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Replacing a gate motor battery with a lithium battery

According to the Elvey Group, it is possible to replace an existing gate motor battery with a lithium battery. However, the company cautions that it is important to use a lithium battery that has been specifically designed for the strenuous demands required by the gate motor.

Some of the points to take note of when selecting a lithium battery include:

• High current. A typical gate motor can draw upwards of 25-35 A when the gate moves. This high current draw requires a specially designed cell and battery management system. The Uniross LFP12-7HD battery is designed with this exact requirement in mind. Uniross uses a customised 5C-capable cell, along with a battery management system, using components designed specifically for high currents.

• Charging: All gate motors have built-in chargers that were designed for the old lead-type battery. However, many people are unaware that the charging algorithm of an old lead battery and the new lithium batteries are the same; with the only difference being the voltage parameters for each chemistry.

Lead batteries typically have their charge voltages set to 13,8 V upper voltage, while lithium can be charged up to 14,6 V. Charging a lithium battery to a lower voltage (13.8 V) as provided for by the lead battery charger, is good for the battery and results in much longer service life.

• Temperature: Because the battery is housed inside the gate motor, which is externally situated, one needs to be aware of the effect of temperature on the battery. Lithium batteries have a wide operating temperature range (-20°C - +60°C) with charging temperature being (0°C - 40°C).

Because these batteries are backup batteries, they are constantly connected to the gate motor charger, and are therefore permanently on charge. If a lithium battery is exposed to temperatures higher or lower than the safe operating limit, it can cause damage to the battery. “Uniross Lithium batteries all come fitted with a battery management system (BMS). This electronic device constantly monitors parameters such as the battery temperature, and if it is exceeded, the system will automatically shut off the battery,” says Norman Clements, Product Manager at the Elvey Group.

Although South Africa does not have a terribly cold climate, there are still certain areas of the country that do drop below freezing in the winter months. In these areas, the charging of a lithium battery becomes a safety concern. If a lithium battery is charged at sub-zero temperatures, something called ‘lithium plating’ occurs on the anode, which can lead to safety issues.

Although many of the lower-grade lithium batteries do have a built-in battery management system, not many of them cater for low-temperature monitoring, making those batteries a significant safety hazard in colder areas.

Furthermore, in instances where the manufacturer has provided for low-temperature monitoring, a ‘low-temperature’ trigger usually results in the entire battery being shut off. In the case of a gate motor application, this could mean finding yourself locked out of your property in the dead of winter.

“The Uniross Gate Motor BMS is designed with this in mind and will not leave you stranded when the mercury drops below freezing,” says Michael Rogers, MD of Uniross.

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