Hi, not sure where to post this but i thought chemistry would be the place for these batteries. My car battery is 4 years old and have been checking it out. Firstly it's charged as much as it can be , the car does long runs 600 miles a week . Lights etc are never left on so it's never run down. The terminal voltage at rest won't go over approx 12.45v. It's not reaching the 12.6 it's supposed to. I put one of them conductance testers on it that measure CCA's. The battery is rated at 570 and it reads just over 400 with the red fail light. A different tester said battery ok but recharge ( but is charged)..
I checked with a hydrometer( green for good, white for fair and red for rercharge), the cell on the end - side reads the lowest into the white at 1225 SG, the rest are are just into the green section i think around 1250 ish.
Does this battery need replacing? The funny thing is though i did a crank test on it one morning at around 32 degrees F. The car was lying up all night. I disconnected a relay to prevent it starting and i cranked for around 15 seconds. It cranked really good and never started to lose momentum so to me the battery seems ok. I'm just confused by the readings i'm getting with voltage etc., anyone know about these batteries on here,