What is the best way to keep a car battery charged?

I recently bought a used 1994 Oldsmobile Cutlass Supreme a year ago and it's been a very dependable car. In April, however, I didn't drive the car for more than three days and when I went to start it, the battery was dead. There is no corrosion on the battery itself and it appears to be in good condition, yet it might be a little weak. What can I do?|||First, you'll need to charge the battery, either using a charger or by getting a boost to get it started.





The next step would be to drive it directly to a shop that sells batteries - most of them will gladly test the battery and the alternator/charging circuit. If you drive it for more than 1/2 hour to get there, the battery should be at least partially charged and that should be enough to give an indication if it is just weak.





Then, if a new battery goes dead, it could be that something is drawing current when the car is off. My father had a dashboard light dimmer rheostat that went grounded, and it would discharge the battery overnight. He measured the current and couldn't believe that there was an ampere or so of current with the car turned off and all lights off. While poking around under the dashboard, he noticed the light switch was warm!





If you suspect current is being drawn with the car off (more commonly it could be a trunk light that doesn't go off), the battery shop should be able to put an ammeter in series with a battery cable and detect that.|||May have a drain on the battery, a light left on, or just an old bad battery, replace it and see if your problem happens again. If so, begin looking for a light left on when it shouldn't be on.|||The battery needs to be load tested simply test takes 1 minute. If good check glove box light ,trunk light, if OK the make sure dome light goes out when door closes,if on timer.If all OK check the blower motor relay which is placed inside the duct work in the engine compartment,when it fails it will turn the blower fan ever so slow eventually draining the battery.Common problem,with GM.|||2 things can cause this... either the battery itself is no good - Quick test at just about any place - I would think they do it for free - we do! But I am in Toronto...


Or you have a draw that is causing it to go dead...





If the car was left for much longer - As I have a few classic cars that I store all winter - and own 3 harleys...





I have a device they call a battery tender - it keeps it always topped up... If it needs charging - it charges... when you don't need anything - it stops! GREAT! GREAT! product... You can buy them many places - I bought all of mine at my local harley Dealer...|||Sounds like you need a new battery. You can take it to most parts store and they will check it for free|||buy a new battery or start your car every day or 2,to keep it charged.