Lights stay on causing battery to discharge - Cars & Trucks

Do they stay on a few mins or stay on tell the battery discharges?

As long as the lights do not stay on, a broken switch should not drain the battery. Why don't you pull the fuse on the headlights and taillights?

I don't know about cars

Tons of possibilities here. Corrosion on terminals builds up over time, causing higher resistance for the electricity going back into the battery from the alternator, causing it to charge more slowly. Moisture (or moisture in dirt) on top of the battery can cause a slow discharge between the poles (worse in humid areas). Short circuits (from bare wires, corroded connectors, etc.). Devices such as phone chargers plugged into power outlets that stay on when the key is off (some do, some do not). Interior lights left on. Remember, also, that alternator recharging will typically not take a maintenance free battery to 100% charge once it has been severely discharged. That means that, even though the car may seem to start fine, it may reach the point of turning the engine slowly (or not at all) much more quickly. It will only reach 100% again if trickle charged (with a battery charger). Probably 4 out of 5 of my battery issues have been solved with a good terminal cleaning and an overnight trickle charge, and my batteries rarely last less than 5 years. My truck battery is still going strong at 9 years. Regardless, though, batteries eventually stop charging, even expensive ones. Hope it turns out to be something simple.

Check alternator charge rate and earth straps

First step have the battery tested, a bad cell can cause a internal drain and kill the battery, if the batt is ok then check for interior lights like visors that stay on or interior light that come on by themselves at night due to defective door switches.

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hi.

the most common cause for discharging like that, is a faulty switch on either the glovebox light, or the boot light. interior lights are easy to spot if they remain on, but boot and glovebox lights can stay on without being seen. try taking the bulbs out of the bootlight and the glovebox for a few days and see if it helps. if it does, replace one bulb to find out which is the problem.

other possible power drains include alarm systems, radios, and various alternator faults.

check the lights first, and if you need more help to find the problem, feel free to ask

If you can hear a click (quite loud) from the engine compartment, but the starter won't crank, this also could be caused by discharged battery. Battery problems - Discharged or dead battery is one of the possible reasons for a car not to start. Very common is the situation when we forget to turn the lights off overnight (the dome light, for example), which causes the battery to drain. In this case when attempting to start a car, all you will probably hear will be a clicking noise - there won't be enough power to turn the starter. Here is the simple way to check if the battery is discharged: Turn the ignition on. With the engine off, turn the windshield wipers on. If they move way too slow, much slower than usual, the battery is probably discharged. Also look at the dashboard lights - if they appear very dim, the battery is probably discharged.
If the battery is relatively new, it can be recharged. All you need to do is to boost your car and let the engine run for a while to charge the battery.

However if your battery is more than three-four years old, you will probably need to buy a new one. Sometimes, an old battery may even die with no apparent reason, even if the day before it was OK.

If the battery is OK, the starter solenoid, starter cables or the starter motor itself could be a problem.

Check it and tell us news.

Check alternator for charge,somebody was boost and fray diode inside alternator,start car when car is runing remove positive cable if car stop you need new alternator