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battery has high voltage


peteretep

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the battery in my escort is showing a red light to say check battery, and appears to be sitting at 13.8 volts when not being charged. i first found out there was a problem when i tried to start the car and it wouldnt turn over. i tried charging it with a trickle charger, but it has done nothing in the last 24 hours

the battery is a gold supercharge battery with 600cca, im going to take it back to the shop tomorrow and see about getting a new one (36tmonth warranty but i dont have a receipt) but what causes a battery to have high voltage? is it something in my car that did it? ive had my alternator checked out because the dash light doesnt work and apart from the light everything else worked fine

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A fully charged lead acid battery should be sitting around 13.8 V. Max charging volts should be 14.4 V.\

Basing it on that voltage I would consider the battery as sweet.

Maybe measure the voltage across the battery while cranking, see what happens. Should not drop any more than 2 volts.

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a fully charged battery at rest should be 12.6v!!! if its high it could be just coming down to 12.6 after being charged by alt.. r100's comment earlier about charging voltage 13.8 - 14.4 is correct. any higher than 14.5 would indicate a fault which could be due to a faulty battery or alt. If your alt charges higher than 14.5 you'll start blowing light bulbs and your battery will turn into a balloon.

P.S. warning light staying on while the engine is running would indicate alt fault (or regulator if external) or slipping belt. Or slim chance the wiring has shorted out. Definetly need to check volts while engine running (13.8- 14.5) may need slight rev to kick alt into life. then check with lights on to make sure the voltage stays about the same.... means regulator doing its job.

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hey thanks fo the input

i trickle charged my battery for 2 days and it was charged, normally when showing a 'clear light' it only takes a day to charge so something funny is going on there. But my battery sitting 5 mins after taking off the trickle charger was showing 13.8 volts, i then tried starting the car although still reading 13.8v and it started ok, i have not gone back and had a look at the voltage now.

i took a current reading off the battery when the car was off and the current was 2.4mA, is this considered ok? i have a feeling my multimeter has an accuracy of more than 2.4mA

just to be clear, when talking about the red light, am i talking about the little indicator on my battery, which changes color based on battery condition. My battery charge light on my dash does not work, there is a fault in my alternator which i have had looked at. the regulator does not work, but the rest of the alternator works as it should, sensing voltage and charging correctly, although maybe a little high, i think it charges at 14.9V

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a lot of alternators and external regulators need the power supply through from your warning light to 'excite' the alt into life..... might be as simple as a new bulb in your warning light, but i would be looking at fixing your warning light as that could fix your whole problem!

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ive completly rewired my car, had my alternator checked out, and checked my dash bulb which is ok, it is definately the alternator, the alternator is an almost new unit from a subaru justy, obviously the justy had some electical problems which is the reason they bought a new one and the bulb still blew

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