2016 vw gti AGM original battery still works?
I have a 2016 vw gti I got new with original oem AGM battery. car will be 5 years old in april 2021. (not sure when battery made, havent pulled it to see date code)
-took vacation for 1 month, come home, slow start, but it works
-drive 45 miles, stop at autozone, tester says 50% charged, go home and charge to 100% then come back to test
-i drove to some stores, then home, then put digital battery charger on at 3amps set to AGM, charger said 77% when i started
-3 hours later at 100%, leave it on 3amp all nite
-next morning still reads 100%, i check voltage, 12.83 volts, i drive 45 miles and stop at autozone again
-same guy, same test machine, says BAD BATTERY and charge at 83%, hmm..only 83% after starting morning with 100% and driving 45 miles?
-guy has me start car and his tester says my starter is FINE
-guy runs test on alternator...not putting full amps to battery..says HMM.....might be alternator or battery bad and alternator is 'smart' and wont give battery more.
-guy says START WITH NEW AGM battery, then test alternator next
-go home charge to 100% again, battery voltage 12.83 volts with charger removed...NEXT MORNING check voltage and its 12.3volts and all the car did was sit all nite