replaced that often.
|
| Would be nice if there was a 3rd-party seller known to use
| quality cells though, rather than unknown off brands.
| lq9AJ8yrfs wrote:
| Seems like this is the kind of thing that could be the basis
| of a community?
|
| It feels like there is a segment the tool co's are selling
| toward, that leaves another segment underserved.
|
| Eip if this is something you want to hobby-horse on.
| cameron_b wrote:
| I have three M18 batteries that are from 2011, and have
| outlasted 4 Ryobi batteries that get much less abuse.
| Glawen wrote:
| Same with my blue Bosch batteries from 2010. They use quality
| cells
| simondotau wrote:
| Define abuse -- because what Lithium Ion hates more than
| anything is long periods stored at over 80 percent, and
| especially heat stress while fully charged.
|
| Batteries which are used regularly and spend more time
| between 20-80 percent full might be less "abused" than
| batteries which are used infrequently, and stored in a room
| which sometimes gets hot.
| therealpygon wrote:
| I'd say the thing any lithium seems hate worse, for me, are
| long periods at 0%.
|
| As a homeowner I've had Ryobi lithium batteries for over a
| decade. Other than having added a couple battery packs from
| deals and a couple batteries from tools, I've not had a
| single one of my batteries fail. All are being stored at
| the maximum charge. Some don't last quite as long these
| days, to be expected with age, but not one has actually
| failed even from being dropped off ladders onto concrete. I
| did, however, have a Dewalt at work that died from falling
| 4 feet to the carpet floor. I've only had one Ryobi tool
| fail in that time, and those circumstances were
| questionable since someone had borrowed it.
|
| Experiences are localized and subjective.
| Panzer04 wrote:
| True 0V is very bad for lithium batteries, but extended
| periods at low SoC should be Ok (2.5V+). If there's any
| drain on the battery though low SoC can easily become 0V
| and dead battery (most chargers should refuse to charge
| those)
| linsomniac wrote:
| I just switched over the last 6 months over to Milwaukee tools
| for my home DIY stuff and they are really exceptional. I got
| one of the 7 1/4" circular saws with a FORGE battery and it
| just cuts everything I've thrown at it effortlessly. I'd put it
| as more powerful than my Dewalt 10" corded tablesaw, at least
| it seems much happier to rip a 2x4 than the table saw. I even
| designed a 3D printed sled for it to run on my track saw tracks
| and it does a great job there.
| TylerE wrote:
| Some of the battery powered tools really are more powerful
| these days, since a home 110v circuit is limited to a total
| draw of 1800w or so. The latest gen 18v/24v batteries can
| actually deliver more than that, at least for short bursts.
| Especially the big 4AH+ packs.
| skunkworker wrote:
| I recently purchased a M18 trimmer after not using one for
| years, it still surprises me that when not on the throttle -
| "off" is truly off, and not the persistent hum of a 2 stroke
| that is too loud in your left ear. No fumes and no fuel/oil
| mix to worry about.
| linsomniac wrote:
| I've tried to minimize the number of battery families I
| have, but I did buy into the Ego set of tools ~10 years ago
| for the yard tools, starting with the mower but I've since
| added the trimmer and chainsaw. Not having to do small
| motor repair and maintenance has been so nice!
|
| I was a little annoyed that some of the Milwaukee tools
| require you to go with the M12 battery (the "bandfile" is
| what sucked me in) so now I've got 2 battery ecosystems for
| the tools, but I guess that's not the end of the world.
| Moto7451 wrote:
| Even TTI's lesser Ryobi stuff (my usual go to as a DIYer who
| bought two tools 15 years ago and the batteries are still
| compatible) has benefited immensely from tabless and 21700
| cells. My 21700 8aH batteries is usually the difference
| between "can't cut" and "huh is slowed a little <shrug>"
| linsomniac wrote:
| I think the Ryobi are a good choice. ~12 years ago I got
| Porter Cable tools, and they worked very well for me over
| that time. But there was a pretty limited set of tools
| available, it did cover the core ones though. I had
| previously had DeWalt tools and felt I didn't use them up
| to their potential, so I went "down" to the Porter Cable.
|
| I almost went with Ryobi when I did my recent refresh. But
| I've changed to doing way, way more with the tools, I'm
| basically using them every weekend now. And the Milwaukees
| are just a joy to use, though you do pay for that. One
| benefit I didn't realize when I bought the hammer drill: It
| will detect if it grabs and the tool starts spinning. I was
| using a mini auger to break up some soil and the Porter
| Cable I nearly broke my wrist when it grabbed. I got the
| Milwaukee partly because it had a second handle you could
| add, but the accelerometer worked even better than that.
| JasonSage wrote:
| Where do you usually look for a sale on Milwaukee? I got lucky
| finding a great bundle sale at a Home Depot once, I'd love any
| tips on where/when to look more specifically.
| spaceguillotine wrote:
| Acme Tools, sometimes Grainger will have a sale too
| reaperman wrote:
| Slick deals: https://slickdeals.net/f/18256009-milwaukee-m18-
| redlithium-x...
| tomcam wrote:
| Home Depot website
| phil21 wrote:
| Home Depot is usually pretty good. Bundles are available
| fairly commonly as starter packs if you need to start from
| nothing. The drill/impact kit is likely where I'd begin since
| both of those (gen3) are exceptional in my opinion.
|
| Where it gets fun are the "buy a battery pack and get a tool
| free" deals. I had a bunch of text typing this out, but the
| stickied Reddit post covers it better[1]. You can typically
| get the tool you want for 40-60% off when/if it goes on sale
| using the "Home Depot Hack". Most common tools do at least
| once a year - the esoteric items are more hit or miss.
|
| I rarely pick up a tool now at full price. Once I know I want
| one, I simply add it to a list and note when it goes on sale
| in one of those combo deals. I've also picked up way more
| batteries than I ever will need due to other sales as well.
|
| The Milwaukee "buy more save more" event also works well if
| you need what is going on sale at the time.
|
| Reddit /r/milwaukeetool is a good place to check in from time
| to time for sales. Slickdeals is great for setting up an
| alert, but the exceptional deals get sold out quickly once it
| hits that site. There are also Discord groups out there as
| well if you go deep down the rabbit hole.
|
| Warning: Once you learn about Packout this becomes somewhat
| of an addiction for certain personalities.
|
| [0] https://old.reddit.com/r/MilwaukeeTool/comments/1gwhvi9/t
| he_...
| thephyber wrote:
| HomeDepot is one of the few warranty retailers. The
| "Special Buy of the Day" is updated a few minutes after
| midnight and usually has power tools about 10% of the days
| or the year. Right now HD is running their "Black Friday of
| Spring". Some of the best deals for hand tools are in-store
| clearance, so you just have to be in the store and find it
| (SlickDeals will try to announce those, but inventory for
| those are store-specific).
|
| Sadly one of the best ways to get cheap Milwaukee M18 tools
| is the "hackable" sales from Home Depot: when 2 SKUs bought
| together makes them both cheaper, but if you buy them
| online and have the 2 SKUs sent to different HomeDepo
| stores, you can cancel one of the SKUs later and the non-
| cancelled one is deeply discounted. It's probably a
| violation of ToS, but customer service reps allow it and
| support it, so maybe it's not actually a violation... ? It
| feels like corporate may eventually ban users who abuse
| that and cost more money than they are worth.
|
| Milwaukee doesn't sell via Amazon or eBay and there are
| notoriously good Chinese clones on those sites.
|
| I did get 3 decent Milwaukee (mostly M18) deals on
| Woot.com, but you have to jump on those quickly.
|
| There is a great website that does good price history +
| price comparison between HomeDepo, Lowe's, and WalMart but
| I can't find the link. If anyone has it, please share.
| phil21 wrote:
| > It's probably a violation of ToS, but customer service
| reps allow it and support it, so maybe it's not actually
| a violation... ? It feels like corporate may eventually
| ban users who abuse that and cost more money than they
| are worth.
|
| I've done this at least a few dozen times over the past
| 4-5 years now. I have way more tools than is reasonable
| for my use-case. No problem so far.
|
| From what I can tell HD doesn't seem to care much - the
| margin on these things has to be insane, so they are
| likely still making money on the transaction. Given how
| the discount is pro-rated across both SKUs you apply the
| deal to they likely did that on purpose. Who knows what
| rebates they are getting on the backend from Milwaukee on
| such promos, but I'd be surprised if there were none.
|
| I imagine if you did this a dozen times in a given month
| they might ban you for outright suspected return fraud -
| but for most folks I don't think it's a major concern.
| nicwolff wrote:
| https://toolguyd.com is good for tool sale notifications.
| mapt wrote:
| > You can just leave batteries in and it knows when to stop
| charging.
|
| This is true of all modern lithium ion consumer hardware,
| because if you don't get this part right, the battery explodes
| and burns down your house the first time.
| sidewndr46 wrote:
| One of my co workers decided to charge his drone at the
| office and found this out . Or more accurately the whole
| office did
| philjohn wrote:
| Is there now a section of the employee policies that
| forbids charging drones in the office?
| lazide wrote:
| The manuals have always told people to charge outside,
| for this reason.
| xnzakg wrote:
| Not when the charger says "for home and office use only"
| sidewndr46 wrote:
| There's probably some weird clause in the usage
| guidelines saying you need to have the charger attended
| all times it is plugged in or something like that.
| simooooo wrote:
| The DJI batteries and charger are very clever too. The
| batteries auto discharge to a safe level after 2 weeks on
| the shelf
| Casteil wrote:
| They're not the only battery tools I have (also have some
| Makita), but I am a big fan of virtually all my M12/M18 stuff.
| From the track saw, to the portable bandsaws, to the band
| files, oscillating multitools, reciprocating saws, jigsaws,
| drills, drivers, blowers, string trimmers, etc... their lineup
| is just incredibly diverse, servicing many trades/tasks, and
| they hardly ever make a 'dud'.
|
| Their batteries, at least in my experience, have also been
| similarly long-lived and reliable over years. And yeah - like
| some others have said - I also get all my batteries from
| 'battery included' tools/deals. I don't think I've ever bought
| one by itself.
| freedomben wrote:
| Indeed, I've been really pleased. They continue to hold a solid
| charge for years as well, even when left in harsh environments
| (like fluctuations between extreme hot and cold, etc). When I
| first started using battery power tools they were terrible.
| They had almost no power and batteries would die rapidly,
| usually at the worst possible time (like when you're using
| arms, shoulders, and knees to hold a piece in place and you
| just need to get a couple of screws in to hold it in position
| and the damn thing dies). A few years ago my wife got me a
| Milwaukee power driver/drill set and it almost instantly became
| my favorite tool. I haven't switched to the saws yet because I
| have great saws that stay in my shop, but I'm impressed enough
| that if I need to go to a work site again I'll consider it very
| seriously, whereas in the past I never would have.
| bityard wrote:
| One Christmas, I was given a shiny new 14.4V Craftsman NiCad
| drill with two batteries. These were not cheap and I was young
| and broke and very grateful for the thoughtful gift. It worked
| great and I enjoyed it immensely. For about a year.
|
| After that, neither pack would hold a charge long enough to be
| useful. Which I thought was pretty disgusting. Come to find out,
| this was basically the normal standard to which Craftsman had
| finally sunk. Rather than do the rational thing and throw it out,
| I held onto it with with a grudge and a goal of actually making
| it useful again one day.
|
| A few years back, I found a decent deal on brand-new 18650 high-
| current LiFePo4 batteries from a reputable supplier ($2.50 each,
| sadly NLA) and bought up a bunch to remake the packs for this
| drill and a couple others I had laying around for similar
| reasons. I added an inexpensive but well-made BMS (which I tested
| thoroughly before implementing) and the voltage was upped to 16V
| nominal for a little extra kick. Don't ask how I spot-welded the
| tabs to the batteries.
|
| 4.5 years later and these drills are still going strong, I use
| them at least once a week on both small and large projects. They
| are not speed demons or torque monsters, but they drill all the
| holes I ask them to. Would I have been better off economically
| throwing these ones in the garbage and just buying the cheapest
| thing from Harbor Freight? Maybe.
|
| But spite, it turns out, is its own reward and I would do it all
| over again a heartbeat.
| mitthrowaway2 wrote:
| It might not have been Craftsman's fault; NiCad batteries are
| vulnerable to the memory effect, which means if they were not
| fully discharged when you recharge them, the maximum capacity
| shrinks.
| kalleboo wrote:
| I thought the memory effect was basically a myth?
| https://en.wikipedia.org/wiki/Memory_effect
| bityard wrote:
| The "memory effect" of NiCad batteries is an urban myth that
| got supercharged with a dose of confirmation bias. Nobody has
| replicated the memory effect in consumer batteries. When
| people think they are observing the memory effect, most of
| the time they are seeing the very high self-discharge rate of
| 10% (or very often more) per month of storage combined with
| regular human forgetfulness. They charge up the battery, let
| it sit for a few months, go to use it, notice it went dead
| faster than they expected, charge it up again, use it right
| away, and see that it's back up to normal capacity.
|
| In my case, Craftsman just used REALLY bad cells, Plus there
| was no BMS, AND they wired them all in series so that if one
| or a few develop high internal resistance, basically the
| whole pack was shot. Very bad design + very cheap cells =
| designed obsolescence.
| xenadu02 wrote:
| The Ryobi lithium batteries I got with my first cordless drill
| bundle at Home Depot in 2006 still work and still hold a useful
| amount of charge today. And the charger I got back then will
| charge the newest batteries - not as fast - but they charge.
|
| Pretty amazing compared to what all batteries were like growing
| up in the 90s.
| maxerickson wrote:
| Yeah, I have had a similar experience with a cheap craftsman
| drill that has lithium batteries. I don't use it a lot and it
| pretty much has a charge when I need it.
| devwastaken wrote:
| why cant i use an external DC power supply to replace the one in
| the chargers? no reason they cant be USB-c given proper supply
| but there seems to be some kind of special signaling.
| TylerE wrote:
| Because usbc doesn't deliver 400w+ that those things use. Some
| of the multi chargers will happily suck down over a kilowatt
| sustained.
| jmb99 wrote:
| The highest-current M12 battery (XC 4.0 Extended Capacity and
| XC 5.0 High Output) can deliver 600W peak; the highest-current
| standard M18 battery (High Output HD 12.0) can deliver 1620W;
| the highest-current M18 Forge battery (Forge HD 12.0) can
| deliver 3240W.[0]
|
| There are vanishingly few AC-DC power supplies that can push
| 600W (that's 50 amps at 12V), let alone 1620W (90 amps at 18V)
| or 3240W (180 amps!!) and definitely none with a USB-C plug on
| them. You'd realistically be limited to ~1500W on standard
| household receptacles, and you'd need some _hefty_ cables on
| the output side of your power supply, especially if you want
| them to be jobsite-safe. For reference, 180 amps is in the same
| ballpark as EV fast charging stations; that's a rough estimate
| on the size your cord would have to be plugged in to the bottom
| of the tool.
|
| For the super light duty stuff like an M12 dremel, sure it's
| doable. But for any tools that need high burst or sustained
| power, either a battery or just running the tool on 120V AC
| directly (or compressed air) is easier, cheaper, and probably
| safer.
|
| [0]
| https://docs.google.com/spreadsheets/u/1/d/e/2PACX-1vRghl-44...
| sidewndr46 wrote:
| if by "vanishingly few" you mean absolutely standard then you
| are correct. The small PSU I have in my home PC is 1000
| watts. I have multiple kilowatt class AC-DC power supplies
| sitting around for other purposes. There is nothing special
| about that power level.
|
| For perspective my DC welder is rated at 10000 watts of
| input. The efficiency is really poor however so I'd only see
| something like 4000 watts out in the best conditions.
| stuckkeys wrote:
| I appreciate the mild humor injected into various scenes.
| noefingway wrote:
| I have a substantial investment in both Dewalt and Milwaukee
| tools that I use regularly in my farming operation. I definitely
| prefer the Milwaukee tools to the Dewalt. I recently bought a 6"
| Milwaukee chain saw for light duty cutting. I get a lot of cuts
| before I have to change batteries. Also the torque in the
| Milwaukee 3/4" impact gun is truly amazing and the battery lasts
| through a lot of bolt removals.
| tstrimple wrote:
| I've found they excel in different areas. For wood working,
| dewalt is the clear winner. They have some of the best most
| cost effective major woodworking tool like planers and table
| saws. Milwaukee has an edge on impact drivers and little else.
| If you mostly work with wood, Dewalt is better. If you need
| impacts for auto work, Milwaukee edges out dewalt. It's rarely
| worth investing in both platforms because the batteries are the
| most expensive component.
| ianschmitz wrote:
| I use Dewalt for my woodworking stuff and Milwaukee M12 for
| this very reason. M12 for automotive for their high speed
| ratchet, 3/8" stubby impact, right angle die grinder, etc.
| Milwaukee seems to have an edge there although Dewalt isn't
| far behind.
| wil421 wrote:
| AVE had tear downs years ago and I think there were a few
| places where dewalt edged out Milwaukee. There was also
| some black magic going on with dewalt impacts and a rebound
| effect. See Torque test channel[1].
|
| For automotive Milwaukee is the clear winner.
|
| [1]https://youtu.be/tPP6exJyILA?si=G1aKZL9yjYwkJ2aH
| ethbr1 wrote:
| > _Milwaukee has an edge on impact drivers and little else._
|
| DeWalt's lighting options are terrible, compared to
| Milwaukee. Low run time and bad ergonomics.
|
| In contrast, Milwaukee lights run much longer and have some
| neat solutions for disaster scenarios (lamp + USB charger).
| quickthrowman wrote:
| Milwaukee makes the best versions of lots of tools, mostly
| related to the electrical trade. The M12 portaband (one
| handed!) and M12 SDS plus hammer drills are amazing tools,
| and so are the M18 versions. Milwaukee has great lighting
| options too. My electricians can choose between Milwaukee and
| Makita, they _all_ choose Milwaukee.
| BonoboIO wrote:
| One of my Makita 18V 1.5Ah failed a few days ago, I m tempted to
| by knockoff instead of the brand name.
|
| Am I in danger?
| throwaway48476 wrote:
| There are a lot of fakes even if you try to buy OEM.
| jmb99 wrote:
| I've used knockoff M12 batteries for a while, no real issues.
| You can get them in larger capacities than the official
| Milwaukee ones which is my main use for them. I would imagine
| the Makitas are the same story.
| bruckie wrote:
| Maybe. There's also a good chance you'll get a battery whose
| actual capacity is not less than what it says on the label.
| This Project Farm video looks into that question.
| https://youtu.be/Xf0qqsRMKpM
| mrWiz wrote:
| My friends and I have very mixed results with knockoff Makita
| batteries. Some work just as well as name brand, others have
| roughly half the rated capacity and perform much worse in the
| cold. I'm assuming your use case is light duty since you're
| using a 1.5 Ah battery now, so getting a knockoff probably
| makes sense.
| oakwhiz wrote:
| I have a big 21 volt power supply hooked up to the empty shell of
| one of these batteries, with a resistor divider supplying 3.3v to
| trigger the tools to accept power. It works.
| latchkey wrote:
| Don't forget that you can buy fairly inexpensive adapters for the
| batteries. So, you can run your Dewalt on your Milwaukee
| batteries and not feel vendor locked.
| mrbigbob wrote:
| Youtube channel Torque Test Channel did a video on various new
| "tabless" batteries from various tool companies and most do
| provide more power per amp compared to the older models.
|
| https://www.youtube.com/watch?v=QJuevwLJyMQ
___________________________________________________________________
(page generated 2025-04-18 23:01 UTC)