Wired vs. Wireless Battery Monitoring System Which One Is Better

Main Keyword:	battery monitoring system
Other Keywords:	battery monitoring, smart BMS

Wired vs. Wireless Battery Monitoring System: Which One Is Better？

The remote battery monitoring is critical to your operations. Without a reliable monitoring solution, you cannot know immediately when battery faults and accidents occur unless you have personnel at the facility 24/7. Even then, you risk overlooking equipment issues or status changes that cannot be detected without the appropriate sensors and battery  monitoring system installed.

While the benefits of using a remote battery monitoring system are clear, the decision to use wireless or wired sensors with the system isn’t as obvious. Wired and wireless sensors both have their advantages and disadvantages. Knowing the specific needs of your application will help you decide which option is right for your project. Here are a few things to consider:

Get the whole picture of both battery monitoring systems

A remote battery monitoring system (BMS) is critical for battery monitoring in operation. A smart BMS would detect the battery type, voltages, temperature, capacity, state of charge, power consumption, charging cycles, and other characteristics. It can increase the optimal use of the battery and decrease the risk of power failure.

However, you can only make the most of the battery monitoring systems by making the best choice between the wired & wireless ones. Therefore, let’s delve into the discussion:

• Features of wired & wireless communication

	Wired Communication	Wireless Communication
1. Description	A wired communication employs wires to link devices one by one to the Master Controller.	“Wireless” means without wire, media that is made up of electromagnetic waves (EM Waves) or infrared waves. Antennas or sensors will be present on all wireless devices.
%1. Transmission Speed	Faster transmission speed: RS485: Max.10Mbps	Slow transmission speed: ZigBee：Max.250kbit/s; Baud rate: 2400bps~115200
3. Reliability	Reliable: a) High-quality communication; b) Low maintenance cost; c) Balance battery cell.	Less Reliable: a) Susceptible to external interference; b) High maintenance cost; c) Unbalance battery cell.
4. Security	More Secured: High level of data security	Less Secured: Keys can be cracked
%1. Power Consumption	Low power consumption： RS485: static is 2-3mA, Max.20mA	High power consumption: ZigBee: 5mA~55mA
6. Distance	Long Distance: RS485: Max.1200M	Limited Distance: ZigBee: Max.100M Limited signal range due to interference, will much less than 100m.
7. Network Node	RS485: Max.256	ZigBee: Max.128
8. Price	Less Expensive: Cheaper than Zigbee	More Expensive: Zigbee IC cost: x 2~3 RS485
9. Installment Costs	High installation cost: Devices must be hard-wired	Low installation cost: Easy installment, but single communication distance is short
10. Configuration	Easy to configure address	Complex to configure an address

• Benefits of wired BMS

a. Speed

In general, wireless networks are slower than wired ones. Wireless signals can be easily affected by the surrounding environment, such as walls, floors, and cabinets in the facility, as well as interference from other electronic devices. Wireless data transmission is also distance sensitive: the farther the sensors are located, the weaker the performance.

b. Reliability

Traditional wired battery monitoring systems have been evolving and enhancing for decades. Significant advancements have been made to ensure they are extremely reliable. They use direct physical connections and encounter less interference compared with wireless ones.

c. Battery balance

Wired sensors can keep the power consumption stable, avoiding fluctuations caused by different wireless signals. Thus, they help to balance the battery and extend the battery strings’ lifespan.

d. Cost-effective

Compared with wired sensors, wireless sensors require additional wireless transmitter hardware for each sensor, which will lead to higher wireless costs than wired solutions.

e. Maintenance

The labor costs of maintaining wired sensors are usually less than those of wireless sensors since the former requires little maintenance. Wired sensors are capable of continuous monitoring over the years, reducing the costs of identifying and replacing expired or faulted units and costs of detecting connectivity issues.

• Drawbacks of wired monitoring

a. Lack of mobility

Because the wired monitoring solution relies on a physical network of cables, there is a lack of flexibility when changes need to be made. Redeploying cables is often a time-consuming endeavor, depending on how many cables need to be rerouted and the barriers between access points.

b. Installation costs

The initial costs of installing a wired monitoring system can be high. Cables needed to be run through walls, under floors, and in some cases buried. The labor costs associated with these projects can be prohibitive, and if a problem is later discovered, gaining access to the cables is a significant challenge.

c. Cable damage

There are situations where the cabling connected to sensors can be damaged, loosened, or disconnected, either due to human error or, in most cases, due to other work being done around it. In these rare cases, damage to the cabling can cause unresponsiveness to the sensors. Accordingly, cabling may need to be simply reconnected or, at worst, replaced. Fortunately, Ethernet and RJ11 cabling are inexpensive, especially when only a line or two is replaced.

• Benefits of wireless monitoring sensors

a. Convenience

One of the main advantages of wireless monitoring is the ability to place sensors wherever needed without running cabling through walls, floors, and ceilings, which helps to reduce installation time, but it needs more time for software address configuration.

b. Mobility

Most wireless sensor manufacturers allow multiple wireless sensors to connect to a single node. Moreover, new nodes or sensors can be added to the existing network without running additional wiring to accommodate network expansion.

UPS will be confirming the design in the early stage. Normally there require no extra sensors to the existing network.

• Drawbacks of wireless monitoring

a. Reduce battery life

Wireless signals can be affected by external influences. Whether the signal is good or bad will directly affect the power consumption of each sensor and aggravate the battery imbalance effect.

Wireless sensors are also distance sensitive. As a result, the long-distance sensors will often worsen the battery cell life.

b. Slower speeds compared to wired monitoring

When analyzing the real-time conditions of critical equipment or facilities, it’s important that the data is transmitted and available as fast as possible. As mentioned above, wireless sensors are susceptible to increased latency, signal interference, and dropped connections which will impact the speed and consistency of the data stream, even missing important alarms and causing accidents.

c. Complex to configure

Configuring wireless sensor networks can be an ongoing challenge as new variables are added to the sensor network. Re-positioning the sensors and redeploying or reconstructing the network are required to maintain the speed of data transmission.

d. Limited signal range due to interference

Wireless data broadcast is facilitated over the radio frequency (RF), which has always had to deal with a wide variety of interference-related obstacles that can lessen signal strength and lower transmission speed. Obstacles such as walls and doors or other devices that operate on the same frequency will create conflicts with data transmission.

The distance between sensors and their monitoring hub is also a limiting factor. A large enough gap or solid structure between these two points can also result in a degradation of data. For these reasons, many operators are often forced to not utilize sensors to their full potential by reducing the polling intervals of data.

e. Maintenance:

In terms of maintenance, since the wireless battery monitoring system has a higher probability of errors, more maintenance can be expected.

Conclusion

The mission of a smart BMS is to find out the faulty battery and pre-alarm users to avoid accidents. If a failed battery cannot be notified in time, the system is meaningless to monitor. Therefore, considering all the benefits and drawbacks, a wired BMS solution is a better choice.