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Powerbox fuse redesign

April 11, 2020 — BarryK

Previous post for new camping powerbox:

A couple of days ago, created a preliminary circuit diagram, with quasi-physical layout:

After more study of other circuits, I have redesigned with two more fuses:


Previously, if the bottom-right circuit breaker was switched to open-circuit, while still charging from the car's alternator, it may have an odd effect on the +bus. Now, that circuit-breaker disconnects from the +bus, and another fuse has been added to the "DC out" (black Anderson plug).

It may be overkill, but I also added one to the grey plug, going out to the solar panel.

I also made a note for the red Anderson plug. Modern cars have "smart" alternators, where there is a shunt between the battery negative terminal and chassis-earth, just like I have done with the lithium battery in above diagram.

For the electronic control system of the car to recognise the existence of the DC-DC charger, the negative lead from the red plug must go to chassis-earth, preferably close to the car battery.

EDIT 2020-05-03:
A "protected +bus" has been added -- the "+bus" is connected directly to the lithium battery, whereas the "protected +bus" is on the other side of a 30A circuit breaker. Also, binding posts have been added. Both of these changes are discussed in a later blog post:

Consequently, the circuit diagram has been updated:


This was created by Dia (a Linux GUI application, available in EasyOS, Quirky, Puppy Linux, and most other Linux distributions). Here is the Dia file:

Here is the file exported to SVG: 

Tags: nomad