so every 2 years I have to replace my alternator is this a common problem for any one else? Both of my q45 have had this issue. I get my alternators from autozone

Still running the original alternator installed on the assembly line, 20 years and 314,000 miles ago

Mikejax25 wrote:I get my alternators from autozone

PROBLEM IDENTIFIED!!!

(Seriously - AZ electrical parts are crap.)

With the factory alternators being non-stock for the Q, the best option appears to be ordering one from Hitachi. I'm about five minutes away from walking out the garage to start putting one on my truck. I found the best deal at RockAuto.

The Hitachi alternators they sell are drop shipped directly from Hitachi's facility in Harrodsburg, KY - so it's a genuine part. Their price is $130.79 + a $45 refundable core charge if you send your old one back. Google for a 5% off coupon code that will pretty much cover the shipping cost. Plan for a delay in shipping... at least that's what happened in my case.

Beyond that, be sure you're not allowing your battery to discharge a lot. If your car sits for long periods of time or you're taking very short trips, I would suggest a float charger. The Q's charging system is minimally adequate at best, and it's designed for topping off a healthy battery - not bringing a marginal one back from the dead.

Heath

I sometimes get my brake light and abs light "on" when driving with a display msg " Low Battery Charge", this usually happens when it rains or had just rained, what a coincidence, but I checked out the alternator and battery and the cables, they are all fine. it must have something to do with not putting the bottom cover back on. I haven't had time with college and work to do a LAN test like Dr. Jay told me to do. but thanks for the heads up, I was about to buy a alternator from auto zone.

ive been looking into having an alternator built but im nervous to do so if this happens on a regular bassis

It's not a super-common failure item if you keep the battery in good shape, and use the Hitachi reman. to replace the original. Parts store remans are where you can get yourself in a replacement cycle... the quality just isn't that good.

I had this happen to me this morning. Huge thunderstorm passed through area last night. I bet close to a foot of rain came down. I got the Low Battery charge and the brake light. First time. I replaced battery 2-3 weeks ago. The Low battery charge message cycled about three times then I got "OK". Then the message quit coming on. I just checked my battery voltage with the engine not running. It was 12.8V. I then started her up and got 14v. Ran her for about 15 min and it was 13.8v. Shut her off and battery went to 12.9v. I think the alternator is ok, but not positive. I will monitor.

As was mentioned earlier in the thread, the alternator (even a new one) is designed to support the car's electrical loads while in operation, and supply a nominal (think 1-5A) top off current for the battery. An alternator should NEVER be used to charge a battery. Can you?--yes, within limits. But it is ill advised. get a stand alone battery charger, and that includes externally charging a new battery prior to install.
14.0v on a cold start is a little light. s/bin the 14.3 to 14.5 range, with 14.0 to 14.1 after 20 minutes or so. Doesn't necessarily mean your alternator is toast-- what is the voltage under max electrical load--hi beams, rear defrost, HVAC on high, heated seats if you got 'em, stereo,idling in gear warm?

3Q Jay, That is a great question. I will try that and report back. Thanks! JG

Check your belts and idler pulleys. You might have a seized pulley or one that's going bad on your alternator belt. This will slow up the drive a bit, which puts a strain on your alternator. You should feel some loss of engine power, if the pulley is seized. But that could be hard to tell, as the pulley bearings gradually go bad over time. Check all your pulleys, as any one of them could affect how well the car runs. They are still available, but make sure it's the correct match. I had to return several that i bought online because they were not the same dimension. The one that is particularly difficult to find is the Water Pump/Power Steering pulley. There were two different belt/pulley configurations, 5 rib or 7 rib.

If you do find an idler pulley bad, and having trouble finding a replacement, IM me.

cbird805, I will look at them. Thanks for the good info. JG

Gort400 wrote: ↑

Fri Dec 10, 2021 4:29 pm

I just checked my battery voltage with the engine not running. It was 12.8V. I then started her up and got 14v. Ran her for about 15 min and it was 13.8v. Shut her off and battery went to 12.9v. I think the alternator is ok, but not positive. I will monitor.

Those voltages don't sound bad.

The alternator voltage regulator is temperature-compensated - which means that it adjusts the alternator output voltage depending on ambient temperature.

In very cold weather, you might see battery voltages in the very high 14's, especially right after a cold start.

In very warm weather, it could be down in the low 13's.

Your 13.8 volts is a very typical number.

Skibane, The temp was cool. Not cold. If I remember correctly. T-Shirt weather. Thanks