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#1
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2014 Terrain battery discharging
Wife's 2014 Terrain needed a new battery 3 months ago, no problem. Last week she hops in and the battery was down and just got the click-click but not cranking. I took battery in and had it charged and tested to be sure, it passed. When I went to put it back in, a big spark when connecting cable, and it was repeatable. Got a clamp DC ammeter and tried it again...3-4 amps intially, but within 30 seconds it stettled down to about .1A steady, and that is all happening with key off. I pulled every fuse possible one at a time and that .1A draw never quit. Started car, 14.50v steady. That was all last week.
I threw a voltmeter on it this morning to see if the battery is staying up. 12.7 off, 14.5 running...but noticed after a minute it drops to 12.4 and stays there. Shut it off, restart, same thing happens...after a minute it drops from 14.5 to 12.5V. I jsut took alternator off and had it tested, it passed, but since it has 104,000 miles, they're gonna replace regulator for $40. Is it possible the computer is de-enrgizing alternator after a minute of idling? Something else?
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Red\black 65 Grand Prix 467 E-head stroker, Viper T-56 6-speed, 4.10 spool |
#2
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It seems obvious something is draining battery, and I've yet to find it. But at same time, I've never seen an alternator work for a minute then quit...nor have it do that repeatedly when ignition is shut off then restarted. Trickle charging battery overnight to make sure its fully up for when rebuilt alternator is ready for installation, see what happens.
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Red\black 65 Grand Prix 467 E-head stroker, Viper T-56 6-speed, 4.10 spool |
#3
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Put rebuilt alternator in, and reconnected freshly charged battery, still got a big spark and 5-6A initial draw, but after several minutes it ratcheted down to about .001A. Voltage idling varied from 14.6 to 13.8V over 20 minutes time. As far as I'm concerned, its fixed, but gonna keep an eye on battery voltage for a while.
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Red\black 65 Grand Prix 467 E-head stroker, Viper T-56 6-speed, 4.10 spool |
#4
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Like every damn thing on the new cars, charging the battery isn't a simple process like it should be. You were correct in your statement about the computer being involved. The Field circuit to the alternator is computer controlled with pulse width modulated signal on the field wire. There is still a regulator in the circuit which may be either in the alternator or in the computer. Sounds like yours was in the alternator and malfunctioning. So there is a good chance you have it fixed. The big spike and 3-5 amp draw when you first attach the battery cable is normal on these newer vehicles. When first attached, you initialize all the modules in the multiplex system. a 2014 Terrain probably has 20+ computer modules that are all sent a wake-up signal when you attach the cable. Then one by one, they shut back off when the main computer alerts each of them that the vehicle is at rest with the ignition off. A continuous draw of 50 ma is typical, and a battery will generally discharge and not start the car if left sitting 30-45 days. That is normal. I have had some cars that I could not get below 90 ma, no matter what I did. They would kill a good battery in about a month. Not much you can do about it other than drive it every week or so at least 1/2 hour.
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The Following User Says Thank You to mgarblik For This Useful Post: | ||
#5
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This morning the battery was back down to 12.6V. I hooked the clamp ammeter back up, .2A with everything off, so had wife watch meter for changes while I started pulling fuses from the interior fuse box. Pulling fuse 12, "HVAC Battery" made a sudden drop in current, settling around 20mA. I'm leaving it out for a while, and see if battery stays up longer. She drives it daily, usually. Between the underhood and interior boxes, I'd say this car has at least 90 various fuses, and numerous relays. Without looking I'd say my 65 GP has 12 fuses.
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Red\black 65 Grand Prix 467 E-head stroker, Viper T-56 6-speed, 4.10 spool |
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