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Graydon avatar image
Graydon asked

Multplus (s) rejecting AC Current, not allowing Bulk Charge

I have a 10 LG PV Panel, 385-415W, solar array, set up as 2s2p x 2, and 2s,. Each array has its own charge controllers, Victron MPPT 250.100, MPPT 150/100, and MPPT 150/35.

I also have 8 SOK LFP 12.8v/100Ah batteries, set up as 2s2p x 2, for a 24v / 400Ah system

The above feed in through a Lynx Power in, Lynx Shunt and Lynx Distributor.

I have the system monitored through a Cerbo GX and a VRM account on the internet.

Originally, I had one 24/3000/50-70 Victron Multiplus, supplying power to a subpanel that normally draws about 500-600W. On sunny days, this system runs without needing to use AC bulk charging from the mains to charge up the batteries.

I also had assistants running on the Multplus to start charging at 20% to 25% SOC during daytime, 7am to 7pm; At nights, it would start charging at 30% to 40% SOC. The charging worked perfectly and I could also manually turn it on, when needed via the VRM app on the phone or Internet

I had been able to run my pool pump during the days when it was sunny, to use up surplus energy. I am planning to add another 6 panels next summer and another 8 batteries. My hope is to be able to run the pool and home air conditioning on hot sunny days. Thus, I needed to add a split phase system to run the air conditioner. (It uses 1600W to run, so 800W per leg of the subpanel)

I bought the 2nd Multiplus (24/3000/50-70) last week, and hooked it up Tuesday to Thursday. During the setup process, both Multplus’s need to be upgraded to the newest firmware, 4.90. After the firmware upgraded, I set it up in split phase, tested it, it worked fine and saved the settings. I set it up in parallel phase, tested it, it wonted fine as well, and saved the settings.


I loaded the split phase settings and let it run. Then I went to test the bulk charging, and this is where it did not work as expected.

After reloading the assistants to allow to SOC monitoring of charging, I manually tried to charge the batteries. I heard the usual ‘clunk’ but the system did not start charging. I thought maybe this was because the assistants were not on the 2nd Multiplus, so I loaded assistants on that, and it still did not charge.

I spent all day Saturday going over all the wiring, testing the voltages and phases. The voltage from the battery terminals, matches the DC wiring to the Lynx, and the Lynx voltage matches the same.

On the AC side, the 120v from the main panel is consistent from the panel bus, through the breaker, through the cable right to the AC in of the Multipluses.

The inverting continues to work fine. MY only regret is not to have tested my Multplus, that has been working fine for a year, to see if the new firmware had stopped it from working (ie. a firmware bug?)

I even reset both Multiplus to default factory mode, and tried to use my original Multplus the same as I haven the last year, and it refused to bulk charge .

Manually switching the Multiplus to charge only mode, does nothing.

I have attached a short video, showing VE Config, and the blue line that runs along the monitor window, as it reaches the end, you can heard the 'clunk' of the Charger starting up..then it just stops, and the process bar goes back to start again. This is one clue.

The next photos show the Victron Connect app snapshot of the system, then some VE Config snaps shots, the first series on the Main, L1, Master, Multiplus and the next series, the Second, L2, Slave Multplus.

My subpanel is basically off lien from the solar an batteries and running off my mains until I can fix this. thank-you

This appars to be a similar problem, without a solution: https://community.victronenergy.com/questions/98200/mutiplus-vebus-fw-486.html


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this next set is of Multiplus L2

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multiplus ve.busac
2 comments
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Graydon avatar image Graydon commented ·

The video didn't upload, so here is a link: https://www.dropbox.com/s/h9tpci1uarh0xmx/Multplus%20Rejecting%20AC.m4v?dl=0


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Graydon avatar image Graydon commented ·
Today, I removed the pairing of the Multiplus’s from its Split Phase mode, then downgraded each to firmware version 4.89. (from VM’s dropbox firmware library). And started with both in default factory mode, firmware 4.89.

Each unit was reset and I left them stand alone, testing each one with default settings, with only a single connection from the Multiplus through the MK3 to my computer. In the default mode, as soon as they detect an AC Mains connection, they immediately try to go into bulk charging. In the attached video, on the left side monitor window, lower right, you can see the blue progress bar moving in the attempt to connect and bulk charge, you will hear the ‘clunk’ as the switch to AC mains is made, then it goes back and tries again. This repeats several times, then seems to give up. Both Multilplus (s) act the same, try to switch to AC bulk charging mode, and then stops..

https://www.dropbox.com/s/mo7x6t7cqc7tqm1/2021-12-07%2014.55.37.mov?dl=0
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6 Answers
Graydon avatar image
Graydon answered ·

I think I have narrowed down the issue, in looking at various discussions, I found this document

https://www.victronenergy.com/live/ve.bus:ve.bus_error_codes#error_11_-_relay_test_fault_-_installation_error_or_possibly_relay_failure


I think this is my problem, the “relay test” the Multiplus performs before switching to grid is failing.

And, when I looked at my VRM logs, this error was reported, though, I had to dig deep to find it, and no other errors got reported. In the VRM Remote Console>Multiplus>Alarm status, the first picture shows the top of the status screen, the 2nd the bottom, and this shows an error “VE Bus Error 8 / 11 report” Clicking on the error report shows the third picture, which doesn’t say anything else.

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However, the Victron document on VE Bus Error Codes

https://www.victronenergy.com/live/ve.bus:ve.bus_error_codes#error_11_-_relay_test_fault_-_installation_error_or_possibly_relay_failure

Shows a Ground Fault Relay test error for Error 8

Shows a Relay Test Fault for Error 11

So, I am thinking the issues lies with the AC wiring into and out of the Multplus. And this is complicated. I think there is a fault detection in the Multiplus because the Main AC current into the Multiplus comes from my home main panel. But the AC out from the Multiplus(s) goes to a stand-alone subpanel, which is completely separate from the main panel, except for sharing a common house ground (PE).

My AC wiring to the Multiplus(s) is as follows.

My sub-panel, that is powered by the multiplus, is essentially a stand-alone system. There are no live or neutral connections between the sub-panel and my main panel.

The Multiplus(s) feed the subpanel via a 50A 4-prong wire, with each of the two Multipluses supplying one leg of 120v power to each side of the sub-panel legs. The neutrals between the Multplus’s and the subpanel are bonded together. The grounds from each Multiplus are also bonded. But the Neutral and the Ground are NOT bonded anywhere outside the Multiplus and Im not sure if the Multiplus bonds them inside?

BUT, the cases of each Multiplus is connected to a common house ground, as are the Lynx and each MPPT, (which consists of two large gauge bar copper wires that run the length of the house, and are grounded outside.)

The Sub-Panel and the Main panel are also grounded via these same large gauge house ground wires.

The Main panel is NOT bonded, Ground to Neutral, in it’s panel housing, as far as I can see. And the subpanel is definitely not bonded, Ground to Neutral, in the panel housing, as I took the bonding bolt out when I installed it.

The main house electrical cut off panel is actually in my garage, several meters from the main panel and this is where Neutral is bonded to Ground.


The AC Inputs for each Multiplus do come from the Main Panel, through single 30A circuit breakers. And obviously they have the electrical coded (Canada) connections for Live, Neutral and Ground.

Adding to this confusion is that the system has been running fine for a year, till I rewired the AC outputs to support Split Phase power to the subpanel.

Graydon



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Graydon avatar image
Graydon answered ·

Update: Still having the same issues

Yesterday, I removed all the AC out loads from the Multiplus(s), attempted to bulk charge, and same results as before, starts relay test, "clunk", then nothing and restarting relay test.


Today I reduced Multiplus(s) AC draw to 5A.

I disconnected the main panel AC feeds into each Multiplus, and wired in smaller gauge extension cord wires, exactly the same lengths.

I first ran off a singe outlet, and got nothing to happen at all.

I then plugged one extension onto an outlet with an opposite phase, and the Multiplus(s) attempted to switch to bulk, then stopped, as per before.

so, doesn't appear to be my AC wiring in.

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Graydon answered ·

Yesterday, I removed all the chassis grounds from the Multiplus(s) and the main and sub panels. I had added a small gauge wire for grounding when I installed the first Multiplus last December. I tested all the AC power connections and found the Multiplus Chassis is connected to ground anyway, as are the main and sub panels. This makes sense, if the Neutrals and grounds are bonded at the main house AC connection from the pole.

With this seeming to be a 'relay' and 'ground' issue, I am still researching what the exact problem is. I am 'presuming' through all this, there are no faults with the Multiplus relay when it attempts to switch to AC power for bulk charging. I say this, 'assuming' an error would get reported if some internal components were not working or broken.

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Graydon answered ·

Update: Still not working, and working through possible soutions

In this document, several possibilities exists for Errors # 8 and #11

https://www.victronenergy.com/live/ve.bus:ve.bus_error_codes#error_11_-relay_test_fault-_installation_error_or_possibly_relay_failure


The first:

Possible cause #1: Neutral-out externally tied to GND

If the neutral-out is connected to GND externally then the unit will always detect that the GND relay fails to open.

Solution: Correct the wiring.

I tested the resistance of each Multiplus neutral to ground.

When powered ON, both Multiplus(s) showed a resistance of 0.6Ω on the AC Out, Neutral to Ground. The same 0.6Ω resistance was recorded between Neutral and the Multiplus chassis.

When power OFF, both Multiplus(s) showed infinite resistance, NO connection, on the AC Out, Neutral to Ground. The same was recorded between Neutral and the Multiplus chassis.

Where both AC outs meet to form a paired leg of 240Vs in a separate, Isolated, outlet box nearby, the resistance was 0.5Ω between Neutral and Ground, with the Multiplus(s) powered ON

So, my system has NO EXTERNAL connection between Neutral and Ground as per the #1 possible cause above, However, when powered ON, there is a connection. This would be an INTERNAL connection which I 'assume' is normal?



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Graydon answered ·

Update, but no solution

Today I tried various grounding and ungrounding of the system, including the AC out and IN connections, Lynx shunt, MPPTs, Multiplus chassis. no difference

I also tried running the system off a 240v split phase supply from a 5,500W generator. VRM showed a good connection and 245v of total input, but, when trying to switch to bulk charging, same results. Multplus switch (clunk) then reverts back, and repeats this 3 more times, then slowly repeats it a 4th.

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Graydon answered ·

another update on grounds:

well, I 'thought' my subpanel was stand-alone. I tested the grounding from he subpanel to the main panel, and sure enough, its connected some how. Then I realized, I had some 'shared' circuits that I can switch back and forth, with Auto and manual transfer switches) depending on how much sun I have and how much more energy I need to us (Pool, office computer, Air Conditioner).

So, I undid all the grounds from these transfer switches since, at least 2 have shared grounds just tied together.

I still detached continuity between the main and subpanel. This is(was) a mystery since now, there are no ground wires connecting the panel.

But, I didn't disconnect the Neutral wires, though, the transfer switches do disconnect live and neutral wires on each switch.

However, after I realized I had a 240V input into the subpanel from the 2 Multiplus(s) inverting power into the panel and supplying selected circuit sin my home. This has a neutral and ground running back to the Inverters.

And, I have 2 AC outputs to each Multiplus from the main panel, also with neutral and ground. So, there is now a connection from the main panel, to each Multplus, back to the subpanel where the grounds are all connected.

I will have to try again, and this time, disconnect the main panel AC outs to the Multiplus(s)

I did try removing the ground wire from the AC in, to each, then both, Multplus(s), and it still didn't bulk charge

I noticed that I can select to ignore LOM and bonding under the VE Configure software, but need a password to set it. I have requested the password and am still waiting for a reply.


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