Sterling Battery Charger Problem

[nightjar]

My boat has a Sterling charger that was fitted when the boat was built 14 years ago. Since I bought the boat 6 years ago the charger has worked fine when needed and was able to supply battery charging and supply the 12V equipment. Normally when we switch the charger on it goes into its high charge cycle at around 14V for usually a couple of hours before it reverts to 12.5V float charge. Having been away from the boat for a couple of months the charger was once again used to boost the batteries, however on this occasion the high charge cycle was maintained for nearly 20 hours at 14V. It did not revert to float. The battery bank is 2 X 120Ah and 1 X 65Ah which are 4 years old. I have checked the battery Sg readings and all cells are indicating the same reading just below full charge so the batteries seem OK. Is there an easy way to check if the charger has a problem ? Thanks for any ideas before I call the electrics man.

 

[David2452]

Where you using an unusual amount of 12v loads during the time you were aboard, or the usual load but for longer?

 

[nightjar]

No nothing unusual, the TV is 240V from shore power so lights only.

 

[sailinglegend420]

...on this occasion the high charge cycle was maintained for nearly 20 hours at 14V...........

I have had reports that older Sterlings had a problem that every time there was a high house load they went straight back into boost mode even if the batteries were fully charged. They could keep doing this which left the batteries almost permanently at a gassing voltage and caused sealed batteries to die quickly. They now have a "Power Pack" mode which will deliver the full current of the charger at the float voltage of 13.5v (not 12.5v as you suggested).

I have asked Mr Sterling for clarification of this but he of course has not responded, so I can only report what has been told me by very reliable sources.

I would suggest you monitor the performance of the charger and your batteries carefully to see if they will stay in float if there is no boat load.

Your batteries could also be shot! A high SG just means they have reached a full charge for the capacity they have left in them. This could be almost nothing! I would be very interested in your further feedback - or feedback from Mr Sterling would be nice.