New stereo, dying battery

[Swangarten]

I put in a completely new stereo in my 70'

JVC head with 4 speakers and a powered sub. I used all top notch wiring/fuses etc on the install.

When I'm driving to work my battery dies.

The battery is 2 months old. The old battery was 6 years old and died before I put in the stereo. Being 6 years old I didn't think twice about replacing it as I had no reason to suspect anything else was going on.

My guess is that the new stereo is drawing more power than the original alternator can keep up with.

This only started once I installed the new stereo system. It could be coincidental but seems highly unlikely to me that its anything other than the increased draw of a modern stereo on a 46 year old system.

My plan is to put in a new HO alternator but before I do I want to poll the more experienced to make sure I'm not overlooking something Bronco specific/problematic.

Thanks in advance!

 

[lsukevinc]

it should not be pulling that much amperage. Did you install a separate amplifier? I had a aftermarket pioneer wired in the factory harness and it was fine. I did upgrade to the 3g alternator and I highly recommend that.

Go on YouTube and search how to track down electrical drains. I had one and it ended up being the voltage regulator. By the way, the old voltage regulator will go away when you upgrade your alternator to a 4g or 3g.

 

[Teal68]

If it died while driving it sounds like your alternator is bad or not functioning properly. Could even just be a bad regulator.

 

[Vin218]

I had a similar issue when I first put my amp and speakers in, picked up a 3g alternator from a scrapyard and haven't had an issue since. Not sure if thats your problem but its a cheap and easy upgrade anyway.

 

[broncnaz]

X4 its most likely your alternator. Id have it checked but also consider the fact that the new battery may also be on its way out. You get just enough to start it then the stereo draws it the rest of the way down. So you may want to get the battery checked as well,

 

[Wanna Ride]

Not sure where you live, but most cities have a reputable auto-electric shop that rebuilds alternators and starters. Would be worth it to swing by and have them check your alternator. Worst case scenario, most national chain auto parts stores can bench test them too. But at these places, you may not get the seasoned veteran who really knows his stuff.

 

[DaveLev]

Check grounds. Also verify your wiring to see if positive from battery is going to ground, or there's wires touching that shouldn't be, particularly on the head unit and the amp. You may have a pinched wire going through firewall, too.
You can disconnect negative battery cable, wait a few minutes, and carefully touch the cable to the ground terminal and see if you get a big spark. If you do, wiring bad.
For what its worth, I did the GM single wire alternator conversion. They are cheap and readily available anywhere. The only drawback is you must drill out the hole for the long pivot bolt to be fatter, which takes under a minute to do on a drill press, then it just bolts up.
Hope this helps!

 

[nvrstuk]

Disconnect the new system after you've charged up the battery and see if the problem still occurs...

if it doesn't then... it's possibly something in your sterro system OR your charging system isn't up to snuff

if it does then... rule out the stereo and follow some of the suggestions above ...

BUT first, stick a voltmeter on it and see what your output is at idle system on and off, check it at 1500 rpm system on and off to verify what stat your charging system is in.

 

[DaveLev]

Someone asked for photo of GM alternator. Ignore those nuts I used for a spacer.

 

[B RON CO]

Hi, the old school test for an alternator is to start the engine and remove the negative cable from the battery. If it runs, the alternator is putting out. If it dies, it is running on the battery. Warning! this is not a tell all test, your alternator may not be putting out enough amps. The way to test an alternator is under load with an amp clamp, and amp clamps are not cheap. A plain multimeter will show volts at the battery. You should see 12. something with the engine off and 13.5 or better with the engine running. Good luck

 

[blubuckaroo]

I don't think you need an alternator upgrade just to run your stereo. Even the standard 42 amp alternator will provide enough if it's working correctly.