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Cordless vacuum battery life question - Battery Management System (BMS)

  • 22 October 2022
  • 7 replies
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  • td47
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  • 2 replies

Hello, we have owned a V11 Absolute for a couple of years now, and it is very good.I keep it clean and well maintained. I have a rather technical question, regarding the “BMC” part of the machine. That is, an intelligent IC (chip) or set of chips that comprise the Battery Managment Controller, that handles and checks the charge and discharge rate, and checks the general state, or health of the battery “pack”, and attempts to keep the individual internal “cells” within the pack at a balanced voltage level (depending on the internal battery design).  

As my V11 is probably NOT yet old enough to have the battery pack near its End Of Life, my question is if any owners of older machines (e.g. V8 etc), have had to replace batteries after say 4 years or more use. The reason I am asking about an expected 4 year battery life, is the fact that SOME manufacturers use charge/dischage counters inside the BMC, that enforce a limit at a pre-defined count, that just stop the battery being used after that point has been reached. So your device gets turned into a “brick”! I have seen figures of 2000 to 3000 charge/discharge cycles quoted as the expected limit for “domestic” Lithium Ion battery packs (and both myself and a relatvie have expereinced exactly this on another manufacturers cordless vacuum, and power-tool batteries). This seems to be a waste, and a very “un-green” way to do things, if there is still actual usable, safe life left in such batteries. 

Does anyone have a way to reach “internal engineering” contacts, to find out if charge/dischage limit counts are used on V11 battery packs. 

Stuart 1 year ago

Hey Everyone! 

Great to see a health discussion taking place on this topic.

In terms of discussing individual components, their development, the technology and investment, understandable this makes up part of Dyson IP and is confidential product related information. It isn’t therefore something we will be able to directly comment upon. 

Furthermore, it isn’t possible for us to provide an exact lifespan for any component, including that of the battery, as this will depend how each individual machine is used, stored and maintained. I can offer reassurance however in that Dyson cordless vacuums come with a free 2-year guarantee, and we do expect the battery to last at least that long. 

You can find some useful tips on getting the best out of your battery here: https://www.dyson.com/support/vacuum-cleaners/cordless/battery-care

Thanks, 

Stuart.

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7 replies

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Hi td47

Very interesting. I hadn’t personally heard of battery control management or was even aware that it was taking place within a battery development community.

I guess this would be similar to that of Apple reducing the battery life of their outdated devices.

I am loosely aware of battery degradation, the expectant charge capacity reducing over a prolonged period. Say 3-4 years plus. I imagine this is why the warranty offered against batteries are set at two years.

The oldest of our cordless Dyson is a DC34, purchased well over 10 years ago. It is still going strong today, we’ve had two batteries in that time. I full expect this of an older product however.

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@Kibbleb Many thanks for that very useful and informative answer. It is very reassuring that the DC34 has such an impressive battery life. This does NOT necessarily mean that later models (like my V11) will be the same, and as the BMC control  code details are embedded in the BMC chips, no-one will be any the wiser, should Dyson decide to limit charge counts, to say 3000 before flipping the software OFF switch for the installed battery to create an additional revenue stream for newer devices (unless there is publicly available information on this, which is doubtful).

I am hopeful that Dyson are using the more user friendly options, of using the BMC for what it was originally intended for, that is to check on battery status and quality (i.e. safe current and temperature and cell balance). See an interesting article here on this:

https://www.synopsys.com/glossary/what-is-a-battery-management-system.html

 

A

Td47. 

It doesn’t necessarily mean that there is a BCM implemented against later models, especially that of  the V11 series or ANY.. 

In my view the question you’ve asked is very subjective. A simple internet search reveals that batteries reduce their charge capacity overtime, in combination with a vast array of conditions. Over charging, too hot, too cold, discharging and leaving for prolonged period, I could go on…

In my opinion, it would be very hard to identify the cause being anything but battery degradation on a 3-4 year old battery.

Kirby. 

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Hi 👋 

We’ve had our V10 since 2018.

We’ve never had an issue with the battery. 

 

Stuart
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Hey Everyone! 

Great to see a health discussion taking place on this topic.

In terms of discussing individual components, their development, the technology and investment, understandable this makes up part of Dyson IP and is confidential product related information. It isn’t therefore something we will be able to directly comment upon. 

Furthermore, it isn’t possible for us to provide an exact lifespan for any component, including that of the battery, as this will depend how each individual machine is used, stored and maintained. I can offer reassurance however in that Dyson cordless vacuums come with a free 2-year guarantee, and we do expect the battery to last at least that long. 

You can find some useful tips on getting the best out of your battery here: https://www.dyson.com/support/vacuum-cleaners/cordless/battery-care

Thanks, 

Stuart.

Stuart - Dyson
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Td47. 

It doesn’t necessarily mean that there is a BCM implemented against later models, especially that of  the V11 series or ANY.. 

In my view the question you’ve asked is very subjective. A simple internet search reveals that batteries reduce their charge capacity overtime, in combination with a vast array of conditions. Over charging, too hot, too cold, discharging and leaving for prolonged period, I could go on…

In my opinion, it would be very hard to identify the cause being anything but battery degradation on a 3-4 year old battery.

Kirby. 

I think you may be misinterpreting some of my points here. The broad term Battery Management System (BMS) is there for most consumer and professional devices that contain recharcheable battery packs, as it MUST be there to keep the device SAFE to use, and not be over-charged, not get too hot, and not be allowed to have a high current flow (either in the charge OR the disharge mode), These usually work in conjunction with “smart charging IC chips” to form a BMC (Battery Management Controller) for any given device that uses LION or similar technology high-current capable batteries, to keep them working in their SOA (Safe Operational Area). The point I am getting at with this post, is if Dyson are using charge count limits in the BMC design, to act as a “planned obsolescence” to force (possible) earlier than expected battery replacement. The positive replies I have seen here, seem to indicated that some users are seeing VERY long life-cycles for their battery packs, which is GREAT news as far as I am concerned, so Dyson appears to be doing VERY good work and design in this area, and NOT imposing usage restrictions. Obviously, a failed battery SHOULD be blocked from use by the specific BMS actions, to keep the user safe at all times, both during charge AND discharge cycles.

DavidTaylor
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Hi @td47, 

I hadn’t previously seen this post!

A very insightful subject and a relatable concern. Not just on Dyson products alone, but on all existing (In market) and future battery-operated devices.

You are right in saying “Battery Management System (BMS) is there for most consumer and professional devices that contain recharcheable battery packs, as it MUST be there to keep the device SAFE to use”. In simplistic terms, this is implemented as a Safeguard to manage the distribution of charge, by managing the power cells more efficiently. Like moving water between cups to allow for the addition of more, over time.

@Kibbleb - A good point to note here is that while this doesn’t necessarily reduce battery degradation over time, it does go some way to manage the effects. This is felt more on modern batteries, with a high charge capacity and overall runtime. On older batteries, where the runtime is so minimal, the effects are felt more so. 

I wouldn’t personally think that limiting charge cycles is something implemented by Dyson, or that of any manufacture. Where we see a 2 year as standard warranty, and batteries purchasable through direct sales, I doubt this is taking place. On the other hand, if I saw a retailer offering a warranty, but then restricting the sales of their own batteries, I would begin to question if they are looking at generating a new revenue stream. 

One last consideration in this space has to be the discontinuation of a product line. If there were say multiple new models coming to market and older models (within the last 5-8 years) where being discontinued, along with their parts, this would cause me alarm. Being slightly bias towards Dyson, they no longer support the DC35 - Their first cordless stick. Which was released in 2009 - 13 Years ago. The battery technology has come a long way in that time. 

David.

David.
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