
Originally Posted by
dr. d
1. you can have the battery charged now. if you connect it next week and the car starts, then your battery is good. if it does not start, then your battery is in need of replacement. (this test determines your battery's ability to hold the charge.)
2. if you are able to start the car as in #1 above, your probable headache-causing culprit is either a defective alternator or poor electrical connections, either of which can result in a weak battery. or, you have a parasite.
3. testing for parasite is easy. all you need is an ammeter: with the engine off, key out, and all other appliances off (but not disconnected) disconnect the main cable to the battery, and connect the ammeter probes in between the battery and the cable, observing polarity. note the ammeter reading. it should be "very small" (less than 0.1 amp). of course, most car owners do not have an ammeter nor know how to use it. thus, bring the car to the fixit shop na lang. heh heh.
4. #3 above is the easy part. the hard part is finding out where the leak is.. THIS is what separates the boys from the men.
seriously, bring the car to the battery shop. a well-equipped shop can test the battery's condition and the alternator's condition. most will not charge diagnosis fees, because it is easy to do. they make their profit on battery you will most likely buy from them.
now, testing for parasites... that takes a little more intelligence.
btw, if your car is MT, try push-starting it to get it going. most efi cars with weak (not dead and buried!) battery will start easily this way. you need just two slaves to push.. and even dying batteries will start a newly-died engine if immediately re-started..
good luck.