Battery drain, possible issue with alternator?

Good afternoon,

Do you have a volt meter to check the voltage at the battery with the engine running?

https://www.2carpros.com/articles/how-to-check-a-car-alternator

The charge rate needs to be 14 to 14.5 volts. The battery voltage with the key off should be 12.6 volts.

https://www.2carpros.com/articles/car-battery-load-test

Is the battery light on?

Roy

Battery light and brake light is on. I have no tester.

Okay, that tells me you have a charging system failure.

You can get a cheap voltmeter at a parts store to do the checks.

https://www.2carpros.com/articles/how-to-use-a-voltmeter

Also, check the fuses. it may have a failed fuse. If it does, the alternator may be the cause of the failure.

Roy

So just go ahead and change the alternator?

I would confirm it first to be sure it is not anything else.

It is most likely the issue but I do not guess. I like to diagnose once and repair once. guessing is expensive if it is the wrong part.

Roy

Does that mean change alternator and fuses?

Thank you. My brother is doing the work. He believes that is the issue I just wanted to make sure. We take excellent care of our Nissan.

Tell him to verify power to the back of the alternator from the battery.

Have him check all the fuses with a test light for power on both sides.

Roy

Thank you very much. I really appropriate the help 100%.

You are welcome.

Always glad to help.

Roy

My car's factory radio and BCM (body control module) are draining my battery. I found a used BCM for cheap, but the used radio is still expensive. Would replacing the factory radio with a new aftermarket in-dash deck solve the problem? Or is there another internal "radio related" component of some sort that should be inspected/replaced?

Thank you,

Replacing the OEM deck with aftermarket should fix the problem. Just make sure that you use wiring harness to connect your new radio to the car, instead cutting and splicing wires together. This guide can help us

https://www.2carpros.com/articles/car-battery-dead-overnight

let us know

Ok, thank you. I'm assuming a professional installation at a Best Buy or something like that would use a new wiring harness... I'll make sure to ask whoever is going to do the work.

Thanks again.

Most install shop will use wiring harness.

Good luck.

battery drains off to non starting within two days of no use. new battery did not help. unplugged radio and cd player with no luck. heater resistor went at the same time. new reesistor fixed heating problem only. Where to next?

Tracing current drain is very PITA. You are at the right direction though. Here is what I would if I were you on a day that you are off from work. Get yourself a DVOM )digital volt/ohm meter).

It is about $15 from you local parts store or even Walmart... 1. Set it to check voltage at DCV V20 (checking DC voltage at around 20 volts). 2. Remove both battery terminals. Check battery voltage without any current draw. Write in a piece of paper. Now you have your base voltage. For example: Battery - no load - 12.65 volts 3. Attach both battery terminals. Check and write down voltage. Battery with terminals attached - 12.48 volts. Subtract this number from your base: 12.65 - 12.48 = 0.17 volts. Now you know, you have 0.17 volts of parasitic current draw. 4. Now, under the hood, you should have (if I remember right) 3 different fuse/relay boxes. Pull a fuse/relay one at a time. Write down what fuse or relay you pull, and check the voltage. Do this until you have tested every circuitry under the hood. If there is no change in the voltage, continue to the fuse box under the dash, left side. 5. You will find one fuse or relay that will give your battery voltage higher than 12.48 volts. Usually a fuse controls one or more circuits. At least now you can concentrate your energy on that particular circuit. Good luck....

The battery in my 1998 Nissan Maxima keeps going dead. Dealer said it was the battery and replaced it. Battery went dead. They said it was the alternator & replaced it. Battery still going dead. Said new alternator was bad and some fuse in the new alternator had blown. Replaced new alternator. Then they tested the system and said there is still a drain that they think is through the dome light and the light on the alarm system. Said they "think" it is the body control module. Told them to stop changing stuff until I find someone who can troubleshoot the problem. I have noticed that the alarm system light stays on constantly, whereas it blinked prior to the problem. What could be causing this? If it is the body control module, about how much does it cost?

Thanks!

How long it takes to the battery to run out of power?
I suggest you to disconnect the alarm system and see if that solve the problem, the thing is that the new vehicles come with all kind of electronic devices that any of them could fail to ground with a resistance and " eat " The batttery in no time.



Best regards

If I don't drive my car for a day or two it will not crank. When I jump it it cranks up okay and continues to crank okay if I use it on a regular basis. But when left for a day or more it will not crank.

I've had the Nissan dealership run a thourough diagnostic on it and the battery, alternator and starter are all good. No one at the Nissan dealership can find the problem. There also doesn't appear to be any lights on when left unrunning that might cause a slow drain.

There are two items that coincide with when the problem started. First, my wife plugged in a phone charger that blew the fuse and second, I changed out a rear brake light that had burnt out about the same time the problem started

Thanks for any help or direction you might be able to provide.

But when left for a day or more it will not crank

You have an electrical short that is more than the normal draw for memories-such a radio/clock etc, that's draining the battery overnite.

You might want to do another load testing on the battery and alternator to confirm that its functioning correctly.

MY car won't start due to constant battery drained. I took the battery for recharge twice and later swapped it out with a new battery. Yet, the new battery only worked for 3 day and shut off. I don't know what exactly drains the battery. What could be the cause?

check the alternator output with a multimeter at the battery posts on 20 volts dc setting if the voltage is not at 13.5 to 14.4 with engine running the alternator is toast.

Electrical problem
1990 Nissan Maxima 6 cyl Front Wheel Drive Automatic 25000+ miles

I think the voltage regulator is draining the battery because the battery is too weak to turn over the battery after we go into the store for awhile (1hr - 2hr) but my husband tells me it couldnt be the voltage regulator. What is your opinion on this?

HI there,

first thing to do is get the battery load tested this is the only way to test a battery condition, then have the alternator checked for charge rate, this will also check the regulator and ensure that the battery terminals are all clean and tight, start here.

mark (mhpautos)

The battery cables have been tight and clean but I will check the alternator...Thanks!