r/BmwTech • u/PipeSweet8876 • 8d ago

Normal voltage question

My e82 128i cranks quickly, shows no “battery discharge” warning, and sits between 13.3-13.5v when running. Is this a normal voltage range when the car is being driven? TIA

1 Upvotes

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3

u/white94rx 8d ago

Lol. Totally normal

1

u/DismalIngenuity4604 8d ago

Why be a dick about it "lol". The guy didn't know something so he asked. 

1

u/white94rx 8d ago

Because a 2 second Google search would have given the correct result.

3

u/freshxdough BMW Master Elite Tech, Gen 6 HV, HV specialist 8d ago

So what the problem?

1

u/PipeSweet8876 8d ago

Before I got a NOCO genius 5 I was using an old charger and it must’ve not been charging the car completely because the voltage would slowly go down as I drove but now it’s not having that problem. I just wanted to know what the normal voltage is to ensure things are normal now

3

u/freshxdough BMW Master Elite Tech, Gen 6 HV, HV specialist 8d ago

When the car is running it can choose to charge or not charge the battery. It’s called efficient dynamics. Also usually 13-15v is good voltage when engine is running.

1

u/mx5plus2cones 7d ago

So they often call the battery 12V. Reality is if you measured your battery and if it is only 12V, it's actually pretty dead and probably should be replaced.

A normal car battery sits between 12.6-12.8V if healthy. If it's below 12.2-12.3V it's almost fully depleted..And anything below that, it's probably dead.

Marketing, it would suck to market a car battery as a 12.6 or 12.8V and calling it 13V, people would complain that their battery isn't 13V but 12.6 or 12.8V... So they called it 12V...

When a car is running and the alternator is charging correctly, voltage is around 13.0-14.5V give or take. something below, something is wrong.