My brake lights wont turn off even when car is off i had to undo battery for them to shut off

It isn't often we get enough information to make a diagnosis, but I think we can in this case.
You have a break light switch under the dashboard that is plastic, and has a "plunger" button.
When you press the brake pedal, that allows the plunger button to extend, which closes contacts inside the switch, and makes the brake lights come on.
If and when that switch either breaks or gets loose, the plunger will stay extended, and the brake lights will stay on, discharging the battery.
God bless your efforts to see & fix this.

Add oil. Check your Brake lights. If they do not work, the problem with starting is the brake safety switch. You are required to put your foot on the brake pedal to start your car.

If the brake safety switch is broken or knocked loose of the holder on the brake pedal lever, you will not get the release signal to engage the starter.

check brake light switch seperate contacts regular brake lights & gate light

check your relays or the off and on switch

Could be a faulty brake light switch on the brake pedal. I would check it first.

Sounds like the brake light switch under the brake peddle change it out should be okay.under 15 bucks at the parts store

there A BRAKE SWICTH BEHIND THE BRAKE PEDAL SWICTH THE OUT AND SEE ,IT,S A BRAKE SENSOR

CHECK FOR BLOWN BRAKE LIGHT SWITCH FUSE OR SEE IF BRAKES LIGHTS WORK.IF YES HOLD FOOT ON BRAKE PEDAL MAKE SURE TRANSMISSION SHIFT ALL THE WAY IN PARK.IF ALL IS GOOD.SOUND LIKE KEYLOCK CYLINDER BROKEN.IF IT WAS SECURITY THEFT SHUT DOWN YOU WOULD SEE SECURITY LIGHT.AND THE KEY WOULD TURN BUT CAR WONT CRANK.JUMP START CAR AGAIN.IF BATTERY POWER LOW THE BRAKE TRANSMISSION SHIFT INTERLOCK NOT GOING TO ALLOW IGNITION KEY TURN IN SWITCH.

look up under feet area brake peddal has a switch hooked to brake peddal could be bad switch or something catching it! good place to start!

Could be a broken or disconnected battery cable. If you are sure that the battery has a full charge, and the battery is connected properly (tight clean connection at the terminals) and the lights do not go on (including the brake lights when you step on the brakes) then there is a bad connection at the battery/terminal/cable for certain.