Car won't start, not sure why!

[Seagal]

Here's the story, someone broke into my car on Friday night and left interior light on after they'd finished stealing absolutely nothing! I didn't discover this until Monday morning by which point the battery was totally dead.
Got a jump start off my old man and took it for a drive to try and charge it back up, drove about 30 miles in a an hour and a half, parked up only to find engine dead again, headlights dim, interior blower weak etc.
Hooked up a battery tester today when I jumped my car off the girlfriends, said the battery was fully charged and the alternator had an 'ok charge' but again, it won't start. Not sure what the issue is here, battery or alternator or something else?
Trying to avoid taking it to garage as money tight just now. Any advice greatly appreciated.

[Piers0930]

This may not be the best advice in the world mate, but this is what i would do..

Check to see if you are getting 14 volt + charge on your battery when the car is running, you can check this by getting a multi-meter, switching to the 20 + DC mode, (anything that isn't going to blow it) thats below 14 volts DC.

Then if that works then try anther battery, do you have a wear indicator on your battery?

Does sound like battery though, can you do a 'drop down test?'

All The best Piers

[Seagal]

Thanks for the reply mate, I'll get hold of a multi-meter from someone at work and see what it's says. I don't have a wear indicator on battery and I've no idea how old it even is as only had the car a year. I get the feeling it probably is battery though. Cheers again.

[alexperkins]

I would put my money on the battery being shot.

[Seagal]

Well it was indeed the battery, replaced it Monday and no problems since, except for the power steering fluid leak I've just found but that's for another day!

[Seagal]

Bumping this thread, 3 days after I installed new battery, the alternator warning light has came on. I can get a used alternator for £25 so am going to try swapping them over this weekend. Hoping that will be the end of it. Is there anything I need to know before switching it over? It look's as if it should be fairly easy but I know that isn't always the case!