question

tpbradysr avatar image
tpbradysr asked

Cerbo GN50 Display


a. When I switch on 12 volt input to a power supply for a laptop computer, the Cerbo reboots. The 12 volt panel controlling the computer and 5 other devices all fused at the panel are on a separate DC feed from the main DC panel. Any suggestions as to what might cause that?

b. On the Cerbo Display. What do the various windows mean?

  1. Is the difference between the shore power watts and the AC load watts the amount being consumed by the Multiplus plus any other AC loads not passing through the Multiplus?
  2. In the battery window, is the value shown as amps the net amps being sent to or being taken from the battery?
  3. When looking at the menu items in Inverter there is a DC current value that doesn’t match the DC current shown on the shunt. Is this the difference between the charge going to the battery and the DC current being consumed on board?
  4. Why is the DC power shown in watts and why doesn’t it equal more closely the amps shown as going into the battery? Even using 12 volts divided into the number of watts it actually shows 1.5 fewer amps than the value shown in the battery window. You would think it would be the opposite of that since energy from the charger is lost as heat in the charging process.
cerbo gx
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1 Answer
Kevin Windrem avatar image
Kevin Windrem answered ·

Cerbo rebooting indicates it's voltage is dropping below 9 volts! That's a huge dip due to turning on your 12 volt power supply. You may need "precharge" circuitry to reduce the spike.

You could also have some odd wiring in the negative side causing Cerbo's voltage drop.


Cerbo and the Multi will not see AC loads if they are connected up stream of the Multi. The power calculations are all within the Multi (unless you have a grid meter). So the difference between the AC input and AC output readings is what the Multi is consuming (charging) or adding to support the load (power assist).

Cerbo allows you to calculate load/charge from components outside of what Cerbo can measure. It's called "Has DC System". With that enabled, currents to/from the battery, Multi and solar chargers plus the DC System numbers should approximately add up to zero.

Make sure your shunt is connected properly: the only thing that should be connected to the Battery - terminal is the battery. All loads, Multi, charging sources connect to the System - terminal.

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