Modular battery packs protect the investment because capacity can be added or reconfigured later, and existing Delta Pro Ultra batteries can work with the newer inverter after the required update.
Pros: output stability, voltage regulation
Cons: solar cable compatibility, UPS functionality
One teardown-oriented reviewer said the internal pack can be reached and replaced, though it is not a simple user-swappable design.
Pros: surge capacity, output stability
Cons: dual-input charging, whole-home integration
The internal battery is not removable, which makes the station a poor fit for buyers who want a replaceable-pack path or future capacity flexibility.
Pros: pure sine wave output, startup performance
Cons: MPPT controller performance, battery expandability