got problems, battery guage jumps like a madman

[camarozrule]

ya so its been 2 weeks ive been runnin my new sub system and now im having problems with the battery... it normaly reads at 12 but after 4 hours of cruzin when i stop it drops down to 9ish!!!. everything dims, and when i accelerate from stop theres this huge jump... it feels like gettin rearended... and when i was turnin on my street my power steering went and the car shut off. this happened 5 times one nite about 2 months ago i describe that in my "i borke down 5 times tonight" post. i think i need a capacitor and a new batery, what do u guyz think?
thankz.
depiction of battery guage: [img]graemlins/fluffy.gif[/img]

[ka50]

Either alternator or battery or both. Autozone/advance check them for free.

[CAMAROWIDBASS]

Wow dude your in desprate need of a HO alt and a new battery.

When the voltage drops down to 9 thats not good for the amp at all.

[3.4 slow to go]

Your stereo should not have more power than your engine ;) Have charging system checked & get boomer caps.

[95Batmobile]

Alternator took a crap.
Happened to me 3 times...

[camarozrule]

will a 1 farad cap cure my problem???

[Slave Labor]

It'll help. You should do 1 farad per 500W of power yo system be boomin' out, dawg.

[badandy247]

if you wanna really do it right buy a HO alternator (130-160 amp) and double up the charge wires and ground wires to the battery

first to do this you just need to run an extra length of 4 gague cable from your alternator to your battery and from the battery to the factory ground you do NOT need to remove any factory wiring from the vehicle to do this

second I'd replace the alternator with the high output model described above

in addition if you want extra protection against this ever happening THEN go with a capacitor but you won't need it if you do what I told you unless you're running a WALL of subs or something insane like that in your car

[strange_trp]

also make sure your power and ground wires to your amp are heavy enough for the distance you're running. with electrical circuits longer distance and smaller diameter both increase resistance which causes a greater load. this is especially nasty with high current circuits because of the excessive heat generated.
a hi output alt may help but a capacitor or two will solve the problem as well.

[96_Fbird]

if i have this same problem but my car doesnt shut off it just jumps alot and someone told me u can check your alt. by starting the car then takin off the neg. i think and if it still runs your good? this true and what could my prob be? o hey if you car is shuttin down like that that happened to mine it wsa the intake manifold and my batt. jumped back then doubt it is that but just throwing it out there

[strange_trp]

DO NOT UNDER ANY CIRCUMSTANCES remove either battery cable when the engine is running.
the battery acts as a big capacitor that will absorb voltage spikes before they can make it to sensitive modules like the pcm, ebtcm, bcm, etc. anybody that tells you to check alt by removing batt cable is shadetree at its best. not only can you felt something up, it can also be very misleading with intermittent problems.
DO NOT DO THIS. maybe on a 57 chevrolet with no electronics whatsoever, but nothing since HEI in 74 should be attempted to be tested like this.

[96_Fbird]

maybe i got the order wrong haha id uno my dad did it he s the one who told me bout it and it worked