question about AC and battery dying
question about AC and battery dying Hey everyone, seems lately, still testing this theory but for some reason my AC has been making my battery die, so when I shut car off, will not restart. Need jump start. I figured this out today, so going to drive with AC off for a few days 
and see what happens.
Only thing I can think of is I did my own tuning with HP Tuners, and with AC on I think idle is set to 900rpm, so maybe rpm dipping too low with ac on??? Any opinions on this? Could AC compressor be going bad?
and see what happens.Only thing I can think of is I did my own tuning with HP Tuners, and with AC on I think idle is set to 900rpm, so maybe rpm dipping too low with ac on??? Any opinions on this? Could AC compressor be going bad?
Launching!
Joined: Mar 2004
Posts: 202
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Hi: I would have the battery tested on a load tester first before you do anything else. I think autozone, and some of the other parts stores will test it for free. Check the fan belt for wear and proper tension. If the idle was set to low and you were stuck in traffic it might not charge enough. I doubt that is the problem though. Probably the battery is starting to go. Good Luck.
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I agree with above about it being the battery....you got 4 years out of the original AC delco....Been in the service/repair business for years and that is an average track record for almost any battery.......
Update, swapped alternator. Getting car repainted, and am about to swap battery. Seems like once my voltage starts dipping down car starts wanting to overheat too, see it getting as hot as 230 degrees. I can't put my finger on what is going on. Anyone have any ideas? HOPE the battery swap does the trick.
The AC makes both cooling fans go on in addition to the AC blower. This is a major power draw and either a bad alternator will not keep up or a bad battery is draining much of the alternator output. It is also possible that there is some kind of short in the AC system but my guess is the system would not work properly if this was the problem (does the AC work right?).
The power loss is probably not your idle. I run 750 idle on my A4 and with a 25% underdrive crank pulley I don't get a full charge at idle and I still maintain power. The discharge rate is simply not fast enough to affect the battery charge unless you sat at idle with everything on for a LONG time.
When you loose power from the bad alternator or battery, there is probably no longer enough to run both cooling fans and your car heats up as a result.
What is your volt meter reading with the AC off and with it on?
Steve
The power loss is probably not your idle. I run 750 idle on my A4 and with a 25% underdrive crank pulley I don't get a full charge at idle and I still maintain power. The discharge rate is simply not fast enough to affect the battery charge unless you sat at idle with everything on for a LONG time.
When you loose power from the bad alternator or battery, there is probably no longer enough to run both cooling fans and your car heats up as a result.
What is your volt meter reading with the AC off and with it on?
Steve
Originally Posted by Michael Ozorowsky
Reading 14 volts, but when I start driving around is once it starts acting up. I'm running M6 now, converted A4 to M6. AC works FINE. I'm confused.
Steve When sitting there at idle. I drive around for a bit, sometimes stomp on the gas, go check and volts are at like 10 or 11. ALSO dunno if related, been doing this for a LONG time, but if I floor car, let off and listen CAREFULLY I can hear my horn chirp. REALLY faintly but it chirps. WEIRD.
