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Potgieter avatar image

Changing solar priority in ESS

Is there a possibility To control when the batteries will be charged by the solar, maybe a specific time or when PV is that the specific high. The batteries is currently being charged in the morning as soon as PV is available and is not used by the grid I will have excess pv later in the day then The batteries can be charged

Thanks

ESS
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Hi all,

(First-time writer, long time reader.)

Sorry to revive an old thread, but I have been wondering the exact same thing, but haven't been able to find a solution. (Preferably, I don't want to run any scripts, just control the system via the CCGX or remote console.)

I have a Victron Quattro 5kVA, CCGX, two SmartSolar MPPTs, and 7.4 kW lithium battery. I have over-specced the panels, meaning that on a sunny day in South Africa, there is a lot of excess PV power at midday. Also, I can feed power into the grid. Accordingly, I would like the option to set the priority as follows: 1. loads, then 2. grid, and (last of all) 3. batteries. The rationale for this is that I want to utilise the inverter at maximum (about 4 kW) to feed into the grid (for maximum RoI) and then the excess PV power (of which there will be enough at midday) will charge the batteries.

Thoughts or suggestions?

Another query (possibly off-topic but related): is there a way, using the scheduling function, the set what time the batteries charge from PV power? As far as I can tell, the scheduling option only details with battery charging from the grid.

Thanks in advance for any responses,

Jim.

5 Answers
Guy Stewart (Victron Community Manager) avatar image

Out of the box: No. This is not a function that we currently provide in the user interface.

However, it should be possible to do with the currently available tools and controls.

One way would be to write your own control loop with a python script that sets the grid setpoint to negative whatever PV is making... times 0.88 (ish) for efficiency. This could also be done using NodeRed and/or a Raspberry Pi via modbus comms.

If you were considering this, I would suggest a new post in the modifications space to get help from other community members with modifications experience.

Reading these documents would also be a good start: https://www.victronenergy.com/live/ess:ess_mode_2_and_3

(You can use register 2902 to flip the ess mode to 3 when you want to do your own thing, and back to 1 when you want normal ess again).

https://community.victronenergy.com/questions/14801/externalexisting-node-red-connectivity-to-venus-os.html

https://github.com/victronenergy/node-red-contrib-victron

A good implementation could be something that gets included in future general releases.

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Guy Stewart (Victron Community Manager) avatar image

The priority use for PV in this system is :

  1. Loads (visible by direct connection or energy meter)
  2. Battery charge
  3. Grid export

There is no function to export PV to the grid before the batteries are charged.

Is this really what you want to do?

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Thank you for responding. Unfortunately the PV is used in the morning to charge the batteries and not being used by the loads, loads is currently taking energy from the grId. Only when the battery is fully charged, or there is more PV available then the loans use the PV. The priority use for PV is thus not correct on my system can you please explain to correct this.

It might be you have a minimum SOC set, and the battery is discharging below that point (through self discharge), or via the BatteryLife algorithm parameter.

I have a BYD battery system on my own ESS, and have less need for BatteryLife.

Is the morning PV charge going to loads once the battery SOC is above the minimum set in this ESS menu on the CCGX?


Potgieter avatar image Potgieter Guy Stewart (Victron Community Manager) ♦♦ ·

Here is my screenshot this shows that the batteries is not less thanthe SOC? Really don’t understand why it’s charging the batteries

I have a Multi with Fronius on AC out 1. All loads are on ACout 1+2. Zero feed-in active.

With steady state loads all is well. But in a domestic environment there are a number of loads that are on/off control. When these are on/off then all is not well at the expense of Solar and no charging (or very little) takes place.

Would really have liked to have the Grid deal with the on/off fluctuating loads, maximize Solar and take up a large chunk of the fluctuation by charging power. Adaptive control. eg when the load is detected to be fluctuating due to say 1 - 1.5 kW on/off type control then change priority could maximize solar?

Hi Guy,

Old thread, I know, sorry. Yes, I would like to change the priority order (using your numbering) to 1, 3, 2. Load first, then grid, then finally battery. Is there a way to do that?

Instead, or in addition, is there a way to schedule battery charging from PV power? (Easy to schedule battery charging from grid.) Aim: schedule the battery to be charged in the middle of the day, and export power to the grid all day (morning, middle, and afternoon).

Thanks,

Jim.

Yep I would also welcome this feature

Martin24 avatar image

As far as I know it is possible to get root access to CCGX or venusGX. Then it should be possible to run a small script to enable/disable charging base on date/time.

But I have not looked into details, yet.


And of course it would be much nicer to get this functionality directly in the firmware ...

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Yes, I was thinking the same sort of thing. You could probably run a cron job to write to the dbus enabling / disabling charging at whatever times you find suitable.

Justinq avatar image

I too am also looking at some sort of solution. I'm in Australia where the network supplier has an export limit of 5kw. I have a greatly oversized system with 6kw of PV on a fronius inverter. On a subboard I have the Victron Multigrid DC coupled with 4kw on a MPPT 250/100 (with plans to take this to 5-6kw). The fronius has a smart meter which ramps the fronius down when it senses export coming from the Victron (so as to not exceed the export limit).


I would like Loads and Export prioritised over charging battery until about 10am-2pm where the "surplus" power that can't otherwise be exported due to max being achieved can then be used to charge the battery.

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Martin24 avatar image

I am thinking about the same problem.

In Germany you are not allowed to feed more than 70% (even lower in some cases) of the total installed peak power into the grid. So during summer time around noon there may be PV energy available that cannot be fed into the grid.

So ideally I would like to discharge the Battery during night, but not start charging when PV power becomes available but later so that this power that cannot be fed into the grid can be used to charge the battery instead of throwing it away because the battery is already fully charged when the 70% limit is reached.

So is there any possibility to start charging delayed (by time or by measured pv power or measured grid feed-in power)?



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