Electicity Question?

[1969Mach1]

Hey I just got a quick question about my 69 Mach 1, I noticed that the battery dies quickly (when car in auxilery). Is this a common problem on the old cars? Like I can't play my radio for more that long without my battery dieing. I was wondering should I change the battery or alternator? or both? if so what kind of battery and alternator.
Because I'm looking to put a CD player in and a good set of 6x9's that will take up alot of juice and at gas prices I can't afford to let my car run when I want to listen to music for abit.

Thanks,
Sam.

[rollin68]

How long do you play it for...In my 68 I have a direct replacement battery, and the stock alternator, and I can run 740 watts thru 4 speakers and a 12" inch sub for at least an hour with no problem...it would prolly last longer I just have never done it, so you should at least be able to last that long...if not have yer battery, alternator, and voltage regualtor tested cuz its prolly one of those...I real quick way to test if its the alt is to have the car running, and take off the positve terminal to the battery, and if the car shuts off its prolly the alt...good luck, hope this helped

[Gearhead999]

Don't pull the cable off an alternator car while it's running to check the output. That is a QUICK way to burn the alternator up. Works with generator cars OK.

Just get the battery and charging system checked by someone with the equipment.

If it only happens with the radio and the engine isn't running. I would check battery and also the radio draw.

[nicolette]

hiya,
well my stang doesn't have this problem as i am restoring it and there isn't any radio yet! i can tell you though that my dads old '83 grand marquis has exactly the same problem. if you leave the lights or the radio on for more than say 10-15 minutes, the car won't even turn over. sorry i can't help ya , but at least you arn't the only one!

[Clark Rodgers]

Sam,
I would go for the battery, if the battery is in good shape you should be able to leave your lights and radio on for a couple of hours. Newer cars have alot more electronics and have a harder time with this.

[1969Mach1]

Yeh the battery looks quite old I think I will change that but now my parents may make me sell my car cause I got into a accident today (Check Blue Oval Lounge)
Well I think I may convince them to let me convince it if I get my licence back and can get two jobs to pay off my debt.

[mustangman65_79]

I don't know about your mustang, but mine when I turn it to ACC, the heater fan comes on too, and that can run down a batt really fast. Trust Me. Also an old batt is no good either, thats what it sounds like.

[PKRWUD]

The older a battery gets, the shorter it's reserve time becomes. When you buy a new battery, look for one with both high CCA's (Cold Cranking Amps) and a long reserve time.

Take care,
-Chris

[1969Mach1]

Thanks for the help. Now I seem to have alot more expenses. (my accident is going to cost me like a $1000) so I gotta hold off on some of the toys I was expecting to get. Ohh... well I'm not going to be driving tell next summer atleast anyway so no biggy. I was just curious.

Thanks All,

[70_Nitrous_Eate]

Originally posted by rollin68
How long do you play it for...In my 68 I have a direct replacement battery, and the stock alternator, and I can run 740 watts thru 4 speakers and a 12" inch sub for at least an hour with no problem...it would prolly last longer I just have never done it, so you should at least be able to last that long...if not have yer battery, alternator, and voltage regualtor tested cuz its prolly one of those...I real quick way to test if its the alt is to have the car running, and take off the positve terminal to the battery, and if the car shuts off its prolly the alt...good luck, hope this helped

Jeebus, what kind of battery do you have and how are you pushing 500+ Watts into 1 sub?

I've got the best battery I could buy from my local autoparts store (1100 CCA). And it'll only run my 1000W - 3 Subwoofer system for approx 10-15Min.

[rollin68]

70 nitrous eate...It's an Xide 840 I believe (I'm away at school durin the weeks , but I get to drive the car on the weekends )...also, I have only 400W going to a 500W 12" sub, but it does seem like it could be too much...the other 340 is going to 2 6x9s, and 2 3x5s...yer system is prolly a lot more powerful, figuring you have 3 subs with the Clarion...what type of alternator do u have?...I had the powermster 160 amp, but when the amp and sub were installed, the little wire that runs to the thing that hooked up to were the voltage regulator was, was hooked up wrong, and it ran the alternator bad...it has a year warrenty, but I was wonderin if you had good experience with another alt...nice car by the way

[70_Nitrous_Eate]

Cool,

I swapped in a 130A G3 Alt from a 98 stang. Pretty common swap for us classic guys. Do a search if you're interested, I'm sure there's a article or two out there...

[1969Mach1]

Nice Nice, I just want to put a nice deck in and a set of Infinity speakers in the rear and change the 1 centre speaker. But I got alot of things I am working on right now so I still have tell summer before I drive that and maybe even part of summer cause it is going to get painted.

[JeffDoyle]

I just joined and read this thread through from your original query about poor battery life in accessory mode. Everyone who posted addressed my concerns, and then some, quite well (and to reiterate, NEVER pull a circuit while the car is running...bye bye alt diodes). ANYWAY, here's my background and spin:

I own my 3rd and 4th Mustangs, a 65 fastback and 91 GT Ragtop, having owned another 65 fb and a 68 GT/CS some 20 years ago. Now, I have also seen the exact set of circumstances in all years of cars due to one OTHER factor: hick wiring.

What I am suggesting is the liklihood some of your leads are fused within the insulation due to current or previously "hot wired" circuits (foil wrapping fuses). If this is the case, the circuit only goes to ground when the car is on or in acc.

In the former case, the alternator is compensating for the draw to ground. BUT, a small dead short will eventually kill your alternator just as if you pulled the battery cable. ANYWAY, I am positive you have a short that only exists when the key is on, otherwise your battery would die overnight.

Startby re-fusing the entire panel using the EXACT rated fuses listed in the manual. Trouble shoot all circuits that burn...and don't be surprised if they are all key-switched (eg acc).

Good luck