question

spinkb avatar image
spinkb asked

Quattro 48/15000/200-2x100 3 Phase Charging Logic Failures

I'm trying to understand / tweak how the charging works for daily solar energy capture. My installer has disappeared and so I know have to try and figure things out myself as they never got around to it.

40kWh Liion EIG cells @ 48v. 27kW peak output from panels.

My issue is the charging logic seems very unpredictable. My theory for how it should work, and how it was explained, is when the solar energy is enough the grid stops being used, and any extra solar starts going into the batteries...up to a amx, and then it starts putting it back into the grid. If there is a cloud and the solar output dips down, the batteries are used to supplement that time period, unless they of course reach their configured minimum (20%)...and when the sun is back, they switch back into charging mode....ideally nearing full capacity so that they can handle the evening hours and night time untilt hey again fall to 20% and it switches back to grid. (Except if the grid is offline, then they are allowed to go down to 0%.)


What I am seeing though is the batteries may start charging, but then a cloud, or some usage causes the available energy to not be enough, and they switch back, and then give up on charging for the rest of the day. The next day it does the same. Even though I have adequate solar all day to charge the batteries to 100%, they never get there, they get to 40% and then slowly discharge at about 800W until the PV energy is too low and then they discharge at a faster rate. Some days I get 40%, some days 70%, and on rare occasions 90%+. But I can't predict it, and it makes no sense to me. Example image from yesterday and the day before...(max on the graph is about 40%)

screen-shot-2021-05-08-at-111244.pngscreen-shot-2021-05-08-at-113129.png


However today, by 11AM, my batteries are fully charged at 100%, and there was a LOT of clouds on and off this morning. It hits some threshold and decides that is it for the day, and nothing can be done.

The solar room has ventilation and I monitor the temperature and make sure its never exceeding roughly 30C in the room.

Can this logic be changed or improved? What decides when to stop attempting to charge the batteries for the day? Today it did what I would expect...although oddly it appears to have been a little too fast.

screen-shot-2021-05-08-at-113313.png

Really need an installer who understands Victron..can't find anyone around me willing to help.

MultiPlus Quattro Inverter Chargersmart solar charging behaviour
screen-shot-2021-05-08-at-111244.png (16.2 KiB)
screen-shot-2021-05-08-at-113129.png (14.3 KiB)
screen-shot-2021-05-08-at-113313.png (10.2 KiB)
2 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

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

seb71 avatar image seb71 commented ·

What device is charging from solar?

0 Likes 0 ·
spinkb avatar image spinkb seb71 commented ·

@seb71 Fronius inverters handle the PV panels, and then pass that on to the Victron inverters which are doing the charging logic.

0 Likes 0 ·
8 Answers
spinkb avatar image
spinkb answered ·

I've also just seen on one day, it charged the batteries, then there was less sun and high demand (charging my car) and so it discharged the batteries down to 20%, then the car was done, and it then recharged the main batteries again. This was the first time I have seen a double cycle in one day... Of course a few days later, I again say it only reach 40%, then quit for the day.


I also think its really bad practice to discharge slowly during the day back to the grid...I mean I am wearing out my batteries to supply back to the grid who pays me very little for the energy I give them, by the time night arrives, my batteries have lost 20 to 30% of what they had at full charge during the day because I gave it back to the grid...


The logic just seems horrible in nearly every way I look at it. Surely someone else has noticed how bad this seems...no?screen-shot-2021-05-19-at-114315.png


screen-shot-2021-05-19-at-114315.png (32.6 KiB)
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

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

gro avatar image
gro answered ·

There are different protocols used depending on your selection. You can set up your Quattros to keep the batteries charged to the max to ensure the use as a UPS, useful in areas where the grid is unreliable. Then there are other ways of setting up such as maximise battery life, minimise grid use, do not feed back into the grid, etc, etc. I think it is a matter of selecting the correct setting. You need to identify what you want and find the settings to work the way you want. I think there are (software) assistants that help you setup the way you need.


this might help

https://www.victronenergy.com/media/pg/Energy_Storage_System/en/configuration.html


you will also need to let the inverter chargers know that you have a Fronius. That way the inverter can communicate with the PV Inverters (Fronius) to throttle them back if batteries are fully charged and you are about to exceed your export limit.

You have not described your system sufficiently to know what is going on. Do you have a power metre that is connected to your system? Do you have a GX network hub, such as a Cerbo or a Raspberry Pi running a Venus OS?

Good luck, there are a few people here who will be able to assist. You should be getting assistance from the retailer of the Victron equipment you got. Victron does not usually deal with the retail customers so your retailer becomes the means to get assistance.

1 comment
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

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

spinkb avatar image spinkb commented ·

The original installer got sick and has vanished. Business is gone. So I am orphaned. I asked another installer, they aren't interested in helping. So here I am. The Victron knows of the Fronius devices.


I'm configured for Optimized, without battery life in my ESS menu. When I used Optimized with battery life for two days, it seemed to try and keep batteries charged all the time like a UPS...so I changed it back.


It's the smart color meter thing...and there is a grid meter installed too.


I'm reading through the link sent...that helps explain some things for me.


screen-shot-2021-05-19-at-134513.png

0 Likes 0 ·
screen-shot-2021-05-19-at-134513.png (33.3 KiB)
Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @spinkb


I've looked into your system, and found:

when battery is fully charged, the system goes into 'float' mode, and the float charge voltage is set to 51.6V, this is the incorrect voltage for this type of battery, and makes the system not charge until battery voltage is down to float voltage.

I don't see a BMS communicating, is that correct?

2 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

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

spinkb avatar image spinkb commented ·

Thanks for the reply! Sorry for the delay, I was travelling and needed to get back to look at the system in person.

I have 3x BMS devices, one for each battery phase. I recall during initial setup there was an issue in how the BMS was going to talk to the Victron that delayed the installation as whatever was missing had to be ordered. So I know there was something...but I don't recall the name.

I've attached a photo of one of the BMS's. All 3 phases from the Victron charge, and draw power from the one common large 41kWh battery. Originally we were going to do 3 separate batteries, one per phase, but the plan changed near the end of the install.

Does this help?



screen-shot-2021-05-24-at-071137.png

0 Likes 0 ·
screen-shot-2021-05-24-at-071137.png (2.6 MiB)
spinkb avatar image spinkb commented ·

I just validated with the company that provided the battery...its the BMV 700 that is communicating with the BMS's. That is the device that was originally missing when we went to add batteries and we had to get that to allow it to communicate.


So I hope that means its able to tell what the BMS is reporting?

0 Likes 0 ·
gro avatar image
gro answered ·

Hello @spinkb





I hope @Daniël Boekel (Victron Energy Staff) comes back on to give you a few more pointers. It appears you have some work to do with respect to your battery settings. Look around on YouTube there is a number of Victron Energy videos one that explains how to set up for a lead acid battery and also Lithium batteries. I’ll see if I can find it for you. Here have a look at this


https://m.youtube.com/watch?v=mEN15Z_S4kE


you will need a Victron smart shunt or a cabled Victron shunt to determine SOC beyond just using a voltage based approximation. With the shunt you can Coulomb count and the system learns through the charge and discharge cycles as to the capacity and SOC of your battery.




I doubt that your BMS will be supported by Victron. I found this discussion on this forum and it points to a list of batteries (BMS) that are supported. Although your trio of BMS is unlikely to be supported, I suspect that you can still get the system to work. The above linked video will help. There is also another discussion going on with links to GitHub where a user/developer is coding to connect to BMS not currently supported by Victron. Here I found that for you also


https://community.victronenergy.com/questions/76159/victron-venusos-driver-for-serial-connected-bms-av.html


You will need to establish what sort of pack voltage will keep your cells safe while allowing your chosen BMS to take care of the individual cells. You will have to prevent the BMS triggering a disconnect. You’re likely to have to manually reset the system as many BMS disconnect themselves or require some sort of reset to recover from a over current/under voltage or over voltage condition.


Once again good luck.


Cheers


Gabriel

3 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

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

spinkb avatar image spinkb commented ·

Thanks, I will check them out. The BMV700 should be doing the communication with my BMS's...at least that was the original understanding we had.

0 Likes 0 ·
spinkb avatar image spinkb commented ·

So I understand what he is referring to in the video, but not how to troubleshoot and diagnose why it may not be working. Since my BMS is supported by way of the BMV700, I'm not using an unsupported BMS. But as Daniel pointed out...it makes sense that I'm charging and hitting the float voltage, then a cloud happens and it stops until its very discharged, then it starts again.

I don't know how to synchronize this or figure out why its not working as it should. Hardware appears to be fine, connected, and functional, but how to I make it synchronize and its a 41kWh battery pack?

0 Likes 0 ·
gro avatar image gro spinkb commented ·

What is the interface between your bms and the BMV 700?

I think the 700 is much like a 712 only without the Bluetooth function. It is a current shunt and two voltage monitors. I can’t see that interfacing to your bms.

Did you see what Daniel had to say. You have to set your parameters for a lithium battery. Go back to the video and note what the system will do when it gets to the various voltages. You need to know what voltage you are going to charge your battery with, if I remember correctly the concept of absorption and float don’t apply to lithium batteries. You need to know how many cells in your pack and what the safe max and min voltage for the cells are then use that multiplied by the number of cells to determine the voltage you are going to push the pack to when charging and discharging.

goog luck

0 Likes 0 ·
Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @spinkb

I'll try again:

I've looked into your system, and found:

when battery is fully charged, the system goes into 'float' mode, and the float charge voltage is set to 51.6V, this is the incorrect voltage for this type of battery, and makes the system not charge until battery voltage is down to float voltage.

to add to that:


Please contact a good engineer to check your system, lithium batteries can be very dangerous in the wrong circumstances.

(sorry, I'm assuming here but I don't think you understood my comment about charge voltages)

1 comment
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

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

spinkb avatar image spinkb commented ·

Sorry, but I am missing something. I thought you were saying the BMS is not communicating and that is why it wasn't charging...but it apparently is working.

EIG C020 cells , 20AH, 13s42p = 40.32kWh...shared across all 3 phases.

39.0 is low voltage, 54.6V would be full charge...they are safe at 3.0 to 4.2 for their range, 2.5v minimum.

There are some engineers I can involve, but they don't know Victron. The Victron people refuse to help me since they didn't install it and they can't be bothered with my system...they have other work. The company that did install everything...well they have essentially dissolved and don't exist...can't be reached at all. So who is going to help me with a system when the Victron people won't? I even offered to buy a battery from one of them to make it worth their time, after slow communication of 2 months, I gave up.

I'm a programmer, I build and fly LiPo and LiIon drone batteries, and understand a lot more about batteries than the average person...but its not my "training" by far. I'm just comfortable with it and get the ideas.

I've gone through every menu I can see, user/installer, and I can't find anything that allows me to control this. I can see the devices that are online with the Modbus TCP...BMV-700,Grid meter,Quattro 48/15000/200-2x100,hub4,Fronius Eco 25.0-3-S,,Fronius Eco 25.0-3-S.

Besides someone who is Victron specific, what am I going to tell any other engineer to do? If the battery chemistry is set wrong for the charging in the system, where can I correct that? Correct the float, etc. I can't get a Romanian Victron installer to assist me, I talked with one in bucharest who is closest to me... I'll do whatever, just let me know what I should be doing. When this was originally setup, Victron people DID go over the config and set everything for the battery and I haven't changed that...

0 Likes 0 ·
spinkb avatar image
spinkb answered ·

What menu items allow configuring the battery chemistry and float values? I cannot find a menu that allows configuring this, and all my searches for manuals explaining where this is at doesn't reveal anything either...

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

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

gro avatar image
gro answered ·

Have you got control of your BMS? That photo you posted looks like a Daly BMS, could be another brand but will most likely be a smart BMS and you should be able to set some parameters via an App and Bluetooth. The first thing I would do is ensure the alarms on the BMS are set such that your battery cells are not going to be over charged or discharged. Although the BMS should be the last line of defence until you get a good understanding of what is going on you should safeguard your batteries.


As far as the Quattro is concerned try this

https://www.victronenergy.com/upload/documents/Manual-Connecting-other-lithium-battery-systems-to-Multis-and-Quattros-EN.pdf

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

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

spinkb avatar image
spinkb answered ·

Through some contacts I was able to get some Victron engineers to actually take control and look at my system. They fixed something in he config, but didn't tell me what. Something related to the "battery" type or capacity. Now its charging and working correctly.


Really wish I knew what config they changed...I went through all the menus many times, and I don't know what they changed that I couldn't change myself.


So the summary...I don't know what config was wrong, or what config was changed. Yes float voltage was wrong, but no one ever revealed where I can change that at, and so I don't know how the Victron people were able to do it either.

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

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