Energy, hardware, household technology: how long can a lead-acid car battery last unused?

This article’s focus is lead-acid car batteries: “battery”, “car battery”, or “lead-acid battery”, herein, means lead-acid car battery.

The following is by my understanding.

One might hear of a person taking a car for a drive to top up its battery, or that car batteries go dead sitting on the shop floor.

A lead-acid battery should always be charged to full before being stored. In such a case, it can sit idle for perhaps 90 days before it needs to be checked and potentially recharged. Permanent loss of capacity may happen if left longer.

In the case of a new battery, nine months seems to be the latest one can wait before putting it to regular use. The less fresh it is, the less storage a lead-acid battery can endure. Lead-acid batteries constantly lose capacity during storage.

Although it’s always worth checking before giving up on a stored lead-acid battery, I’d say that if it wasn’t fully charged when put into storage, one can’t count on it starting a car after three months.

Source:

dxiang (Apr 26, 2022). “How to Properly Store Vehicle Batteries.” https://www.midtronics.com/blog/how-to-properly-store-automotive-batteries/

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