Is it recommened to drive with the battery light on
 

CEO just got home and I checked the battery - it's full.
As well, I've dropped the trickle charger on it at 8 AMPS and it detected the battery was full and dumped to trickle charge..


Planning to bring it to the shop to check it out. She drove it with as minimal electrical load as possible, no lights, radio, etc. A good 20 miles and go figure, it seems normal just short of the light. However, she did mentioned it did ~strain~ for a extra sec when starting.

So whaddya guys think . Is it the battery or the alt. I plan to give her a test drive tonight to see if the battery light disappears...

If there is still a light, should I play it safe and have her towed.
Or it's just fine to drive it if the alt seems to be charging the battery...

Haul out the DC Meter
 

Put a meter on the engine battery terminals while the engine is idling and check the voltage with the DC meter. Normal voltage should be around 13.7V or better.

Usually the battery light will indicate the alternator is putting out low voltage. Note that at higher RPMs, the alternator will put out more voltage, so the battery light may go out when you are on the freeway and driving at high RPMs. It also depends on how many accessories you are using since the voltage goes toward the accessories instead of the battery. This includes lights, wipes, fan, heated seats, etc.

If the alternator goes and the battery is full, you'll get maybe 20-30 minutes of drive time before the battery can't sustain normal engine electrical draw, i.e. spark plug and you will ungraciously get stuck and need a tow or another fully charged battery to get you 30 minutes farther.

If I was a betting man, I'd put $100 of Monopoly money on the alternator heading south, especially as you describe the battery with plenty of juice.

I hope you don't end up getting a piggy back to your indy.

GL.

My dealings with the battery light...

I once worked on a 1999 528i that had the battery light on. The owner replaced the alternator with a new one and the light never went away. I checked the fuses and found a few that were blown. Replaced them and the light came back on (fuse blew too). Did some poking around and found the oil level sender to be defective (sensor was shorted). Replaced and probelm solved.

Another case, my 330i, battery light came on. Immediately thereafter, the DSC and other lights came on. Then the radio started cutting out. Just made it home and hooked a DMM to the charging system. The car was running on 8 VDC. Alternator was toast. Replaced and problem solved.

As mentioned above, hook up a DMM up to the charging system. LEt us know what you find.

Daniel

spend today shopping online for a new alt...looks to be $400 on average...
was planning to DIY but instead I'm just going to have it towed to the shop and have them deal with it along with a laundry list as well. It's been awhile since it's been in the shop and I'd rather have them deal with the laundry list in one shot.

I have the same issue. Did you change out your alternator? If so, did the light go off?