Alternator voltage

Today I had a recurance of my electrical problems, so I tested the battery with the engine running at 3000rpm I'm reading around 13.9 this seems low to me? What should I be reading and would this voltage give me significant problems?

Normally with engine running would expect up around 14.2 to 14.7 could be an early indication of battery trouble

The battery is only 6 months old, so I guess the alternator is on its way out??

Simplest way to tell would be to disconnect the battery and charge it, modern smart chargers will charge at over 14 volts. What's the voltage with the engine off and headlights on?

? Forgive me , but how will that tell me what state the alternator is in?

A dead or shorted cell will be pulling the voltage down when the car is running. Measuring the voltage of the battery under load without the engine running should spot that. If it's maintaining around 12.4+ volts whilst being discharged then it's unlikely to be a dodgy cell (or battery) in which case I'd blame the alternator diode pack.

I see, I'll check it with lights on in morning

Mine measures 13.9 at the battery....and (fingers crossed) no electrical issues thus far!

it is the alternator regulator

Saint.V8 said:

Mine measures 13.9 at the battery....and (fingers crossed) no electrical issues thus far!

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Depends on the battery. These modern gell thingys need a good bit over 14 volt to charge them.

I've put a fully charged battery on this morning and still got electrical gremlins, the only fault registered by all comms is lcm error message in the instrument pack which cleared but didn't resolve anything. I'm contemplating getting diagnostics read at the stealers , although a local garage has autologic, does anyone know if there's any major differance between Testbook 4 and autologic?

dogsbody said:

Depends on the battery. These modern gell thingys need a good bit over 14 volt to charge them.

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They are not GEL in the L322 as far as I know, they are lead calcium and need between 14.2 and 14.7 volts to charge correctly.

Understand all the above, but mine reads 13.9 at the battery, and I have had no issues at all regards battery problems in the year I have had it!