Replacement battery for robotic vacuum (AirRobo P20)

[edy]

I have a few cheaper robot vacuums similar to the Roomba. A few brands that look almost identical and seem to have interchangeable parts include Eufy, Kyvol and AirRobo. I’m sure there are at least a dozen others that all look the same. In any case, it seems my AirRobo vac battery is toast. I looked online (Amazon) and found a whole bunch of replacement batteries for those other brands but not my AirRobo P20. Even the AirRobo site itself does NOT provide an option to buy a battery only:

https://us.air-robo.com/collections/airrobo-p20-accessories

Some of my other robots have 2 wire batteries but I assume this 3-wire battery has the 3rd yellow wire for a sense thermistor to prevent overheating the battery during charging.

Pretty much all robovac batteries on Amazon have 2 wires and even IF the actual connector is compatible I’m worried about using these batteries if they have no 3rd wire for safety. You will see some Amazon batteries with 3-wire connectors but only the black and red outside wires are used, with no central wire on the middle pin. I’m not sure whether this is designed to be a cheap way to replace 3-wire batteries or if it was just easier for them to get 3-wire connectors that day. Like look at this one… clearly it has a 3-wire connector and is supposed to fit a bunch of different brand robovacs but do the original batteries on those units have 3 wires or what:

https://www.amazon.ca/BAKTH-2600mAh-Replacement-Battery-Compatible/dp/B08R9XPWLG

Presumably the robot vac will need to detect some resistance value on that wire to whatever it considers to be “good” calibration value in order to charge the battery. Either way, without that 3rd wire at best the robot will refuse to charge the battery and at worst it will charge it and not detect temperature of the battery and potentially cause a fire. Alibaba and Aliexpress have some options but I’ve never really purchased off those sites directly before and not quite confident of the quality either (like they have a “fake” 3rd wire which connects to nothing). For all I know the AirRobo yellow wire may also connect to nothing.

Any suggestions as to what may work and your thoughts on the 3rd yellow wire? The battery pack looks pretty much like this (the connector seems to be for 3 wire but only black and red used):

https://www.amazon.ca/Sparkole-2600mAh-Replacement-Battery-DN622-11/dp/B089VPKN7G

This is the 3-wire version for the P10 which I assume is the same as used in the P20 (although it seems to have 4 wires as I see 2 yellow):

https://www.aliexpress.com/item/1005003954767489.html

I have another battery already at home from another psychotic Kyvol robovac (2-wire type) that will fit and has the same specs (14.4V Li-Ion) but I’ll have to change the connector on it to fit the AirRobo. The Kyvol has a good battery, it failed due to some strange motion sensor issue which seems to be on the main board somewhere that is not worth repairing so I can scavenge parts from it. As I mentioned, most of these all seem to be similar and I’ve been able to swap many parts to keep them going. So my question is, should I either modify the Kyvol 2-wire battery and see if AirRobo even accepts it, is it risky, or should I try to source a 3-wire battery although it doesn’t appear to be readily available? Some people suggest creating a fake signal on the yellow sense wire with a 10K resistor to simulate a normal-range thermistor but then the charging circuit on the Robovac has no way to really know whether the pack is heating up and by how much. I’m not going to be able to easily take the thermistor off the old pack and bodge it on to a 2-wire pack either. NOTE: I have since been able to find a few 3-wire battery options on Amazon but they usually cost about twice as much as the 2-wire! Thanks for you help!

PS - I just found this link which seems to offer a whole bunch of different connector configurations for “robo sweeper” batteries so this is used in all of these knock-off Roomba robovacs (my AirRobo connector is like 4, 5 or 6):

https://www.aliexpress.com/item/1005006594149802.html

[DarrenHD]

Nice post, thanks.  Our P20 as of yesterday started flashing red and now it won't charge, even though it says "Starting to Charge"....but the battery level stays at 0%.  I saw on AliExpress there was a replacement battery but I'm a bit leery to buy it if it doesn't solve the issue.  I'm waiting to here back from AirRobo tech support.