shalombi avatar image
shalombi asked

BlueSolar 150/70 and Pylontech -- High voltage reading on MPPT - Won't charge to correct voltage

Hello everyone,

For the last few months I've been trying to debug an issue and I think I got to the bottom of it but I need some advice.

# The Setup

This setup has been running flawlessly for the last 3 years +-, issues started a few months ago.

Assume that everything is up to date and configured according to the Victron - Pylontech guide.

- 2 X Pylontech US2000 batteries (updated to latest firmware, 94% health)

- MultiPlus 48/3000/35-50 (running latest version)

- BlueSolar 150/70 (running latest version, external control, power cycled 1 hour to make sure)

- BMV-700 (running latest version, not strictly necessary in this setup)

- CCGX (running latest version, some doubts about some settings)

- Generator 7KW

This is a 100% off grid setup.

# The Issue

- PV will charge correctly up until 60-65% then slow down and stop at 72% (reads idle on the battery) --> BMS will mark that it's sill accepting 50Ah 53.2V

- When charging with the generator it will charge to 100% at 35A but as soon as the generator is on, MPPT will produces 0A instead of supplementing till 50A like it used to.

# What I think is happening

So after going through all the settings, update the batteries with Pylontech etc... My current assumption is the problem is with the MPPT and the voltage it's reading.


I've been testing all day and I'm seeing a big difference in reported voltage by the MPPT compared to the real voltage read from the other devices and a multimeter. So we have 3 reading marking 50V and the MPPT saying 52.4V

This means the battery isn't getting charged fully and sits Idle after a generator charge:


This makes sense if the BlueSolar thinks it reached the max 52.4V while really it's at 50v and why it would turn off when it sees the generator charging the batteries at what it thinks is 53.2V.

And the MPPT reports networked operations at :


BMS is reporting it accept 53.2V and 50 A until it gets charged with the generator to 98%+-


There is almost no difference between min and max cell on Pylontech, less than 0.02V.

# So solutions I can think off:

- Fix the MPPT voltage reading, no idea how to do that, cables are secured and seem to be in good conditions / not heating up.

- Set the MPPT to charge with a 2V offset, but I don't know how to change the max CVL which is forced by Victron at 52.4V.

Any ideas are welcome, this has been on my mind for many months and I feel like I'm getting there but I don't know where to go from here.

Thank you for reading.

CCGX Color ControlPylontechBlueSolar PWM
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Alexandra avatar image Alexandra ♦ commented ·

It should not matter what the mppt reads if the Pylontec is controlling the system through DVCC.

What do you have set as the battery monitor in system setup?

it may be a good idea to check wiring between the mppt and battery for corrosion or loose connections.

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shalombi avatar image shalombi Alexandra ♦ commented ·

it's set to automatic which selects Pylontech BMS:


DVCC is on as per the Victorn-Pylontech guide, controlling BMS Pylontech on this screen as well:


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1 Answer
kevgermany avatar image
kevgermany answered ·

If you're measuring battery voltage at the MPPT battery terminals and the MPPT reports a different value, there's an internal fault in the MPPT. Confirmed by the other readings from battery etc. This can cause the problems you describe.

Sorry, but dealer/warranty job. Hope you're still inside the 5 year warranty period.

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Related Resources

CCGX Product Manual

CCGX Product page

Victron Pylontech battery compatibility guide

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