Battery died after using AC all day (air conditioning, best, engines)

[PatrioticSuperman]

Kind of a weird one. 2004 Ford Taurus. Had an "extended cranking" ... okay. This HOT 100-degree day.. used AC from start of car to turning it off.

The fourth or so trip, the battery just died.

It is charging back up now.

After the charging, it starts up just fine, no extended crank so I feel it was battery related.

Are these two things related? (use of AC and battery dying in use on hot day, car wouldn't start during regular use in errands on hot day. Needed a jump)

[turf3]

Probably battery's going south.

Could be alternator.

No modern car in good condition will have any problem with the small added electrical power draw of the AC system.

[OyCrumbler]

I know someone in the Pacific NW who's been working out of their car (and with the spouse and dog, too!) because they never bothered to install AC since it's just never that hot. Thankfully it's an EV so they can run it in the shade of the garage without poisoning themselves.

[PatrioticSuperman]

Well, this MAY be easy.

Battery light is on.

MAYBE the Alternator died.

If it doesn't begin charging again...

[PatrioticSuperman]

Originally Posted by turf3

Probably battery's going south.

Could be alternator.

No modern car in good condition will have any problem with the small added electrical power draw of the AC system.

Think the heat killed it?

I just saw 8.25V with the car running so...

Maybe even the alternator but not the battery..

Battery light is on
and CHECK CHARGING SYSTEM message.. which has come on intermittently in previous months too...

[tickyul]

Yeah, sounds like a charging-system failure.

[rstevens62]

Air conditioning systems take more power in modern cars than most people assume!


Try turning the A/C on in the middle of going up a steep incline and listen for it to 'kick in'...and notice the reduction in engine power as a result, they may not take much electricity, but that A/C pump is being powered by the serpentine belt.

[PatrioticSuperman]

Yep.

My car had all the signs of a "slow alternator death."

Burning smell.
Sounds like a supercharger. Hint: A 3.0 Vulcan does not have a Supercharger (it's a pretty good engine though. Never had a 3.0 Duratec. Which is one of Ford's best engines, of all time, ever. I think the Vulcan 3.0 is too but hey.)
I thought I had other issues.

Now, this morning I hear the alternator beating. Quieted with WD40..

It awaits an alternator at this time.

[JONOV]

Originally Posted by turf3

Probably battery's going south.

Could be alternator.

No modern car in good condition will have any problem with the small added electrical power draw of the AC system.

It's one of the two, it could be both.

Given the age of the car, I'd assume the alternator is bad. The age of the battery will tell you if it's a likely culprit too.

[V8 Vega]

Better get it fixed fast before you get stuck somewhere.