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alansmith avatar image
alansmith asked

Victron 712 Smart Not Showing Display At All

I have no display on my BMV 712 Smart today. I did yesterday. Admittedly I was messing around in the engine bay in the area with the shunt in it yesterday and may have knocked it. But I'm pretty sure it was working when I finished. I see @theferrett had a similar issue at the start a couple of years ago so I have checked the red wire in B1 as suggested by @Gravely Headstone in that chat. I was getting 12V+. I have taken out and reinserted that wire multiple times and also the other cable that goes to the monitor (hoping for just a dodgy connection). I am thinking I will have to replace the PCB on the side of the shunt to see if that is the problem but is there anything else I can try before I spend money and wait for the part to arrive? Is there anything I can do to fault find at the actual monitor?

BMV Battery Monitor
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kevgermany avatar image
kevgermany answered ·

I don't think spares are available, except through Victron service centres, and they will insist on testing/repairing themselves.

First guess would be the cable between the shunt and monitor, but you really need another BMV to test the parts individually. So back to dealer.

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alansmith avatar image
alansmith answered ·

I have found a PCB online https://www.sunshinesolar.co.uk/Item/SPR00053 I think this just screws on to the side of the shunt.

I am going to try and check further wiring but not sure where power for monitor comes from - learning as I go along


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kevgermany avatar image kevgermany ♦♦ commented ·
I just checked your PCB link.

The 712 PCB has a double green connector with 2 orange press buttons. You can see the empty space marked on the board for the extra connector. Either the wrong photo, or the wrong part.


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alansmith avatar image
alansmith answered ·

I'm now puzzled by the connections on back of monitor. I was only expecting to see a telecom cable connected not black and red wires as well. Anyone know what these are? Are they the power supply to the monitor? There is no voltage across them - haven't traced the wires yet, its going to be tricky.img-4650.jpeg


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nickdb avatar image nickdb ♦♦ commented ·

Consulting the mystic manual, those are relay cables.

img-1585.jpeg

Power is supplied over the RJ12 connector.

There is a fused red cable going to the shunt and battery positive. Make sure that both are good.

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img-1585.jpeg (259.2 KiB)
alansmith avatar image alansmith nickdb ♦♦ commented ·

Thanks @nickdb That's interesting. I can see I am getting 12V to two pins of the RJ12 connector at the monitor end of the cable. I have also tested the red wire to the shunt and that is getting 12V to the shunt as well. Does this imply that the monitor itself has packed up for some reason? That is my main question.

As for the relay cables: I can see the black does in fact got to a relay I have not managed to trace where the red goes to. I do not know what the relay is for or why it is there.

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kevgermany avatar image kevgermany ♦♦ alansmith commented ·
The relay in the monitor is a simple switch. I'm surprised it goes to a relay, unless that's being used to switch something which needs a heavier current than the 712 can supply.
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nickdb avatar image nickdb ♦♦ alansmith commented ·

Obvious question. Have you tried to remove the RJ12 and leave it unplugged for 30 seconds or so, then plug it in again?

Can you connect to it via blueteeth? Iirc it is the head unit that broadcasts. Will help eliminate if it is dead or just the display.

I suppose you couldn’t measure the pins without disconnecting the head unit.

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alansmith avatar image alansmith nickdb ♦♦ commented ·
Yes I expect the RJ12 cable was disconnected for at least 30seconds from the monitor (head unit) while I checked to see if I was getting any voltage on the pins on it. Found 12V but whether it was on the correct pin(s) I don't know. I am not able to connect via bluetooth either (that was what first alerted me to the problem this morning).
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alansmith avatar image alansmith alansmith commented ·
No Devices found on the app.
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nickdb avatar image nickdb ♦♦ alansmith commented ·
If the serial number year (first 2 digits) is 20 then it is still in warranty, looks like you need to submit for an RMA
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