My son has a 86 Ford Ranger and the battery keeps being drained.The battery was tested and it was fine.?

Question

Nothing in the truck is being left on. This only happens if the truck is not started for a few days.

Answer 1

the alternator is not charging properly and needs to be re-built.

Answer 2

I assume that alternator is/has been checked and is ok too!

Lets re-phrase that sentence, -- "nothing is being left on",- (that we know of!)

First thing is to remove the battery cable (either side) and leave the battery disconnected... If it still "runs down",-- the battery IS bad. Sulphation in bottom is making a "high resistance" short and running it down!

However if it stays "up" in good condition you do have something "on" in the system. It may not be intentional, but it is draining the battery anyway!

Wire in an old lightbulb, or use a test light between the battery, and the "disconnected cable", - it will complete the circuit! If anything is consuming power, it will light the bulb. This will be obvious, if you open the door or turn on anything inside the car! So make sure everything is turned off, (including the interior lights if possible, -and the door is open)! From here you can pull out fuses, and disconnect accressories till you find out what is causing the problem! Once you have found it, you can leave disconected, (if not essential for driving car, - or safety), -- at least till you want to spend the time to run down the problem and cure it permanently!

Answer 3

If your alternator isn't working you would have a few hours at best, and not terribly long at all at night (headlights). If your alternator is somewhat working, it may not be putting out enough juice so the battery dies slower. Get a multimeter and check it out. Search online for how to test an alternator. I'll give you the short version: Set the meter to DC Volts so that it reads 00.0 Hook it up to the battery with the car off, should read around ~12.0V. Start the car, check again, should be about 13.5-14.5V. With the car idle, turn on the headlights and high beams, make sure it is still in this range. Finally, have someone rev the car constant at 2000-3000RPM with everything off (but the engine clearly) and someone else check to make sure it doesn't go above 14.5V (unlikely in this situation, but an easy check). Also you could have a slow leak somewhere. In my source there's a link to check for that. You use the same multimeter (on DC Amps though) but you have to remember you MUST connect the meter in series with the battery when checking amperes. In other words, take off one battery cable, and hook up the battery and removed cable through the meter. Get someone to start pulling fuses one by one (usually there are fuses under the hood and in the driver side door) and if the current (amps) drops on the meter, something connected to that fuse is draining it. Finally, since car batteries are lead acid type, a weak battery will still show close to ~12V, so you can't use voltage as an indicator of battery charge.

Answer 4

Alternator...

Answer 5

To check your alternator do this: While the vehicle is running disconnect the positive cable on the battery, if after a few minutes or shorter the car cuts off, you have a bad alternator. This will help you eliminate one possible problem. Newer batteries don't recharge like the older one's use to. Make sure your battery cables are clean and have no rust on the inner grooves. Make sure your posts on the battery are rust free and clean.

Answer 6

i own a repair shop,and it has to have a drain on it somewhere,,i,ll try and tell you how to do a drain test on it,,if you own an old cheap 12 volt test light ,you can take the negative battery cable off of it,now connect one end of it to the test light on the cable you took off of it and connect the other end of the test light to the negative post on the battery ,where you took the cable off,now you have bridged a connection,and if the light comes on it has a drain on it,if it don't open a door or something to test the light to see if it comes on,if it does ,,good its hooked up right ,if it comes on as soon as you first hook it up,it has a drain on it,and you can find it by pulling fuses until the light goes off ,at that point you have found the drain on the battery,also try the alternator wire too as part of this test it may be sticking and draining the battery down ,good luck with it ,,i hope this help,s.

Answer 7

So clearly NOT an alternator.

If he has added an alarm, stereo components or something like that I'd check those first.

If not I'm pretty sure it's gonna come back to a bad ground.

Someone smack the person who said to go to AutoZone to buy an alternator. Worst electrical parts ever.

Answer 8

depends on how many different lights and or accessories are being used, the altenator may not be charging the battery properly which would cause it to be only running on existing power in the battery and that would ultimately run out in minutes. or you may have some sort of problem with the wiring going to the battery. you can have the altenator checked at autozone for free, or have the engine codes ran there also.

Answer 9

The battery is definitety the culprit.That is if nothing is being left on.

Answer 10

Bad ground,loose wires, or check the selaniod it is mounted to the fender on the passenger side they go bad alot if it is just making clicking sound that is what it is

Answer 11

there is a bad ground somewhere is it will slowly kill the battery, I would check any connections on the tail lights and whatever else that grounds on the body, my 86 grand marquis was doing the same and it was just a rusty bodypart where it was grounded(or not)