dead battery...again

[86isuzu]

92 Ranger 2.9L

replaced the crappy duralast battery on friday because i was having hard starting issues and a noticeable power draw whenever i had more than a couple acc on (heater, radio, headlights, turnsignal).
dropped in a energizer batt and no probs till today after work. no power whatsoever left in the battery (no dome light, no ignition click, no guage movement) and jumped it and the battery level went right back to normal. got home tonite and tried firing it up again about an hour later. same problem.

wtf?

and no, i didnt leave the headlights on.

 

[86isuzu]

o yeah, had the alternator and starter checked and nothing wrong

 

[BlaineM]

I had the same thing happen to a new tractor battery last week. Was a bad battery. Replaced it and it has been good since.

I must also remind you to make sure the battery cable ends are clean and in good shape. Sound like it could be a bad connection.

 

[dennis461]

ok, so same problem with two different batteries, so that is not it.
Is the fan belt slipping? Serpentine belts don't always squeal when loose/slipping.
That may be just tight enough to keep the truck running, but not enough to recharge the battery, so, the battery goes dead as you are driving. Dead quicker in the winter cause you are driving with lights on more.

Another check, loosen the battery cable on the positive side of battery, ignition off, key removed; disconnect it in the dark and look for a spark, a tiny spark is expected, a big spark says something is still on draining the battery. (This is if you don't have electical testing tools available.)

 

[Ranger5.0]

uh, that last lill test is enough to damage the ecm. its not recomended, unless, you wanna shorten the life of your ecm, then, by all means go for it. your either looking at a charging system failure, or, you have a phantom drain. So, either your battery isnt charging, or whne you shit the truck off, there is a short drawing amps from the batt, OR somthing is on that shouldnt be.Im leaning to a charging system failure. An alternator can pass a bench test, but your charging system can still be trouble. Shut the ignition ogg, disconect the batt from the truck, then charge it. USE A DMM to test its open circuit voltage. If its less then 12.4 then its not fully charged. When its charged, use your DMM set on the 10Amp scale and place one lead on the negative post of the battery. The other lead on the termanal of the negative battery cable. IF the display reads close to one amp or higher, you have a phantom drain. This will usualy kill your battery in a day or two, add to the cold temp to the factor, and it juss gets worse. If its less then an amp then its a parasitic draw. This can be caused by radios, clocks, keep alive memorys and the voltage regulator in the alternator. Since is passed the bench test, i wouldnt point a finger at the regulator yet. If you dont find a phantom draw then re conect the negative cable. Unplug the alternator, turn on the key, dbut dont start the engine. With the key on, you should be getting 12 volts at the I termanal of the alternator conector. This is what first gets the alternator to produce amperage. Without this enitial voltage the algernator is a paperweight. Is your charging syatem light on whn the engine is runing? If not, is the bulb burn out? if there is voltage at the ignition feed wire, then start looking for bad conections. Try this stuff out, then let us know what you have. DONT just try looking for a spark in the dark, thats just dumb. if you dont have the tools or feel you have the undrstanding to pull off a quick and dirty diagnosis, get a shop to look at it, or ask around and see if you can find somone who has some experience. Dont be intimidated tho, with a DMM and a beer you will be fine.

 

[94STXRanger]

12.6V is full charge right? 12.4 is 3/4 im pretty sure...

 

[Ranger5.0]

ya, depends who ya talk to, or what txt you read.

 

[86isuzu]

ok, my multimeter is a pos (friggin harbor freight). gonna take it to a shop tomorrow morning.

 

[red85]

Try this. Go through the relays that control pwr to ECM and fuel pump. Touch the tops of them. If any are warm after the truck has been off for more than 2 hrs, you've found your culprit. Just to back up this test, I like to check both of the circuits I just mentioned with a logic probe. I have seen this more than once. Relays are cheap and batteries aren't.

 

[Big Red Ranger]

i replaced my cables and it worked fine after that