What causes the energy to drain from my cars battery?

on newer cars, there are many small devices that are always powered by the battery. so even if you just let the car sit for a few weeks you may not be able to start it. since your car is an '89 I doubt it has many modern computer draining devices like an '07 or '08. it is probably the alternator, but before you try anything, check the battery terminals, clean them, and change them if necessary...if they are real dirty they can drain a battery and prevent a weak battery from starting. good luck

Your battery may have a dead cell and is not holding a charge. Also, just because there are no visible signs of "something on" inside your car, there remains a possibility that you have a small short. I would start with a free battery check at an Autozone or similar auto parts store with a portable electronic battery tester/analyzer. They can tell you in a few seconds if you have a bad cell or if you have a short somewhere thats draining the battery.

It sounds to me and im 100% sure that your battery has a crack in a cell which will cause it to not charge real well and then when you switch the car off it will drain within 30mins. Buy new battery its stuffed dude

I would also have the battery checked you can get a charging system done at your AutoZone or Advanced Auto

a bad alternator or just a battery going bad on it will cause it,usually its the alternator that causes this if nothing is being left on and your sure the battery is good in it,even a short circuit can cause it,have it checked,any parts store can check the alternator for you and tell you if its bad,good luck.

If you've recently had some work done (engine work, or electrical work like radios, tail lights, etc.) I would concentrate on those areas.

If not it would probably be what everybody else wrote above.

Good Luck...

Sounds like a ground short to me. They can be a pain to trace out, too. Know a good auto electric shop? That's your best bet.

yup, its your alternator it suppose to charge youre battery, but its doing the opposite, check that then your battery connections

i think maybe a bad alternator

u can go to autozone and have them check it out for u for free : )

it is you alternater. 100%