Viomi 2-in-1 robot vacuum – Model V2 and V3 cleaner and mop (review)

Viomi 2-in-1 ropbot vacuum

This is a review of two Viomi 2-in-1 robot vacuum cleaner/mops – The V2 Pro (V-RVCLM21B) and the newer V3 (V-RVCLM26B). While both are functionally twins, there is a technology generation difference.

What is Viomi?

It is a Chinese public company. Xiaomi is its strategic partner and major shareholder, and Viomi is part of its ‘mi HOME ecosystem’.

Viomi has developed an ecosystem of smart products including water purifiers, refrigerators, range hood, switches, speakers, fan, water dispenser, mirror, gas and electric water heaters, water processing, dishwashers and more.


You do not see the whole range in Australia – we are a very small market compared to its target – China’s young, modern, ‘new middle-class’ consumers. It sells factory-to-consumer (F-2-C) in China and via Xiaomi mi-store in Australia.

Interestingly another Xiaomi strategic partner is Roborock  (24.7% of shares), making robot vacuum cleaners and more.

Australian review: Viomi 2-in-1 robot vacuum cleaner and mop

  • V2 Pro (V-RVCLM21B) Website here and RRP $649 but on run-out at $399
  • V3 (V-RVCLM26B) Website here and RRP $899 but on special at $624
  • Warranty: 12-months ACL compliant on the robovac and 6-months on the battery, charge dock and charger.
  • Country of Manufacture: China  

If you see two figures separated by a /, it is V2/V3.

What is a Viomi 2-in-1 robot vacuum cleaner and mop

It is actually a three-in-one. Vacuum, mop, and vacuum and mop. It does that via three separate ‘dustbin’ inserts. The V2 is equally capable but has shorter battery life and 20% less suction power.

The dustbin holds 550ml (dust equivalent); mop water tank 550ml (of water) and the combo about half each.

It is a mop in-so-far-as it has three levels of water adjustments that spray into a washable, reusable mop pad. It also can sweep using a disposable paper sheet.

Viomi 2-in-1 robot vacuum Mop

First impressions – another round robovac

All observations are on the V3. Apart from a few cosmetic differences, (the V3 is black and the V2 is silver), the V2 is functionally similar, albeit with some older tech.

Quite large and round at 350 x 94.5mm x about 4kg. The round Laser Radar (LiDAR) turret is at the back, and the IR collision sensor is at the front. It uses the familiar motion-activated bumper avoidance system on the front half. A single right whisker sweeps small detritus into the vacuum brush.

Underneath is the motorised brush (15.5cm wide) and a slide-in rear dock for the mop plate. The ribbed rubber wheels are 65mm – reasonably large – and should clear up to 20+mm sills.

There is a dock. The V2/V3 has a 20V/1.2A/24W and 20V/1.8A/36W charger. We found the robovac pushed it around and may benefit from some double-sided tape to hold it still.

Set-up – easy

In Australia download the Xiaomi mi Home app from Google Play. Don’t use the barcode in the manual as it points you to an Android APK file – this is for China that does not have Google services (Xiaomi advises that the new manuals will be corrected).

The app will discover the device and update the firmware. It also states that you cannot use the device (except in a manual ‘dumb’ mode) unless you agree to the Terms and Privacy Policy.

The app is quite comprehensive. It has all the usual smarts like schedules, multi-floor maps, named room cleaning, no-go and no-mop zones.

Then you let it go, and it builds a map. It must complete a full cycle starting and returning to the base station to create a map.

This stage is vital to later define go-and-no-go areas (for example, carpet with a mop) and to be able to clean rooms by name.

Map building – hard

Both units could not complete the mapping process due to Wi-Fi connectivity issues. It ignored two rooms (master bedroom and ensuite) and an area approx. 15m from the router.

Viomi 2-in-1 robot vacuum map
The router is in the middle of the home (red circle). The left and right solid red lines were the extent of Viomi’s ability to operate. There are still rooms past that as the LIDAR image shows.

The test home has a Netgear RAX80 AX6000 6-stream router. Signal strength in the master bedroom is between -45 and -55dBM and 150Mbps (good). We can only surmise that the Viomi antenna signal sensitivity is fairly low, and if it loses Wi-Fi, it is unable to function.

In later tests, we placed a Wi-Fi extender in the bedroom and both robovacs were able to complete mapping.

When we disconnected Wi-Fi, the maps ceased to function. They are obviously not stored on the robovac but in the mi Home cloud.


It uses a pretty standard LDS laser (LiDAR) and Simultaneous Localisation and Mapping (SLAM) to create a 2D map out to about 8m claimed (tests show that it is closer to 5m). The maps are fairly accurate.

Error handling

The IR sensor stops it bumping into things. The mechanical bumpers help it find its way out of tight spots.

But it gets quite ‘aggressive’ when cornered and there is only one way out. It keeps bumping and turning and twisting – sometimes winning and sometimes giving up.

We also found that it always got lost under a particular bed. It is dark under there – the bed linen hangs to the ground.

Vacuum power

The suction force (claim) is up to 2100/2600Pa. There are settings for silent, standard (default), medium, and Turbo (the Pa measurement above). Our observation is that the default settings are for longer battery life, not for greater cleaning efficiency.

Clean efficiency

We have been doing vacuum reviews for many years and use a 300m2 three-bedroom home as the test bed. It comprises about 30% long and dense shag pile carpet (that few robovacs have conquered), 30% bamboo hardwood floor, 30% sisal ribbed carpet and 10% ceramic tiled bathrooms.

A round robovac will never be as efficient as a D-Shaped one because the latter has a far wider  (nearly 2X) rotating brush and can get closer to edges.

We set up three tests excluding the feature rug.

First, the V2 vacuumed the area. Second, the V3 to see if it could pick up more detritus. Third, the Neato D7.

The picture below shows dustbin’s contents – V2, V3 and D7.

V2 picked up 100g, V3 picked up another 100g and the Neato D7 another 145g – on the same floor area in sequence! Viomi does not deep clean.

 In subsequent tests over three weeks, we found that it should be set to medium for hard floor and Turbo on carpet to marginally improve the detritus pick-up. Turbo is better all-round but louder and sucks battery life.

On hard floors, it picks up almost every small piece of detritus. The whisker is reasonably effective up to about 20mm outside the device’s diameter feeding detritus into the rotating brush.

But anything larger than a rice-bubble tends to be left behind.

It does not like ribbed ‘sisal’ carpet. It simply will not pick-up lint and tissue fragments from the ribbed pile. When set to Turbo, it picked up about 50%. You may not see the detritus (in red) in the image below but this is after several passes.

It will not work on longer pile carpet – few robovacs do.

It is about half as efficient as the Neato D7. That is not to say the Viomi is bad. At the price, it is pretty good.

Cleaning time – slow

Part of the issue is that it has a 15.5cm rotating bush versus Neato’s 28cm brush. That means it has to make twice as many passes to cover the same area. And that takes twice as long too. It takes nearly two hours to clean what Neato does in under one.

Edge Clean – fail

It avoids coming closer than 100mm to any cupboards or overhangs. You will need to use a hand vac to clean this area.


The V2/V3 have 33W/40W batteries. The V3 lasts about 20% longer.

The batteries are Viomi specific, and I can’t find any for retail sale here. You will likely find generic Lithium-Ion replacements on AliExpress for around $30.

We can only speculate that these use 4×3.7V 18650 (or similar) round rechargeable cells connected in serial so, at worst the battery pack could be repacked locally. Using such cells (especially in serial mode) gives you way less than 200 full charge cycles – 2-3 years weekly use at best.

Battery life claim is 120/150 minutes on hard floors. That is correct for vacuum only in standard mode. In Turbo the V3 got 45 minutes – still reasonable. Straight mopping increases battery life a little as there is no vacuum.

Viomi claims it will clean up to 180/250m2, but the reality is around 100/150m2 with a mix of surfaces.

Recharge time is about five hours.


Place the 550ml water container in the dustbin receptacle. It will do about 150m2. Then slide in a wet the mop pad and let it go. It will follow the map sans any no-mop areas.

It pulls a soft cotton, damp mop pad behind it. That gets dirty quickly (15-20m2) then it pulls along a dirty, damp pad.

Like all robomops, you are only supposed to use water. Depending on the floor surface (care with stone and porous surfaces), a teaspoon of vinegar may help to cut grime.

Perhaps the Chinese definition of ‘mop’ is different from mine. I want to see more than a water streak on the floor and I expect good edge mopping.

My take – it is great for redistributing grime but not so good for serious mopping. It is for maintenance mopping – it won’t remove grime and food/milk drops.

Mop and Vacuum

I find the combination a little redundant as it halves water and dust capacity. But for smaller areas (<20m2) it is fine. User reviews tend to reinforce that its best to vacuum first then mop.


You can use ‘one use’ sweep pads instead of the washable mop pads.


Typically 66dB but can get to 75dB at times.

Under furniture

It will go under furniture with at least 100mm clearance. The LIDAR turret can get caught on hanging cables.

Sill negotiation

The claim is 20mm with the mop attachment that is conservative.

Sill Viomi 2-in-1 robot vacuum

Cleaning pattern

A U-shape pattern with about a 5m turnaround. It also has a secondary cleaning option that essentially does the area twice. That doubles the clean time and we found it only marginally more effective than the Turbo setting.

One user review sums up, “Bought this recently, took me a couple of days to understand how everything works. You must use the secondary clean option on vacuum and mop always if you want to see good results.

We agree.

Sensors – not a lot

It has a cliff sensor and an IR front collision sensor. While it claims 12 sensors It lacks sensors for dust bin full, water empty or carpet boost.

Maintenance (all prices are from the Viomi Shop on AliExpress and exclude freight)

The HEPA filter is washable and will require replacement every three months to maintain airflow. A pair costs US$7.99

The power brush is easily removable and should last 6-12 months (we think longer if the bristles remain intact).

The Side whisker brush is most likely to need replacement every three months.

Wheels should last the life of the device but are available for US$18.99

Privacy – generic advice

While a robovac should have a low privacy risk, we suggest carefully reading the Privacy Policy and Terms and Conditions that you must agree to before using any product.

All collect some personal information when you sign up to enable the company to target its own and third-party advertising to owners.

As with any China-based AI cloud, the government can access whatever information is collected.

A robovac can collect

  • Location
  • Home layout
  • Wi-Fi network credentials
  • Phone details
  • Registration information – name, email, phone number
  • If a device has a camera, image and microphone, voice

Site prep

The nirvana is that a robovac can be left to clean any area in any ‘state’. Nirvana does not exist. You cannot expect any robot cleaner to work unaided! As a guide

  • Lift all dining chairs, stools and side tables off the ground (if you want it to clean under tables)
  • Lift floor rugs with tassels that could tangle in the brush
  • Tie up loose electrical cables off the floor
  • Remove clothes/shoes/bags off the floor
  • Build lower gradient ramps if it has issues with door sill heights
  • Use no-go lines on mapped areas or close doors to rooms you don’t want it to clean

We are relatively confident that you can set and go after the above preparation.

Fit for purpose

A segue first. My sister-in-law loves her cheapie round robovac from Aldi. You see for what she uses it for it is fine. Viomi is a value robovac/mop.

Most users, especially single level apartment/townhouse dwellers with predominately hard floors, will love the Viomi 2-in-1 robot vacuum cleaner and mop – either V2 or V3.

On the other hand, I am a technical reviewer and look for both the upsides and downsides based on real-world tests and comparisons to other robovacs.

The best robovacs tested are Neato D7 (9.2/10), LG R9 (9.2/10), Roomba i7 9.4/10) and ECOVACS OZMO T8 AVI 8.2/10). But these are all well over $1000. BTW a pass mark is 8/10!

Issues to be aware of

It will not map a room out of Wi-Fi range – it does not exist to Viomi. You will need to ensure the area has reasonable 2.4Ghz signal strength.

It does not like being picked up and moved. It is far better to tell it to return to base and then initiate a specific room clean.

Viomi 2-in-1 robot vacuum V2 and V3 are good value and fit for purpose. If all you have is $399/624, go for it. Just don't expect everything. You will pay twice as much for better performance.
Value for money
Ease of use
Good sill height clearance
Good on hard floors
Value for money
Consumables are reasonably cheap from AliExpress
Clean the mop pad every 20m2, or it will smear rather than mop floors
Connectivity issues – you need a strong 2.4Ghz Wi-Fi signal
The turret ridge can get caught in overhead cables
Privacy – that's your call, so read the terms
Low cleaning efficiency on standard settings – use medium or Turbo
Edge cleaning - fail