1998 Frontier 2WD 4 cylinder, 5 speed, stock. I've had this 2 years, and gone through 4 batteries, last three replaced at no charge. All suddenly read about 4 volts, Autozone recharged, but then when put on the checking machine, all read bad, so they gave me new battery each time. When running, alternator puts out 14 volts like it should. Autozone said it was putting out 73 amps, so that was too much, as the stock 70 amp alternator should only put out about 66% of its rated amperage (does that sound right to anyone?); they said charging voltage and diodes were fine, and suggest putting in a new alternator. Does this sound like the next step, does anyone relly know?
CT - what you you mean "frying the battery" - like too many amps? If so, what about the guys who install higher-capacity alternators?
The alternator is not regulating the voltage properly. If you were to measure the voltage at the battery with the engine off you would measure between 12.3 to 12.6 volts DC. With the engine running the typical voltage at the battery terminals is 13.0 to 14.5 volts DC. A high voltage boils the water from the electrolyte and renders the battery useless. This is "frying" the battery.
If you do not have a voltmeter ask the guys at Autozone to check the voltage at the battery in the vehicle while the engine is operating. Also, check your connections. The regulator senses voltage to control amperage. A faulty connection at the alternator may cause the alternator to sense an incorrect battery voltage and cause overcharging. A high output alternator has the ability to deliver more current but it still does so at 13.0 to 14.5 volts DC.
Last edited by azrocketman : Apr 24th, 2006 at 10:28 AM.
CT - what you you mean "frying the battery" - like too many amps? If so, what about the guys who install higher-capacity alternators?
It might be as simple as the alternator belt being too tight. Check the tension and try loosening it up a bit before you shell out a couple hundred bucks on a new alternator.
When you eat food, your body knows when to stop. It's the full stomach sensor at work. All battery charging circuits have a similar sensor: it senses when the battery is at full charge. Once full, the battery can no longer accept power and convert it to chemical energy. So the power goes into fryng the battery. After four batteries, I'd spend the money for an alternator which has the integral voltage regulator.
i support the above i highly think its the alt. get one from autozone and take the 2 hours to put it in. i dont know how long it would take on a frontier but it took about two hours on my TA cuz it was at the bottom of the motor.
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02 Desert Runner 5sp, 6cyl, lots of scatches but low on miles...
My first try will be to clean all the cable terminals, maybe replace the battery cables. This apparently is not a common issue. Voltage never goes above 14.5 volts, but alternator may deliver more amps than necessary because of faulty feedback due to resistance. I'll also monitor the electrolyte level each month.
I found the battery negative cable to be practically cut-through at the factory crimp-fitting where it bolts to the engine, so I replaced the end, and cleaned up the other connections. Now I just have to wait to see if problem doesn't re-surface in a few months.
Update: I replaced the 98 Frontier battery negative cable in May 2006, and used some foam to try to isolate the battery from the engine compartment heat. That battery lasted until June 2007. So I really doubt that there's a non-battery electrical reason for this. When I changed the belts a few weeks ago, I did notice that the alternator does have a little more drag on it than others and generators I've spun over the years.
OK, spoke too soon. The recent battery just died today, was about three weeks old.
Cusser,
Did you put a heat shield around the latest battery to protect it from the engine compartment heat? As a fellow Zonie I'm sure that you've seen air temperatures in the 110's over the past week or so. Are you buying batteries that are "tailored" to withstand our temperatures? Is there a chance that something in the engine compartment is causing the batteries to run hotter than normal (maybe something directing hot air at the battery? Is the battery firmly mounted so it's not getting vibrated to death? Is there a chance that you have a short in the truck that's pulling the battery down?
Check your frame and body grounds. Make sure you don't have a draw on the battery when the engine is off. You said the Autozone people told you that your alt was putting out 73 amps on a 70 amp alt. You need to isolate the problem, determine whether something is pulling that much amperage or whether your alt can no longer regulate output. I'm willing to bet your alt is full fielding. Time for a replacement alt.
Last edited by nissanmadness : Jun 25th, 2007 at 04:27 PM.
I would recheck the voltage on the battery with a known good digital voltmeter, when hot, engine running. 14 volts is OK under those conditions. Next i would check the parasitic current draw. To do this disconnect one battery terminal and put a milliameter [or a digital meter on the DC current range] between the battery post and the battery-this should be done with the engine off, everything turned off, key out. You should not get more than around 50 milliamps- 0.050 amps. If you do, it means that something is drawing current that shouldn't be. It is remotely possible that you got a defective bunch of batteries. Do you have a known good battery laying around you could try??
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