Default [Q] Replacement battery problems

Hey guys, I've had my Nexus 4 for about a year, never had any problems, except a week ago when I dropped it in a Scottish river.

It was in the water for about 10 seconds, I was about to shut it down but the screen flickered and shut off itself, upon getting home I tore it down and put it in rice for a week like a good boy.

After which, the battery was screwed, from what Googling told me about a solid red notification light when plugged in, so I ordered a new OEM battery, put it in today, and it doesn't appear to want to charge.

I'm aware of batteries being too flat etc, I left it plugged in for about 4 hours, tried various button combination tricks, some give me the solid red light, some give me the flashing red light, which it didn't do before I changed the battery so that seems like progress.

Is something else in the phone screwed or am I doing it wrong?