Voltage drop

That is far too high a voltage, it is likely that the alternator is faulty.

Agreed - bet your battery is fizzing away. Best dealt with asap.

Thanks. I thought so too! It would explain things like the corrosion that keeps coming back on the battery + terminal, the rubber hoses perishing nearby... but then I went and put a new battery in my voltmeter and it now reads 12.9V engine off, 14.2V engine on - which is more like normal, isn't it?

But the alternator warning light is still over-bright...

I nearly put are you sure your meter is OK !!

The revised readings are absolutely OK.

Take another reading after the battery has stood overnight and before starting the car.

The low idle would give a reduced charge and slightly dimmer lights at idle, that would be expected.

Assuming your battery is OK then I would wait and see what develops.

Mrcheerful

The volts look normal, never trust a DVM with an old battery in it. It may be worth checking the battery earth wire's connection to the body is clean, likewise the alternator may be in need of it's bolts tightening to get a better earth return, otherwise as said elsewhere you'll have to forget about it until something happens.

Op doesnt say what vehicle it is some vehicles do charge around the 16 volt mark

Digital meters often start reading incorrectly when the (meter) battery goes down.

Out of interest, which vehicles?

Chris

Yes, unless the vehicle was fitted with a NiCad battery, I would think it unlikely. Charging voltage has to be matched to the battery type, and as pretty well all have lead acid type, then the norm is a tad over 14 volts

Brian pretended :

Agreed - expect around 14.4v shortly after starting, the it will usually decline to around 13.8v. 16v will quickly boil a battery.

Which ones?

Dunno myself but I do recall a reference to some other batteries being fitted which require a higher voltage in a thread down there V somewhere

Yebbut nowhere near 16 volts!

Silver Calcium batteries, fitted to many cars since around 2000, *can* be charged at a slightly higher voltage. This is normally around 14.6 volts, compared to 14.4 volts for a standard battery.

Normal batteries should not be fitted to cars that have the higher charge rate; Silver Calcium can be used on cars that were intended to use standard ones.

Chris

My old 1983 Subaru GL had a temperature-compensated voltage regulator.

Corrected for temperature, 14.4V at 25ºC equates to 15.7V at

-10ºC.

John

Variations of lead acid batteries can require slightly different charging voltage - like 'calcium' types but this is only about 0.2 volts - not 2.

Don't know where the OP is but unlikely to be getting temperatures down to -10 at the moment.

And of course, unless some sort of other voltage regulation was also fitted, no lamp bulb would last more than a few hours, unless someone knows where to get special 16v bulbs.

:-)

I'm not sure the sensors, ECU, et al would survive either!

Chris

They might, as probably it is regulated down to 5v for the ecu etc.