Can I Use Bi-directional Power Supplies for Battery Testing?
Bi-directional Power Supplies vs. Battery Cyclers for Battery Testing
When deciding between a bidirectional power supply versus a battery cycler for testing batteries, there are important considerations. Selecting the wrong battery test equipment will lead to major integration challenges as well as setbacks including hidden development costs, delayed test start dates, increased complexity, project risks and reduced safety.
Testing battery modules and packs involve more than just battery cycling. More often than not, testing a battery involves some form of automation software and controller to coordinate the test steps and integrate additional devices needed to communicate with the battery.
What are the Differences Between a Bi-directional Power Supply vs. a Battery Cycler?
Typically, there are additional components involved in testing such as communication modules, temperature chambers and chillers, and additional power sources which factors into the required testing needs. Using a bidirectional DC power supply for testing batteries raises a very high risk of damaging the power supply or the battery, and many manufacturers will even warn about this risk themselves. There are also many limitations in functionality as it is designed as a traditional power supply, not for testing batteries.
Unlike a traditional power supply, batteries are chemical energy storage devices which can be inherently dangerous and require specific capabilities for testing. Using a bidirectional DC power supply means building your own test system, involving addition external equipment and significant customization to provide the functionality and safety required for effectively testing batteries.
NHR provides comprehensive battery test solutions with NHRs Battery Test Systems, from the hardware to the system and enterprise level lab management.
Leakage Currents
Is Powering Off Actually “Off”?
Power supplies often contain bleed down resistors to dissipate stored energy, and can become an uncontrolled load, continuing to discharge the battery even when powered off, which can lead to unsafe situations with the battery. NHR Battery Cyclers have built in safety isolation relays not present in power supplies that prevent this power draw when turned off.
Capacitance
Is Capacitance Good or Bad?
High output capacitance of power supplies result in high inrush/outrush to the battery, increasing safety hazards and damage to the equipment and battery. This inrush causes pitting of the contactors, arcing, and other damage to the safety contactors, causing failures or even uncontrolled damage to the battery itself. NHR Battery Cyclers have very low output capacitance and features a built-in pre-charge circuit designed to prevent current inrush when connecting to and testing a battery.
Is Safety Designed into the Product?
Is Safety Designed into the Product?
Power supplies require add-ons for safety contactors, polarity checkers, and pre-charge circuits, effecting set-up and performance. Adding these components is time intensive and significantly complicates the test set up, adding time delays and additional labor costs. NHR Battery Cyclers have all of these, as well as multiple layers of safety, built-in.
Set Up Complexity
How Complex is the Setup and Integration?
Communication with the battery and external equipment such as temperature chambers or chillers often requires extensive software development that adds significant time and cost to any battery test set-up. NHR Cyclers and software have key battery test features such as safety already integrated while allowing for easy and flexible integration of third-party tools.
Support
Who do I Contact for Support?
There is no single point of contact when building your own system with bidirectional power supplies. Software, additional safety features, or integration challenges fall on the user to resolve, adding time and cost. NHR is an expert in battery test and your partner in test.
Set Accuracy
How Accurate is the System?
Set accuracy is not typically specified by power supplies. NHR clearly documents empirical control accuracy.
Set Methods and Control
How Easy is it to Use and Control?
NHR Battery Cyclers have operating modes designed to support battery test, and our software solutions provide ready to go control solutions to eliminate integration time and effort. Power supplies involve significant software program development before testing can begin.
Measurement Accuracy
What is the Measurement Accuracy?
Power supplies are general purpose products, and battery specific measurements such as Ahr or kWhr are often left to the user to track and determine. NHR battery cyclers take precision battery test measurements directly on the hardware, making programming simpler and more effective.
Control Speed
Will the Control Speed Meet Real-World Conditions?
NHR Battery Cyclers are designed with low output capacitance for very fast change of set points, while power supplies which usually have high output capacitance, providing much slower response rates.
Future Proofing
How can I Expand the System to Higher Power?
NHR Battery Cyclers are designed to operate in parallel. Power supplies are not easily scalable and all the components need to be sized to the system, further complicating integration challenges.
