Robovac 11 beeping four times while charging

#21

Open the battery case.
Unplug the battery for a few minutes.
Plug and close the battery case.
May be this helps, as a kind of reset.

#22

Thanks for helping. I did what you suggested. Unplugged the battery for 5 minutes. After 1 minute of charging the beeping is back again. 5 times 4 short beeps, then 25 seconds pause and it repeats. Goes on until I unplug the charger. The Robovac cleans fine for the expected duration, but after a full charge it start beeping.

#23

Take a damp cloth and clean the contact points on the vacuum and charging base. See if that helps. Also I’m not sure if your vacuum can do it, but can you plug it in directly to the plug and omit the base? To see if it still does that

#24

Yes, you can plug in the charger directly, this gives exactly the same behavior, after fully charged it starts to beep.

#25

This should be normal no? Once its fully charged it beeps to let you know so you can unplug it :man_shrugging:
I mean before it wouldnt charge, now its after its fully charged so I say that’s progress

#26

Not normal.
If the robot is fully charged the light turns from blinking red to constant blue.
Silence when charging and full charged.

#27

We had the same problem - it cleaned perfectly well but after a cleaning cycle and after the battery charged up on the dock, 4 beeps and a solid red light, repeated five times, then just a solid red light.

We did however notice that it didn’t run for quite as long as it used to.

Changed the battery, no more problem!

I don’t know, but maybe when the battery starts to wear out and no longer fully charges, the firmware may detect this as a stuck roller.

1 Like
#28

Ja, that’s an idea.
Might be possible, the battery is checked by the software.
I have mine about 1 1/2 year and no such battery issues have occured.

How old is the robot and have you used it very often?

#29

We use it regularly, at least every other day, and we’ve had it for just over two years.

#30

OK!
So the battery could run down with intensive using after such a long time.
I would call this normal.
No issue.

#31

I recently started using the ‘max’ setting for certain areas, so maybe that accelerated the battery’s demise :smirk:

Yes, batteries don’t last forever, so I’d expect to have to replace it at some point…

#32

I am not an expert in batteries.
But using max power indicates a higher charging cycle which will shorten battery life of course.

#33

For those after a more detailed explanation of the problem, hopefully I can provide some insight.

The Problem:
After charging, instead of a solid blue light indicating a full charge, you get a red light and four beeps which repeats several times.

The Cause:
The battery is either disconnected or appears disconnected due to the batteries own protection circuitry kicking in.

The Why:
The battery protection circuit prevents the battery from being over-charged. It will trigger when any one of the four li-ion cells of the battery pack reaches its max. voltage of ~4.2V. If the other 3 cells haven’t finished charging then tough luck!

This occurs as not all cells are made equal and some have greater capacities than others so while the battery manufacturer tries to match the capacities as best as possible, over several charge/discharge cycles some cells become more and more discharged.

You can check this by measuring the voltage of the battery with a multimeter and see it is below 16.8V (4x4.2V). Mine was at ~16.4V.

The Fix:
Replace the battery… or if you have some experience with li-ion batteries you can dismantle the battery pack and charge each cell individually to ‘sync’ the cell voltages back up. This can be done with a li-ion charger or simply with a lab power supply. DO NOT ATTEMPT THIS IF YOU DON’T HAVE THE PROPER KNOWLEDGE OR EQUIPMENT as this circumvents the protection circuitry!

These batteries will catch fire, explode, murder your Mum if they are not handled properly! And remember to recycle your old ones!

4 Likes
#34

Thank you! :grinning:
Those information is absolutely perfect for all others.
Great Job you published.

#35

I have not seen this battery pack or the bms circuit. Do you have a picture to share?
Matching cells in a battery pack is outdated concept. If the pack is properly made there are provisions for individual cell charging. Li-ion cells are so reproducible these days that the capacity matching is not even a issue.
Did you measure 16.4 V while cell is charging or after charging?
4.2 V is the cutoff voltage for charging and once the load is removed the OCV drops rapidly to 4 V and most of the usage voltage will hover around 3.6-3.7 V (nominal voltage for li-ion).
Yes you are correct that no one should disassemble a battery pack if you dont know what you are doing. Also dont try to solder a li-ion cell :grinning:

1 Like
#36

The battery pack is an INR18650 M26-4S1P and has just the two wires. There is no provision for indivudual cell charging as the BMS uses the 20-pin version of the BM3451 - without balancing circuitry.

The 16.4V measured was on the disconnected battery immediately after charging (with the on-board charger). Individual cells measured at approx. 4.2V, 4.1V, 4.05V, 4.05V. I charged each cell individually back up to 4.2V and the problem was resolved.

I have not gone as far as testing the capacities of the individual cells.

I hope this answers your questions?

3 Likes
#37

Great observation :+1:
Yes it seems the BMS could have been better. May be the cells were not installed in same soc and thus were not charging since BMS is so rudimentary.
Glad you solved it :clap:

#38

My Robovac 11s charges normally but when you turn it on, it doesn’t start and beeps 4 times with blinking red light.
Changed the battery for a new one, brush is not stucked and already cleaned the bumper sensor.
Any ideas?

#39

OK if you charge it -> orange led blinking to steady blue, but after starting it, it beeps 4 times and doesnt start at all.
Tried the ON/OFF switch at the bottom when showing that issue?
Still the same?
All wheels are running freely?
Is there anything disturbing the bumper function?
Its “mobile” (moveable)?
May be something stucks there.

#40

FIRST OF ALL THANK YOU FOR YOUR HELP.
WILL COPY AND ANSWER ALL THE QUESTIONS ONE BY ONE:

Tried the ON/OFF switch at the bottom when showing that issue?
YES
Still the same?
YES
All wheels are running freely?
YES, ACTUALLY IT TURNS 180 DEGREES AS USUAL, AND WHEN IT SHOULD START VACUUMING IS WHEN IT STOPS AND STARTS BEEPING
Is there anything disturbing the bumper function?
NOTHING, EVEN DISASSEMBLED THE BUMPER FOR CLEANING
IT
Its “mobile” (moveable)?
YOU MEAN THE FRONT WHEEL? IT’S OK
May be something stucks there.
DISASSEMBLED THE WHOLE ROBOVAC AND NOTHING STUCKED

I THINK THE PROBLEM IS THE ELECTRONIC BOARD OR THE SOFTWARE