Enclosure design: don’t risk equipment failure, choose the right battery and house it properly

In equipment enclosures that partly or fully rely on battery power this essential resource is often taken for granted. However, not considering enough factors, specifying the wrong type of battery or not housing it properly may severely affect the performance of equipment it supports. Shane Thomas of ICEE, a leading provider of complete equipment enclosure solutions for many industry sectors, explains why making the right decisions about the battery and its proper accommodation in the enclosure pays dividends in the long run

WHEN A BESPOKE EQUIPMENT ENCLOSURE is specified by a customer, we notice two kinds of approach. First, those who are highly specific about exactly what they want in terms of the battery or batteries. Second, those who provide an outline requirements specification only and leave us to find a complete solution, (which we are perfectly willing and able to do). Common to both cases is that details for accommodating or housing one or more batteries is mostly left to us. That’s because we have the experience and access to expert advisers and suppliers to propose the right solution, or options. In enclosures requiring a battery, it may either be the primary source of rechargeable power for the equipment (or a fail-safe backup for emergencies),or is part of a multi-source power supply system. An example of this kind of power system is pictured below.

The battery must always be utterly reliable, safe and perform properly to specification over its designed lifetime. It will only do so if 1) the right type of battery is selected for the application or requirements of the equipment it supports and 2) the battery housing or accommodation within the enclosure meets the battery manufacturer’s recommended upper and lower limits on ventilation, temperature, humidity and other key factors.

Battery types

Battery science and technology is a highly specialized subject outside the scope of this article, so here I am sticking to basic principles. There are many sources of technical information that deal with deep cycles, charging rates, series and parallel connection, and other essential details.

What ICEE is best-placed to advise on and deliver is not only the importance of matching the battery’s power and recharging characteristics to the equipment being supported, but also the practicalities of ensuring the battery operates in the best conditions. In other words, the design and manufacture of the accommodation or compartment within the enclosure has to be right to protect the battery and related kit.

But first, let’s briefly review the main battery types available. Batteries today are mainly based on two well proven technologies – lead-acid and lithium-ion (Li-ion). Both come in various types and sizes and performance outputs. Lead-acid technology has evolved ever since the first rechargeable electricity storage device of its type was invented by French physicist Gaston Planté in 1859. Much developed, the lead-acid battery is still widely used, particularly in equipment enclosures. Today, enhancements include improved storage, faster re-charging times and reduced maintenance. Emissions and risk of leakage is often controlled through valve-regulated lead-acid (VRLA) ventilation.

Although this long-established technology offers many benefits including relatively low cost, the lead-acid battery is comparatively heavy and bulky. As a result, demanding industries such as aerospace and computer and telecommunications sectors have led to the introduction of lighter, more compact and higher performance batteries, such as Li-ion.

Higher performance comes at a price, which may be more than offset by cost-benefits. In practice, opting for compact Li-ion may be a ‘no-brainer’ if space in an enclosure is limited, or a bank of several batteries is required to support equipment demanding extra power, or certain energy characteristics are essential which only that technology can provide.

Another case justifying the more expensive option is where maintenance visits are costly, such as equipment enclosures located offshore. Longer-between-charge Li-ion batteries may mean less frequent visits and therefore substantially less servicing costs.

Hydrogen fuel cells are increasingly adding another dimension to being part of a hybrid or combined power system for equipment enclosures. This technology offers low fuel consumption, long breaks between servicing and has environmental benefits. These include no toxic emissions and noiseless operation. Working as part of a combined battery, solar panel (PV) and wind-power generation system, the addition of a hydrogen fuel cell represents a highly sustainable way to solve power problems in remote or off-grid locations. But ensure the battery is right for the demands of a solar-based power system and check the Cycle Life rating.

Deciding what’s required

An important factor in selecting the right battery and designing the way it is housed in an equipment enclosure is environmental temperatures in and outside the cabinet. The performance of a lead-acid battery is affected by extremes of upper and lower temperatures. Its life may be halved if operating in a hot temperature above the limit set by the manufacturer. Excess heat within an enclosure may be a result of an exceptionally hot summer (now becoming normal), or because the equipment produces a lot of heat. Excess cold is less of an issue in the UK, but at lower than -15C a VRLA battery may freeze.

The solution might be to specify air conditioning inside the enclosure. Or, because the operating environment is imperfect and too costly to control, it may be decided to accept the battery will have a shorter than normal life before replacement. These options must be assessed at the design stage, not expensively corrected later in the field. To ensure reliable performance consider environment, battery type, risk mitigation steps, the economics of maintenance and replacement, and other key factors.

To specify the right battery type, let’s look at a list of requirement factors.

First, some top-down fundamentals

• What is the application and power requirement of the equipment?
• Is the power source primarily the battery, with a means to automatically re-charge it? Or is the battery part of a power generating system, such as including solar photovoltaic (PV) panels and a wind-powered electricity generator? Is Cycle Life rating an issue?
• How often will battery maintenance and replacement be required? If the enclosure is located offshore on a remote island and service visits are costly, it may mean specifying cost-effective, high-performance batteries that require long intervals between maintenance
• What operating conditions and limits are demanded by the battery manufacturer inside the enclosure to ensure the battery delivers to specification reliably, consistently and for its design life?
• Consider risk management and contingencies
• All the above dictate what type of battery is appropriate, whether conventional lead-acid or advanced lithium-ion, if one or more batteries will be necessary, and other factors relevant to the particular circumstances

Next, a few design questions

• Any safety or construction regulations and standards that apply? For example, BS EN IEC 62485-2:2018 Safety requirements for secondary batteries and battery installations. Stationary batteries (IEC 62485-2:2010)
• Does Ingress Protection Rating (IP) or is any other rating applicable, such as the National Electric Manufacturer’s Association (NEMA) standard, common in the USA?
• Is it sufficient to locate the battery on a shelf, or does it require a dedicated compartment?
• Lead-acid and VRLA batteries generate and emit hydrogen gas, so the compartment must be vented to the outside environment, what does this mean for design and construction?
• Any chance of corrosive battery liquid spilling and as a precaution, is it advisable to use battery accommodation materials resistant to corrosion?
• Is there any risk of a battery overheating or exploding, any safety precautions needed?
• Are special security measures required against theft or vandalism?
• Consider ease of access for maintenance and battery replacement
• Should the battery shelf or compartment be designed with flexibility enabling enlargement if in the future an extra battery or several batteries require fitting in?
• Is ancillary equipment necessary such as a battery charging device and limiter, connection to an inverter, or a device to support remote performance monitoring?
• Where more than one battery is necessary, will it be wired in series or parallel? Make the difference clear for servicing and replacement purposes
• Consider how much futureproofing is advisable and what potential changes in years to come may affect the equipment and in turn battery requirements?
• Should a combined power system, maybe featuring a hydrogen fuel cell, be considered?
• Any other factors particular or unique to the application and battery provision?

And lastly, some practical tips . . .

Again, battery technology and specification is a highly specialist subject. At ICEE, we are experienced but we know when to consult experts and source the right battery products from reliable and knowledgeable suppliers. That way lies right-first-time solutions and best outcomes for customers.

In the process of maintenance, we have found:

• To economise, in multi-battery configurations, don’t be tempted to mix a little-used battery with a batch of brand-new ones, it doesn’t pay
• Be sure what you want – wiring batteries in series or parallel respectively gives you higher capacity or higher voltage, but if a battery is removed or replaced, be sure to make it easy for the service engineer to re-connect the right way. Damage occurs if done wrongly
• Think about the service engineer and working conditions, it may not always be warm and sunny on site. With the access doors open for servicing equipment and battery, ensure the enclosure interior, the equipment and details like the battery compartment are protected from the elements (like driving rain) and easy to work on

And lastly, if you are looking for bespoke equipment enclosures with the right battery solution ICEE has considerable expertise and knowledge. This is our core business and we have been competitively selected by many leading telecommunication enterprises, prime contractors and partners seeking our well proven resources, processes, products, and high standards of quality.

We are very willing to not only advise but also provide a range of complete equipment enclosure solutions for different industry sectors. Our total, one-source approach to service delivery covers not only design, development, prototyping and manufacture, but also fit-out, installation, commissioning and lifetime maintenance. All, of course, supported by our years of expertise on the subject of batteries.

To find out more on our off grid products take at look  https://www.icee.co.uk/off-grid-enclosures-product-range/