How Store Car Battery

The design of a car battery has not changed very much at all in the last 60 or 70 years. Traditional car batteries contain a mixture of sulphuric acid and distilled water, with plates and terminals to allow electricity to travel from the battery and into the circuit.

Because car batteries contain acid, they must be transported and stored carefully. The acid can be incredibly damaging to the environment, and to humans, if it leaks out of the battery. In addition, car batteries will lose their charge – and can even freeze – if they are not cared for properly. These tips will help you to look after your batteries properly.

How to store a car battery for winter?

If you know that you aren’t going to be driving your car during the winter, then it’s a good idea to disconnect it from your vehicle, and bring it indoors.

For best results:

  • Make sure that the battery is fully charged before you store it.
  • Disconnect the battery from the car.
  • Perform a full visual inspection to make sure that the battery is in good condition.
  • If the battery is cracked, leaking or bulging, then handle it with care, or, preferably, call an expert to remove it and dispose of it for you.
  • Clean the top of the electrodes to remove any corrosion.
  • Check the fluid levels, and fill the cells to the required level with de-mineralized water if necessary.
  • If possible, fit a smart charger to keep the battery’s power level topped up as much as possible while the battery is in storage.

How long can car batteries be stored?

Ideally, you wouldn’t “store” your car batteries for too long. The best way to make a car battery last for as long as possible is to use it. Going for a 30 minute+ drive at least once a month will help to keep the battery’s charge topped up. Ideally, you should not leave a car parked and unused with the battery still in it for longer than two weeks, because the natural ‘parasitic discharge’ of having the battery hooked up to the car will make it discharge very quickly.

The natural rate of discharge for a car battery, simply by existing, can be between 1% and 25% per month depending on several factors, including:

  • The age of the battery (older batteries discharge more quickly)
  • The ambient temperature (extreme heat or cold means faster discharge)
  • The level of charge (the lower the current level of charge, the faster the discharge)
  • Whether the battery has ever been “frozen” (damaged batteries discharge more quickly)

Storing a battery in your home or garage is better than leaving it in a car, but there is still the risk of the battery discharging and then sulfating. Do not leave a car battery unused for more than a couple of months, if at all possible.

How long can new car batteries be stored?

Even brand new car batteries will lose charge over time while they are sitting on the shelf. When you are buying a new car battery, be sure to check the date of manufacture, which is printed on the battery. Most retailers will send a battery back if it has sat on the shelf for a year, and aim to sell batteries within nine months. If you have a choice, try to get a battery that is less than six months old.

Can you store car batteries on concrete?

There is a long-standing myth that you cannot store batteries on concrete. The reasoning behind the myth is that the cold concrete will damage the battery and cause it to discharge more quickly. This is incorrect, but as with most old-wives tales and misconceptions, it is based on some truth. The original battery designs from the 1950s featured glass vessels full of acid, that were encased in a wooden box that was covered with tar. If the wood got damp (as it would, if it were left on a cold, damp concrete floor for a long time), then it would expand and crack the glass.

Modern batteries are made from plastic instead of wood and glass. This means that they can safely be left on a concrete floor. In fact, concrete is actually a better option than many other surfaces. If a battery is left on a cold floor in a room that is otherwise warm, the battery can sulfate because of the difference in temperature between the upper and lower parts of the cells. A cold concrete floor will usually keep the ambient temperature relatively stable for the whole area surrounding the battery.

The best place to store a battery is a fairly cool (but not freezing cold) environment, where there is not excessive moisture that might cause corrosion of the terminals. So, on the floor in a clean, cool garage is a good option.

Can you store car batteries on indoors?

You can store car batteries indoors, but it’s best not to store them right next to a heat source, because extreme heat can damage the battery. The cooler the room, the better, as long as it’s not so cold that the battery will freeze. In addition, try not to store them on an unstable surface, or anywhere that a child or a pet is likely to get access to them. Battery acid is incredibly dangerous, and could cause severe burns, or even blindness, to a child if they are exposed to it.

Keep your batteries on a counter, or in a room that children aren’t allowed to play in, so that they are left undisturbed as much as possible.

Wherever you decide to keep your battery, try to hook it up to a battery conditioner that will monitor the charge and gradually top up the battery when necessary. This will help to ensure that the battery doesn’t completely discharge – reducing the risk of sulfation and reducing the risk of the battery freezing too. Ideally, try to use the battery for 30 minutes every few weeks, and do not keep it in storage for more than a few months at a time.

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