An AGM deep-cycle battery is a sealed lead-acid battery that uses Absorbent Glass Mat (AGM) technology to deliver steady, sustainable power over extended periods and can be repeatedly discharged and recharged.
The term AGM deep-cycle battery combines two distinct technologies: AGM and deep-cycle. AGM uses a liquid electrolyte that is typically absorbed into ultra-thin fibreglass mats between the lead plates, making the battery spill-proof, leak-proof, and completely maintenance-free. By contrast, a deep-cycle battery is built with thicker lead plates designed to be safely discharged and recharged without damage.
When choosing an AGM deep-cycle battery for a compressor, match the battery’s power output to the compressor’s startup surge and continuous power draw. A compressor draws heavy electrical loads at startup, so an incorrectly sized battery will quickly overheat or trigger safety shutoffs. Let’s explore how to choose an AGM deep-cycle battery for an air compressor.
Calculate the Required Amperage
Choosing an AGM deep cycle battery begins with calculating the air compressor’s required amperage. Check your air compressor’s specifications for its amperage. However, an electric motor typically requires 3x to 5x its running amperage for a split second to start under pressure.
Additionally, if you are running a 120V AC compressor and an inverter on a 12V DC battery system, you must multiply the AC amperage by 10 to determine the DC amperage draw from the battery.
Evaluate Key Battery Specifications
Once you have calculated the battery voltage requirement, the next step is to evaluate the battery’s specifications. When choosing an AGM deep-cycle battery, look for two key ratings: Marine Cranking Amps (MCA) and Amp-hour (Ah) capacity.
The battery must meet the MCA requirements. Although deep-cycle batteries are designed for continuous discharge, a compressor requires a hybrid battery or a heavy-duty AGM battery capable of handling high momentary surge currents without significant voltage drop.
Amp-hour (Ah) capacity determines runtime. For example, a 100Ah battery can theoretically deliver 5 amps for 20 hours, but for heavy inductive loads such as compressors, a higher Ah rating, such as 100Ah to 200Ah, is highly recommended.
Factor in the Depth of Discharge
To maximize the lifespan of an AGM battery, you should avoid discharging it below 50% of its capacity. However, if your calculations indicate the compressor needs 50 Ah for your specific task, you should purchase at least a 100 Ah AGM battery to safely meet that demand without damaging the cell chemistry.
Match with the Right Inverter
This is the final consideration when choosing an AGM deep-cycle battery. Match your battery to the right inverter. If your compressor plugs into a standard wall outlet but runs on your battery, your battery’s charge won’t handle heavy loads on your inverter. Thus, you need to use a pure sine-wave inverter because modified sine-wave inverters can overheat and damage energy-efficient air compressor motors.
Champion Air Compressor
Choosing the perfect AGM deep-cycle battery will be useless if your air compressor is malfunctioning or has damaged parts. Before you choose a battery, replace any worn or damaged parts with Champion air compressor parts to maintain your compressor’s performance, ideally before adding the battery.
Bottom Line
Choosing an AGM deep-cycle battery can be challenging, but following the steps above, such as calculating your required voltage, evaluating battery specifications, considering discharge factors, and matching the right inverter, makes the process much easier.