Cerbo and VRM connection problems

Q&A and troubleshooting
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1

Hi there. Very new to this and it’s a very steep learning curve for very little preparation to find my self in an off-grid situation, so please bear with me.!

So, I have a multiples inverter/charger 48v, bmv 712, a shunt, 100/20 mppt and a Cerbo gx.

When I first installed the system, I charge my batteries with a generator as it was the only thing that I had that would be reliable for the winter months. When I first installed the Cerbo, it would accept any Bluetooth pin and would load up to 80% and no more. This was take back to the dealer for testing and was subsequently replaced, which then worked fine.

I bought the charge controller a couple of weeks ago and have set that up with success. I’ve tested voltage from PV before breaker and after, all good. Tested the voltage from the mppt to the battery and at the battery, all good.

However, the charge controller doesn’t show on my device list on the VRM online portal. My inverter, Cerbo and shunt are there just fine.
It does show and I’ve successfully connected to it via Victron connect, so I know that works.
I decided to look for firmware updates and carried out said updates on the inverter, mppt and Cerbo.
Now, I have the same problem with the new Cerbo as before, won’t load past 80%. I tried old and new passwords and was told by the supplier to find the PUK number on the Cerbo, there’s not one there. He told me to follow online instructions to connect via wifi and reset the password after following the instructions, there is no option to do this on VRM or anywhere else that I can find.

Now when I try to open the Cerbo in VRM bias the connect app I have an error message saying,

An error occurred attempting to connect to the VRM portal. Please check your network connection and try again. Error code #R3

I’ve contacted the place where I have bought it and I’ve been told to consult the manual and that they are not experts and it would appear as though there has been a ‘washing of hands’ to my problem.

Any ideas as to what I’m missing and how to proceed please?

2
  1. Is the data from the charge controller connected to the CERBO with a ve-direct cable?
  2. When powering up the cerbo, do you get the 2 flashing LEDs on the front panel, what colours are shown? The top wifi access should be flashing green, and the bluetooth led flashing blue. If the Wifi led stays flashing orange, then the cerbo firmware is most likely corrupted, and needs to be reloaded from SD card.
3

Hey Mike, thank for your reply. Yeah, mppt and Cerbo are connected with a VE direct cable. I have both green and blue lights on the Cerbo itself and they flash together.

4

ok, So can you connect to the Cerbo’s access point wifi? or do you have a laptop on the same LAN as the cerbo?
You should be able to see the Cerbo with Victron connect from a phone, - using Bluetooth, or via the wifi connection. best to try over the LAN if you can - even using a web browser on a phone. Use venus.local as the URL. You mentioned that the Bluetooth does not connect. This is why I would recommend using the LAN to connect. Check for the 2 (green & orange) LED’s on the LAN socket.
Bluetooth stopping at 80%: I’ve found this issue connecting to MPPT’s on my phone, where the phone software does NOT bring up the bluetooth pairing automatically. I’ve found the answer to this is to manually pair the device before opening victron connect. typically pin is 000000 or as on the label on the side of the device.

5

Having trouble connecting to the access point reliably, but I managed an hour ago and through the menu, which didn’t show the Cerbo but when I scrolled through settings/bluetooth there were two options. One was to enable or disable Bluetooth, which I left enabled, and a password. The password was the same password as the Bluetooth for the Cerbo.
I changed the password upon original set-up and when I changed the password in this window, it told me I may need to unpair from the device.
I’ve now gone into the VRM portal through a web browser and I have the BMV, the shunt and the Cerbo listed under the device list. No mppt there and oddly, no option to remove device under the Cerbo.
Both the shunt and the BMV have a highlighted option to remove device, but nothing for the Cerbo. I’m very confused, to be honest.

I upgraded all the firmware for all devices at the weekend and before that, things seemed to work ok?
The mppt wasn’t showing on anything but the Victron connect app, but I hadn’t received the VE direct cable until yesterday.

I have been using my phone hotspot for all my connections for the hardware as I haven’t manage to get Starlink at this point. But I’ve not really had any issues until the weekend.

6

OK, The unpair warning would relate to the bluetooth settings page on your phone, but sounds like that’s not necessary.
The menu you are looking at is a mirror of the menu on the cerbo, you should see the cerbo listed as a ‘gateway’ in VRM, there won’t be an option to remove it. You should be able to browse to the Cerbo using the venus.local link on a web browser on your phone. This can cut out the remote portal of VRM.
The MPPT should show up. Make sure the MPPT has power, and then plug the VE direct cable to the MPPT and then one of the sockets on the cerbo. This should auto detect. IF not, try one of the other VE-direct sockets, or reboot the Cerbo. The connector is very small and needs care to insert correctly - noting the little tab and cut out.

7

Thanks, I’ll check that when I get home later but I have a feeling that I’ve done everything that you have suggested in your last message and still no mppt shown on that menu. I rebooted the Cerbo again last night, but still no joy. I will definitely check the VE cable and make sure it is as you’ve described and will try another socket if necessary.

I will let you know how it goes

Cheers Mike :+1:

8

Hey Mike,

So, I finally got things figured out, but don’t really know what caused the issue in the first place. I did a factory reset from an SD card and it seems to have don’t the trick. Thanks for your help.

But, next question! :face_with_peeking_eye:

I have 4 12v agm batteries in series to get my 48v battery bank. They are 147a/h batteries. I really don’t use that much power and my supplier told me that a 100/20 MPPT should charge my usage just fine.
On average, I get about 850kw/h per day over the two weeks I’ve had the mppt. That equates to about 17.5 a/h of power to my batteries. I use about 9 a/h a day.
What I can’t seem to figure out, is that my battery voltage seems to remain about the same and don’t seem to increase the charge on them.

At this point, I have had any kind of SOC readout with my bmv because I did have another bank of 4 12v but in parallel to give me better a/h. I had a sulfated battery so had to remove that string. This is when I lost the SOC readout and had to charge the batteries today with a generator to synchronize that.

Connections seem good, I’ve tested the panel voltage into the mppt, that seems good, if tested the voltage on the battery side of the mppt, that seems good and I’ve tested the voltage at the battery connection, which also seems good.

Any ideas would be greatly appreciated mate.

Cheers

9

Ok, so if the MPPT is showing up on the Cerbo now, then you should be able to see the charge current and the charging history.

I think you must mean 850Wh/day? 15 - 17Ah /day, @ 65% efficiency gives about 11Ah on discharge, so you should be getting close to full charge on most days if you are using 9Ah.
If the MPPT is a ‘smart’ version, you can connect to it with a phone & Victron connect app, this will allow you to see the settings in the MPPT. you need to make sure that the battery type is correctly set, and the absorption and float voltages are right for your batteries. It will also show you history, and trending information for battery voltage and current.
I think you should set the BMV to reset the SOC to 100% at about 52.8V being 13.2*4, or maybe slightly higher. this can give you a daily reset. this can be trimmed upwards, so as you get an SOC reset at least once a week.

10

Yep, that’s what I meant!:wink:

So, I have agm batteries and I believe the float charge is 13.5 - 13.8v*4 = 54 - 55.2v

When I open up the mppt>settings>battery, without enabling expert mode, absorption voltage is set at 57.6.

From what research I have recently done, this seems somewhat within the realms of being correct ?

11

yes.
14.4 * 4 = 57.6 This is ok, and is subject to temperature correction (done automatically).
However, setting the BMV to this voltage for resetting SOC is unlikely to generate a reset. So best to back it off by 1 - 2V. Do also check that the float voltage is correctly set, and that automatic equalisation is off. AGM batteries can be damaged by eualising, unless the manufacturer directly recommends this.

Personally, I would look at increasing the solar charge somewhat - as you get further up the charge curve on AGM, they become less efficient, as more energy is used in producing gas.

Lithium batteries don’t suffer from this, and have ~95% cycle efficiency.

12

Hey Mike

Yeah, I think I will need to do that later in the year as we get back around to the winter months. I kind of knew that would be the case.

Everything seems to be working after I factory reset the cerbo with the sd card and we had a good day of sun yesterday and my batteries read at 100% SOC when I got home.

Lithium will be on the shopping list also. The AGM batteries were cheap as I got a deal through marketplace. I had to do everything on a tight a budget as possible as I had very little notice that I was going to be heading into an off-grid situation so, needs must.

Thanks for all your help and it may be possible that I will be bending your ear in the future.

All the best

James