question

saman-daneshvar avatar image
saman-daneshvar asked

DC Coupled

I am working on a research project involving a DC-coupled battery and solar setup. In this system, an AC/DC inverter is connected to the battery, and the solar panels are connected to the battery through a DC/DC converter. The goal is to remotely control the amount of power flowing from the solar panels to the battery and from the battery to the grid through a PLC using Modbus (or any other protocol). I have seen posts about enabling and disabling the inverter remotely using Modbus, but I haven't found any information on controlling the power flow. I am trying to understand if I can use Victron products for this custom design and to determine which products/specs might be necessary. Any support would be greatly appreciated.

MPPT SmartSolarbatteryorion dc-dc
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

5 Answers
markus-001 avatar image
markus-001 answered ·

@saman daneshvar On the smart solar MPPT’s you can defiantly throttle the charge current to the batteries using Node Red. The increments are whole numbers so no decimals and each one in the system can be controlled separately. You can add a dashboard with the charge currents and access that through the VRM portal for remote access. You could also automate the charge current based on your own unique conditions. You would require one GX device (Cerbo gx) in the system and depending on the number of MPPT’s required you may need to use the VE.Can MPPT’s as you can string up to 25 together. No PLC required everything is included on the Cerbo when using the enhanced large image (free online update) modbus functionality can be added by downloading one of the modbus nodes but is not required as most of the control options are already included in the standard Victron node.

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

saman-daneshvar avatar image
saman-daneshvar answered ·

@Markus_001

Markus,

Thank you so much for replying and providing the information. This topology is exactly a DC Coupled system. I have checked with your team and found that your DC/DC converters are not bidirectional. Therefore, we will use two converters for charging and discharging. The components should be under 500W or below 1000W for now, as this is a research project. I would appreciate your assistance in selecting the right components. Please find a comprehensive schematic attached.

Much appreciated.

Best regards,1721187277926.png


1721187277926.png (307.5 KiB)
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

markus-001 avatar image
markus-001 answered ·

You will need a bidirectional inverter to synchronize with the grid, an item from the inverter/charger range. Check with Victron sales on the smallest one I think it’s the multiplus 500va. You won’t need the dc/dc converter, the multiplus handles everything when you install the ESS assistant.


In your schematic you’ll need to break the link between the PV panels and the inverter, the MPPT’s have a dedicated connection for the PV panels as they operate at completely different voltages to the battery side. Battery side/bus gets connected to the multi plus directly through fuses.

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

nickdb avatar image
nickdb answered ·

@saman daneshvar this topic is starting to overlap with one you already have open on Q&A where you have been given answers.

The community does not encourage broad design topics, these really need to be had with a qualified supplier who can advise you.

There is a huge amount of free reference information available here, on www.victronenergy.com and professional.victronenergy.com

As a researcher, that would be the best place to start to skill up and would answer most of your questions.

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

saman-daneshvar avatar image
saman-daneshvar answered ·

@Markus_001 Thank you so much Markus.

@nickdb Nick,

With all due respect, this is a new system we are working on, which is why we haven't found any existing products that fit our specific application. As researchers, we have thoroughly reviewed all the related information before reaching out. We still need further assistance if someone can provide it. Your help would be much appreciated.

Best regards,

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Related Resources

Additional resources still need to be added for this topic

MPPT product page

VictronConnect manual

PWM or MPPT

MPPT calculator

MPPT codes

Victron DC to DC Converters Product Range

__________