Unofficial firmware upgrade for Dyson V6/V7 vacuum battery management system
github.com
github.com
Long story short, the fireware was indeed full of bugs. It is possible that these controller boards haven't been working right for the last 10+ years. I managed to add a few lines of code to bypass some initial values when the board is first powered up, and that fixed the issues. It is indeed an "on demand" defrost controller now. I'm still slowly writing a blog post about it but probably won't get more time to publish for a few months.
But I guess the point is, after messing with this, there seems to be an entire world of embedded firmwares that are just riddled with bugs and will never be fixed.
I’d love to see this blog post, if you end up having time to write it! Can you share a link to your blog? I didn’t see it in your profile.
Trane had the original patent for computer controlled defrost: https://patents.google.com/patent/US4573326A/en In the first image you'll see a chart with different temperature "bin" factors. In one place in the code, the temperature offset from 32 degrees (freezing) is added to a hardcoded value and the PC then jumps into a certain spot in a lookup table. The values in that lookup table help determine at what "DT" (delta temp between outdoor coil and outdoor ambient) a defrost should initiate. In another location, a hardcoded value is added to the PC along with a loop counter.... On loop 1 through the code, jump to this location, on loop 2 jump to this location, etc. Kind of a strange way to code, but after buying different revisions on ebay of this board going all the way back to the early 2000's, and on top of the patent being from 1985, perhaps this was the norm in the 80's and mid 90's.
On the other hand, carefully hand-crafted and super clever machine code written in the '80s and subsequently fucked up by successive generations of maintainers who didn't understand it is an entirely plausible scenario.
I purchase my Dyson V7 as an official refurb and the battery went in to lockout a few months after the short refurb warranty expired. Thus prompting the project. The vacuum is pretty handy for my small apartment, and when I bought it, I wanted something that had decent reviews and was from a real company, not just some Amazon seller with a bunch of random characters for a name. I still like the vacuum, I just wish Dyson hadn't designed it to fail.
I think there are two issues here: 1) The left out the cell balancing circuitry which is pretty standard for battery packs. 2) They designed their firmware to go in to permanent lockout when the cells go to far out of balance (300mV).
For the sake of discussion, I've heard interesting two arguments on why they might have disabled cell balancing: 1) Cell balancing could be a weak point on the ISL94208 IC they used, so they could have disabled cell balancing to actually increase overall reliability. We'd never know for sure, but I could see this being plausible. This is from someone on the EEVblog thread (https://www.eevblog.com/forum/projects/fu-dyson-bms-an-(unof...)
2) Cell balancing isn't actually useful because a poor battery cell will plummet in voltage under load anyways due to the higher ESR in the poor cell. At least, that was my interpretation of their argument after translating it from Russian to English in a comment on the YouTube video. While I see their point, especially in the vacuum's turbo mode which draws 17A vs the usual 3A, I think there would still be some usable capacity to be gained by balancing the cells even if one did have a much higher ESR.
https://hackaday.com/2022/05/23/fighting-back-against-dodgy-... https://news.ycombinator.com/item?id=31487401
Also, this resembles why I'm very reluctant to buying an e-scooter in Sweden since basically all the ones available here are rebranded OEM Alibaba scooters with poor/fake battery implementations, so when it fails you'll be standing there with no way to get back on the saddle again.
Even the Swedish-branded Vessla scooters were rebranded OEMs from Alibaba, with minor cosmetic changes and a hefty premium. After a while the batteries turned out to be of poor quality, and after their v2, they quit that vertical entirely.
Looking forward to Segway launching their e-scooters in Sweden, at least I know it's a reputable brand standing behind it and can honor warranties etc. I want something quite small that I can have in the apartment (theft and vandalism otherwise), and can use to scoot my kid to school with.
The cordless one does not quite match the suction, but it's so much more convenient and sufficient nonetheless.
Dyson aren't awful but they're definitely overpriced.
It's made of really cheap plastic and has cracked in a few places.
Being bagless is good in that I can see what it's collected but bad in that when come to empty it the dust I'm allergic to goes everywhere. (If only someone would invent a bag to keep the dust in eh?).
The suction is also pretty poor, however it makes up for it by having a roller in the vacuum head which picks up the dirt.
If you have anyone in the house with long hair its almost unusable as the roller will be clogged up after a single vacuum. A traditional vacuum with better suction and no roller wont have this issue.
On the plus side they are light and manoeuvrable, and the wall mount means you always keep it charged.
The Dyson 'bagless' idea is a bit of a sham. Yes they work, but they don't work that well. They don't make as much suction as their bagged competitors so they cheat and use smaller orifices to increase suction instead of by having a larger motor or alternative design. Then in order to have 'like new' performance all the time you have to continually wash (which doesn't really clean well enough) or replace filters.
Some people love them but they don't make sense to me. If I'm emptying my vacuum I'm going to empty it into a bag anyway so I may as well use a bagged vacuum that works more consistently and doesn't throw dust everywhere.
It's not a sham, different use cases call for different things.
Personally I'm never going back to a corded vacuum if I can avoid it.
The friction to use a cordless vacuum is very low compared to a corded one. And consequently, vacuuming change from being a chore that's done once few weeks for a an hour to some short 5-10 minutes burst every few days.
The newer models offer larger batteries and debris capacity, and higher power (suction), but as you mentioned the V10 has been plenty for my household, so they don’t seem worth the extra weight let alone expense.
I previously had a V7 that worked well enough in a smaller home for a few years. After the battery started deteriorating I replaced it with an aftermarket one, but that was slightly larger so it no longer fit in the charging dock. Now the V7 lives in a campervan where it’s still plenty useful.
- The Roomba goes once a day. It doesn't pick up much in one pass, but my house is much cleaner because it runs all the time. Covering the same spot many times, it does well.
- The Dyson cleans very well, and picks up all the places the Roomba doesn't get to or emergency spills. It's never run out of batteries.
On the whole, it's less effort and cleaner than with my old big'un vacuum.
And if I want to do a deep clean, I'd rather wash in either case.
It doesn't pick up a lot of trash on one pass, but it makes many passes. Even with many passes, it sometimes misses stuff that my old big vacuum would have picked up, but I run it every day or every other day.
The carpets stay really, really clean.
A side benefit -- to me -- is that I need to keep the floors Roomba-ready. If you leave laundry, cables, etc. on the floor, you've got a problem. YMMV if you have family; with some visitors, I can't use the Roomba at all.
I currently own a Dyson cordless for vacuuming the mattress when I change the sheets, a Bosch class M industrial vacuum and a Miele from before the dawn of time.
I’ve previously owned a Roomba.
I have the Bosch as a workshop vacuum and if I need to clean up something I don’t want blowing back into the air it’s the one I use. Eg brick dust or MDF dust.
Both my Dyson and my old Roomba were bagless and when you empty them it goes all over place.
I also don’t trust the filtering on them. They say hepa filters but that doesn’t mean it’s not leakng out case somewhere.
You only get one set of lungs so if it maters to you get something better than a Dyson.
My Miele still works well but I don’t trust the filtering on thar either.
If the Roomba kicks anything up:
- If it lands back on the carpet, it will get it on the next pass.
- If it doesn't land on the carpet, the air filter will get it.
My allergies are a lot better with this setup than what I had before.
However, the Dyson has a HEPA filter, but it's definitely not a sealed HEPA filter or "true" HEPA. Air goes around. The air coming out smells dusty. It's fine because it's only for things which the Roomba can't get to, but I'd be very unhappy with it as my sole vacuum cleaner. For what it does, it's super-convenient.
I should also mention: I have a carpet washing machine too. I rarely use it (much less than I should), but it's a huge step up.
The point of anything cordless is how it eliminates the hassle of, well, dealing with cords. In case of a vacuum cleaner, one has to:
- pull the cord out
- plug and re-plug it
- ensure it doesn't get stuck around the corners and under furniture legs
- ensure it doesn't pull some other furniture and topple them over
In addition, corded vacuums have practically no power envelope or weight restrictions, so they end up being bulky, heavy and loud, even if the context in which they are used doesn't require the power.
Dyson cordless (I can't speak to any other) in contrast:
- weighs lot less and can be carried around with ease
- can be moved around without a second thought of where the cord is or whether it can be maneuvered in a certain way
- is a lot quieter (can be used at night)
- is instantly accessible without any setup so it makes sense to use it for a few seconds to clean something up
- can be used outside of the house where there is no power outlet - e.g. in the car in a rental apartment parking
Since I switched to cordless (which has been 6 years or so), I no longer dread vacuuming. It's actually a pleasant experience and sometimes, when I get a few minutes, I do a clean of areas that get dirty often (entrance).
The battery life and the power available have improved to the point where it's no longer something I worry about (especially for my two bedroom apartment).
Bought a Shark upright that I used in between my more thorough weekly rainbow vacuumings. But the shark was slowly falling apart, and you can't buy replacement parts and there are so many models, that finding used parts is not really possible either.
So I did the "buy once, cry once" routine and bought a Sebo E2 canister. Like many other European brands, parts are easily available and you no longer have a disposable product which is a win in my case.
Our next kitchen won't be a Siematic.
I've been using Dyson products since 2005. Happy to shine some light on why people pay for it voluntarily :)
Removing and replacing paper towels with hand dryers in public bathrooms has been an unfortunately shortsighted move that's been copied without much thought. Hands aren't the only thing that get wet in a public bathroom. You may wash your face, you may be removing stuff off your clothing, and countless other uses that a hand dryer alone can't accommodate.
Seriously, if paper napkins and no Dyson Aerosol-Your-Skin-Cells-9000 means I don't have to think about the sanitary habits of my fellow citizens, that would be reason enough to stop installing them.
They also scream like a banshee and don't dry your hands. I happen to also wear a beard, perhaps you can see why having only the Scream And Don't Dry My Hands Machine available would be unsatisfactory.
The ultimate bachelor's vacuum cleaner was the Dyson DC15 Animal. It just cleaned and cleaned and cleaned, their newer stuff I dont rate.
Vacuum wars were impressed at least https://youtu.be/rFbkGM9Lm18
No idea about battery balancing in them though, maybe I need to open it and try to find out. My gut feeling is that they wouldn't save out on a few resistors.
I knew that cost cutting in consumer electronics was bad, but I didn't know it was THAT bad, especially for a premium brand like Dyson.
And that's coming from someone within the industry.
Not assuming that is the reason, but it certainly seems like a "positive" side effect for manufacturers.
As another commenter here said, this is an obvious case of planned obsolescence.
I even fitted a larger aftermarket battery. Still awkward to use. Eventually I gave up, and bought a corded Henry from Numatic.
I cannot recommend a cordless Dyson for anything except light dust busting.
Maybe it would have cost too much to provide a better BMS or charger, or just wanted to eliminate a risk factor.
1.Series battery cells in a battery pack inevitably become imbalanced. This is extremely common and why cell balancing was invented.
2.Dyson uses a very nice ISL94208 battery management IC that includes cell balancing. It only requires 6 resistors that cost $0.00371 each, or 2.2 cents in total for six.
3.Dyson did not install these resistors. (They even designed the V6 board, PCB 61462, to support them. They just left them out.)
4.Rather than letting an unbalanced pack naturally result in lower usable capacity, when the cells go moderately (300mV) out of balance (by design, see step 3) Dyson programmed the battery to stop working...permanently. It will give you the 32 red blinks of death and will not charge or discharge again. It could not be fixed. Until now.
On the V6 batteries, you could theoretically install the missing resistors and handle the rest in software, but the balancing would be very slow since it would also have to go through a 1K resistor Dyson included on the other side of the internal balancing MOSFETs. On the V7 and up models, they actually shorted the internal balancing MOSFETs of the ISL94208 on the PCB so you'd have to cut the very fine traces here and then solder on balancing resistors. I think you could actually just place a short in place of the balancing resistors because of the 1K resistor already in circuit.
All said, I figured that of the limited number of people willing to take apart their battery, buy a programming tool, and install my firmware, there would be even few willing to make those very delicate modifications. And anyone willing to do all that probably already owns a bench power supply they could use to rebalance their battery pack manually.
I'd initially planned on adding cell balancing until I saw that the ISL94208 balancing connections where shorted together on the PCB. That's something that just can't be fixed in software. Maybe one day I'll add balancing to one battery, just to show it can be done.
I’ve replaced the original w some random one from Amazon, because it wouldn’t last as long. (Choosing from the many generics was not easy reviews are seem very uneven)
Maybe BMS could make it last longer in charge behavior similar to iPhone?
I’m more interested in a guide on how to replace the red bristles in the long vac head.
Also +1 on the dyson v6, it changed how I clean. Have not tried the cheap knock offs but anything w o a cord is the way to go.
Eventually I persuaded her that a Henry was the way forward. She bought it and now knows what I mean - I have one as a "garage/DIY" one and another as the house vacuum. There's a reason why professional cleaners in the UK use them!
[1] https://www.vanttechbatteries.com/products/for-dyson-v6-upgr...
I suppose they work mostly like the Power Wheels hacks but have no personal experience with the vacuum variant. YMMV.
Meanwhile on the V10 I have, batteries cost $130, can't be hot-swapped easily, and use a higher voltage that makes the 20v tool battery modification impractical. I planned to replace (and upgrade) the cells on the refurbished model I bought because the battery has been subpar since I received it, but so far I haven't managed to get past the abnormally-tricky plastic clips.
I consider it the Apple of vacuums.
> By using this firmware, your battery pack will not become unusable if the cells become imbalanced, you will just have reduced battery capacity as usual.
> Cell balancing is not implemented. I know this is ironic, but because the cell balancing resistors aren't installed and Dyson used 1K resistors for the VCELL# connections, even if you shorted out the connections where the cell balancing resistors would go, which most people aren't going to do (and you'd have to cut some very fine traces on the V7 BMS PCBs), the cell balancing would be extremely slow through the 1K resistors.
So I guess the only use of this currently is reviving a dead battery pack.
I did add a way for you to at least monitor the cell balance level via LED blink codes so you know when the cells need to be manually rebalanced.
You are correct that in the end, this project doesn't provide a ton of extra utility. Especially since another user from the EEVblog forum thread, dvd4me, found the EEPROM values you can reset to clear the permanent lockout on the original firmware.
In general, I have come to hate battery powered stuff including laptops, power tools and cars because they just dont pack enough raw power for my needs.
I was asking because I wondered what sort of use case would electric cars not fulfil properly, and although not perfect they're getting pretty good.
I can live with electric cars struggling on a track, it feels niche enough.