i don’t think we need to say more.
RenewSolar have never sold pylontech batteries for good reason.
The Looming Failure: Pylontech Batteries and Their Fundamental Flaws
The time is coming where the battery packs from Pylontech are failing more and more, and for RenewSolar, this was an entirely foreseeable outcome. This accelerating trend is a direct consequence of both poor manufacturing practices and fundamental design limitations that render these units unsuitable for their intended purpose.
From an engineering perspective, the problems with Pylontech batteries were plain to see from the outset. As qualified engineers adhering to stringent standards, we at RenewSolar critically evaluate the specifications of any energy storage solution. It became immediately apparent that Pylontech’s offerings fell significantly below the required benchmarks for the demanding use cases we encountered in the field. Consequently, RenewSolar made the principled decision to never sell or promote Pylontech products, a stance vindicated by the escalating failures now being reported.
ITS Technology vidicates with Over 60% of Pylontech battery failures are due to incorrect installation
Under-Specification and Inadequate Cell Technology
A core issue lies in the fundamental design of the battery cells themselves, particularly the pouch cells utilized by Pylontech. While pouch cells can be effective in certain applications, their specific implementation and integration within Pylontech’s packs presented critical red flags:
- Insufficient Energy Density and Capacity: The actual energy density and usable capacity of the Pylontech battery packs consistently fell short of the demands of typical solar energy storage applications. This meant that, in real-world scenarios, the batteries were subjected to higher effective C-rates than their design could comfortably handle, leading to increased internal stress.
- Subpar Cell Quality and Consistency: Anecdotal evidence and emerging failure patterns suggest a lack of consistent quality control in the manufacturing of these pouch cells. Inconsistent cell characteristics within a pack can lead to imbalances, accelerated degradation of weaker cells, and ultimately, premature pack failure.
- Inadequate Thermal Management for Cell Type: Pouch cells, especially when pushed beyond their optimal operating parameters, generate significant heat. Our analysis indicated that the thermal management systems within Pylontech packs were inadequate to effectively dissipate this heat. Excessive heat is a majoraccelerant of battery degradation, leading to:
- Reduced Cycle Life: Higher operating temperatures directly shorten the lifespan of lithium-ion cells. The rapid charging rates and high discharge demands placed on these under-specced cells, without sufficient cooling, would inevitably lead to a drastic reduction in their expected cycle count.
- Capacity Fade: Sustained exposure to elevated temperatures causes irreversible chemical changes within the battery, leading to a permanent reduction in its ability to store and deliver energy.
- Increased Internal Resistance: As cells degrade from heat and stress, their internal resistance increases, further exacerbating heat generation during charging and discharging, creating a detrimental feedback loop.
The Peril of Rapid Charging and Discharge Rates
One of the most critical oversights, or perhaps deliberate design compromises, was the fast charging and discharge rates permitted, and often encouraged, for these battery types. While rapid charging can be a desirable feature for users, it must be supported by robust cell chemistry and sophisticated battery management. In the case of Pylontech:
- Excessive C-Rates for Pouch Cells: The instantaneous power demands placed on these batteries often translated into C-rates that were simply too high for the inherent limitations of the pouch cells used. High C-rates stress the internal components of the cell, leading to:
- Lithium Plating: During rapid charging, if the lithium ions cannot intercalate into the anode material fast enough, they can deposit as metallic lithium on the anode surface. This ‘lithium plating’ is irreversible, reduces usable capacity, and can pose safety risks.
- Accelerated Electrode Degradation: High current flows can cause physical and chemical degradation of the electrode materials, leading to delamination and loss of active material.
- Inadequate Battery Management System (BMS) Response: While Pylontech batteries include a BMS, our observations suggested it was often insufficient to truly protect the under-specced cells from the stresses of high charge/discharge rates. A robust BMS should actively manage cell balancing, temperature, and current to prevent damage, but if the underlying cell chemistry and thermal design are fundamentally flawed, even a sophisticated BMS can only mitigate, not eliminate, the problems.
The Disconnect: “Fan Boy” Promotion vs. Engineering Reality
While “fan boy” videos and certain promoters often glossed over these fundamental problems, offering disclaimers and making excuses, this did not stop false information from being taken as fact by a less informed public. This phenomenon is a stark reminder of the critical difference between marketing hype and genuine engineering assessment. Crucially, Pylontech themselves, to their credit, often provided enough technical data in their specifications for those with the requisite engineering knowledge to identify the inherent limitations and foresee the eventual problems. They never explicitly claimed their products were suitable for all aggressive use cases, but the market’s interpretation, fueled by less critical promotion, led to widespread misapplication.
One disapointed pylontech customer reported
“Funny enough i have had a issue with 2 US2000 batteries. I had to shut the system down because i knew i didn’t have enough power to last the night and wanted to preserve the charge for the next morning to use. Shutdown at 34% SoC and startup 7 hours later showed 2 batteries at 4% SoC. Logs showed before shutdown the charge was at 34% and 4% the next entry hours later.
Contacting Pylontech they had me download and send them the logs. which i done over 2 days as they took so long for the first two batteries to download and bad weather meant i wanted to conserve power. They have said “We actively hope to solve your problem, but two of your batteries have been recorded as frequently overcharged and I have found that your inverter MPPsolar 7248Max is not in our compatibility list, these are signs of improper use and will not be covered by the warranty.”
This is the reply(sic) today from Pylontech
“Let me clarify that it is not because your battery has reported a fault that your 10 year warranty has disappeared, it is because the 54V has exceeded the maximum charge voltage indicated in the battery manual and this is considered improper use and therefore we cannot offer a warranty for subsequent failures, customers have the right to decide how to use their batteries, but our warranty can only be offered to batteries that have been used properly.”
Conclusion: A Wake-Up Call for Battery System Selection
The escalating failures of Pylontech battery packs serve as a vital lesson in the importance of due diligence when selecting energy storage solutions. For RenewSolar, our commitment to engineering integrity and rigorous technical evaluation allowed us to identify these issues proactively, safeguarding our clients from unreliable systems. As the industry matures, the distinction between genuinely fit-for-purpose battery technologies and those designed with critical compromises will become increasingly clear, often unfortunately, through the bitter experience of widespread failures.
On our website, there are several articles in respect of battery life, maintenance and charging as well as picking the correct battery. There is also a 15 page report in our shop.
A Note from RenewSolar: Our Commitment to Engineering Integrity
At RenewSolar, our engagement with clients often begins long before a sale is finalized. We frequently identify potential problems and misconfigurations within proposed orders. Our proactive approach involves flagging these issues, explaining the underlying concerns, and suggesting appropriate corrections and fixes. We see this as a critical part of our service, ensuring that the systems our clients ultimately deploy are robust and reliable.
Sometimes, the issues we uncover stem from flawed calculations or mismatched components. While we always strive to assist and educate, there is a fundamental line we will not cross: we will refuse to sell hardware if doing so would compromise our legal obligations or invalidate a client’s warranty. This is not about being difficult; it’s about upholding our standards and protecting your investment. It’s important to note, however, that when orders consist of single, isolated items, we cannot always preemptively identify potential problems that might arise when those items are integrated into a larger, unforeseen system.
You might perceive RenewSolar as selling “upmarket” hardware or perhaps even attempting to “up-sell.” This is not the case. Our product selection is driven purely by engineering principles and a commitment to providing a total solution. We meticulously match components to ensure optimal performance, longevity, and safety. Our due diligence is extensive, and while we don’t always delve into the minutiae of every product detail in our public-facing materials, rest assured that every item we offer has been carefully chosen.
Whether components are developed through our in-house engineering expertise or are rigorously screened and tested before being made available, we ensure that what you’re buying is the right thing from the right place. Our goal is to provide you with peace of mind, knowing your energy system is built on a foundation of quality and engineering excellence.
PS Told you so.
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