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thomas-w asked

Centaur 12/40 erratic behaviour

Hey Folks, I need a bit of advice here.

Just bought a boat with said charger installed and seemingly worked fine for the first weeks, or I simply didn't notice. The boat is from 2007 so the charger is likely from 2007 as well.

I have two battery banks the chargers connects to, directly, one house and one engine. The third output is not connected. The engine battery is 75Ah and the house bank is combined 360Ah (3x120Ah)

I would like to run the fridge permanently which pulls around 6A.

When returning from cruising, I can see the charger (using the VIctrom battery monitor) quickly go up to 130W charge, which in return very quickly (minutes) tapers off until around 10-20 minutes later it would stop. Voltage (according to BMV) goes up to around 13.05V maximum battery voltage. Charge diminishes after 10-20 minutes where in the end if would only charge with a few watts if at all.

Once it turns off, the fridge necessarily depletes the battery. The Centaur never switches on again and subsequently my separate battery fail safe triggers and the fridge turns off. Periodically, it seems, the centaur IS trying to charge as upon returning to the boat after 1-2d, the fridge may be powered off, but the contents are not entirely cold. So It seems at some stage it will try to charge but I never been able to see it when returning to the boat.

Once I do return to the boat, the BMV says -5W (consuming) or so - the stand-by draw of a few devices. If I turn off the charger, and turn on again I can bring it back to live for a while. Initially 130W charge, then tapering off and quickly stopping charging entirely. I can repeat this a few times and actually do get the thing to charge when just basically tripping the switch every 10 minutes.

I've opened the device and nothing looks amiss, looks really great. Fans run, device seems not to be overheating but wouldn't know where to look. Nothing blocking the fans etc. I've tried three battery settings, all to the same conclusion. I have LA batteries and the corresponding setting has been made.

Is it possible that there is an issue with the temperature sensor inside the unit? The engine battery is kept at 13.30V (LA setting) and seemingly always hovers around this point which is perfect. I've never seen 13.30V on the house. The symptom I have seems to be compatible with overheating (the manual says that there's an internal temp sensor which when triggers will reduce charge current).

Additionally, I've never seen more than 130W (10.5A) going into the battery despite the engine battery sitting full and really expecting 500W (or at least 400W) charge. This is confirmed by the amperemeter on front of the device which never exceeds 10A (it may for a brief moment when the charger is turned on after returning to the dock which I've never seen - it normally shows < 5A if it does charge at all).

The battery bank is new and seems to charge fine with the alternator. I'm currently sitting on ~ 50Ah consumed (according to BMV) and cannot convince the battery charger to charger the battery fully.

What could be the issue here?

Thanks guys,


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