Gordon wrote:ADDENDUM to my above post.
pfile, I ran across an -R3 schematic in my archives that you will need. It was created almost a year ago, explaining why I had forgotten about it! That's what happens when you get old!
I'm going to link you to a post containing the d/l link to the pdf. This one: viewtopic.php?p=98692#p98692
Welcome! And it was just by happenstance that I came across this post of yours, since I have not been receiving consistent 'new-reply' e-mail notifications from rr.pfile wrote:...Hi Gordon, thanks very much for the reply and the additional resources. sorry i have not checked the thread in a few days.
Not a problem. It can be beneficial to avoid knee-jerk operations!i have not yet mustered the desire to open up the roomba.
Too much guessing by me would be required to respond, so I'd rather not. Getting direct answers by checking dc voltages throughout the charging circuit would be more satisfying.... i used a Kill-A-Watt to measure the power consumption during charge. the roomba pulled 26-28W AC continuously for the 30 minutes from plug-in to error 5. if we assume 80% efficiency, the battery got just about 11Wh of energy in that 30 minutes.
because error 5 apparently means the charging current was 400mA or less for 1/2 hour, it seems like a nonsensical error... because 28W at the wall is roughly 22W at the battery (again 80%) and if the battery voltage is ~20V you're talking about ~1A. it's not like the roomba is getting hot; i don't think all this energy is being dissipated as heat.
Your Fast Charger's output characteristic of CURRENT ROLL-OFF curve could tell what that battery's terminal voltage is during normal (when charging FETs are held in the continuous conducting state) high-rate charging -- if you had your own curve. Until you plot that curve we will have to be satisfied by looking at this old one:what is the actual voltage at the battery terminals during charge? i realize the answer is probably in one of the posts you linked to...
While such resistance shift is always possible, I do think you will find the shunt to be OK.anyhow, does this indicate that the current sense circuit is bad? ... it's probably difficult to get a good reading of a 0.05ohm resistor!
Gordon wrote:One of the better ways to determine the shunt's resistance is to pass one to two amps of measured current through it in a bench test setup. With a specific current injected, just measure voltage drop to ensure dV is in the range 0.05V to 0.1V.
I don't see that as surprising. If you were to repeat what you just did, but measure PSU-output charging current, I expect you would measure more than 1.3 amperes dc current.wrattspider wrote:... I tried charging directly from the charger for 15 minutes, while measuring voltage at the battery terminals. What I see is that the terminal voltage stays at approximately 17.3V the whole time, then when I cut power at the end of the charge it drops to 16.3V.
I can't recall any either....Sorry if this has already been covered, but I haven't seen any documented cases where the power charger was tested and found to be faulty.
Some of us are interested in the odd cause(s) of err5.wrattspider wrote:Wow... that's quick response! 2 replies within 1.5 hours!
No surprise to me!... I measured 17.08V charging, 16.88 V once the charger was unplugged, and 1.42A (wow, surprised me there!).
Please take that sentence apart and reconstruct it. As it is, I make little sense out of it. Why are wheel behaviors being associated with err5?It ran for more than 10 minutes (then started getting alternating "error 5, spin left/right wheel" errors).
I don't see why the battery is in the clear; and, don't you think the PSU should be load tested (at a load current in excess of 400mA) for a longer period than 30-minutes?So I tried charging it again. After 30 minutes, the charging error 5 popped up.
From this, I now assume I've got a motherboard problem, and the battery and charger seem fine.
'Please take that sentence apart and reconstruct it. As it is, I make little sense out of it. Why are wheel behaviors being associated with err5?
I don't see why the battery is in the clear; and, don't you think the PSU should be load tested (at a load current in excess of 400mA) for a longer period than 30-minutes?
If Roomba issues Uh Oh + five beeps while performing in Clean Mode, that is 'normal' fault behavior. But, if Roomba also issues charging-err5 (Check Robot = red + five blinks) while in Clean Mode, that is abnormal and suggests the MCU is sick.wrattspider wrote:'Please take that sentence apart and reconstruct it. As it is, I make little sense out of it. Why are wheel behaviors being associated with err5?
I'm not sure whether there is a relationship, it just seems that the wheel errors ("Uh-oh" code 5) and the charging code 5 errors started happening at the same time.
To load the charging PSU, a 20 ohms resistor with 50 watts power rating would do it, but, that's not likely something you'd have around the house. An alternative for that task would be an incandescent lamp filament, actually a pair of automotive lamp filaments connected in series. The T-211 interior lamp (looks like a glass cartridge fuse but larger) draws about one amp when powered with 12V. Two in series would give a 24V x 1A load. But, powering it with the 22.5V PSU would run current through the pair at somewhat less than an amp, but safely more than the 400mA err5 level.If I had the equipment to do a good load test (maybe just a power resistor?) it would be a good idea.I don't see why the battery is in the clear; and, don't you think the PSU should be load tested (at a load current in excess of 400mA) for a longer period than 30-minutes?
I tend to agree that the battery is not at fault, but I want to point out two things: 1) voltage measurements say little about a battery's capability to perform as expected, and 2) "a new battery" does not always equal a battery capable of delivering its rated capacity.I think the battery is in the clear because it's been charging up to 16V+ and it is rated for 14.4V. Also, I have been testing an old battery and a new battery and neither fixes the problem. ...
You are off to a good start, wrattspider! But one thing to keep in mind is (as best I know) err5 only relates to the high-rate period of battery charging -- which is the initial and long term portion of charging.wrattspider wrote:... I flipped over the roomba and took off the bottom cover. I have taken the alligator clips, and clipped the battery terminals to the Roomba's charging tabs, with one multimeter in series (to measure current) and another in parallel (to measure voltage). I have also did extension clips to keep the battery's thermistor in play. Then I plugged the power supply directly into the Roomba's side charging port.
What I measure when I do this is 15.7V at 0.28A continuously (for a couple of minutes). My understanding is that the charging error 5 will happen when the charging current is below 0.4A for more than 30 minutes. In this test, the current never exceeded 0.4A, so the error will be declared 30 minutes after plugging in the power supply. ...
Well, that confirms the PSU is doing its job -- at least for 15-mins....If I then direct-wire from the power supply to the battery, the 15 minute test starts at 16.7V, 1.4A and ends at 17.8V, 1.39A. ...
I can't think of any....Is there something I can try unplugging on the system card to find the cause? Thanks!
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