Observatory Power Distribution Box

[Gina]

[Gina]

[Gina]

Circuit diagram.  Because of the way the digital ammeters work they need a higher voltage supply to allow them to be placed in the positive line to the devices.  They are normally placed in the negative line but with the earthing (grounding) system employed, this is not possible.  The higher voltage is supplied with an up-converter - the step up version of a buck converter.  With the battery being separate from the observatory wiring, the VA display can be put in the negative side.  Battery negative is only connected to observatory Ground via the current shunt in the display.  The PSU is also isolated from observatory Gnd.