Battery Management Systems – The Hidden Evolution


Above: Enatel’s EM4X energy manager

by Charles Watson

Batteries are now ubiquitous with the capabilities and costs of the various chemistries well known. While the traditional lead-acid battery is far from obsolete, there are now price-performance choices for telcos, integrators and DC system designers where the safety and temperature range of ferrous phosphate cells can be considered against the energy density of lithium-ion options and so forth. Quality of cell, form factor, battery module design, and the international standards around them are now part of industry know-how with a multitude of vendors to select between. And the options will only proliferate in the not too distant future. Breakthroughs in sodium ion, aluminium oxide cells and other technologies are regular news, the potential of graphene and similar supercapacitors is well recognized, there are many possible entrants into the market going forward.

Yet amongst all the hoopla of energy storage technology development, there is a fundamental aspect of  system design of critical importance that cannot be ignored – the battery management system (BMS) incorporated into the battery. It is here, in the smarts of the battery, that when the lid is lifted we find a sad tangled mess of diverse communication protocols, wild variance in functions and safety features, and a complete lack of industry uniformity. Intelligent battery management is at the heart of modern efficient DC system design. Knowing the battery chemistry is not the full picture. In application, a BMS no longer means just monitoring a lead-acid battery string but effective control and reporting of all aspects of a battery’s performance.

However, this complexity of electronic design integrated into a battery carries its own risks. Bugs are inevitable, which in turn demands the ability to upgrade the battery BMS firmware remotely.

Then there are other issues. Individual battery vendors have little consideration of a DC system design that might wish to incorporate multiple battery chemistries and/or multiple voltages or even simply multiple strings.

Which brings us to the DC system controller that must receive data, interpret, display and provide overall management of the batteries along with the system. The capabilities of the system and the batteries are inextricably intertwined. This device at the heart of the DC system, which in the past may have been termed simply a monitor, now is much more. The choice of system controller is critical. Enatel has approached this challenge with the EM4x energy manager which serves as a useful benchmark. The EM4x can be honestly termed a site manager, not just a DC system controller, with sophisticated programable IO to replace the PLC of many sites. Incorporated is the necessary comms and functionality to manage different battery chemistries, multiple bus voltages, renewable energy sources in solar and wind, gensets and hybrid functionality, plus HVAC control. As well as introducing unique new features such as phase balancing. Then all this capability is brought together to optimize energy usage efficiency such as with programable peak shaving by batteries. Which in turn puts new requirements on the batteries with daily charge and discharge cycles rather than purely back-up functionality.

It is this dynamic field of intelligent battery management that in its own way is as much a revolution as the battery chemistries themselves, and vital for DC system purchasers to understand. The functionality options, the value-add in opex that can be achieved, the ability of flexible modular design to upgrade an existing site versus the capex of cabinet change and similar. The list is endless and Enatel can assist. Contact us here for solutions regards site-specific DC system design integrated with proprietary battery BMS solutions.

Next month: the dualCOMPACT. A dual bus 2U DC system, with charging and monitoring of 2 battery voltages. For example, 12 and 24V DC for emergency service critical radio applications.