Rep Power: 0

I have 2012 civic Lx. On my scanguage i bring up the voltmeter and it shows 12.0 volts with engine running. When i turn lights on it jump up to 13.9-14.0 volts.

I noticed this on my vacation trip to tenn. I did notice after stopping for lunch break and getting back on highway it was showing 14 volts till i got to families house.

The next morning it was doing same thing and thats when i found it went up with headlights on. Is this just something thats helps with fuel mileage and load on the engine or is it something to get checked out??

 
Rep Power: 243

Honda's have a system called ELD that adjust the output of the alternator based on load demands. I am sure the newer Honda's have it as well. Someone correct me if I am wrong.

 
Rep Power: 518

It's the ELD system. It can turn the alternator charging voltage up and down as needed. Honda has used this system for decades.

FYI for SOME 2012 Civic and CRV there was/is a PCM software update for the charging system, for the battery being undercharged in certain driving situations.