splescort

iTrader: (16)

i will double check the ground and yes i am sure it is droping that much i drove round with my digital multi-meter .
some thing else that has been happening. i use to be able to listen the the stereo with ther car off for round 30-45 min at high volume before the car would not start but twice i have listened to it a very low volume level for like 10 min and the car would not start i am starting to think battery went bad

splescort

iTrader: (16)

thats what i am thinking now is to take the battery out and get it tested and if it is done for then get a new one from the dealer underwarranty then sell it to get a deep cycle or some thing

scroudt111

I wouldn't add a second battery with a stock alt. it will just add more stain on your alt and cause it to die faster. get the battery and alt tested.

BIGEVIL

^^^^^

I agree. In a small system, the battery is only there to start the car.

kevmurray

Couple things: Depleting a normal (non-deep cycle) car battery several times will seriously affect it's longevity. If you have done this several times and it will no longer last half an hour at low volume, I'd say it's done. I learned this the hard way.

Regarding alternators, they are current limited and should not be damaged by running them at max output for long periods of time. Same goes for adding a second battery, no big deal for the alt. The regulator meters the field current, not the output current so there is less stress on an alt than it would seem. All bets are off with a cheap alt. I had a factory alt last 14yrs after installing a 1kW system. A $200 replacement lasted about 7 days. The next replacement was $300 and was still working when I sold the car years later. It came with a factory test sheet and 3yr warranty. Alternators are actually pretty simple devices and there is no reason they can't be built to last many many years. Go ahead and install a second battery if you want but I'll bet one fresh battery will cure your ills. Just don't drain the new one.

BIGEVIL

Well, except for burning up the brushes in a hurry. Also, running an alt at full output generates an enormous amount of heat. Heat might burn up the internals of the alt.

danyman

iTrader: (1)

i woundnt worry about getting burnt. the alt can only spin as fast as the rmp can, and can only produce so much amperage from the design, and when the amperage is depleted you get the voltage drop and the battery kicks in after. but allways depleting an alternator everyday every second will kill it from overuse and abuse

kevmurray

Yup, the faster the rpm the more power available and the more air passing through the alt. If an alt burns itself up the design was wanting. Before someone jumps on me, yes there are exceptions, Death Valley or the surface of the sun for example...

splescort

iTrader: (16)

ok well i check my ground and it was mint. i took the battery out and got it tested and it tested fine i took the alt out and got it tested and it was fine i put a new battery in and no change

do i did some experiments.

with the fuse out for the stereo.

at idle the car was at 14.41 at 2000 rpm 14.53 with notting on no head lights anything.

at idle with head lights 14.29 @ 2000 rpm 14.61
at idle with heater 14.31 @ 2000 rpm 14.63
at idle with defroster 12.87 @ 2000 rpm 13.81
at idle with heated seat 14.39 @ 2000 rpm 14.66

when i put the fuse for the stereo back in the idle went down to 14.40
and @ 2000 rpm it was 14.51

splescort

iTrader: (16)

and it is really only one song by ludacris that really takes the voltage down i can play just about any other song and the voltage does not go down much