Battery Care Maintenance & Off-Season Storage | BSLBATT

We get a lot of questions about how to properly store batteries. Let’s break down the real do’s and don’ts for storing your batteries in the offseason.

Some old batteries may not accept a charge and will heat up on charging.

CAUTION: If at any time the battery gets hot (above 125 degrees F) or acid comes out of vent caps, STOP charging. Have your battery checked？ Charging may not be possible？ It may have to be replaced.

CAUTION: If you feel your battery is not charged after these times, have it checked. Charging for longer times may damage your battery. Stop charging and have the battery checked.

Do: Get It Clean and Keep It Clean

Dirt and corrosion can increase a battery’s discharge rate. It’s important to clean the battery casing and the terminals thoroughly before you connect anything to it and throughout the battery’s life cycle. As long as you properly cleaned the battery before you store it, you should be able to just keep it clean and dust-free with a clean dry rag for dusting.

Don’t: Put Your Battery In Storage Without a Charge

One of the worst things you can do is store a battery away for a few months without charging it. All batteries have a natural rate of self-discharge. By not charging the battery fully first, you are just asking to come back to a completely dead battery that can’t be revived.

Do: Make Sure It’s Completely Disconnected

If you’re not planning on removing the battery completely from the equipment it’s connected to, you’ll need to make sure that the battery is disconnected from any and all terminals. It’s important that nothing touches the battery terminals that could potentially create a discharge.

Don’t: Forget To Plan For Off-Season Charging

Whether you will be using a trickle charger or just simply hooking up a standard charger every so often while the battery is in storage, it’s important to make sure that you have the charger you need and that it is in good working order.

There is virtually no self-discharge below about 4.0V at 20C (68F); storing at 3.7V yields amazing longevity for most Li-ion systems. Finding the exact 40–50 percent SoC level to store Li-ion is not that important. At a 40 percent charge, most Li-ion has an OCV of 3.82V/cell at room temperature. To get the correct reading after a charge or discharge, rest the battery for 90 minutes before taking the reading. If this is not practical, overshoot the discharge voltage by 50mV or go 50mV higher on a charge. This means discharging to 3.77V/cell or charging to 3.87V/cell at a C-rate of 1C or less. The rubber band effect will settle the voltage at roughly 3.82V. Figure 1 shows the typical discharge voltage of a Li-ion battery.

Figure 1: Discharge voltage as a function of state-of-charge. Battery SoC is reflected in OCV. Lithium manganese oxide reads 3.82V at 40% SoC (25°C), and about 3.70V at 30% (shipping requirement). Temperature and previous charges and discharge activities affect the reading. Allow the battery to rest for 90 minutes before taking the reading.

Li-ion cannot dip below 2V/cell for any length of time. Copper shunts form inside the cells that can lead to elevated self-discharge or a partial electrical short. (See BU-802b: Elevated Self-discharge.) If recharged, the cells might become unstable, causing excessive heat or showing other anomalies. Li-ion batteries that have been under stress may function normally but are more sensitive to mechanical abuse. Liability for incorrect handling should go to the user and not the battery manufacturer.

There’s nothing more frustrating than to check on your batteries and find out the charger you have isn’t working or isn’t an effective charger for your battery. A battery that has been kept charged throughout its lifecycle will last longer and perform at peak levels throughout its lifespan.

Do: Keep An Eye On The Environment

While not storing your batteries on a cement floor isn’t really an issue anymore, it’s still the safest bet to keep it off the ground and in a temperature controlled environment. Moisture and extreme temperatures are a sure fire way to increase your batteries rate of self-discharge.

A good rule of thumb is to store the battery above 32°F and below 80°F.

Do Charge the battery before putting back into use.

● Tips for Battery Maintenance
● Batteries will lose power in storage and may need to be recharged every three months.
● The charge voltage should not exceed 15.0V during usage.
● The battery should be fully charged after a discharge. It should not be kept under the discharging situation.
● The battery connector contact points should be kept clean to avoid a short circuit. The battery should be kept away from fire.

Never lean over a battery when testing or charging. Exercise caution when working with metallic tools or conductors to prevent short circuits and sparks.