1990 Volvo

I bought my car in 1990 & have been the only driver. I had no trouble ever until 2004 when the battery went dead. Bought a new one same thing. Took it to the local mechnic, tried couldn’t figure it out. Took it to the dealership, they disconnected the phone & the electronic antennae, worked for about 2 days & then the battery went dead. After about 3000 $, I decided to buy a new car & parked the volvo. 2 yrs. ago my teen started to drive so I bought a new battery & tried the volvo again - worked for about 24 hours & then went dead - then I tried something different. I disconnected the battery every time I stopped the car & reconnected it when I was ready to drive - works perfectly. Now my other teen wants to drive this car more regularly so I want to find out what is causing this problem with the battery? What is draining the battery if it is left connected? Help

You have a parasitic draw somewhere in your car. Check for things like a trunk light staying on, glove box light staying on, brake lights staying on, etc. If there is nothing obvious, you either need to take the car to an auto electric shop, or try to find the problem yourself. For this test, you need a digital multimeter, which can be bought for $10-20 at most tool or hardware stores. Make sure all accessories are turned off, the key is off, and all doors and the trunk are closed. Disconnect your positive battery terminal, set the multimeter to DC amps, and connect one lead to the cable and the other to the battery terminal. You will get a reading on the meter. When you do, start pulling fuses and relays. The one that makes the multimeter reading drop to little or nothing is the circuit that is causing the problem. Look for corrosion, damaged wiring, sticking relays, short circuits, etc. Hope this helps, and hope it saves you a bundle if you resolve it yourself.