Voltage from alternator?

Pauliil1948 said:

Hi guys, a few things went of in my evoque 2017 ,
No heater , radio, heated seats, checked alternator it was putting out 13,6 , disconnected battery and that was at 11.2 , so new battery on everything working for a day then nothing again , so put the meter back on the alternator left it on and the charging was at 13.5 and slowly dropping to 12.45 , so I am looking for a bit of expert advise from you guys , thanks for any help,

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Datatek said:

Either the alternator has failed or there is a bad earth engine to chassis, corroded positive connection or such. You should see around 14.7 volts from the alternator immediately after starting, maybe more. Not sure, but you may need to tell the car that a new battery has been fitted, this would need diagnostics.

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kermit_rr said:

when you replaced the battery, did you tell the car it has a new one? the charging profile will be different old vs new

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Graculus said:

Did you replace the battery with the same capacity and chemistry? It sounds like the vehicle is using load management, which shouldn't occur with a new battery, even if the BMS hasn't had a reset. Be careful using voltages as a state of health indicator, charge management will allow system voltages down to 12.6VDC, provided it 'sees' the battery being 80% charged. The system voltage can be as high as 15.2VDC, dependent upon conditions so your 13.6VDC isn't abnormal - BUT, load management shouldn't be kicking in with a running engine and a healthy battery, as noted above, a poor engine ground connection, positive connection, or a defective alternator could be the cause, with the original depleted battery being a symptom. The alternator is controlled by the gateway module, so if you can, check for any DTC's ('fault codes') before anything else, depending on what, if any, diagnostic equipment you have, it may be possible to check the duty cycle and compare to specification.
I've attached an old version of the diagnostics - it's still valid as physics hasn't changed in the meantime, although the control systems have.

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Pauliil1948 said:

Thanks for advice, I will have to get it plugged in somewhere as I don’t have the diagnostic equipment

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