lights dim down when i come to a stop.

[Jcomnislash]

i got a 91 5spd festiva with 140k km on it, and i recently got my altrenator rebuilt from 50amps to 90amps, i am running 2 weak pathetic 300 watt mono amps to power my 10 inch subs and thats all i got. I checked the voltage on my battery and its like 14, even when the system is completely off the lights still dim down a bit when i'm just idling, but when i rev it up the lights brighten up. What else should i check?

[stefan]

battery?

[Jcomnislash]

yeah, i checked the battery with a volt meter, and it just about 14...i'm gonna go and drive around for a bit and see if the battery charge changes after a long drive.

[Damkid]

get a volt gage and check it while driving and at a stop

[Jcomnislash]

so here are my findings, i drove for about an hour on the highway today. when i got home i checks my voltage with the car parked and everything on (engine fan, high beams, sound system, heater....etc)...the voltage went down to an average of 12.15 or so, when i hit the accelerator it would fly back up to 14.4 or so....i dont recall this dimming ever happening prior to my alternator being rebuilt, but maybe with only 50 amps it wasnt noticable, but with 90 amps it is.....what do u guys think?

[batstiva]

Loose belt??? Perhaps with a load ie high rpms, the tension is there, at low rpms it's not...Just a thought.

[Jcomnislash]

hmm, yeah, could be the belt. I put the alternator in myself so i'm sure the tension was nice and snug, i'll check it tomorrow....thanks for the tip batstiva.

[GenevaDirt]

either loose belt or faulty rebuild...?

[packrat427]

I thought my belt was tight , I had to tighten it 2 more times , before it stopped squealing .

Do your light just dim real quick and recover , or stay dim till you add some RPM's

I have a 150 amp on the Caddy , the headlights will dim real quick when I tap the brakes at a idle , and it is a fairly new rebuild .

[Jcomnislash]

well, mine doesnt squel or anything, but the lights stay dim until i give er some rpms.

[WmWatt]

Don't make the belt too tight or it will wear out the bearings in the alternator. I'd call the place where the alternator was rebuilt and ask them about it. They might want you to bring the car in to get the alternator tested. Or you can take the alternator off and take it to some auto parts store for a free, independent test.

[Jcomnislash]

yeah, i'm just waiting for my buddy to come back from vacation cuz i got it done at his shop. Hopefully i can figure this out soon cuz its kinda bugging me.

[Hot_Wheels]

put a cap in?

[Jcomnislash]

capacitor???....dont those only hold a small charge in case of power lag?????...when the car is off, the battery holds steady at 12V...i'm pretty sure thats normal, right?????

[Damkid]

yup that sounds normal to me