14v idle voltage, 12@heavy load, normal?

[Sami]

Battery light flickering on often and sometimes stereo cuts out when too loud, checked the voltage across the battery earlier, it was 14v with no load, then 12v when I had on stereo, de-mister, hazards, rear+front fogs, full beam everything with a switch lol.

Does that sound ok or fcked?
Cheers

 

[Djw John]

Sounds fine to me

 

[Dink]

well if the engine is running it's shouldn't drop too far below 13v

other wise you are discharging your battery and it will die

90A @ 12v is only 1080W + you alt won't be able to do full output current at idle

 

[Rob Clark]

ye unless you have loads of after,market stereo stuff then 12v @ full load is a little low. you certainly wont be running for long like it. iirc alternator voltages should be ~ 13-14V @ 3000rpm

 

[Sami]

Hmm that was @ idle wasn't revving it at all... Could it mean a stuffed alternator, bad earth, bad alternator wire?

 

[RichMcc]

Yep 14 is normal for idle

 

[Rob Clark]

the higher the enginve revs = higher voltage produced from the alternator = higher voltage seen on bat. unless something is pulling it down like a larger load or iffy gnd / alternator

 

[Sami]

So 14v@idle is ok, but what about 12v@full load?

Does this mean the alternator is ok but wiring could be fcked?

 

[Rob Clark]

12v full load is ok iirc but at idle revs ? and is that with a standard or hoofing great massive stereo / amp / sub ?
it should be fairly rare all that lot are running simultaneously and is probably an indication that the system is overloaded. If your getting 14v at idle with no load then id guess your alternator is ok. If you have uprated the stereo then id suggest upgrading the alternator is u plan to run things that much. if not then perhaps an iffy gnd somewhere ?
Are you having any issues starting or just stereo cut ouut whilst driving ?
from memory that only used to happen when the feed used to drop significantly below 12v ie 8-9V

 

[Sami]

Nope standard stereo, battery light flashes pretty much everytime I drive the car now, sometimes stays on for quite a while

What could it be??

 

[Lagerlout]

Sounds a little on the low side to me wheilst on load. I reckon you may need a new alternator.

 

[Sami]

Hmm wiring is a bit crap in my car so wouldn't be suprised if it was that... should the wire from the back of the alternator run straight to the positive on the battery? Might try putting a wire straight across and see if it makes a difference...

 

[LRTom]

12V at full load? Sounds fine! And if you're seeing 14V at idle then you're alternator is doing it's job OK.

 

[Sami]

Hmm so why is the battery light flashing and stereo cutting out :S

 

[Dink]

with the engine running it shouldn't get anywhere near 12v

i get my system voltage to drop to 12.2v when i've got my subs up full tilt and that with the engine NOT running

i think most amps will cut out between 10-11v which is really killing your battery

 

[Sami]

So alternator is fubar'd then :S