Customers often ask, “What type of battery works best with the Maxwell Engine Start Module (ESM)?” Since the Maxwell ESM handles the engine cranking, the number and type of batteries you need can be determined by the following factors.
CCA & RC MINUTE RATINGS
To begin with, once you install the Maxwell ESM, you no longer need batteries with a high cold cranking amp (CCA) rating since the batteries are no longer connected to the starter motor—only the Maxwell ESM connects directly to the starter motor. Industry experts familiar with the ultracapacitor-based ESM recommend batteries with a high reserve capacity (RC) minute rating. If you take a look at battery manufacturing datasheets, you’ll see that high RC minute rating batteries provide longer run times for onboard electronics when the engine is off.
The battery choices available today include standard flooded lead-acid, deep-cycle, or high-cycle batteries, and absorbed glass mat (AGM) batteries. Several battery manufacturers offer these types in a standard Battery Council International (BCI) Group 31 form factor for heavy-duty commercial vehicles. The specifications of several battery manufacturers reveal that standard flooded lead-acid batteries typically have higher CCA ratings and lower RC minute ratings. The deep-cycle or high-cycle batteries and AGM batteries will typically have a higher RC minute rating. Several customers install the Maxwell ESM with high-cycling or AGM batteries with great results.
Are you operating a heavy- or severe-duty truck with extra loads that need extended battery run time when the engine is off? Are you operating with minimal electrical loads? In either case, experts typically recommend high RC minute rated batteries. The number of batteries required in parallel with the Maxwell ESM depends on your engine off and parasitic loads. Maxwell has several vocational fleet customers operating with only one battery and the Maxwell ESM. These fleets have found that deep-cycling, high-cycling, or AGM batteries meet their requirements.
Electronic hours of service logging equipment, GPS units, telematics communication systems, and camera systems are prevalent today, as well. Sometimes drivers or fleet personnel connect these loads directly to the vehicle batteries without thinking about how the power requirements will affect battery life. Be sure to consider all of your loads and then determine the type of battery that best fits your vehicle’s needs.
Fleet maintenance personnel should fully understand their overall power requirements and select batteries based upon their parasitic load and add-on aftermarket equipment current requirements. It is also important to make sure the alternator is appropriately sized to recharge the batteries based upon your vehicle loads.
ABOUT THE AUTHOR
Jeff Brakley, senior marketing and business development manager, Truck, Heavy Transportation, Military, and Aerospace, has contributed to the development of the ESM from its inception. He serves on the S.1 Electrical and Instruments Task Force and recently contributed to the SAE J3053 Task Force to develop the Heavy-Duty Truck Electrical Circuit Performance Requirement for 12/24 Volt Electric Start Motors Recommended Practice.