Battery voltage at 15V

[mjollnir]

I have a strange issue with my battery

I did charge it for a few hours (it was low to 3V) and checked the water levels

After charging, I put the voltmeter on the poles and it showed an increasing value of 12V initially to more than 15V after 2 minuts

Should I throw it away or is there an explanation/fix to this?

[1963SS]

A voltmeter won't tell you much. You'll need to test it under a load and to see whassup. Of course you could just try to start it and see what happens. A good slow charge for a day and let her rip.

[iburke]

What are you charging it with, and at what rate???

[mjollnir]

With a car charger

But now I wonder if it's not my voltmeter going crazy, I will test with another one

[grumpyvette]

Most alternators fail when they can,t keep the battery charged , most defective battery's fail to maintain 12-13 volts or retain a charge, usually reading less than 12 volts or drop off very rapidly under load, If your getting over 15 volts at the battery Id suggest retesting, the first step would be to remove the fan belt temporarily for a short duration test, and start the engine with the MULTI meter to see what the battery is actually doing under load VS what the alternator is producing.
if the battery stays under 14 volts and only reads higher than 15 volt with the alternator connected its more than likely the alternators internal voltage regulator is defective

http://forum.grumpysperformance.com/...ternator#p8575

[mjollnir]

Sorry I had an Internet failure for a few days

I found the problem, my multimeter battery was low thus giving false readings (increasing and incorrect voltage)