My car battery is getting old and I am ready to change it. However, I won't be able to drive my car for three months or more.

Should I change car battery now and let the battery sleep for three months? Does idling shorten a new battery's life? Or should I wait another three months and change later?


I think a question you need to ask is Will the current battery work for the next three months? Is it just time to change the battery, or is it currently failing to produce enough energy to start the car? If it can wait for the three months, my suggestion is to just wait.

A battery, whether new or old, if to let sit idle, will lose charge over any given length of time. If left long enough, permanent damage may occur to it.

Whether or not you decide to change out the battery, the best thing you can do for your battery is to put a "battery tender" on it. This will keep the battery fully charged and in tip top shape without fear of sulfation (sulfur crystals forming on the lead plates) which can happen when a battery is allowed to fully drain of its charge, which may happen if left to sit too long in a vehicle. When I say a battery tender, I'm not talking about running your battery charger on it at 2A, but rather, there are specific built tenders which will provide just the amount of amperage the battery needs to maintain it all the while checking the battery to ensure it is fully charged. These are a lot cheaper than a new battery and do a great job of keeping it fully charged.

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  • Yes, I'd like to know idling how long is too long to have permanent damage. Thank you for telling me "battery tender". Is it something like this amazon.com/Battery-Tender-021-0128-Maintain-Damaging/dp/… ? What is "2A" by the way? – Ying Jan 3 '18 at 5:25
  • The battery is about four years old and sometimes I can feel the engine did not start as quick as before. Both my dealer and auto shop told me it is on its way out. I want to change it sometime but not sure it is right now or wait. – Ying Jan 3 '18 at 5:38
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    @Ying - 2A is Amps. This is usually the lowest setting for a regular battery charger (at least ones I'm used to). Batteries are "usually" good for about 5 years. So, 4 years it's probably showing its age. Really, though, if it's still working at least acceptably, I'd wait the three months. – Pᴀᴜʟsᴛᴇʀ2 Jan 3 '18 at 7:36
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    Waiting 3 months will also give you an extra 3 months on the warranty of the new battery. – JPhi1618 Jan 3 '18 at 14:44

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