Originally Posted by Soksta

Cat, I'm just a few minutes away and would be able to come out tomorrow and bring a multimeter should you require it.

Originally Posted by Jeckle

Easy way to check the alternator, but needs a $20 multimeter.

Start the car, Open the bonnet, set multimeter to DC Volts, its the volts with the straight line. Put the red on positive on the battery, black on the negative, the other way will only show negative volts, so no problems.

Should be 13.8 volts or so on idle. If its 12.4 the alternator is dead and not charging.

Also check that the plates in the battery are covered in liquid, if not pour enough distilled water in to cover them, not filled to the top.

The alternator doesn't drain a battery, even when its failed, it just doesn't charge. Its all the electrical components that drain the battery, and its not being topped up.