I think, that the problem might be in the battery, you should check the battery /motherboard connector. That usually might be little bit out of it’s position. The motherboard seems to be clean. It does not have any problems, as I can see.
* You should check the connections
* if you have another macbook / mac, you should try the battery with that macbook / mac
* ''The liquid damage could even damage the battery ( like it might be dead, if a little bit of water went into connections ), so you should look a bit into that also''