Battery drain

Hi all,  I have a 2015 Warwick XL. I have just returned from a trip abroad and parked in the drive to allow unloading and cleaning. After about 10 days I checked the batteries and noticed that the leisure battery was down in the red. I fully charged both batteries and checked again, the leisure battery is drawing 0.4amps with nothing switched on. I then put a meter on the battery and pulled the fuses on the ec500 one at a time, but this made no difference. Is 0.4amp draw Normal?  I also have an 80W solar panel fitted, but it does not provide much power at this time of year.

Perhaps there needs to be a forum sticky on this as it seems to get asked about every week!

The current monitor on all Sargent controllers that have the feature is inaccurate, and drifts with the passage of time. So it needs recalibrating on a regular basis or its output cannot be given any serious credence. If the manual for the EC500 doesn't tell you how to recalibrate, Google will find the info for you.

Irrespective of this, the system may have a current drain that is sapping the battery power, but more likely the battery is knackered (yes, I know - on a 2015 van it should not be, but batteries are to a certain extent unpredictable, and you can't know any battery's complete history - it may for example have been dropped before being installed). You can work out which by getting an accurate voltmeter and monitoring the voltage, both with the battery connected and then disconnected. Alternatively you can put a current meter in circuit and measure what the current is with everything supposedly turned off. It should not be more than a few milliamps (in fact in theory it should be fractions of a milliamp).

I have put a meter in the circuit and noted a drain of 0.4 amps, I then pulled the fuses one by one and noted no change. I will have the battery checked just in case.

Apologies - your statement "I put a meter on the battery" was a little vague, but if by that you mean that you measured the current with an independent meter (It seems obvious that you do now I re-read it) then there is something wrong and I would not suspect the battery.

Have you pulled ~all~ the fuses, including the ones external to the PSU? To state the obvious, 0.4A is quite a large current drain - enough to make whatever is using it warm to the touch, I would think (roughly 5 Watts power consumption).

Have you disconnected the solar panel? A friend who used a cheap free standing panel experienced a drain on the battery whenever the sun went down. He told me it turned out to be a faulty diode in the controller which allowed power to seep back from battery to panel.

I have only pulled the fuses on the psu. when I talk about putting a meter on the battery, I mean disconnecting the negative terminal and bridging it with my fluke meter.

As bikeral suggests, there's a possibility of a fault in the solar panel, though in my experience that type of diode is far more likely to fail open circuit (and the panel just won't work) than to go short circuit when reversed.

Purely for the purposes of testing, I would remove the external fuses as well - for example there should be one for the split charge and (probably) another for the link from the habitation side to the vehicle battery. In particular, the former can be the source of issues if it the contacts get welded in the closed position. The fuse on the circuit to the fridge could be also be pulled - but I hope there is zero chance of that having any effect on the situation...