question

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doublebubble asked

12v lights dimming

I wonder whether someone could advise as to why our 12v cabin lighting in our yacht dim for a split second when our 240v freezer cycle's on? We have had a Phoenix Multiplus 12/3000/120 fitted for around 10yrs now without any problems but we have always had the issue with dimming lights when a load is applied to the Multiplus, this happens when we are on shore power or in inverter mode, we have an 800ah battery bank which is always fully charged according to the Multiplus, in float mode and also indicated by the Victron BMV, can anybody explain as to what could be causing this, wiring problem?

Phoenix Inverter
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dazey77 answered ·

The fridge compressor is a high load, so your getting a dimming effect from voltage drop. It could be that the load is causing the battery voltage to drop enough to be seen on the lights. Alternative is that the lights and compressor share some wiring and your lights are seeing a voltage drop on the cable due to the current.

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doublebubble answered ·

Thanks for the reply, thats exactly what I was thinking, the only thing I can think of is as a shared wiring situation is the pos & neg connection to the Multiplus for it to run in inverter mode, could the Multiplus be getting a bit tired.

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wkirby avatar image wkirby ♦♦ commented ·

It's more likely that your battery bank is getting tired. Even a well maintained lead acid battery will degrade over time.
If your battery bank is also 10 years old, then it's doing pretty well!

You could double check your high current connections between the battery and MultiPlus for corrosion or check for bad connections for good measure.

The MultiPlus will just keep going and if something does go wrong, then it'll just stop.

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doublebubble avatar image doublebubble wkirby ♦♦ commented ·

As we got 12yrs out of our last battery bank, Lifeline GPL-16T, and have replaced them one year ago let's hope they are ok, I'll go through the battery cable connection's and have a look, I guess it's possible to have a bad connection with one of the parrelling switches.

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