It turned out that for a year and a half in the off state, the battery of the iRobot robot vacuum cleaner “kills itself”, and it is no longer possible to restore it without disassembling the battery. Well, I took it apart and rebuilt it.
It so happened that the iRobot Roomba i7 + robot vacuum cleaner was not used for a long time. When I tried to turn it on, there were no signs of life. I removed the bottom cover (for this you need to remove the side brush and unscrew the four screws).
The battery occupies half of the compartment (this is done so that you can install a battery with twice the capacity).
The battery voltage was less than a volt. I had to open it. The whole structure is non-separable, but if you really want to, you can disassemble it. The lid is held by a micro latch along the entire contour. With the help of a knife, we managed to slowly remove the lid, breaking most of the thin surface of the latch, but there is nothing wrong with that – the rest holds the lid normally.
It is also not so easy to pull out the batteries in the cassette from the case – the cassette is held on by four latches in the depth. They can be bent relatively easily with four thin objects inserted into the slots between the cassette and the case.
The voltage on each of the four cans was about 1.5 volts – it seems that “woe from wit” happened to the battery – its smart circuit, which protects the cans from overdischarge and controls the charge, also consumes a little. For a year and a half, she consumed all the energy of the batteries, turned off the output and continued to slowly eat up the batteries. At the same time, the battery could no longer be charged by regular means.
The iMAX charger refused to charge the battery, reporting that the voltage was too low, so I simply connected the laboratory power supply directly to the banks (negative to TV1, plus to TV5), set the voltage to 16.8V (4.2×4), the current to 1A and the batteries were charged no matter how what didn’t happen.
Moreover, the balancing circuit of the board also balanced them – the voltage on the banks after charging is 4.2 V + -0.01V.
I collected everything back, put the vacuum cleaner on the base and it immediately came to life. Works, cleans up. Now the main thing is not to leave it without charging for more than six months.
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