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This is the third one I've encountered. This is a 250/85 VE.Can model.
MPPT clearly reading a full 1V higher than the shunt and inverter:
This is 2am with the charger idle, so current is not influencing it. This clearly does not meet the 1% allowance in the RMA troubleshooting doc.
Have you actually measured it with an accurate meter?
No. I am helping a completely non-technical person from 1,150 miles away.
This is either a situation where the MPPT is wrong or both the Lynx Shunt AND Quattro pair are wrong.
This system has been unable to attain full charge due to the lower charge voltage observed by the MPPT.
I have enabled DVCC and SVS, so the MPPT is now using the shunt voltage:
I think the inescapable conclusion is that ONE or TWO Victron devices measuring the same battery are in error.
Connections will be checked, but if connections were an issue, 50A would cause way more than +1.2V vs. +1.0V @ 0A:
Ive sked similar a while back and have something odd to add.
I had a .3volt difference between batteries and the easysolar. The Easysolar had the higher reading
I recently 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. Perfect.
Maybe it's to do with the style of batteries
When you can't see the install or setup it makes it difficult.
Some loss is usual. If there is incorrect or poor quality equipment/wiring between the mppts and the DC bus then you could see a loss, so the only way is to grab a meter and actually measure along the chain, at each connection/terminal.
Then you know for sure if the reading is right or wrong.
I had one brand of batteries that seemed to have inherent loss in them, once replaced with another it was fine. So problems can exist in weird places.
The probability of multiple devices having an identical fault is small.
One can deduce installation issues comparing voltages and currents.
50A produces a +0.2V difference vs 0A. This is produced by 0.2V/50A = 4mΩ resistance between the MPPT and battery and everything in between (wires, lynx distributor). This resistance is not indicative of a significant installation issue.
So, one or two victron components are measuring faulty voltage. Given the probability of multiple identical devices having an identical fault puts the MPPT has the greatest probability.
You just can't see the install or measure what is required.
This problem is being proxied via yourself for a third party,
If there was an issue we wouldn't know as a community, and we can't use the channels we have because the info is second hand and no one has tried to actually measure what is happening or show how it is installed.
There are not enough of these complaints, and the ones that exist are often install related.
So, I suggest you either get the user to do the legwork and come post detail, first hand, or log a ticket via support.
If a meter shows that the mppt is outside of tolerance, RMA it and then provide feedback on the testing and results, then we, as a community team, will happily raise it through the mechanisms we have. But as long as it remains anecdotal there isn't much that can be done here.
Help us to help you.
I'd been meaning to make my own post about this, but since you've started this one, I'll just add my experience here.
My system: MultiPlus 48/5000/70-100 with Freedom Won 20kWh
I believe I have the exact same situation, with a difference of around 2v in my case. The battery was also not charging to 100% for a long time (often stopping below 80%), and I never quite knew why. I only recently realised that the voltages in the different parts of the system were reading very differently. Then, after some digging around on these forums, I discovered the Shared Voltage Sense (SVS), and decided that might solve my problem. It does indeed seem like it did, and I now get 100% every day. See screenshot of the various voltages, and where I enabled SVS (then disabled, then enabled again).
Here's what my daily SOC was doing before I enabled SVS. The max SOC was slowly drifting downwards every day, and then eventually one day it would just randomly hit 100%, and then start drifting downwards again. (Note that there was never a lack of sunshine that would account for charging to less than 100%):
So, I finally got around to taking some measurements, and I can confirm that the voltage that my MPPT is reporting is not the same as the voltage that I measured with my multimeter. I took measurements at the inverter battery terminals, and the MPPT battery terminals, and the voltage I measured was the same. However, the voltage reported by the MPPT was around 2V higher than what I measured.
I took measurements in a few different situations: With moderate load, then almost no load. With PV production, then no production (night time). In all cases, the MPPT reported voltage was consistently 2V higher than what my multimeter was reading at the MPPT terminals.
@nickdb You said that this is a known issue with the FreedomWon batteries, but how can this be explained as a battery issue?
Same thing here. All connections checked. Voltmeter at the MPPT battery terminals measures consistent with shunt and Quattro. About 1V difference between meter and MPPT reported value @ 0A. It doesn't increase significantly with peak current (about 1.2V).
I've just left DVCC enabled, and charging to 100% occurs when conditions allow. The idea of pursuing warranty and replacing this thing with this user makes my brain bleed.
