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dennis-clayton avatar image
dennis-clayton asked

Unstable DC information on a colour controller

We have a new installation of a quatro 5kw, mppt, bv bus, cyrix, BMV700, Lithium batteries and a colour controller. The system is up and working ok on AC input, inverting and battery monitoring and SOC display but the DC power box is a little crazy. Even if there is no DC load called for it shows a fluctuating value in minus and plus values. If you put on the inverter to pull a load from the batteries the controller shows an output but not consistant. Also it does not show any input from the alternator when the engine is running(its a marine installation)

Any ideas on why the DC values are all over the place. Also the line connection on the screen seems to show the current flowing the wrong way considering the minus or plus figure in the DC box.

CCGX Color Control
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2 Answers
Paul B avatar image
Paul B answered ·

check that your BMV is displaying correctly, Ie is your shunt installed backwards.

the DC power is a calculation and there can go up and down when the watts is very low so there is always some ambiguity there. ie it takes the solar plus what the battery is being charged plus what the inverter is using and any difference is presumed to be DC power, so any calculation errors end you there.

well thats my understanding of it anyway


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pwfarnell avatar image
pwfarnell answered ·

Make sure that the alternator current also passes through the shunt, i.e. the alternator should connect to the load side of the shunt. Then when the alternator is running, the DC power will show a large negative value. For example, on my boat when charging starts I can see a DC power of -1500W, which at a charging voltage of 14.4V is just over 100A from the alternator and the battery will show this 100A being charged. As noted above, the DC power is calculated as a balance of the measured powers so it is not an exact match.

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