question

@Der Hannes

It sounds similar to this problem.

https://community.victronenergy.com/questions/136049/critical-load-shows-high-values-how-can-i-check-th.html

Maybe "3.5mm jack trick" will work for you.

Hello marekp,

I tried the "3.5mm jack trick" and plugged and unplugged my PC-headset 10 times. What can I say...everything is going great at the moment...I'll of course be a bit suspicious of this, but it's going great at the moment!

If you're ever in the vicinity of Frankfurt a.M., here's a free beer waiting for you!

But now the question: Why do I only have the problem now, after the system has been running without problems for almost 2 years? And I've also observed how the problem has occurred more frequently and more severely in recent weeks! Has any potential built up on the 3.5mm plug over the weeks/months and with the "trick" has it been dismantled for the time being?

@Der Hannes

I am glad that this "3.5 plug trick" helped.

The problem stems from the tarnished side contact in the 3.5mm socket for external CT. When you use external CT you have to separate the internal CT and that "side contact" does the job when you plug in the external CT.

When this separating contact gets tarnished internal CT is not seen by the system because is separated. The 3.5mm plug trick cleans the tarnished contact and internal CT is once again seen by the system.

I think Victron should add a jumper short, for those that never use external CT, and make the internal CT connection more secure.

The "hard core" solution would be to solder a jumper yourself but that would probably void the warranty.

@MarekP

for the good and plausible explanation of the cause, I'll raise another free beer!

Unfortunately, the problem reappeared, so I reconnected the "critical loads" to the "normal network". Now it's running fine again and it would also fit your explanation, which I assume without the "critical loads" the MP-2 does not need to evaluate the internal current sensor either and thus does not come up with incorrect measured values.

I'll watch it again and report back ;)

I wouldn't have a problem soldering in a jumper either, the question is, is it possible to achieve something with just the 3.5mm contact and a pull-up/pull-down resistor on the connector itself? Then you would also have a solution for laypeople and there shouldn't be a problem with the guarantee...

So the problem doesn't seem to be fixed for me yet. I wouldn't have any problem buying an external current sensor either, but it should always show 0 because I no longer use the output on the Multiplus.

I had already considered simply shorting the 3.5mm plug. Thus, fixed 0 amperes should always be faked.

The only disadvantage would be that I can't use the outputs on the MP-2, but that wouldn't be so important to me once the MP-2 regulates well again and no longer swings up so much. At the moment it does it very often...even at night, with o solar power and a constant load (about 150W), the MP-2 gets totally unbalanced as soon as I switch it on. So it is absolutely not usable at the moment!

Well, now the problem seems to be solved. I bought the external current sensor and plugged it into the MP2's supply line. Since then it has been running without any problems.

Thank you for the great support!

I'll let it run like this for now. As soon as problems arise again, I will unscrew the MP2 completely and take a close look at the contacts and plugs, clean them and possibly solder in a jumper.

Best regards

Hannes