question

Hi all,

Does nobody from this Community use a Multiplus II 5000 GX who can check this on his/her installation?

Would be very helpfully for me to know.

Thank a lot.

Dirk

Hi @Dirk_S

I've an earlier Multi 48/5000 and see a V difference of up to 0.2V. It varies for some reason, maybe a Temperature thing? I 'fixed' it by using DVCC to pass on to it a better V from a Smartshunt.

With your Pylons I don't think you can do that, but the Pylons should be controlling everything anyway if set up correctly. What the Multi reads itself shouldn't really matter. But I've little experience with the Pylons, so check this out for yourself. With managed batts (at least the Victron-supported ones), if they say they're happy, then all should be good.

Picked up a similar problem. The chart below shows differences between the VE.Bus (MultiPlus) and the BMS (Freedomwon). Conditions: no load, no charging, no solar. The variance is sufficient to put the system into Absorb charge when the BMS battery SoC is being reported as 49%. In the large (6 month) chart, the difference between the voltages is increasing over time. In April at the start of the flat line section, the MP II firmware was updated. Going to confirm the bus voltages using a meter to confirm which is more correct, the BMS or the VE.Bus

Bonjour, j'ai un problème identique. Mon multiplus II indiqué 51,8v alors que la tension de batterie est de 50v. J'ai mesuré la tension réelle au borne du multiplus elle est de 50v mais le multiplusII indiqué au cerbo 51.8v. Quelqu'un sait-il comment résoudre ce problème ou si je dois l'envoyer en réparation ?

Merci

Same problem here now.

MP II measures 56,8V when the real voltage over the terminals is only 55.6V. The BMS measures 55.6V, the MPPTs show 55.6V but the Multiplus shows more than 1V more.

Anything I can do about it?

In my case, there was an inverter hardware issue, and an update to the Venus OS resolved the problem.

My Multiplus II 48/3000/35-32 has about a 5.1% error.

Actual battery voltage read on the Multiplus terminals is 54.0V (Confirmed with two multimeters). Reading in VictronConnect shows 56.84V. I also tried with VSense (Kevin connection) and no different.

I just disabled VSense in the charger settings and the battery voltage is pretty much spot on. The setting has a comment "For diagnostic purposes only" - What is the practical implications of leaving this setting on?

@dirk-s:
Exactly the same situation here, Multi II and Pylontech US5000, just a few weeks old.
Battery-BMS reports around 0,3V more as VE.Bus DC (independent if load/idle/sharge). Meassured with two Multimeter, the Battery BMS is the correct one.

Did you ever got a solution? I think in another thread a user reported that Victron was able to re-calibrate the DC-sensor by a remote session.

Kind regards,

This may have something to do with the voltage variances seen with Pylontech.

Checked a site with Pylontech UP2500 and saw voltage variances between VE.Bus and battery BMS. When fully charged, the variance is consistent at 0.2V. I don't see this at other non-Pylontech sites.

https://www.victronenergy.com/live/battery_compatibility:pylontech_phantom

Just came across this post as I have the same problem with around 350mV discrepancy between measured and real voltage. Did you ever get to the bottom of the problem? It obviously a wide fault/issue.

I asked similar a while back and have something odd to add.

I have an easysolar 24v 3000

I had 12x2v 500ah lead acid batteries that would always read .3v less than the easysolar. Now I would think a voltage drop and might get less at the Easysolar.

The cables are 500mm long and well sized. No shunt installed.

Then recently I changed to 8 x 3.2V 200ah self build Lifepo4. This is connected to a Daly then a new smart shunt. All with the same cables.

Now the voltage reads exactly the same at the batteries, the Daly and the Easysolar.

Go figure?