# Diagnosing and repairing a Dyson DC16 vacuum that just won't suck!

#### -Ty-

Joined Feb 5, 2017
83
Hey all,

So many years ago, my father picked up a Dyson DC16 handheld vacuum, powered by a lithium-ion battery pack.

Ever since like the third month in basically, though, the thing could not hold a charge. Its kept plugged into its charging base, as its meant to be, and the battery indicator lights on the unit show that it is completely charged. However, when you try to use it and pull the trigger, it comes to life as normal, but only stays working for 2-4 seconds, before quickly tapering off in power, and then stopping altogether. Pull the trigger again, and repeat the process. You can typically pull the trigger to do this 4-second "burst-vacuuming" about 10 times or so before each burst becomes successively less powerful.

Even stranger still, sometimes, by pure chance or luck, one pull of the trigger out of the 10 will last longer than the 4 second mark, seemingly never ending, though the power and loudness drops with every passing second until it sounds so weak that you WANT to let it rest.

What I'm wondering is: is this a battery problem, or a machine problem, and is there any way to figure it out if all I have at my disposal is a soldering station and a multimeter? I have no battery capacity or discharge testing machine so I can't tell if the cells are fried or something, unless there's a way to do that with a multimeter. My dad just doesn't want to purchase a new battery only to find out it was never the battery in the first place.

Any help is greatly appreciated, cheers.

#### AlbertHall

Joined Jun 4, 2014
11,610
Can you get access to measure the battery voltage?
Check the voltage while charging and when you pull the trigger.

#### -Ty-

Joined Feb 5, 2017
83
Can you get access to measure the battery voltage?
Check the voltage while charging and when you pull the trigger.
I can't get access to the terminals while the battery pack is plugged into the handheld, so i wont be able to test it while the trigger is pulled.

However, removing the battery and testing it yielded 23.15 V between the + and - terminals, and measuring the terminals of the charger itself yielded approximately 27 V.

For reference, the battery has a nominal voltage on its sticker of 21.6 V

#### LesJones

Joined Jan 8, 2017
3,573
From what I can find on the web the battery pack consists of 6 cells your voltage reading of 23.15 volts gives a voltage of 3.86 volts per cell. That seems a bit low for a fully charged cell. I would expect near 4.2 volts straight after charging. It is probably the battery that is faulty but it could also be the charging circuit not cutting off at the correct voltage. If you can't find a way to monitor the battery voltage wile on charge and under load the diagnosis can go no further.

Les.

#### -Ty-

Joined Feb 5, 2017
83
From what I can find on the web the battery pack consists of 6 cells your voltage reading of 23.15 volts gives a voltage of 3.86 volts per cell. That seems a bit low for a fully charged cell. I would expect near 4.2 volts straight after charging. It is probably the battery that is faulty but it could also be the charging circuit not cutting off at the correct voltage. If you can't find a way to monitor the battery voltage wile on charge and under load the diagnosis can go no further.

Les.
Granted, 4.2 x 6 = 25.2 is a noticeable difference to the 23.15V I'm picking up, but even at 3.86 volts per cell, the vacuum should be able to operate for more than 2 - 4 seconds, no?

Unfortunately, just like a battery pack on a cordless drill, the terminals are connected to, and blocked by the handheld... there would be no real way for me to get a lead in there and then ALSO get the handheld connected... unless in theory i connected every terminal of the battery to the handheld with a jumper... but i don't know how I'd do that.

#### LesJones

Joined Jan 8, 2017
3,573
If it was mine I would take the item apart and work out which were the power pins inside. But if you are not reasonably knowledgeable about electronics then that is probably not an option.

Les.

#### -Ty-

Joined Feb 5, 2017
83
[...] But if you are not reasonably knowledgeable about electronics then that is probably not an option.

Les.

The voltage across the pins reads at 24.25V (why its gone up in the past two hours, i have no idea)

When the trigger is pulled, the voltage immediately drops to 15.5V, and a second later, the vacuum dies and the low-battery light flashes.

#### -Ty-

Joined Feb 5, 2017
83
Bump?

#### LesJones

Joined Jan 8, 2017
3,573
It looks like the battery is the problem.

Les.

#### JoeJester

Joined Apr 26, 2005
4,390
Measure the battery voltage, turn the machine on. I suspect your voltage will drop very low.

When it does, replace the batteries.

#### -Ty-

Joined Feb 5, 2017
83
Measure the battery voltage, turn the machine on. I suspect your voltage will drop very low.

When it does, replace the batteries.
I did that and posted the results already:

Nominal voltage on the sticker: 21.6v
Measured voltage at rest: 24.25v
Voktage across the charger's terminals: 27.9v
Voltage within one second of pulling the trigger and turning the vacuum on: 15v

#### wayneh

Joined Sep 9, 2010
17,155
I did that and posted the results already:

Nominal voltage on the sticker: 21.6v
Measured voltage at rest: 24.25v
Voktage across the charger's terminals: 27.9v
Voltage within one second of pulling the trigger and turning the vacuum on: 15v
Yup, that's almost certainly a bad battery cell. Excessive resistance to turning might draw a lot of current and give a similar result but I think you'd be able to tell it was binding, not turning, not sucking, and so on.

You might find that just one of the 6 cells is really bad, and that opens the option to just replace that one. I think that's a temporary kludge but it could work - until it doesn't.

#### -Ty-

Joined Feb 5, 2017
83
Yup, that's almost certainly a bad battery cell. Excessive resistance to turning might draw a lot of current and give a similar result but I think you'd be able to tell it was binding, not turning, not sucking, and so on.

You might find that just one of the 6 cells is really bad, and that opens the option to just replace that one. I think that's a temporary kludge but it could work - until it doesn't.
Good to know. And given that a new battery is only 32 bucks, I'll just give that a try. Thanks!

#### JoeJester

Joined Apr 26, 2005
4,390
I did that and posted the results already:

Nominal voltage on the sticker: 21.6v
Measured voltage at rest: 24.25v
Voktage across the charger's terminals: 27.9v
Voltage within one second of pulling the trigger and turning the vacuum on: 15v
Low battery under load = high internal resistance. Visit http://batteryuniversity.com for more info.

#### WBahn

Joined Mar 31, 2012
26,398
Hey all,

So many years ago, my father picked up a Dyson DC16 handheld vacuum, powered by a lithium-ion battery pack.
A significant clue that it is likely the battery is the phrase "many years ago". It's hard to say what the problem was a few months after you bought (if I'm reading correctly and that the problems you describe started very early one). But by this point, many years later, the batteries are probably bad. The symptoms you describe, particularly the immediate drop under load, all point to that.

#### WBahn

Joined Mar 31, 2012
26,398
My wife just bought a small Dyson and cleaning it is a royal pain and you can't do it without pulling out a lot of the crap with your hands. To get it clean enough to not lose most of the suction, you've got to basically disassemble the thing three or four times over the course of vacuuming the house. Given the dog poop and vomit, dead insects, wood bits, glass shards, and all the other stuff that ends up in carpets from time to time, this just doesn't seem a very decent solution.

#### wayneh

Joined Sep 9, 2010
17,155
My wife just bought a small Dyson and cleaning it is a royal pain and you can't do it without pulling out a lot of the crap with your hands. To get it clean enough to not lose most of the suction, you've got to basically disassemble the thing three or four times over the course of vacuuming the house. Given the dog poop and vomit, dead insects, wood bits, glass shards, and all the other stuff that ends up in carpets from time to time, this just doesn't seem a very decent solution.
A friend was looking at getting herself a knockoff Dyson, a Shark I think it was. So I went to read reviews and there was pretty good consensus that the knockoff brands work well, until they don't. Once they fail, they're done because you cannot get parts and they're not built to be repaired. Apparently, the Dyson units may or may not last longer before they fail, but if they do fail you can get them fixed. That's nice, but I wasn't convinced that the TCO would be better in the long run. Is an expensive vacuum you own for a lifetime better than a cheap one you buy once a decade? I doubt it, but I'm not certain.

#### WBahn

Joined Mar 31, 2012
26,398
A friend was looking at getting herself a knockoff Dyson, a Shark I think it was. So I went to read reviews and there was pretty good consensus that the knockoff brands work well, until they don't. Once they fail, they're done because you cannot get parts and they're not built to be repaired. Apparently, the Dyson units may or may not last longer before they fail, but if they do fail you can get them fixed. That's nice, but I wasn't convinced that the TCO would be better in the long run. Is an expensive vacuum you own for a lifetime better than a cheap one you buy once a decade? I doubt it, but I'm not certain.
That's a very good question. We've had a number of cheap vacuum cleaners in the last ten years -- maybe five. But a couple were given to us and I don't think we've spend more than $30 on any of them since my wife is a master of the garage and thrift store sales. But with the pet hair problem, they were always clogging. So my wife got fed up and decided that it was worth it if an expensive vacuum cleaner got rid of that aggravation -- and I would have agreed with her had she asked me beforehand. I think she paid$300 for it and it is specifically advertised as being for houses with shedding animals. I'm far from convinced that the aggravation factor has been reduced much at all. Although the Dyson clogs just as quickly, it IS easier to take apart (without tools) to unclog. With a couple of the others it was quite a task to disassemble them enough to clear the clog and it was also evident that they were not intended to be disassemble that way very often since they used self-tapping screws into plastic in some places. They Dyson is also quite a bit lighter than the others and is cordless. So, IF it lasts long enough, it was probably still worth it.

#### atferrari

Joined Jan 6, 2004
4,476
If a PSU is available a test could be run easily. Objections anyone?