BV650 is the smaller of the two units and it is matched to what is actually plugged into it: the router, the display and the network gear, which together sit well inside 375W. Line-interactive with automatic voltage regulation means brownouts and spikes are corrected without draining the battery at all, which is the common case here rather than a full outage. Four Schuko outlets on the rear cover the network stack without a power strip.
It stays plugged in permanently and does nothing visible unless the power fails. Its job is that a brownout does not take the router and the displays down at once.
650VA is not enough for a desktop and a monitor together, which is why the larger unit exists — splitting the load across the two is the whole arrangement. The stepped approximation to a sinewave output is fine for PC power supplies with their own filtering, but it will upset sensitive or older hardware. The Schuko outlets take a plug straight from the wall with no C13 lead, which is the whole point of this build, but it also means you cannot feed it a C13 cable to daisy-chain into the other unit. There is no USB communication port, so there is no automatic safe shutdown — if an outage outlasts the battery, everything downstream loses power anyway.
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