matofill, I am 99.999% certain that I will be unable to help you relative to this post. I am both too ignorant about some things you write, and too uninformed about others. First you write:
matofill wrote:...Roomba 530 have before FW 02 and i upgraded to last FW to 07 ... , after that Roomba do not want to charge battery , they charge it only 15 minutes ...
I know nothing about any FW-07 upgrade. (Maybe vic7767 has some knowledge about it.) But, then you write:
...Then i check the thermistor, battery was 1 year old original Metapo 3500 mAh NiMh and thermistor have at 25 st C only 4, 2 k OHM ...
In that sentence I interpret that "1 year old original Metapo" battery had been powering your 530 properly for a year; and, that means the thermistor resistance was correct (viz., 10k ohms at 25C). No FW upgrade can affect thermistor resistance, so how did it become "at 25 st C only 4, 2 k OHM"? I can only guess that you may have run a charging session, and when charging stopped you quickly removed the battery from the robot and measured thermistor resistance. Is that what you did?
... so i thing robot are now after FW upgrade more careful and they thing that battery is too hot approx. about 40 st C and that they are full and then they stop with charges it ........ and normally if they charge it only 15 minutes, they can work only for a short time...
Well, let's say iRobot
revised Roomba's battery-temperature sensing algorithm such that high-temperature cut-off would occur in the 40 to 45C temperature region, and with the result that Roomba's battery could not be fully charged in the charging time taken to elevate cell temperatures to the cut-off temperature. I find it hard to believe that iRobot
would not find some way to carry charging to completion, even though it takes six hours, or more, to do it. One way would be to incorporate cool-down periods between charges to temp-cut-off. Another would be to moderate charging current to lower levels, thus avoiding heating until cells obtain full charge levels.
... i tested another OEM battery 4500 mAH NiMH and they also have at 25 st C 4,8 k OHM, but my basic 581 robot works OK with it even i thing that they charge it too short time ???
I question the use of "OEM", the abbreviation for Original Equipment Manufacturer. Someone may tell differently, but IMHO iRobot
has never sold any "4500 mAh" Roomba battery. If what I say is true, then your 4500 mAh battery is a third party battery, not 'OEM".
So what do you thing can be this thermistor problem, that robot charge battery to short time or ?...
I think: 1) it might be possible for a FW revision to reasonably shift calculated battery temperature as you have determined via ultra short charging periods, and 2) I suspect your ohmmeter ought to be verified to read about 10k ohms when a new 10k ohms resistor is measured.
Sorry for my English, but it is not my native language, Greetings from Slovenia in Europe.
Not to worry, your English is 10,000X better than my Slovenian!