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trip-tracks asked

MPPT 100/50 not using VE Smart Networking voltage

Background:
I have an install where a customer wanted to charge their RV LiFePO4 batteries via solar panels mounted on their shed and also use the RV power for running fridges in the shed, but they did not want the solar regulator mounted in the RV. A SmartSolar MPPT 100/50 was mounted on the shed wall with a 10mm2 x 5m cable length (10m return) between the solar regulator and the batteries. I knew voltage drop under load was going to be an issue, so planned on using VE Smart Networking to resolve the issue.

The customer already had a BMV700 installed in their RV, so I added a Smart Dongle to provide the BT connectivity to the Smart Solar MPPT100/50, created the VE.Smart Network on the BMV700 and connected the 100/50 to the same network, and the displays on both devices verified the voltage and current were being used (apparently).

The absorption voltage was set to 14.2V and float to 13.5V.


Result:

The displayed battery voltage on the MPPT 100/50 was showing 14.21V almost immediately on switching on the charging, the displayed voltage on the BMV700 was 13.5V (13.88V on the captured image, but that still shows it as different). The 100/50 immediately went to absorption, ignoring the BMV voltage. I would have expected the MPPT to display the BMV voltage and stay in bulk until the absorption voltage was reached.


Firmware versions:

SmartSolar MPPT 100/50: v1.53 (latest) at the time (Oct 31 2020)
BMV: v3.10 - also latest at the time

I have included screen images to verify my testing and configuration.


There appears to be a bug in the software, if someone can have a look at this, please?


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MPPT ControllersBMV Battery MonitorVE.Smart Network
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trip-tracks avatar image trip-tracks commented ·

Can anyone help with this, please?


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2 Answers
mkuiken avatar image
mkuiken answered ·

Hi @Trip-Tracks,

I can confirm the issue. We've been able to pinpoint the problem and it's more likely to occur on systems with smaller batteries and batteries which are full or almost full.

This issue will be solved soon. I'm sorry for the inconvenience in the mean time.

Best regards

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trip-tracks avatar image trip-tracks commented ·

Hi @mkuiken

The system in the report above was 400AH @12V, and the system was initially at 60% when first observed.

The issue with this system was due to the regulator not being able to be placed too close to the battery the voltages were very different and the regulator went to absorption even at 60% SOC (LiFePO4 batteries).

The issue just appears to be the solar regulator not using the transmitted values, as published, and as expected. I suspect it to be more of a problem with long cables between the regulator and the battery than short cables, but this is the issue it is supposed to resolve.

Thanks for confirming. How will I know when this issue is resolved?




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mkuiken avatar image mkuiken trip-tracks commented ·

The acknowledged issue is dependent on a bunch of circumstances, like battery capacity, its SOC and then also the voltage drop over the cable. Longer cables will therefor indeed contribute to the occurrence of this issue.

The fix will come with a new version of VictronConnect, though I don't know if it'll already be fixed in the next released VictronConnect. An update of VictronConnect will always come with a changelog (visible in the app store) and this will list changes to the Solar MPPT firmware.

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pauls avatar image pauls mkuiken commented ·

Hi,

I just stumbled upon this problem. It appears to be still present in v5.39beta3? Do you know if this is still an open issue and if there is an intention to fix it?

Thanks,

Paul

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trip-tracks avatar image trip-tracks mkuiken commented ·

Any updates on a fix for this, please?

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canalsman avatar image
canalsman answered ·

I also have this problem.


Is there any information as to when it will be fixed?

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