수리 사례

2026. 6. 30. 작업

증상

Do car batteries degrade when left charged, boxed and unconnected for long periods, e.g. in a shop?

처리 내용

All batteries have a self discharge rate. This comes form the inherent nature of their chemistry. Lead acid batteries are one of the worst offenders when it comes to their self discharge rate. The estimates are all different but between 5% and 20% of capacity discharge a month is the general consensus. Because the discharge rate is a function of current capacity the discharge is a decaying exponential. The battery will go flat eventually but the less charged it is the slower the rate of discharge is. Allowing the battery to discharge while in storage is not inherently bad. What is bad is allowing a lead acid battery to go totally flat, ie 0V. This is where the damage comes from. If the battery didn't go below roughly 9v I would not be concerned about its health.