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Over the past 20 years, BatteryDAQ has received hundreds of RFP/RFQs (Request for Proposal/Quote) worldwide, ranging from a simple page to extensive specifications. We understand that properly preparing an RFP/RFQ is a comprehensive job, that requires deep knowledge about battery maintenance and business operations.

The essential purpose of a RFP is to define an effective (NOT fantastic) solution to meet the important practical information objectives. The first consideration must be to list the requirements for a Battery Monitoring System (BMS) for the specified battery type and working mode, and reflect how the BMS will aid battery maintenance, and ensure a safe environment and reliable backup power system:

Battery Type and Working Mode –> BMS Identification –> Installation –> Effective Monitoring –> Data/Alarm –> Battery Maintenance and Replacement –>–>–> Reliable backup power when needed

Battery Type and Working Mode

Battery types, working modes and their working environments shall be described on the starting page. If there are significant differences, it may be the best to separate them into multiple RFPs. There is no “one-size-fits-all” BMS.

Important information for the description will include:

  • Battery type (Lead acid vented/valve regulated, NiCad, Li-xxx), capacity range, cell/block voltage, string voltage, number of cells per string
  • Number of battery banks in a site, implementation scale (total battery banks/locations)
  • Backup or deep cycle, indoor/out door, rack/enclosure, working temperature range
  • Charging/discharging current range, backup time, any charging mode other than floating charge 

Effective Monitoring

When it comes to continuous battery monitoring, “Effective” means “monitoring battery working condition and detecting battery deterioration/problem with correct method and essential hardware”. 

For backup stationary state-of-health (SOH) applications, such as power plants/substations, telecom sites, and datacenter UPS, batteries will remain at floating charging status until needed.  For these applications, the purposes of the BMS will focus on:
1) monitoring each battery’s working condition, with regard to any under or excessive charging, and thermal risk
2) identifying battery connectivity issues
3) detecting weak batteries by measuring internal resistance. [“Pulsed DC” is the most accurate/reliable method. AC method in modular BMS cannot penetrate the battery plate, thus gathered data is less relevant to battery aging/deterioration.]
4) monitoring floating current, ripple current, ambient/pilot (1 or 2 sensors per string) temperature
5) providing local and remote battery data access 
6) delivering data/alarm to NOC/SCADA

Less Is More” concept has been proven to be true for battery monitoring implementations. Less wiring, less nodes/connections, less sensors, smaller footprint, concise data all contribute to long term reliable operation.

Some “luxury” functions waste money and may actually cause harm:
1) Cell voltage balancing. Industrial batteries never need a balancer for individual cells. It does more harm than good. The function will cover up “bad” batteries and mislead on needed battery maintenance/replacement. There is no reporting data available to support that balancing will extend battery life.

2) Individual cell temperature monitoring. This is NOT recommended. It only creates installation and maintenance hassles. There is no chance for individual cells to have significantly higher temperatures than the entire string and even if they did, problem will be detected earlier by monitoring its voltage/internal resistance/connection resistance.

3) Electrolyte level monitoring. BMS will never play a role to eliminate necessary/routine maintenance for vented batteries. Technicians will always observe the electrolyte level for each cell and top off, when they visit the site during required intervals. End users should never trust a remote electrolyte level monitor. Besides, if the electrolyte level needs attention for any reason, the BMS’ internal resistance measurement will catch it, and generate an alarm well before an electrolyte monitor.

4) Wireless or Modular. We have seen many “wireless modular” systems in the field. They are not unique, nor exclusive.  The reason BatteryDAQ does not use modules is because they are not suited for certain environments.  When environmental conditions destroy exposed components, system may continue reporting the last received data, even though they have been functionally dead for months. Additionally, a technician may have to visit site often to restart or re-calibrate some modules. As mentioned previously, modular units often utilize the AC method to measure internal resistance, due to the nature of their design demanding modules be as small as possible.


Installation cost may exceed your budget, if you have chosen a wrong product, or require certified technicians to implement the system.

What is included in the package? 

Monitor, sensor/transducer, fused leads (connecting to battery posts, specify post size), cable, connection plugs, mounting, communication device, data display/interface(HMI)


Accurate Data/alarm is the most important functionality you purchase.

An independent dedicated computer system is not needed for modern BMS. Designated user(s) can access battery data from any computer in the network via a browser.

For multiple locations/units, centralized data management shall be provided. 

NOC and SCADA integration. Modbus-TCP or customized API. [Outdated SNMP is not going to work. DNP3 creates unnecessary complexity and expenses.]

Battery Maintenance and Replacement

BMS installation should not obstruct nor hinder any battery service and replacement projects.

Any BMS must be graded on how it aids your routine battery maintenance.

A well-designed BMS can be removed and reconfigured for similar battery banks in the same, or different locations.


  1. Contact BatteryDAQ
    This is the best first step and most efficient way to get started and finish in shortest time. We can provide reference materials and templates that will guide you through filling in your specific requirements and reviewing with your team. Afterward, you will be able to make confident, informed decisions. [Contact us]
  2. IEEE Standards
    IEEE Standards for Stationary Battery Maintenance and Monitoring
    This link will provide some essentials for what should be considered to meet IEEE standards.  Although, be aware that IEEE standards are for basic requirements, and some contents may not reflect updates to the latest technology. 
  3. NERC Standards
    NERC PRC-005 Battery Maintenance Requirements
    For utility applications within the United States, care must be taken to meet/exceed NERC requirements.  Safety and avoiding large fines depend upon it.  To forge the easiest path to achieve these goals, BatteryDAQ provides “auto-fill NERC reporting” in Excel format, which you can easily customize to match your company’s approved NERC audit report.  This exclusive BatteryDAQ offering will allow you to manage hundreds of battery banks on one workbook. With a single mouse click, it “magically” collects real-time battery data from remote site(s) and fills the fields on the Excel sheet. [Read more
  4. Consultant
    Instead of relying on manufacturer representatives, or worse, to provide the best system for your needs, BatteryDAQ can recommend one of only a few qualified independent experts. Implementing the best BMS is not overly complicated, but a trusted, knowledgeable partner is a must to get it right.