87 honda prelude SI 2.0 automatic chews through batteries (for years..)

www.youtube.com/watch?v=KF1gijj03_0 --- check this out. Perform parasitic draw test to find what's draining your battery

Thank you for the fast response Mark:) I'll ask my mechanic to do this test (parasitic).

Your welcome. Hope you get it figured out. Drive safe.

exactly what dandyoun said you have a parasitic draw on your system,, cant believe none of the mechanics knew to or how to test for this, its almost mechanics 101, my only unique suggestion would be to make sure you take it to a shop that specializes in electrical work

I had the same problem with an 84 Honda prelude it turned out to be the alarm system

Sure parasitic draw is always a possibility...and you have to consider what remains on when everything else is not! However, consider that the battery is not receiving a full charge do to a bad ground! In this situation, non parasitic, even thought you have a new Alternator, due to the poor main ground, the battery never passes full current. (It is similar to a bad battery connection, but this one bolts to the frame or tranny bell housing. Try it...clean up the connection and remount...simple, and very possible culprit.

You can also create an additional heavy ground lead...from the negative battery terminal to the frame! Easy stuff...and I cannot understate how often it becomes involved in such power gremlin scenarios.