question

Check the wiring - this description indicates that something is installed incorrectly. Nothing may be connected to the "battery" side of the shunt other than the battery, and nothing may be connected to the battery negative other than the "battery" side of the shunt.

Thank you Justin for your reply.

I'm quite sure that the installer respected the IP65 connection rule you emphasise. Here is the wiring scheme:

However, the alternator wiring is not evidented there, but the CamperVan producer assures that by default it charges both, the vehicle and the leisure battery. I guess that the alternator + must come out of the B1+ and the B2+ and that alternator - is on chassis (ground).

I don't exlude that the IP65 readout is correct and that there is a malfunction in alternator circuit feeding liesure battery just because in the three years of CamperVan experience we strictly practice connection to the aux power line (except while driving). Unfortunately I never paid much attention to leisure battery so now I'm not in position to identify any irregularity or even change in the battery behaviour. I tried to compensate the lack of experience with IP65 as the first time we wanted to rely on battery for a day, we run out of energy after 6 hours, with the house control pannel showing 3/4 of remaining capacity....

Any idea how to nail the problem?

Like @Justin Cook - Bay Marine Supply USA wrote: Nothing may be connected to the "battery" side of the shunt other than the battery, and nothing may be connected to the battery negative other than the "battery" side of the shunt.

And your wiring scheme shows someting else.

You need to connect the IP65 shunt connection Batttery Minus directly on to the leisure battery minus terminal, and what was connected to the leisure battery minus terminal must be connected on to the IP65 shunt Load Battery.

To help lesson any confusion other readers may have about what "IP65" means it is nothing more than a dust and liquid Ingress Prodection code. This code can be applied to many other devices as well. From Wikipedia: IP Code.

To say it more simple: in between the IP65 shunt and the battery negative nothing can be connected.

The drawing below shows that the shunt is connected first to the battery, no additional wires first.

Thank you theo74.

I would sware that this is how shunt is wired in my camper. A single cabel connects Batt - to Shunt Batt side! There are no other connections in between! At least - this is how it can be seen. So, IMHO, to solve the problem a wire that is hidden to the eyes should be searched for, or, there must be a hocus-pocus on the alternator charger part of the circuit. I don't have a clue how to approach each point and I count that the shunt installer and the CamperVan producer would join forces to figure it out.

I wonder if I should involve a car-electrician/service and could it help to enable or speed-up the diagnose of the problem?

I guess there must be at least tens of CamperVans based on Ducato/Jumper/Boxer vans with common CamperVan 12V infrastructure built-in (exactly like mine) with an add-on of SmartShunt IP65 circulating around Europe. Am I the first and the only to experience such problem?

KInd regards,

When the shunt is connected directly on to the battery negative and not any wire is in between the shunt and the battery negative, then the discharge current from your battery alsmost must be true, and not something which has to do with a wrong connection of the shunt it self.

Or the shunt it self is not calibrated, but I don't think this is the issue in case of unclear and higher discharge currents... Out of the box the shunt is accurate enough to measure normal currents.

Then you need to search for a load or fault, what is probably causing more current to be consumed than the alternator can deliver.

1. Bad grounding of the alternator. Check, clean, measure.

2. D+ signal from the alternator is not ok/missing. Check, clean, measure.

3. Charge relay/Cirix does not get the D+ signal, or is broken. Measure In and Out

4. Alternative to point 3; DC-DC charger booster is broken, or does no deliver enough current.

5. Refrigerator is pulling more amps at 12VDC during driving, than the alternator can deliver.

6. Connections in the 12VDC circuit are bad, loose, filthy. Check, clean, measure.

When the engine is off, a healthy domestic battery or starter battery should be at about 12.5V.

When the engine is running, you should measure about 14,0-14,4V charge power on both batteries.

If you have a current clamp meter, than you can measure all the different cables leaving the busbar to their loads. To find out which load is pulling a lot of current as a result of which the battery drains.

Excellent theo74, thank you very much!

I have the feeling that from here we can get to the diagnose and to the solution.

Why? Because I do not recall that at the end of the journey/drive with the CamperVan I have ever read all the 8 LEDs on the CamperVan control pannel indicating the full level of the leasure battery. One or two were always missing. But until recently I have never run into leisure battery capacity problem (I guess due to strict and prompt usage of mains power) which was the trigger to seek for better monitoring. So the cause of the problem seems not to be "binary" - right/wrong or on/off, but something in beetween: just good/bad enough not to be easily noticed.

Let's hunt the problem by your list, then!

Be sure I will report the result.

Kind regards,

I'm assuming that the device on the left of the diagram is a relay that connects the vehicle and leisure battery positives when engaged. If so a discharge of the leisure battery could happen if the leisure battery voltage is HIGHER than that of the vehicle battery and the alternator. You should make those voltage measurements with the relay open.

The best way to insure no back-charging occurs is to use a DC-DC charger instead of a relay.

Kevin Windrem, thank you!

This explains why the problem might be there since a long time, but never caused "black outs": The leise battery would feed the car battery until the voltages are even while alternator manages to keep a decent level of both, but never fulls the up to the edge.

Something to consider to troubleshoot at first, I guess.

Anyhow, with the help from this forum I gain confidence that the problem coud be sorted out, sooner or later and that the purchase of SmartShunt was a real "bingo"!

Kind regards,