[mark48]

hi fellas any idea what voltage my 4ltr alternator should be putting out as im not sure this cars killing me :doh:

 

[The Mad Hat Man]

14.7 . see the alternator thread in the FAQ section

 

[sandyt]

check the voltage at the alternator and then at the battery the leads from the alt to starter and starter to battery corrode internally if you get a voltage drop it causes all sorts of problems I had to replace mine and problem solved

 

[Datatek]

If the battery is duff, you may not see 14.7 volts at the battery even if the alternator is good.

 

[sarstad]

whwn i look atmin i get 13,6v on the bat is that to lov???

 

[wammers]

whwn i look atmin i get 13,6v on the bat is that to lov???

It depends on the batteries charge state. The alternator does not generate 14.7 constantly, if it did it would boil the battery. I think charge rate should vary between 13.5 and a max of 14.7 when the battery is under load, Eg headlamps on. It will also be high just after starting.

 

[Datatek]

whwn i look atmin i get 13,6v on the bat is that to lov???

Yes if the battery is good and you have had the engine running for a while.

With the engine off, the voltage at the battery will drop to around 12.8volts. After starting the engine the volts should rise slowly and eventually reach 14.7 volts. If it doesn't reach 14.7 volts, there's 3 possibilities.

1) A duff battery.
2) High resistance connections to battery, alternator or chassis.
3) Duff alternator.

 

[Datatek]

It depends on the batteries charge state. The alternator does not generate 14.7 constantly, if it did it would boil the battery. I think charge rate should vary between 13.5 and a max of 14.7 when the battery is under load, Eg headlamps on. It will also be high just after starting.

Voltage stays up, but current drops right down.

 

[wammers]

Voltage stays up, but current drops right down.

Not according to my all singing and dancing alternator/battery tester. This has a row of six leds 5 volts (low) 12 volt (medium) 12.5 volt (normal) that is for checking battery without engine running. Then 13.5 (low) 13.8 (normal) and 14.5 (high) for use with engine running. According to instructions as i recall (i lost them years ago) with engine running 13.8 should be lit. 14.5 may flicker for a few minutes after startup but charge should drop back to 13.8. With headlamps on 13.5 should be lit but at 2000 RPM that goes out and 13.8 should come on. It works for me.

 

[The Mad Hat Man]

Alternator Troubleshooting

 

[wammers]

Alternator Troubleshooting

Much the same as my little tester then.

 

[The Mad Hat Man]

erm

possibly

 

[wammers]

erm

possibly

Almost exactly i would say. At least reference the charging rate.

 

[mark48]

thanks for all the feedback guys its all been useable seem to be getting just about what you have all said cheers

 

[mikky140]

My rule of thumb 13.5v with the engine running all well and good. 14.6 up and I'm looking for signs of a frazzled battery, eggy smell. If so alternator u.s