high amps at idle, voltage drops as rpm's increase

[blackbonnie 5,000+ posts]

i have started my install and right now i am running 1 ia 20.1 for the time being until this weekend. i have noticed that my voltage sits around 14 at idle, and around 13.1-13.2 as im driving, is there a reason for that. doesnt the alt put out more as it spins faster. maybe i have it wrong but even if im not playing my system i still am sitting around 13. i have an 1800 under the hood and a batcap 200 in the back off my stock alternator. its on a chevy 1500 and i believe the stock alt is maybe 160. not sure but i am wondering why this happens. any answers?

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[blackbonnie 5,000+ posts]

ttt

 

[rumple4skin 10+ year member]

well i can tell you that your stock alt is not 160

 

[blackbonnie 5,000+ posts]

im not sure, what would it be?

 

[themommyvan 10+ year member]

Your stock is a 105

 

[MEMPHISFLEX 10+ year member]

Your silverado has the same size as my tahoe stock around 130-135amp alt, and your alt shouldnt be going out but not sure, kinda sounds like your alt is going out!

 

[blackbonnie 5,000+ posts]

its that low, jesus, well either way when im running my system at idle i dont drop much lower then 14...maybe 13.6 at the most. but when im driving and have my system off, its running at around 13. any ideas?

 

[MEMPHISFLEX 10+ year member]

Your stock is a 105

Ok i remember now he is right, the tahoes and suburbans are 130amp, they have more to power than the trucks i remember that now

 

[blackbonnie 5,000+ posts]

Your silverado has the same size as my tahoe stock around 130-135amp alt, and your alt shouldnt be going out but not sure, kinda sounds like your alt is going out!

its a 06 and i just hooked up the 20.1 last night and have never had problems with it before. you think the extra bat is putting alot of strain on it|?

 

[MEMPHISFLEX 10+ year member]

its that low, jesus, well either way when im running my system at idle i dont drop much lower then 14...maybe 13.6 at the most. but when im driving and have my system off, its running at around 13. any ideas?

Your alt is going out or you have a ground that is weak

 

[blackbonnie 5,000+ posts]

well i did my big 3 but was getting alot of whine resonating through the cab, not the speakers. so i took that off but still have the stock one. i am hooking that up to a diff. spot friday...you think that would cause it, just that one wire not upgraded?

 

[rumple4skin 10+ year member]

Your alt is going out or you have a ground that is weak

id have to say your alt is going out, if its a bad ground its got to be one from the big three or the exstra bat.

 

[rumple4skin 10+ year member]

well i did my big 3 but was getting alot of whine resonating through the cab, not the speakers. so i took that off but still have the stock one. i am hooking that up to a diff. spot friday...you think that would cause it, just that one wire not upgraded?

what did you take off??? i would make sure all your grounds are the same gauge wiring

 

[blackbonnie 5,000+ posts]

you think it would go out that fast, even though i have never had problems

 

[blackbonnie 5,000+ posts]

what did you take off??? i would make sure all your grounds are the same gauge wiring

the engine block to chassis, just the big 3 wire, the stock one is still there.