Electrical Issues - Car wont start

[Tamataz]

So a couple of weeks ago i bought my first E30, a 1991 318is slick top.

Some lights weren't working properly (headlights, high beams, turn signals, brake lights, reverse lights...) So i check the fuses and found 2 that were broken. So i replaced them, they were number 6 and 30 i believe.

http://forums.pelicanparts.com/uploads14/E30_FuseBox1230049790.jpg

Anyways, so i changed those and then i was checking random electrical lights with the ignition in stage 2, then suddenly i started loosing power to stuff, like the lights on the instrument panel, radio, interior lights are dimming.

Thought it was the battery so i took it to my work and charged it, brought it back into the E30 and its reading 12v. Yet lights are dim and the only thing that comes on when i turn the key to 2nd position is the red light for (low?) oil on the instrument panel. :(

I don't get it, its really pissing me of because i just want to get the thing running I'm kind of regretting buying it.

Any help would be greatly appreciated.

[Tamataz]

Anybody? I'm new to car ownership so even the most basic things i can check would help, i don't know where to start.

Battery is reading 12v, but everything seems to act as if the battery had little power, dim interior lights and only the first red light in the instrument panel to the right is lit up. The only thing i changed from when it was working then not working was replacing those 2 fuses, and messing around with the directional light bulbs. Tomorrow I'm going to clean the battery terminals.