Can anyone tell me the correct voltage across the battery when the engine is running on a 1999 saxo 954cc. I thougt the old alternator was overcharging and bought a recon unit, but its showing the same voltage as the old one which was approx 16.5 volts when running. Thanks in advance
14.5 ish would be normal with engine running. 16.5 seems a little high. What do you read on the battery when the engine is off?
Approx 14 volts which I think is about normal.
What is it with engine running and with electrical load - head lights on main beam, demister etc.?
Approx 16.5 volts
So you are seeing 14v when the engine is off, and 16.5 when charging. I would actually doubt your voltmeter here, as I would not expect to see more than 12.5v on a battery not on charge assuming it has been standing for half an hour or so. Can you double check this? What type of meter are you using? Digital meters can give incorrect readings if their internal batteries are low. Also is the car battery the type which you can top up? If so, check the electrolyte level. If it really is charging at 16.5 you will be boiling the battery dry. You would also be blowing light bulbs too I would imagine. Most battery suppliers will check your system for you , as will many car accessory places. If the battery elecrolyte level is normal, then
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