Strange Battery Monitor Behaviour

[Richard10002]

A couple of nights ago, the engine wouldnt start so I moved the connections to one of the starter batteries. (In addition to the thick red and black wires, there is also a thin cable with red and black - I dont know what this does, but moved it with the main cables).

Watching the Sterling Battery Monitor Domestic Bank, under the above arrangement, whilst it would show current discharge, it would not register above +0.0, even though I knew that charging was +ve i.e. nothing switched on other than battery charger on shore supply. After a day of this, the monitor showed about -45Ah.

Moving the wires back to the old battery, (and now the replacement battery), and the monitor shows +ve charging and I am guessing the batteries will be as good as full.

Clearly, attaching the cables from the engine battery to the domestic bank made this happen, but I merely wonder why - although I dont think it really matters).

Presumably, I can just press the buttons to zero the -50Ah reading when the batteries are showing a full charge .... but how many Volts is this in real life?

Cheers

Richard

 

[hightech]

The charging side of your set up was not being passed through the shunt, although the discharge side was, usually just a case of getting the wire on the non battery side of the shunt.

 

[BlueSkyNick]

Richard, I'm not sure about this because you have changed your engine battery, not your domestics ..... I believe. However you are looking to see if your domestics are recharged as well. The voltage varies, (assumng you have the charger turned off! /forums/images/graemlins/smile.gif ), depending on the load. Now, I always turn everything off and waiti a few minutes for it to settle down before taking a reading. It should be close to 13volts.

However, you can also determine if the batteries are charged by looking at the current going into them (now with the charger on!). Again with everything turned off, you should be down to approx 1 Amp - that's when I recalibrated my battery monitor to show full charge. Mine is a Xantec (?) not a Sterling, but I am sure it works in a similar way.

Hope this is along the right lines - I've just got back from the CLub after a few beers so could be rubbish ! /forums/images/graemlins/smile.gif

As for the leak in the aft cabin, I've just fixed one of those too !!