Guide is looking great, thought I provide some feedback, from the perspective of this newbie. (I usually don't like doing this as it can be perceived as something like telling a mother her baby is ugly, so let me say it again, it really looks great)
Instead of using Isc? use the full name, it makes it easier to read, but lengthier. On a side note, om my screen the "sc" part is really small and my eyes are not what they used to be.
In section 5.2 my eye was drawn to the relay board, you might want to put the description for it as the first discription and/or provide images for the other parts.
In section 5.4 you write "If you use one for this purpose" you might want to replace "one" with "Victron Battery Protect" to make it clear for the reader that is what you meant.
In section 7 you use the term "ampacity", I think that is a word more common in the US, it is certainly new to me, maybe "current rating of the wire" would be a better choice and keeps the terminology consistent with the other items, like fuses and circuit breakers?
In section 7.3 needs some work. Explain why automotive fuses are not a good idea with lithium (I never thought about it myself until just now and I am quite interested as well) Maybe reword the "Your inverter will need its own DC fuse on the supply side" with something like "Pay special attention to wiring the inverter, the DC cable between the battery and the inverter needs to be sized and fused appropriately." And replace "and an AC breaker box on its load side" with something like, "connect the AC from the inverter to a seperate AC switch panel and from there to the outlets." Not sure how to word it myself either to be honest.
In section 7.4 replace "If there won’t be a resistor in the circuit, then they should have a fuse instead." with "If there isn’t a resistor in the circuit, you should use a fuse."
in section 8.3, you might want to point out that the SBMS0 put the shunt(s) on the positive side, while most BMS's use the negative, so it can confuse people. (There can be a short wire between the shunt and the battery, just no fuse or circuit breaker as I think that disconnecting the positive can damage the SBMS0)
In section 8.6 "If you aren’t using a PV shunt, set ‘PV1 shunt On/Off’ to 0. " I believe 0 (off) is the default and needs to be turned on. (I spend hours looking for that problem last month)
The problem is that the more we read those documents, the harder it is to look at it from the perspective of a newbie, so I hope you can use some of this. Again thank you for writing it, I am sure many people, including myself, will find it very useful.