The Simplicity Trap – Why Solar Installers Need Battery Choice

When it comes to choosing batteries for your solar and storage system, it’s not always as simple as it seems. You might initially think, “Wouldn’t it be great to have the battery and inverter from the same manufacturer?” It sounds convenient, right? Certainly installers prefer having two brands together, knowing they can rely on a single company like for support with both battery and inverter issues. However, while having an integrated battery and inverter may appear simpler at first glance, there’s a crucial factor to consider: the end-of-life implications for your batteries.

Simplicity in solar battery design is often a good thing – it’s a driving force behind solar design. But there are long-term challenges that arise when the battery and inverter are too closely tied together. Consider this analogy: when the batteries in your TV remote die, you simply remove the old ones, dispose of them properly, and pop in some new batteries. You don’t toss out the entire remote and buy a new one just because the batteries are depleted. The same principle applies to your solar and storage system.

The reality is that batteries have a shorter lifespan than inverters. So, if you’re locked into a specific battery brand or model that’s directly integrated with your inverter, you might find yourself in a tough spot 10-12 years down the line. It’s not about whether the manufacturer will still be around – it’s about whether they’ll continue to support that specific product. Technology evolves rapidly, and if your inverter is designed to work only with a particular battery that’s no longer supported, you could be forced to replace the entire system, even if the inverter itself is still functioning perfectly.

That’s where battery choice comes in. By opting for a battery-agnostic or battery-choice platform, you give yourself the flexibility to adapt as technology advances. When the time comes to replace your batteries, you can select the best option available based on factors like cost, features, and compatibility. This approach ensures that your inverter remains viable, and you can continue to benefit from your solar and storage investment without unnecessary expenses.

Now, let’s talk about cost. There’s no denying that batteries are the most expensive component of your system – they’re the part that drains your budget the fastest. Everyone dreams of living off-grid, relying solely on solar and batteries, but the reality is that the cost of batteries alone often makes that impractical without additional considerations like a backup generator or careful load management. So, if you’re aiming for the lowest possible project cost, where do you turn?

Low Cost Server Rack Batteries (even lower cost without the server rack)

The answer lies in the history of lithium-ion batteries. Initially, these batteries were used to power server rooms, and the most cost-effective form factor was the server rack battery – a simple box with the cells built into it. While server rack batteries like those offered by Pytes might require a bit more labor during installation due to additional wiring and communication setup, they ultimately provide the most bang for your buck.

That being said, there are some high-quality server rack batteries that defy the norm. Blue Planet offers an expensive server rack option but combined with an industry leading warranty and incredibly high cycle count. Storz also makes a server rack battery with a solid value proposition and a strong focus on warranty terms and conditions. The key takeaway is that there are a diverse range of features to suit different needs and budgets, even within a generic server rack form factor.

Stackable Pylontech Pelio Series with Wiring Compartment and Clever Lifting Handles

A more advanced battery feature is stackable batteries. They’re a bit pricier than standard server rack batteries, but they offer easier installation and built-in structural elements that streamline the wiring process. HomeGrid, for instance, features batteries that simply stack on top of each other and plug in like power tools, with a BMS unit on top and conductor runs coming out of the unit. Pylontech’s Pelio battery is another stackable battery option. While it does not have integrated stackable battery connectors, it has a very easy wiring cabinet running down the side of the battery stack, and its upright battery design allows it to hug the wall closely, making it incredibly space-efficient. The lifting handles built into the case make it easy to lift batteries. Combined with the easy access wiring compartment, its one of the most user-friendly batteries I’ve encountered. Small details like the two-wire screw connector for communication, rather than an Ethernet connector, make the installation process smoother and more reliable.

EMP Hardened ESS with Battery Cabinets

EndurEnergy is another battery pack manufacturer which stands out for its versatility in cabinet design, voltage options, and EMP hardening features. They offer a battery which can be used in both low-voltage (48V) and high-voltage applications. This flexibility is particularly valuable for installers looking to simplify their inventory and accommodate different project requirements. Their wide range of cabinet options span various scenarios, including cabinets which house both the inverter and batteries. While most residential installations don’t require a cabinet for both the inverter and batteries, there are situations where it’s beneficial. For example, small EV charging stations in parking lots or publicly accessible spaces with limited power access can benefit from a self-contained setup that keeps the equipment protected from tampering. Endure’s thin profile cabinets are another notable offering, designed to fit seamlessly in tight spaces like the narrow section between the garage wall and the door. These cabinets provide a clean, bundled solution without exposed cables, making them an attractive option for homeowners who prioritize aesthetics and space-saving designs.

In addition to their diverse cabinet options, Endure is offers EMP (electromagnetic pulse) hardening battery options, popular when pairing with Sol-Ark EMP-hardened inverter models. Tested to military standards for EMI resilience, an EMP-hardened battery can only be achieved with use of high-quality internal components within the battery management system. For homeowners who want to be prepared for any scenario, an EMP-hardened battery and inverter combo from Endure and Sol-Ark is a compelling choice.

One advantage of high-voltage batteries is the use of series wiring instead of parallel wiring. In general, voltage is cheaper than amperage, meaning that high-voltage power lines are more cost-effective per watt than low-voltage lines. The smaller cable gauges associated with high voltage are also cheaper and easier to work with compared to the larger gauges needed for high-current applications. However, it’s important to note that high-voltage batteries are not necessarily cheaper than low-voltage batteries at this point in time. They are less widely available, and there’s a higher potential for issues to arise in a high-voltage system due to the series wiring configuration. In a parallel system, one faulty battery may not bring down the entire bank, whereas a single point of failure in a series system can have a more significant impact. To address the specific needs of commercial projects and the challenges associated with high-voltage systems, Sol-Ark has developed a line of high-voltage batteries to pair with its commercial inverters. So perhaps battery choice is a more valuable feature for residential systems, which need maintainable upgrade paths when parts whereout, as opposed to commercial systems, where the critical nature of commercial backup power and the complexity of high-voltage configurations might warranty a single brand solution.

Now, let’s dive into the inner workings of a battery management system (BMS). It’s surprising that the NABCEP Energy Storage Installation Professional exam and associated documents like NFPA 855 and NEC 706 don’t delve into the intricacies of BMS components. Understanding the role and function of these components is crucial, much like how a high-end stereo’s sound quality depends on the quality of its internal parts.

Various BMS Components Require Power to Run

At a fundamental level, there are two types of battery management systems: those that rely solely on PCB (printed circuit board) components like MOSFETs to manage energy flow, and those that incorporate contactors for higher amperage handling. MOSFETs, commonly found in solar optimizers, microinverters, and rapid shutdown devices, are well-suited for managing low-current, high-voltage applications like individual solar panels. However, they have limitations when it comes to handling the high currents often encountered in low-voltage battery banks.

MOSFET-based BMS are less expensive but are only rated to handle the current of a single battery. In a scenario where one battery in a bank is significantly more discharged than the others, attempting to charge that battery can result in excessive current flow from the fuller batteries to the depleted one. This can lead to BMS failure, as the MOSFETs are not designed to handle such high currents. Consequently, the system may require maintenance, troubleshooting, and potential component replacement.

On the other hand, contactor-based BMS, like those found in electric vehicles and many high-quality stationary battery systems, are capable of managing much higher amperage than MOSFET-based systems. Contactors are essentially heavy-duty relays that can handle the high currents associated with low-voltage battery banks. However, this increased current handling capacity comes at a higher cost and with a slightly higher parasitic load on the battery.

The parasitic load of a contactor-based BMS is worth considering, especially in systems where each battery module has its own BMS. While a single BMS managing an entire battery bank may not have a significant impact on overall efficiency, the cumulative parasitic load of multiple contactor-based BMS can be more noticeable. In a 5 kWh battery, for example, an inefficient BMS could potentially drain 10-15% of the battery’s capacity over the course of a day when combined with the inverter’s power consumption and other factors.

Despite the higher cost and parasitic load, contactor-based BMS are often the preferred choice for their robustness and reliability. The automotive industry, in particular, has embraced contactor-based systems due to their ability to handle high currents and maintain low failure rates. Additionally, the slight inefficiency of contactor-based BMS can actually be beneficial in cold weather, as the waste heat helps keep the batteries warm and at an optimal operating temperature.

Ultimately, the choice between MOSFET-based and contactor-based BMS comes down to the specific requirements and budget of the project. For the absolute lowest cost, a MOSFET-based system may be the way to go, but it requires careful commissioning to ensure all batteries are at similar states of charge to avoid overloading the MOSFETs. Contactor-based systems, while more expensive, offer greater peace of mind and long-term reliability.

Another crucial aspect of battery system design is understanding the short circuit current rating, also known as the available fault current. This rating is often overlooked in standard battery certification exams but is essential knowledge for any battery professional. A battery’s short circuit current can be significantly higher than its continuous output rating, and it’s typically regulated by an internal overcurrent protection device, such as a fast-acting fuse.

When a battery is shorted directly to ground, it can deliver an enormous amount of current in a very short time, potentially causing severe damage to the system. High-end BMS often incorporate fast-acting fuses rated for much higher amperage than the battery’s continuous output to protect against these scenarios. For example, a 100 Ah battery might have a 300 A fuse, which may seem counterintuitive. However, these fuses are designed to blow within milliseconds in the event of a short circuit, limiting the available fault current and preventing catastrophic failure.

Proper fuse sizing is particularly important when paralleling multiple batteries together, as the available fault current becomes cumulative. The bus bars connecting the batteries must be rated to handle the combined fault current of all the batteries in the system. In some cases, additional external fusing may be necessary to limit the fault current and protect the system components. It’s crucial to consult the battery manufacturer’s data sheets and guidelines when designing these systems to ensure proper fuse selection and coordination.

Pre-charge relays are another important component of a battery management system that installers should be familiar with. When a battery is first connected to an inverter, especially a large inverter with empty capacitors, there can be a significant inrush of current as the capacitors charge up. This inrush current can potentially damage the battery or trigger overcurrent protection, preventing the system from starting up properly.

To mitigate this issue, many high-end battery systems incorporate a pre-charge relay that allows a small trickle of current to flow into the inverter’s capacitors when the battery is first turned on. This gradual charging process helps to minimize the inrush current and allows the system to start up smoothly. Once the capacitors are sufficiently charged, the main contactor closes, allowing full current to flow between the battery and the inverter.

The pre-charge relay can also be used to recover a deeply discharged battery. In some cases, a battery that has been severely depleted may have its BMS lock out charging and discharging to protect the cells from further damage. To resolve this, a knowledgeable installer can use the pre-charge relay to slowly charge the battery back up to a safe voltage level, at which point the BMS will unlock and allow normal operation to resume. This process may involve repeatedly power cycling the battery and allowing small amounts of charge to trickle in until the voltage threshold is reached.

Having a dedicated 48V lithium battery charger on hand can be a valuable tool for installers, particularly those working with 48V residential systems. These chargers, available from companies like Aims for a few hundred dollars, provide a low-amperage trickle charge that can be used to gradually bring a deeply discharged battery back to life. For those on a budget, an electric bike charger with alligator clip adapters can serve a similar purpose, as long as it’s rated for the appropriate voltage range.

Now, let’s take a closer look at an the most recent server rack battery offered by Pytes. The battery incorporates several familiar features, such as a toggle switch for battery-to-inverter communication, communication ports, and positive and negative terminals. However, one standout feature is the inclusion of a dry contact, which is typically used to override the BMS in cases where the battery has been deeply discharged and locked out. This dry contact allows a skilled technician to bypass the BMS’s safety mechanisms and charge the battery back up to a usable level, potentially saving the customer from having to replace the entire battery pack.

While it may be tempting to use the dry contact for remote on/off functionality, similar to a rapid shutdown system for solar arrays, I would caution against this approach. Rapid shutdown requirements exist for solar panels because they are often located on rooftops, far from the inverter, and may have long conductor runs through attics and walls. Disconnecting power close to the source is important in these cases. However, batteries do not face the same challenges, as they are typically installed in close proximity to the inverter and are already equipped with built-in disconnect switches.

Moreover, using the dry contact for remote shutdown could potentially introduce unnecessary risks and complications. Repeatedly power cycling the batteries to force a shutdown could lead to unintended consequences, such as blowing fuses or damaging components if the batteries are at different states of charge. It’s important to remember that the NEC already has voltage thresholds in place for battery systems, requiring any serviceable parts to be below 100 V, which a 48 V system inherently satisfies. While some competitors may market a “rapid shutdown” feature for batteries, it’s crucial to recognize that this is not currently a code requirement, nor should it be. The existing battery disconnect switches and voltage limits provide sufficient safety measures. Overengineering a solution to a problem that doesn’t exist can lead to increased costs and potential failure points.

Now, let’s shift our focus to the different types of battery cells used in lithium-ion batteries. The three most common form factors are pouch cells, cylindrical cells, and prismatic cells. Pouch cells, like those found in laptops and cellphones, are lightweight and compact but lack the structural rigidity of other cell types. Cylindrical cells, such as the familiar AA or 18650 format, are known for their high energy density and good thermal management but are less commonly used in stationary storage applications.

Prismatic cells, on the other hand, have become increasingly popular in both electric vehicles and stationary storage systems. Despite the somewhat intimidating name, a prismatic cell is essentially just a rectangular prism-shaped battery, similar to a traditional lead-acid car battery. The key advantage of prismatic cells is that they offer a good balance between the high energy density of pouch cells and the mechanical stability of cylindrical cells. This makes them well-suited for applications where vibration, impact, or compression may be a concern.

When comparing the different cell types, it’s important to consider the specific requirements of the application. Pouch cells are often the most cost-effective option, but their lack of built-in structural support means that the battery pack or module design must account for this. Cylindrical cells are highly standardized and have well-established manufacturing processes, which can make them easier to source and integrate into a system. However, their shape may not always be optimal for maximizing energy density in a given space.

Prismatic cells, with their rectangular shape and sturdy construction, offer a good compromise between cost, energy density, and mechanical resilience. They can be efficiently packed into a battery module or pack, and their flat surfaces make them easier to cool than cylindrical cells. However, prismatic cells may be more expensive than pouch cells due to the additional manufacturing steps required to produce the rigid casing.

When it comes to selecting the best battery for a given application, the operating environment plays a crucial role. In a temperature-controlled server room, for example, a pouch cell battery may be the most cost-effective option and therefore the best choice. Historically, cylindrical batteries have been cheaper than prismatic cells, but the industry has been trending towards prismatic designs due to their superior durability.

The load profile of the application also has a significant impact on battery selection. A residential home, for instance, has a much more volatile load profile compared to a stable server room. Residential systems often lack the sophisticated heating and cooling systems found in electric vehicle battery packs, which makes prismatic cells the preferred choice for stationary storage in residential settings.

One of the key advantages of prismatic cells is the ability to monitor the voltage of each individual cell. In a 16-cell prismatic battery module, for example, there are individual cables connected to each cell, allowing the battery management system (BMS) to read the voltage of each cell independently. This level of granularity enables the BMS to detect and flag issues like a single cell with abnormally low voltage, which could indicate a dead or failing cell.

Prismatic cells are typically larger in form factor than cylindrical cells. A 5 kWh battery pack might contain 100 cylindrical cells, whereas the same capacity could be achieved with just 16 or even 15 prismatic cells. This larger form factor has several implications, including the minimum room size required for fire safety testing.

When a large prismatic cell undergoes thermal runaway and catches fire, it releases a greater volume of gas compared to a smaller cylindrical cell. This can be misleading, however, as the thermal runaway in a lithium iron phosphate (LFP) battery is typically confined to a single cell or group of cells, unlike the lithium chemistry made popular by Tesla, lithium nickel manganese cobalt (NMC), where the thermal runaway can easily propagate from cell to cell throughout the entire pack. This distinction in thermal runaway behavior is a key safety advantage of LFP batteries over NMC. It’s one of the main reasons why LFP has become the dominant chemistry in stationary storage applications, particularly in residential settings where safety is of utmost importance.

The ability to monitor individual cell voltages is another significant benefit of prismatic cells. While this information may not be directly accessible to the installer or the end-user, it provides valuable data for the manufacturer when assessing warranty claims. With cylindrical cells, it’s not feasible to have a voltage sensor on every single cell, so the BMS can only monitor the voltage of groups of cells rather than each cell individually.

This difference in monitoring resolution can have important implications for detecting and diagnosing cell degradation issues. With prismatic cells, the BMS can clearly identify when a specific cell has failed or is degrading abnormally. With cylindrical cells, the BMS may only be able to detect a general reduction in overall pack capacity, without being able to pinpoint the specific problematic cell or cells.

In the context of warranty claims, this distinction is crucial. If the BMS can’t identify a specific cell failure, the manufacturer may not be aware that there is a valid warranty claim to be made. The reduced pack capacity might be mistaken for normal degradation rather than a premature cell failure. With prismatic cells and individual cell monitoring, these issues are much easier to detect and diagnose.

The difference between normal cell degradation and a genuinely faulty cell can be very difficult to determine, even with individual cell monitoring. A skilled technician with a voltmeter may be able to identify a problematic cell more easily in a prismatic pack compared to a cylindrical pack, but it still requires careful analysis and interpretation of the data.

As shown in this chart, a key differences between LFP and NMC chemistries is nominal cell voltage, with LFP having a lower voltage per cell compared to the other chemistries shown. This difference in cell voltage has important implications for the performance and safety characteristics of the battery. If you’re designing a high-performance electric vehicle, such as a sports car that will only be driven occasionally but needs to accelerate from 0 to 60 mph in under 4 seconds, you might choose NMC cells to take advantage of their higher cell voltage and corresponding power density. With NMC, its possible to push the cells harder. They also burn more brightly in other senses, wearing out faster as well as coming with lower activation temperature for thermal runaway.

If you were to put an NMC battery pack in your oven and turn the dial to the maximum, the cells would quickly go into thermal runaway and catch fire. An LFP battery, on the other hand, would be much more resistant to thermal runaway under the same conditions, requiring the oven setting to get all the way to broil.

To illustrate this point, let’s look at a comparison of two pouch cells undergoing the nail penetration test, which is a standard safety test required for UL certification. In this test, a conductive nail or spike is driven into the cell to simulate an internal short circuit. When the nail pierces the NMC cell, we can see a significant amount of gas venting from the cell, followed by ignition and sustained burning. This is classic thermal runaway behavior.

In contrast, when the same test is performed on an LFP cell, the results are dramatically different. While the nail penetration still causes the cell to short internally and vent some gas and smoke, the cell does not ignite or go into sustained thermal runaway. Even when the nail is left in place to maximize the heat generation from the short circuit, the LFP cell may get hot and vent, but it doesn’t reach the critical point of thermal runaway and self-ignition.

This behavior is further illustrated in the UL 9540A fire test, where cells are subjected to external heating to intentionally induce thermal runaway. For an NMC cell, the heat from one cell in thermal runaway is sufficient to cause adjacent cells to also go into thermal runaway, leading to a cascading failure that can consume the entire battery pack and spread to neighboring packs. With LFP cells, the heat generated by one cell in thermal runaway is not enough to ignite the next cell, so the failure is inherently limited in scope.

This inherent resistance to thermal runaway propagation is the key safety advantage of LFP batteries, and it’s the main reason why they have become the preferred choice for stationary storage applications, especially in residential settings. Even in the event of a fire or other catastrophic failure, an LFP battery is much less likely to contribute to the spread of the fire or cause secondary ignitions.

Another important aspect of battery system integration is the choice of communication protocol between the battery and the inverter. The two most common protocols are CANbus and Modbus. Many battery manufacturers will use CANbus to communicate with the inverter, as it allows the use of Modbus port for other devices such as energy meters, home automation systems, or inverter controllers which are traditionally using Modbus protocol.

When wiring battery communication to an inverter, it’s important to carefully review the pinout of the communication ports on both the battery and the inverter to ensure compatibility. In some cases, a custom communication cable may be required to properly connect the two devices. While some battery manufacturers include the necessary communication cable with their products, installers should always be prepared to fabricate a cable on-site if needed.

Having the right tools and supplies on hand is essential for any battery installer. A reliable set of cable crimpers, including a hydraulic crimper for larger gauge wires, can make field terminations much easier and more secure. Investing in a quality punch kit with a variety of die sizes can also be helpful, particularly when dealing with conduit or enclosure entries.

In addition to basic electrical tools, installers should also have a few specialized items in their kit. A CAN bus analyzer or diagnostic tool can be incredibly valuable when troubleshooting communication issues between the BMS and the inverter. Similarly, a dedicated 48 V battery charger can be a lifesaver when dealing with a deeply discharged battery that needs to be carefully brought back up to a safe voltage before being connected to the system.

When it comes to battery cabling, it’s important to use properly rated wire that is suitable for the expected current and voltage levels. In most cases, fine-stranded cable is preferred over solid wire due to its increased flexibility and resistance to fatigue. However, it’s crucial to be aware of the ampacity derating that applies when using fine-stranded wire in conduit. NEC ampacity tables for flexible cabling only apply to wires located outside of conduit, and additionally, NEC general wiring rules require ampacity derating of conductors in raceway when there are more than three current-carrying conductors in the conduit. This is often referred to as the “more than three rule” and is intended to account for the increased heat buildup that occurs when multiple conductors are bundled together. In practice, this means that if you have a four-conductor battery cable in conduit (two positive and two negative), you must size the conductors as if they were only rated for 80% of their nominal ampacity according to the general rather flexible wiring ampacity tables. Failing to account for this derating can lead to overheating and potential fire hazards, so it’s essential that installers understand and follow this rule.

Another important consideration when working with battery systems is the proper use of overcurrent protection devices (OCPDs). Every battery system should have a means of quickly disconnecting the battery from the rest of the system in the event of a fault or short circuit. This is typically accomplished through the use of a circuit breaker or fuse that is rated for the maximum expected fault current of the battery.

When sizing the OCPD for a battery system, it’s important to consider both the continuous current rating and the interrupting rating. The continuous current rating must be greater than or equal to the maximum continuous discharge current of the battery, while the interrupting rating must be sufficient to safely clear the maximum fault current that the battery can deliver.

In some cases, the BMS may provide an additional layer of overcurrent protection through the use of internal fuses or contactors. However, these devices should be viewed as supplementary to, rather than a replacement for, a properly sized external OCPD. The external breaker or fuse serves as the primary means of protecting the battery and the connected equipment from damage due to overcurrent conditions.

Battery warranties are another critical factor that installers and system owners must carefully consider. Most lithium-ion battery manufacturers offer a 10-year warranty that guarantees a certain level of remaining capacity at the end of the warranty period, typically around 60-80% of the original rated capacity. However, some manufacturers are now offering extended warranties of up to 25 years, often through third-party insurance providers. While a 25-year warranty may sound attractive, it’s important to understand the terms and conditions of these extended coverage plans. In many cases, the guaranteed end-of-life capacity is significantly lower than what is offered under the standard 10-year warranty, often around 40-60% of the original capacity. This means that while the battery may still be functioning after 25 years, its usable energy storage capacity will be greatly reduced.

Moreover, these extended warranties often come with strict requirements for battery usage and maintenance, such as adhering to a certain depth of discharge (DoD) limit or performing regular capacity tests. Failing to comply with these requirements can void the warranty, leaving the system owner responsible for the cost of any repairs or replacements. As with any long-term investment, it’s essential to carefully weigh the potential benefits and risks of an extended battery warranty. For some system owners, the peace of mind and potential cost savings may be worth the additional upfront expense. For others, a standard 10-year warranty may be sufficient, particularly if the battery is expected to be replaced or upgraded before the end of its useful life.

Regardless of the warranty term, it’s crucial that installers and system owners maintain detailed records of the battery’s performance and any maintenance or repair activities. This documentation can be invaluable when filing a warranty claim or troubleshooting issues with the system. Most battery manufacturers provide some form of monitoring software or portal that can be used to track key metrics like state of charge, cycle count, and temperature.

Temperature is the last subject of this article. The simple fact is that all industry data sheets are misleading with regard to battery temperature. The problem is the operating temperature range of battery chemistry is not the same, nor even close to, its ideal temperature range. Yes, lithium batteries work outdoors in the Texas heat, up to 130 degrees Farenheit. And yes, in the wintertime, lithium batteries work in cold temperatures – charging in near freezing conditions and discharging even below freezing., there’s a range where you can continue to discharge the battery.

But what I want to point out is that, like solar panels, batteries are rated at a standard test condition of 77°F (25°C), which is a lot different than 130°F (55°C) or 32°F (0°C). The battery cycle rating and throughput warranty are also calculated assuming an near standard test condition for normal operation. But most residential batteries are not air-conditioned – they’re put outside, subject to the heat and cold. So there is a concern that the industry forgets this fact, amongst the cycle warranties, and the reinsurance with ever longer warranty terms, and drinks its own Kool-Aid so-to-speak. Without a doubt, batteries will have lower performance out of the battery in extreme heat and extreme cold.

There are batteries – Pytes with their newer battery model and HomeGrid options as well – that have heaters built into their batteries. If the site regularly getting down to near freezing or below, heating the battery somehow is important. Whether its simply putting the batteries indoors or wrapping in an electric blanket or incorporating a cabinet heater, keeping the batteries above freezing will extend its life and performance. Will the heaters take up energy? Yes! But there’s not real difference between that and not having the battery to use if it cuts off below freezing, or even worse, if it degrades because it is too cold! Battery manufacturers try to strike a balance by putting freezing as the cut-off point, but fundamentally there isn’t anything magic to a battery about near freezing or at freezing. It’s not water inside the battery that is at issue.

Again, not many batteries have heated battery options on the market, at least for right now. That’s brings us back to our original topic of the importance of battery choice is important. If you’re in Los Angeles, solar battery design is fundamentally different than Wisconsin. In LA, you might get the cheapest server rack battery possible, put it outside, and be fine. Not so in Kansas! This temperature consideration is a critical factor that often gets overlooked in battery system design. While manufacturers may advertise a wide operating temperature range, it’s important to remember that the battery’s performance and longevity are rated at a specific, ideal temperature.

Deviating too far from this optimal range can have significant consequences for the battery’s health and capacity over time. Simply relying on the battery’s stated operating range is not enough – active measures must be taken to ensure that the battery stays within an acceptable temperature window, particularly in extreme climates. In milder regions with minimal temperature fluctuations, a basic battery enclosure may be sufficient. But in areas with harsh winters or scorching summers, more advanced temperature control measures are likely to be necessary. This is where having a diverse range of battery options can be incredibly valuable. Installers can tailor their designs to the specific needs of each customer and location.

At the same time, it’s important to educate customers about the realities of battery performance and the importance of proper temperature management. Many consumers may not be aware of the impact that extreme temperatures can have on their battery system, or the steps that can be taken to mitigate these effects. By having frank and informed conversations about these issues upfront, installers can help to set realistic expectations and ensure that customers are making informed decisions about their energy storage investments.

Ultimately, the goal is to design and install battery systems that will provide reliable, long-lasting performance, even in challenging environmental conditions. By staying informed about the latest battery technologies and best practices for temperature management, installers and system designers can help to push the industry forward and deliver the kind of high-quality, sustainable energy storage solutions that customers increasingly demand. While it may be tempting to focus solely on factors like price, brand name, and installation ease, the reality is that there are many battery features which impact on the long-term performance and value of the system.

As we’ve seen throughout this discussion, battery storage systems are complex and multifaceted, with a wide range of factors that must be carefully considered in order to achieve optimal performance, safety, and longevity. From cell chemistry and form factor to BMS architecture and communication protocols, every aspect of the system can be thoughtfully designed and integrated to meet the specific needs of the application.

For installers and system integrators, this complexity can be daunting, particularly as new technologies and standards continue to emerge at a rapid pace. However, by staying informed about the latest developments in the field and working closely with trusted manufacturers and suppliers, it is possible to navigate this complexity and deliver high-quality, reliable battery storage solutions that meet the evolving needs of customers and also set them up for future success.

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Posted March 12, 2024 by John Cromer in category "Blog