Good morning, I’m an electrical power systems engineer by trade and decided to draw up an SLD for our offgrid cabins out in the northern wilderness of Quebec in Canada.
Feel free to comment, and add suggest improvements.
Curious, why do you isolate the 12V battery from the 12V loads on the left?
001-DP-001 can be powered by one of two different sources.
It operates either from 001-BB-001 through the 48V to 12V converter (001-DCC-001), or alternatively from 002-BB-001.
001-MTS-001 is a manual transfer switch that isolates the positive and negative terminals of each power circuit.
To answer your question more practically: there is approximately 50 meters between the two buildings, and therefore between each battery bank. During maintenance on the main system—regardless of the reason—essential loads such as the fridge, lighting, and water pumps can remain energized using the alternate battery bank.
As you may have gathered, this system was initially a much smaller scale 12 V system, hence why all loads are on 12 V.
I was just curious why you wouldn’t use the battery as a buffer on the DC/DC, effectively combining the capacity. Although that might inhibit fully charging the PbA bank, and the distance changes the equation.
I have a mixed voltage system on my coach, I like to see what others do in similar situations.
I would generally advise against mixing network circuits unless the equipement is explictely compatible to be paralleled. For example, if I had two dc to dc converters feeder the distribution panel that had parallel capabilities it would be ok.