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System now not keen to use battery


Bobster.

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Happy long weekend, everbody.

I recall I reported on the problems I was having with my system "losing sight" of the batteries. There were also recurring problems with wifi connectivity.

OK so... supplier speaks to Revov. I don't know what was said, but supplier ended up buying a BYD BMS. This has now been installed and various firmware upgrades applied. Also there is now a cable between the BMS and the Goodwe.

Initially (first day) it was very unstable. In fact we ended up with no power at one point and had to bypass the solar system. Main problem here seems to be that the DIP switches on the BYD were incorrectly set. The installer asked me to change the DIP switches, reconfigure the Goodwe to see the battery as BYD B-BOX 10 and to restart the system. Now the Goodwe "sees" the battery and SOC very reliably. Good.

BUT.

It draws grid power in preference to using the battery, as it if is in backup mode. This is not a problem on a sunny day when we have lots of PV. At night I can fool it into using the battery by turning off the mains input into the inverter. But this morning, for example, with 56% SOC and the panels (on an overcast day) pushing 1 KW, when the wife turns on the microwave instead of pulling from the battery, it pulled from the grid to get the extra that the microwave used. Again turn the mains off, and it uses the battery.

I've checked. It is in general mode. But it behaves like it is in backup mode.

Yesterday the installer was back to "tidy up" but ended up trying to reverse the firmware upgrade. This took some time. The result is that we are now on 16169.

The wifi is constantly restarting.

The system draws from grid even when there is battery available.

And the portal (but not Ez Manage - more about that later) NEVER shows any draw from the grid since the swapping of the BMS on Thursday. The yellow "meter" line on the graph stays flat, even though the lights on the Goodwe and the app on my phone tell me that energy is being drawn from grid and the battery is not discharging.

This leaves us nicely set for a load shed, but is not so lekker for my back pocket because we use grid when there is plenty of power stored in the battery.

DOD for on-grid is set at 60%  - IE 40% left before it resorts to grid. We have always been above that, yet the system invokes the grid all the time.

So two problems - which may have one answer
1) How do I get this thing working in general mode again?
2) Can I find somebody else to look at the system (obviously for a fee) because the current bunch are chasing sales and sacrificing support, and don't create confidence that they are familiar with the kit they sell. I appreciate that they have some big money jobs that are going to be financially rewarding for them, but what I paid for my system was not small change for me.

I'm in Randburg.

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18 minutes ago, Bobster said:

How do I get this thing working in general mode again?

I would disconnect the communication link between the batteries and the inverter. Based on what you have described it is clearly not working. You can always establish the link again if Revov and  Goodwe eventually sort out their problems. In the meantime let the inverter and the batteries do their own thing. Make sure that all the Goodwe battery settings are in line with the Revov recommendations. 

Edited by Fuenkli
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Disclosure: I just found out that my electrician has done something.

My pool pump is on a sub-db that was connected to the solar system but not protected by it. If the grid went down, the sub-db lost power. Now that sub-db seems to be connected directly to the grid. When I turn on the pool pump, it no longer shows as an increase in load on the portal, nor does the app show any power going to non backed up circuits.

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57 minutes ago, Fuenkli said:

I would disconnect the communication link between the batteries and the inverter. Based on what you have described it is clearly not working. You can always establish the link again if Revov and  Goodwe eventually sort out their problems. In the meantime let the inverter and the batteries do their own thing. Make sure that all the Goodwe battery settings are in line with the Revov recommendations. 

Thanks for that. But the battery is now described as "BYB B-BOX 10" rather than self defined, and there are not many parameters I can change. 

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8 minutes ago, Bobster said:

But the battery is now described as "BYB B-BOX 10" rather than self defined, and there are not many parameters I can change

Change the setting using PV Master or EzManage  back to battery "self define". This will allow you to set the required parameters. 

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29 minutes ago, Bobster said:

Disclosure: I just found out that my electrician has done something.

My pool pump is on a sub-db that was connected to the solar system but not protected by it. If the grid went down, the sub-db lost power. Now that sub-db seems to be connected directly to the grid. When I turn on the pool pump, it no longer shows as an increase in load on the portal, nor does the app show any power going to non backed up circuits.

It wasn't him. He doesn't read the forum, but I've cleared the air with him anyway. He was last here on Monday. Thursday morning the portal still shows the pool pump kicking in and the panels driving it. (once the battery is charged, the PV tracks the pool pump). Then Thursday afternoon the BMS was changed and now lots of stuff is acting differently.

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OK... I spent a lot of time last night looking at the installation manual. That EZ Meter wotchamacallit seems to have a lot to do with the anti-islanding and what juice goes where. And the latest message I have from the installer is that they suspect that it is that meter - this also explains the non-movement of the meter line on the portal.

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13 hours ago, Jaco de Jongh said:

Please [post a pick of the BMS, I have a client who already bought Revovs with BMS but I cant find out what type of BMS it is and installation might need to happen soon. 

OK... I can only take a photo of what is there now. There are now two boxes, the bottom, bigger one looks exactly the same as what was there before (it's not the same unit, a little mark on that was on the old one is now not present). What is new is the smaller box (labelled BMU) on top. That receives a connection from the COM OUT port on the bottom box, and then in turn connects to the BMS port on the Goodwe.

 

IMG_20191215_075212[1].jpg

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The problem turned out to be the comms cable. Turns out the whole world uses a standard RJ45 pin out except for BYD. The cable was modified so that only pins 4 & 5 are connected end to end. 

Bingo!

Apparently the use of a non-standard pin for earth on the BYD shorts out some of the EZ meter functionality.

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