Voltage drops?

[cris2216]

Before I got my new alt I was dropping to about 11.6 volts at full tilt with 2 optimas and stock alt and the amp is a hifonics bxi2610d and I changed the alt to a 250 amp alt and my voltage still drops to 11.9 what gives? All my wiring is knukonceptz kolosses and big 3

[Guest]

is your car on idle when you got that 11.9? if so, thats your problem. not many HO alternators can output alot of current at idle and you need to be driving for the alternator to output what it says it can.

[cris2216]

is your car on idle when you got that 11.9? if so, thats your problem. not many HO alternators can output alot of current at idle and you need to be driving for the alternator to output what it says it can.

yea it was in idle so I have to rev it to 2,000 rpm for 250 amps

[kmalinich]

what alt is it? i'd be curious to see what it produces at idle...

[Decaf]

yea it was in idle so I have to rev it to 2,000 rpm for 250 amps

if its a 250a alt it makes 250a max

more like 100-150a at idle

[kmalinich]

hmm 150a from the alt... 2 yellow tops... anyone know the AH rating on the yellow tops?

and what voltage does it make...

1) in the morning

2) at idle with the system off (ideally with your HU faceplate removed and all amps off)

[Team_DC-Derrick]

do you have a DMM hooked up to the batt to know its dropping to 11.9 or is it a volt meter hooked up to the radio? I used to have a volt meter hooked up to the radio and it would drop down low as well, till i changed it and ran it through my firewall to the battery and no more issues from that

[kmalinich]

yeah, the HU power line (especially in a factory harness) isn't exactly a high-current place to draw power from.. so it would show lower than normal..even worse when coupled with the factory HU ground..

or is really obvious like lights dimming, heating and cooling fan slowing down, RPMs dropping...

[stphating]

ah rating on the yellow top is 55, i got 2 yellow top with a dc power 270xp alt an my voltage stays at 14.9 at idle on a t2500bd