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Is it possible (or recommended) to use ESS in an OFF-GRID system for a household, using the following components:
Hi Mohamed. Not an answer to your question but I'd be interested to know about the hybrid Lithium-Lead Acid battery setup that you have. I'm considering doing something similar and was wondering if you have the batteries directly connected in parallel or if you have some sort of controller/isolator between the Lithium and the Lead Acid?
Hello @Spudgun
OHRES Project detailed information: https://ae4h.org/projects/ohres
Breif Summery: The Hybrid Storage system is one of it's kind now installed and operating since only few days in a remote area in BC, Canada (where I am writting this message from now using the electricity from the system)
it's a 48 VDC coupled stand-alone off-grid system, which is so far the 1st system like this using the Hybrid technology in the world so far.
We are installing the 2nd system in Uganada soon as well, in a remote area.
All details are always updated on the webpage above, let's get connected in case if you are interested: https://www.linkedin.com/in/mohamedelkadragy/
And of course will be happy to answer any questions you post further.
Hybrid batteries have been used in the past when lithium was much more expensive than it is now, but it can still work.
google is your friend:
https://www.google.com/search?q=Lead+acid+lithium+hybrid+battery
They are not used in commercial-scale in such system structure we have designed them for so far as our main industrial partner is -BOS the 1st company you get in the search page in Google-, and we are developing together with other industrial partners the 1st 48V DC-coupled system based on Hybrid storage, which is running now in Canada.
you may get more details in our project website mentioned above.
Off-grid systems - either with or without generator.
Marine systems.
Automotive systems.
Inverter priority, also known as 'Intentional islanding“ or 'Ignore AC' input systems.
Thanks for the answer, I am familiar with the Manual and have been through it into deep details.
The issue is in an off-grid system some people like our system supplier recommended using the ESS, and I can't see why it can't be used even from the settings
In case we don't use ESS what is the alternative then?
technically you can use ESS, but for what reason do you want to use it? what functions do you want to use that are not in 'non-ESS' systems?
The C rate Dynamic cut off is the main attractive part in the ESS for our application of using a Hybrid Lead-Acid + Li-Ion battery storage system for our Off-Grid application.
This is not compensated by any other way so far for Off-Grid rather than the ESS! So I believe Victron needs to have such Dynamic specified settings for the battery included for offgrid as well.
Without grid input, I don't think the dynamic cut off is being used. I believe it will drain the battery until the normal low battery settings.
If there is no AC input available, most of ESS functions do not work.
But: if you have a battery monitor (the internal monitor of the multi can also be used, but is less precise), you can use SOC levels to switch off the inverter.
Also I assume you have a generator you want to start before the battery is empty? this can be done by the Venus device or the Multi (more options in the Venus)
Hey @Daniël Boekel (Victron Energy Staff)
I came to the conclusion that ESS using for our case of having this newly designed hybrid li-ion + lead-acid battery storage system isn't the best choice so far.
I really wish that VICTRON works on providing an alternative C-Rate based Dynamic cut-off function for Off-Grid application, as it is really needed in all our off-grid projects.
We can provide more details about our technical needs for Victron for that as well.
Hi Mohamed,
Your battery has a BMS, the BMS should be coupled to the Victron system, either by CANbus or by a 2 wire connection.
This way the system will listen to the BMS to prevent over charging / discharging.
The Dynamic cut-off function is -not- what you want.
Hi Daniel,
I have posted a new answer to your last comment so weasily easly followup the discussion better than having long raw here.
Hello @Mohamed Mamdouh Elkadragy. In my personal opinion, ESS is best suited to manage a stable grid input with a key objective to reduce input from the grid. It runs in parrallel to the grid and does not replace it. Even even if the battery is depleted, the grid will keep you going. In a "true off-grid" setup, there is no grid input for ESS to manage. In one of the video's you will also be made aware due to the fluctuating frequencies of a generator, it could result in a more unstable system. I am not qualified on the topic, but there are many reasons why Victron provides these guidelines. You'll be Binging it for ages so in my opinion, it is best to stick with tried and tested solutions. PS - I personally run both types of systems on two different locations.
@ejrossouw thanks for sharing this experience, I beleive ESS is very confusing for the off-grid application
It is Much way better without using it. But I believe victron needs to develop a similar dynamic battery assistant for off-grid as well.
Hello @Daniël Boekel (Victron Energy Staff)
Thanks for your answer.
What you are saying is applicable for pure Li-Ion storage I agree. But it seems like you are not familiar with the details of how a Hybrid i-ion + lead-acid system works as your suggestion is not applicable in that case at all.
I can briefly say here that you can imagine the Hybrid storage as the inverter having to interact with the lead-acid storage ONLY, as the Li-ion performance can be simplified by saying that " it is sitting on top of the lead-acid storage to support it's performance and techno-economic behaviour over the lifetime of the storage"
So the BMS of the li-ion, in that case, is designed is a totally different way of a normal BMS of a li-ion only storage, and is not controlling the charging algorithm through the CAN communication, as it would not work for the lead-acid. But I believe there is no room here to get into more details.
Conclusion answer
As others have posted, the ESS Manual clearly states not to use in an off-grid scenario. Specifically the issue I see with implementing the ESS assistant, is that even when grid setpoint is 0W or higher, and there theoretically should not be any feedback, there sometimes can be a little trickle back when you have a large load like a microwave turned on, which suddenly is shutoff. I would be concerned that there would be some energy sent back over the AC-Input which may damage the generator.
Hello @ee21
Thanks for your answer, we do know that ESS is not specially designed for off-grid, but as I mentioned in the answer conclusion that the main motivation is to use the dynamic cut-off feature which is needed for a Hybrid lead-acid/li-ion battery configuration in off-grid.
it is maybe that the technology is new for Victron and not widely used there is no special assistant for it so far, but hopefully, there would be in the future as this is what we are trying to understand deeply and develop as well in our research facility at Germany
