Battery Troubleshooting Advice

Shawn Parr · Joined: 18 Jun 2008 Posts: 2 Location: NW Louisiana

Hello all, new member here.

First off, yes I did read the FAQ's and I've done quite a bit of research online here and elsewhere. I think I need a new battery, but I want to make sure that something else isn't going on. So I'm hoping one of you with much more experience can help me out.

Two years ago I bought a Roomba Discovery (white, which I believe is a 4210). It worked very well, until about 2 months before its warranty was up it started having charging issues. When on the home base eventually the 'charge' light would start to flicker rather than be solid, and when running the robot it would not last very long (15 - 20 minutes).

iRobot replaced everything but the battery (i.e. the roomba, the charger, the home station, etc. etc.) and it has run fine up until about a month or so ago.

So now it appears to charge normally, however it has very short run time. In many cases when the power light is green on the charger when you unplug and then hit the power button it will immediately be orange rather than green.

The first thing I did was to reset the charge system by removing the battery and holding down the power button, then letting it charge 72 hours. Once or twice this worked very well. Since then the battery life is still rather short, even after a charge system reset. We get at an absolute maximum maybe 20 minutes of run time, often less.

Next I removed the home base, and started plugging in the robot directly to the charger. This has not had any significant effect on the run time.

Since I am well out of warranty at this point I decided today to run through some of the diagnostics. Everything seemed to pass just fine. I did end up in a situation where when a test passed the robot automatically went on to the next one, so when I got to the power/charge tests and plugged in the robot, it shot through all the tests. This leads me to believe the robot thinks it is fine, but who knows what that really means... ;)

I'm planning on buying a LiIon replacement battery from Roomba Exchange, but before I drop that cash, I want to be sure it will be an actual fix. I would hate to buy a $90 battery to find out the charge circuit is not happy and the new battery doesn't help.

Any advice anyone can give will be greatly appreciated.

RoombaExchange · Joined: 21 Aug 2006 Posts: 1248 Location: Florida USA

From your description it sounds as though everything is fine, Your battery at 2 years is nearing the end of its life cycle.
You could further test the charger with a voltmeter to be certain that the output is a stable 22v before going with a new battery.

As for the manual diagnostics and test 15-20, when entering the diagnostics be sure to wait for the ascending and decending tones to finish before you release the buttons, if you release them early and only hear the ascending tones then you have enetered AUTO advance mode and each tests will advance automatically to the next test as each one reports as a PASS.

Test the charger and run the diagnostic tests again to confirm that everything is as it should be before investing in a Li-ion or replacement battery from our store.

glo69 · Posted: June 18, 2008, 10:49 am Post subject:

It certainly sounds like the battery. You could make an adapter, get a voltmeter and dummy load and make sure. I would be glad to talk you through the testing.

However, if the battery is 2 years old you won't be wasting your money even if something else was acting up. A 2 year old battery is past the normal Roomba battery life by quite a bit.

I would save the time and effort and replace the battery.

Shawn Parr · Joined: 18 Jun 2008 Posts: 2 Location: NW Louisiana

Thanks Chris & Gary!

I'll go ahead and do the diagnostics again just to be double sure. Then I'll most likely be purchasing a replacement battery.