Ian Dedic, ask any manofacturer why whey switch from copper to aluminum in windings. The answer is not because it is better electric wise, it’s because it is cheaper. It is also presenting some challenges and they need to put effort to counteract those challenges. One of this would be change in core size, wire cross sections, etc. But all these is only the consequence of the primary decision to go cheap. Not the way around. If Victron had done the opposite, everyone would have been singing with delight at how fantastically they had improved the design 
I’m not going to fight with victron fan boys. My whole system (apart from batteries) is Victron based, i like it but it has nothing do to when it comes to the fact that going “aluminum technology” ( just citing Victron expert from the above mentioned video ) is not to save weight or to make the design better. It is to make it cheaper!
@mac - have you compared internals of 8000 model with the smaller ones? Is it valid to compare heavy tank with light armored vehicle? Have you seen cheapish, thin DC connectors on 6k5 and compared with heavy duty on 80000 model? They carry almost the same current.
Let’s ask some real transformers vendor, i.e. ELSCO what they sa on their website about alu vs copper transformers:
Citation from https://elscotransformers.com/
“Differences Between Copper and Aluminum Transformer Windings
While most low and medium voltage dry type transformers rely on aluminum windings for energy transfer, many engineers and plant operators prefer copper windings for specific applications. Here are some of the primary differences between the two types:
Initial Costs
At the outset, aluminum windings are generally less expensive than copper transformer windings because the material itself is relatively cheap to produce. Moreover, aluminum’s price has proven to remain stable over long periods — translating to cheaper windings.
Copper’s initial costs have historically been more volatile than those of aluminum. Still, even though copper windings tend to be slightly more expensive, many experts believe this type offers more long-term benefits than its aluminum counterpart.
Operating Costs
Aluminum windings usually take up a larger cross-sectional area of dry type transformers than copper options. The more expansive design of the aluminum windings produces a lower current density, resulting in a lower rate of heat loss and saving more energy when compared to older-model copper wound transformers.
Copper transformer windings usually feature tighter coils that can also be optimized for lower current density. In modern designs, thanks to advancements that allow for reduced copper winding heat loss, copper windings often outrank aluminum windings in their long-term operational cost-effectiveness.
Reliability
While both copper and aluminum windings provide the same general functions for low and medium voltage transformers, copper outranks aluminum when it comes to reliability. Aluminum has only 62% of the electrical conductivity of copper, making copper a much more effective conductor.
Proper insulation can ensure that the energy loss factors for each type stay equivalent. Heat loss also depends on the size of the windings — and aluminum can easily be sized to compensate for this issue. Nevertheless, copper generally provides more long-term reliability due to its physical strength and resistance to deformation.
Operating Life
If copper and aluminum windings are properly installed and cared for, their operating lives should be nearly equal. One drawback of aluminum is that it’s typically more difficult to install than copper, which sometimes results in preventable operational issues.
Although modern design improvements have let transformer experts navigate the technical problems associated with aluminum, copper is typically a superior option for protection against fault current stresses and overall longevity.
When to Choose Copper or Aluminum Transformer Windings
While both materials are common, many operations prefer copper because of its improved quality and performance. Copper’s superior conductivity, mechanical strength and resistance to deformation make it the preferred choice for installations where reliability and longevity are critical. Although the initial investment may be higher, many find that copper’s long-term benefits outweigh its premium price.
Copper windings are typically ideal for:
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Critical operations where reliability is paramount, including hospitals, data centers and manufacturing plants.
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Applications with frequent overloading or high ambient temperatures.
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Environments with vibration or mechanical stress, where copper’s resilience provides a longer service life.
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Industrial applications with harsh operating conditions.
Aluminum windings often work well for:
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Budget-conscious projects where initial cost is a primary consideration.
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Applications where weight is a significant factor, as aluminum is approximately one-third the weight of copper.
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Standard-duty applications with stable, predictable loads.
At ELSCO Transformers, our engineering team can analyze your needs — including load profile, environmental factors, space constraints and budget considerations — to recommend the optimal winding material for your application.”
Whether the new models will prove to be as reliable as the good old series remains to be seen. For now, there’s no point in telling stories about aluminum being better, because it’s never been better than copper.
Get my point? I don’t care actually if you get it. Don’t be offended though. That was not my intention.