Alternator charging - running A/C (1 Viewer)

[Alron67]

Is it normal for the battery gauge to drop to just over half when running the A/C? We rarely use the A/C so I'm not positive.. My alternator went out and killed my battery bout a year ago on a trip. I replaced my alternator with an autozone unit (that's what was available at the time). Last weekend on a short trail, I notice the battery gauge drop to bout mid way (bout 10 or so) when at idle with the A/C on in trail traffic. When I rev the engine to bout 1200 rpm, the charge would go up a bit but not much...all wires and connections are in decent shape. Do I just go back to an OEM alternator or do the Sequoia upgrade already. PFA TIA

 

[flintknapper]

If by 'Battery Gauge' you mean the Voltage Meter on the dash....I don't know that I would trust that necessarily. Better to put a multi-meter on the battery to check resting voltage and also check the output of your Alternator.

Typically, with increased electrical load the alternator will try to produce MORE voltage...not less (but not to exceed 15 volts or thereabouts).

The OEM 80 amp alternator is quite reliable (I'm still running my original at 325K miles) with only the brushes and one bearing replaced.

But IF you have a lot accessories that you run simultaneously or a single high draw item (winch) then upgrading might be a good idea. If you run dual batteries (hopefully isolated) an upgrade makes sense as well.

 

[george_tlc]

^ it's a voltmeter, not ammeter (in the dash)

And yeah, put a real multimeter on the battery to see what the voltage really is when the AC is running. The AC compressor will pull a bunch of amps when the magnetic clutch activates.

'Usually' replacing the brush pack on the OEM alternator takes care of problems.

cheers,
george.

 

[flintknapper]

^ it's a voltmeter, not ammeter (in the dash)

And yeah, put a real multimeter on the battery to see what the voltage really when the AC is running. The AC compressor will pull a bunch of amps when the magnetic clutch activates.

'Usually' replacing the brush pack on the OEM alternator takes care of problems.

cheers,
george.

You are correct. Old brain of mine 'farted'. Edited my post.

 

[jonheld]

You said you replaced the alternator, but did you replace the battery as well?
A flooded cell battery will not come back to 100% after a full discharge.