Review Roborock S4 vacuum robot: The improved S5?

Since today (09.10.2019) the Roborock S4 is available at Amazon. We have tested the model in advance.

After the Roborock S6 and S5 Max, we assumed that it would be calmer again around the Chinese manufacturer. But now we are back with another model. The Roborock S4 was first introduced as “T4” in China (we have reported), now it should also be accessible for us. A Lite version of the S6? Or even the S50?

Roborock S4 vacuum robot design

Technical data: Comparison to Roborock S6

Roborock S4 (T4 in China)

Roborock T4 vacuum robot design

Roborock S6/T6

Roborock s6 vacuum robot model

Suction power 2000 pa 2000 pa
Navigation Laser Space Surveying Laser Space Surveying
App Xiaomi Home (Android, iOS) Xiaomi Home (Android, iOS)
Noise level 50-65 dB (depending on suction mode) 58 dB (at highest suction level)
Battery 5200 mAh 5200 mAh
Dust chamber/water tank 0.42 l/ no wiping function 0.48 l/ 0.16 l
Charging time 5 h 3 h
Working time 2.5-3 h (depending on suction mode) 2.5 h
Weight 3,8 kg 3,6 kg
Dimensions 35,4 x 35,0 x 9,6 cm 35,3 x 35,0 x 9,65 cm
Inclinations 1.5 cm, with rounded obstacles 2 cm 25°, over 2 cm with larger tyres
Features/ Functions 🏠 Laser room measurement
🗺️ Mapping with map storage
⛔ No-Go-Zones and Zoned Cleanup
🗃️ Room layout (single and multi-room cleaning)
📢 Voice control via Xiaomi AI Speaker
🔻 Carpet detection (increases suction power)
❌ Wipe function
❌ Multi-storey cleaning
🏠 Laser room measurement
🗺️ Mapping with map storage
⛔ No-Go Zones and Zoned Cleanup
🗃️ Room division (single and multi-room cleaning)
💦 Wipe function
📢 Voice control via Amazon Alexa
🔻 Carpet detection (increases suction power)

How do S4 and T4 differ, except that the T4 is intended for the Chinese market? According to Roborock, there are a few differences in the app and the side brushes, but these are marginal. Just that you heard it once. 😉

Scope of delivery of the Roborock S4

As usual at Roborock, the robot comes with additional contents finely packed in a brown cardboard box. It is always impressive how everything can be packed so neatly in such a small space. The scope of delivery includes the S4 itself:

  • Charging station with (EU) charging cable
  • V-shaped main brush (to be mounted on underside)
  • small cleaning tool for the brushes
  • additional filter
  • Operating instructions and instructions for app/network integration in German, English, French, Italian and Spanish

The scope of delivery clearly shows that Roborock also takes the European market into account. It is not common that manuals are translated into German and an EU charging cable is included (when ordered from within the EU).

Roborock S4 vacuum robot Scope of delivery
The scope of delivery of the S4.

In addition, there is a CE mark on the underside of the robot, which means that nothing stands in the way of sales in this country. Nevertheless, according to Roborock, the robot is primarily intended for sale in the USA. But of course there is nothing against using the model in Europe, there are servers available and selectable.

Design and workmanship

Roborock hasn’t had to worry about workmanship so far, even the S4 doesn’t change anything. Everything is clean and solid, nothing jolts where it shouldn’t and the high-quality plastic provides a weight of 3.8 kg. Irrelevant, every now and then you lift the robot. More important are the dimensions of 35.4 x 35.0 x 9.6 cm, accordingly you should measure some pieces of furniture before buying, or the robot fits under it (count on 10 cm).

Roborock S4 vacuum robot flap
Roborock has done everything right again when it comes to processing.

The buttons on the upper side have been slightly changed compared to the other models, otherwise the color reminds very much of the Roborock S55. A very nice design element is the transparent spot on the matt black surface, which gives you a glimpse of the filter in the dust chamber. Has no deeper meaning, but is chic to look at.

Roborock S4 vacuum robot laser distance sensor
The transparent area on the top is chic, but has no deeper meaning.

Well thought-out by the manufacturer: the bumper is located at the front as usual, cushioning collisions with pieces of furniture. Interestingly, however, there is a rubber device at the bottom of the bumper that hits the obstacle in front of the rest of the protection and thus ideally causes no to fewer scratches. If the robot actually works in practice, it will tithe much more gently against obstacles (if it ever drives against something at all).

Roborock S4 vacuum robot Bumper
The front bumper has an additional rubber protection.

However, with a Roborock robot, you don’t worry too much about furniture in general, after all, except for the Xiaowa series, they all work with reliable laser navigation, which allows obstacles to be detected at an early stage. This is said to have been further optimized in the S4, more on that now.

The charging station

By now, most people should know the function of a charging station: The suction robot starts from there and returns autonomously to the charging station as the battery level decreases. For the S4, finding it again is a matter of seconds thanks to its laser space measurement. Nevertheless, the robot should also be started from its station, if only for the mapping to function correctly. Back there after its work, the robot recharges the 5200 mAh battery.

Roborock S4 vacuum robot charging station design
Optically quite a block, but serves its purpose.

After a working time of 2.5 hours (a very good value), the vacuum robot has to return to its station for a loading time of 5 hours. Currently, only the Puppyoo R6 should have a longer working time. Roborock has also thought about the design of the charging station, as with the previous models: The charging cable can be rolled up on the back of the station, rubber surfaces are attached to the underside, which give the station a firm stand.

Roborock S4 vacuum robot charging station rear side
The charging cable can be rolled up on the rear side.
Roborock S4 vacuum robot charging station bottom side
There are rubber surfaces on the underside to stabilize the stand.

Up to 250 m² can be cleaned with the battery power of the S4. If it becomes more (clear, rooms are divided up differently), the robot finds its way autonomously to the charging station, recharges the battery (up to 80%) and sets off to work off the rest of the area to be vacuumed.

Roborock S4 vacuum robot Charging station
After a working time of 2.5 hours, the robot must return to the charging station for 5 hours.

Operation and navigation

As one is used to from the Roborock and Xiaomi models, the household robots (Roborock produces them for Xiaomi) work with only one brush head on the underside. This rubber brush pushes dust and dirt in the direction of the V-shaped main brush in the middle of the underside, from where the dirt enters the intake hood in the direction of the dust chamber with filters.

Roborock S4 vacuum robot bottom side
On the underside there is a rubber brush head and a V-shaped main brush next to umpteen sensors.

According to rumours, the S4 should bring along a different, new type of laser room surveying, which also has an effect on the map display in the app. After several test drives we can say with certainty: They were only rumors, here no difference to the predecessors could be determined. Nevertheless, the surveying works very well.

Roborock S4 vacuum robot navigation
The navigation is very good, but no better than with previous Roborock models.

Using the LDS (laser distance sensor), the robot scans the premises. Inside the robot, an AI and a SLAM algorithm (Simultaneous Localization and Mapping) are used to create a visual map. The collision sensors prevent frontal collisions and falls from heights, such as steps.

Roborock S4 vacuum robot LDS
The vacuum robot measures the premises very precisely via the LDS.

Performance and Functions: Roborock S4, a pure vacuum robot

The Roborock S4 comes without a wipe function, even though it was mentioned in some shops shortly after release. Personally I don’t mind that, because the wipe function can’t replace the manual wipe with a wipe mop very effectively with most hybrid models.

But the voice control is included in the software package. For the Xiaomi AI Speaker (Xiaomi’s Alexa counterpart), voice control is also possible. In the future, the robot will also be controlled via Amazon’s Alexa or Google Home. However, this is not yet possible with the current firmware version.

Roborock S4 vacuum robot Performance
The S4 cuts a very good figure on hard floors.

The suction power of 2000 pa is currently the measure of all things, even if manufacturers such as Blitzwolf with the BW-VC1 and Viomi with the V2 or even the Spanish manufacturer Conga are preparing to top this value. To regulate the suction power, four different suction modes can be selected within the app (more on this later), which of course also work with different operating volumes:

  • Quiet (50 dB, 1200 pa)
  • Balance (55 dB, 1400 pa)
  • Turbo (60 dB, 1800 pa)
  • Max (65 dB, 2000 pa)

Here, the size of the rooms must be taken into account when selecting the suction stage; after all, the battery power decreases at different rates depending on the suction mode. If the apartment is less than 100 m², the robot can be operated at the highest suction level without hesitation; from 150 m², “turbo” is more suitable, which is completely sufficient in terms of suction power. You only choose “Quiet” if you are in the same room and don’t want to be disturbed by noise. All values were measured directly at the back of the blower.

Roborock S4 vacuum robot surface
With a operating volume of 50-65 dB the S4 is in midfield. That’s not too loud.

Not all functions already ready for use

From the new top features of the S6, single and multi-room cleaning has made it into the software package. Multi-storey cleaning, as with the Ozmo 950 from Ecovacs, is not included. Accordingly, the S4 cannot store and retrieve multiple cards. If you create a new card, the S4 deletes the old card again. Saving a card is not a problem.

Roborock S4 vacuum robot Room layout
The S4 recognizes rooms independently. This allows you to drive off individual and multiple rooms in a targeted manner. Theoretically.

But the problem during our test phase was: The single and multi-room cleaning is still in a beta phase/beta version, accordingly it does not work with our model (despite the latest app and firmware version) yet. We will update the test article here as soon as a firmware update is available.

Allegedly there should also be a carpet detection (increases the suction power on carpets by itself) as well as the spot cleaning (rotates in growing circles around itself), but is not the case yet. Neither can anything be found in the settings, nor did the robot increase the suction power on the various carpets in our test phase.

Roborock S4 vacuum robot carpet
Carpet recognition? Unfortunately no.

What Roborock also praises as particularly innovative is that, compared to other models, the S4 should be able to manoeuvre particularly well out of difficult environments. This means that if it gets lost in rooms with corners or between pieces of furniture, it will quickly find its way back to its route thanks to an improved backward movement. In practice, this is exactly what can be determined. Here is a video example of how to use the laundry rack:

Youtube Video Preview

Until now, almost all of the household robots we tested tried to run over the clothes rack legs and spent many (loudly working) minutes with the clothes rack. The Roborock S4 notices that it is in a complicated area, resets and simply drives around the rack legs. Optimally solved.

Registration and integration into the Xiaomi Home App

The Xiaomi Home App (Android, iOS) already knows the users of other smart Xiaomi devices. After downloading the app and successfully registering via the disposable email address and selecting the mainland, you switch on Bluetooth and WLAN on your smartphone. In addition, you have to give the app one or the other authorization, which is (unfortunately) not uncommon nowadays.

Roborock S4 vacuum robot App WLAN connection
The vacuum robot is quickly connected to the app via Bluetooth.

As always, we would like to point out here that vacuum robots can only be connected to 2.4 GHz networks. However, the Roborock S4 did not care whether the modem was transmitting at 2.4 and 5 GHz simultaneously, which is not a matter of course with suction robots. So you don’t have to change anything.

Of course, the correct WLAN password must also be entered and the robot must be in the same network as the smartphone. Via “Add device” the app automatically finds the Roborock S4 within seconds (see screenshots above).

Roborock S4 vacuum robot App connection
The integration into the app and the connection with the WLAN works as usual very fast.

If the connection with the robot should cause difficulties, you can reset the WLAN – as with the first and second generation – by holding down the two buttons on the top side (Power and Charging Station buttons) at the same time (for example 3 seconds). Then “Resetting WiFi” sounds and the connection with the WLAN can be re-established. If you encounter any difficulties, just describe your difficulties in the comments and I will be happy to help you.

Roborock S4 vacuum robot WLAN connection Operating elements
By holding down the buttons you can reset the WiFi.

Since the S4 is an international version, the region “Germany” can be selected in the Xiaomi Home App, but there is no German language package for the robot yet, English is available. The app interface is multilingual, only the robot speaks English. The volume of the speech of the S4 can be muted, if the speech comments disturb.

Control of Roborock S4 via App

If the vacuum robot is integrated in the app, we look on the smartphone at an extremely tidy interface, which we already know in almost the same form from the Mi Robot 1S. Although Roborock releases its own models and only acts as an ODM (Original Design Manufacturer) for Xiaomi, Roborock uses the Xiaomi Home App as well.

Roborock S4 Vacuum Robot App Settings
The selectable settings.

If you wish, you can control the vacuum robot via remote control, send it back to the charging station via the app and adjust the suction power. Of course, firmware updates can also be downloaded and executed (docked to the charging station). Roborock’s update policy is not always optimal, but compared to other manufacturers it is praiseworthy, so you can be happy about it.

Roborock S4 Vacuum Robot App Remote Control
On the left and in the middle the remote control, on the right the selectable language packs.

The functions and settings within the app listed briefly:

  • Mapping with single and multi-room cleaning as well as map storage (still beta)
    • Drawing in no-go zones, go-to zones and virtual walls
  • Remote control (buttons or joystick)
  • Adjusting the suction power (four levels)
  • Localization of the robot (reports “I’m over here”)
  • Condition of wear parts and sensors
  • Schedule working times (once, daily, weekdays, weekends, user-defined)
  • DND-Mode (Do Not Disturb; time the robot is not working)
  • Adjusting the volume of the robot’s “language
  • Installing and Using Voice Packs
  • Password protection for the robot
  • Integration into SmartHome

This is a concentrated load of functions, but you have to admit that you can expect this amount for models above $300 nowadays. The most exciting and of course most useful function is the mapping, the visual creation of a map in the app and the “brain of the vacuum robot”.

Mapping, zone cleaning and virtual walls

After the Ozmo 950 from Ecovacs recently delivered, the Roborock S4 is now in the direct comparison – and see there: When it comes to mapping and navigation, the S4 is pretty much a winner. Within a few minutes, the robot knows the premises inside out thanks to its laser distance sensor, all of which can be viewed live on the map created in the app. It is also very precise.

Roborock S4 vacuum robot App Mapping Begin
The beginning of the mapping. The S4 knows after seconds what it looks like around it.

Especially the fast pace of work quickly becomes noticeable, even if the robot never leaves out an area or drives the same are twice, as its predecessors also did. The more frequently the robot travels in the same sequence, the better it finds its way around. It optimizes the routes and updates the map when it detects changes (example at my home: the football is elsewhere on the ground than before).

The robot automatically detects when it has finished cleaning and then returns to the charging station. No-Go zones (areas that the vacuum robot should not travel) and virtual walls (vacuum robot recognizes drawn lines as walls) can be drawn on the map. No real innovation, but nowadays a top model has to be included in the software package. Practically speaking, even meter readings are displayed, so that it is possible to determine even more precisely where the robot should not travel. You can also zoom in with two fingers.

Roborock S4 vacuum robot App Mapping No-Go Zones
Every one of us has an area at home where you don’t like to let the vacuum robot drive or not at all.

Theoretically, the Roborock S4 should automatically divide the captured rooms into different living areas – or at least mark them as different rooms. As mentioned above, we still have to wait for the beta phase of this feature to finish. Then (at least in theory) it will be possible to specify different working times for the individual rooms (e.g. living room at 10:00 o’clock, bathroom at 12:30 o’clock). Keyword firmware update.

What the Roborock S4 has difficulties with

The Roborock S4 then has one or two difficulties with more complicated rooms. Although it masters them all satisfactorily, it is not yet completely mature in its mode of operation. It has the same problems that other models in the same test arsenal had. You can still let the robot drive without worrying about its premises. Only cables should not be freely accessible on the floor (otherwise regulate with No-Go zones).

For instance:

  • Balls: Footballs and egg-shaped footballs are not recognized as obstacles by the robot, which moves them and later reappears elsewhere.
  • Shoes: It simply drives over shoes, where it runs the risk of “swallowing” depending on the slipper or shoe model.
  • Dark carpet: The robot does not recognize it as a carpet. After all, it also drives onto the carpet and does not leave it out. Despite the uniformity of the carpet, it only reaches the carpet at certain points.
  • Table: Well solved, drives under the table, under which there is also a dark carpet.
  • Clothes drying rack: it optimally solves the complicated clothes drying rack by simply moving its legs around instead of getting stuck in them.
Roborock S4 vacuum robot door threshold
Thresholds like this cable bridge are no problem up to 2 cm height.

In between, the S4 also announced via voice and push notification that it had noticed “Error 6” that the side brush should be removed, cleaned or replaced. In fact, I couldn’t find anything about it, simply clicking the message away made the brush turn again. Strange. To see (and hear) here in the video, just like the difficulties with the dark carpet:

Youtube Video Preview

Conclusion: buy Roborock S4?

If you don’t need a wiping function and are looking for a pure vacuum robot, you can be sure that the Roborock S4 has a few more functions than the Roborock S5. Too bad that many features don’t work yet, we will deliver a text update soon. It’s priced in a similar range as the S5, maybe you should wait a week or two before buying it until all the features are available. The same applies to the test verdict, as the vacuum robot has only been available since today.

One would like to keep the wipe function as a unique selling point of the other models, but with a quite high price the Roborock S4 is anything but cheap – even for Amazon with prime shipping. Moreover, it is difficult to say why one should choose the S4 without a wipe function if it is not cheaper than its older brothers. The maneuvering out of tricky situations is really strong – but not worth more than $300 yet. Let’s wait and see how well the room layout works, then the price might be a bit more justified compared to the Roborock S50. Assessment now: The S4 will not coexist well between its big brothers.

What is your impression of the S4?

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Why doesn't this affect our review in any way?
Profile picture from Tim

Tim

I'm interested in Gadgets, that make our life at home easier - especially when it comes to cleaning the floor or the windows. I was able to test about fifty robot vacuum cleaners since now.

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Comments (2)

  • Profile picture from Arne Beerens
    10.10.19 um 16:42

    Arne Beerens

    Hi, I think you should use the Roborock app instead of the Xiaomi Home app, to enable all the features of the S4.
    The S4 is not branded as Xiaomi, but very related (basically same company).
    Hence it works with both apps, but it is intended to be used with the Roborock app.
    Could you do an update using that app?

    • Profile picture from Tim
      11.10.19 um 11:09

      Tim CG team

      Hi @Arne Beerens, let me check that and I will update if it works. Thanks for your comment!

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