Roomba stops and restarts after a few seconds during clean

[CitrixGrl]

I have a Roomba 415, that once or twice during the cleaning cycle it just shuts down for about 5 seconds then starts backup and continues it's clean. I have two that are doing this. When it happens there are no beeps, sounds, or lights (it's like someone walked up to it and hit the power button). Then after a few seconds it just powers backup and continues to clean. Any idea what is may be causing this?

[mfortuna]

My reds sort of do this but their LEDs don't go off. If loading on the brushes gets too high the roomba will shut down the brush motor for a few seconds and then resume.

[CitrixGrl]

I clean the brushes after every use.

[vic7767]

It's also possible that the battery is not making proper contact. Verify that the battery snaps into place in the battery well and that the spring loaded clips engage the edge of the battery holder at the top of the battery well.

[richnorto]

I had one that did this. I don't know quite what fixed it, but I did take it apart, clean and regrease the gears and clean the wheel sensors. This was one which had been run over a pile of talcum and had issues...
It would run fine for the first 20 to 30 minutes, then start the weird start/stop issues for the next 20 minutes while staying green. I thought (because I put the battery into another roomba and it turned red and took off to park itself) it possibly had a board issue - didn't recognize it was low on power. I did blow out the entire thing, board included, while I had it apart and pushed on all the connections to make sure they were tight.
Try a deep clean and regrease and maybe dust or a bad connection on the clips are causing the problem. Hope this does help fix the problem. Wish I could tell you exactly what worked for me.

[matofill]

I have the same problem as described Citrixgrl, my Roomba 400 works, but when it hits an obstacle in the way, thay stops then, and after 2 seconds they start itself, usually after the fourth stopings Roomba no longer starts alone, unless I press the START button again.
After all tests I have not found any mistakes, and then, only found out that the problem is battery, the robot had at home made batery from NiMH cell - SUB C in a total capacity of 4600 mAh. This battery is only 6 months old and is repaired from bad original 2000 mAh NiCd.
So when I give a 2 years old NiCd battery to my Roomba, which operates at approximately 1 hour and robot operating smoothly, without any stopping.

When i put this at home-made battery in my DirtDog at once begins to stop and starts this is exactly the same as previously done my Roomba 400 .

This battery 4600 mAh is in measured OK. Is it possible that these robots simply do not work with NiMH batteries or over capacity? Any idea? Sorry for my bad English i hope you can understand it !

[mfortuna]

It is probably not related to battery capacity it is probably a bad or marginal cell in the 4600mah pack.

[matofill]

Now i test all cell at battery and all are OK, so I thing in battery is also one temperature sensor and also one another element ????

And I am sure that there is problem, because all battery cell are OK and have the same voltage.

And i put this battery again on Roomba to test and in 10 minutes Roomba did not stoped, but after i put Roomba to charger the light on Roomba switch OFF and at that time Roomba doesn t want to start and also to filling battery ??????

I put this battery to another my dirt Dog robot and all the same ???

Maybe somebody known ehat exactly are that two another element at battery that i can replaced it ?????

Any idea about all this ?????

[vic7767]

Now i test all cell at battery and all are OK

What tests did you do?

in battery is also one temperature sensor and also one another element

There is a thermistor and a resetable fuselink. I all my years of working on and building Roomba/Scooba batteries I've never had one that had a defective thermistor or fuse.

Any idea about all this ?

I suspect that there is a defective cell or two inside the battery. Just a Mike has already suggested.

[matofill]

1. : all cell at battery

2. : ???

3. : all cell are 100% OK i made test with full cell and empty cell and voltage is all time betven 1,35 V to 1,42 V !
As i known if one cell is death, they must have voltage less than 0,8 V or less and than this cell kills olso another OK cell but in longer time and if battery with one death cell is full and stay 14 days will be after 14 days empty, because this death cell eat energy, but my battery is also after 14 days full !

[vic7767]

It is possible that there is a poor connection where the battery plugs into the Roomba. Do you have another battery to test with?

[matofill]

Yes i have 2 robots one 400 and one Dirt Dog and both works fine with another battery and with this problematic battery both have the same problem, and also contacts on this battery are OK ! ??? Strange problem !

Can i pull out this termistor, or it must be ???

[vic7767]

That thermistor is used by the Roomba charging system firmware to help determine when to lower the charging current being sent to the battery during a charging cycle. If the thermistor is removed then the battery will not charge.

I have never seen a robot review member post that they had found a defective thermistor inside their battery. The fuse may possibly be opening up during high current operation. Just as a test you could try and bypass the fuse with a piece of wire and see if the Roomba operates correctly.

[matofill]

I spoke with somebady in Slovenia, which have the same problem, with fuse is all OK, because in another Roomba will not working, but problem is probably termistor, that man replace this termistor with 10 K ohm element RESISTOR and than work all OK, it is not safe as original, but it works, because we do not known ??? what termistor is original there ??? So i will try to do this today !

Thanks a lot VIC for

[vic7767]

Some hackers have fooled the charging system by installing a 10k ohm fixed resistor into their battery case hacks. Normally the thermistor will be at about 10k ohms at room temperature and drop in resistance as the battery temperature increases. The thermistor resistance inside the battery can be measured by using an ohm meter and placing the probes on the negative terminal and the side plate next to the two battery terminals.

It is not a good idea to install a fixed resistor inside the battery and leave the battery charging unattended.

[matofill]

I bought new corect termistor 10k ohm i found this value on another topics at this forum and then i disasamble batery and realy betwen minus and red extra contact was not any contact, so,than i want to pull old termistor out of batery and i seen that cable was without any conection , so broken , than i check termistor and it was Ok ( Yeah VIC known all and everything ant he told me, that this element never die Bravo VIC and ) and then i only repair this connection and now this battery work with out any starts and stops Roomba and i solve problem ! Than i check still another 2 battery which i have for 400 series and i found, that one battery which i bought from USA by Ebay, but very cheap for only 29 usd + shipping costs, that the battery which seller sell like 3200 mAH , have inside cell with only 2600 mAH NIMH and this battery does not have another thermic fuse like varistor?? and have only termistor. But enyway this non original, but like OEM batterie works fine and good allready 6 months, because i bought it like for tested what will received for the cheapest price, but NiMH and from power seller, and for that amount is this OK !

Thanks again to VIC for help me !

[vic7767]

Very happy that you identified and fixed your Battery problem.