Hi all,
All the Multi Rs’s I’ve seen were without over voltage protection. In a review on Youtube lately, I saw a unit being opened with over voltage protection off the shelf.
Does anyone know how to recognise the presence or absence of the overvoltage proteioc from the serial number?
It may be Trivial, but I would like to ensure that I offer the lates model to my customers. As I buy them online, I can not find out otherwise…
Thanks ahead!
It’s NOT an overvoltage protection, it’s a relay that shorts the PV input unter fault conditions.
You need to install a surge protection externally.
Have you seen the video?
You are probably right, but how do I disciminate the serialnos that have it and which not? They do not all seem to have it
What video?
The relays have been added a while ago (a year ago? The relays are mentioned in a manual Rev 13- 05/2024) and the whole production has been stopped in the meantime for a while.
So I don’t think there are any old models without the relays out there for sale.
From what I read in the manual you sent along, the relays are to protect for an internal fault possibly causing a hazardous situation.
This is not very relieving… So is the Multi RS capable of causing a hazardous situation? Have Victron designed and applied a special device to prevent tis incident from letting the internal fault causing a hazardous situation in the exeternal (customer) network?
If this is the case, it is not a fail safe design. The root cause seems to be unadressed.
Or am I exaggerating?
Should I sell these units to my customers?
Could you post a link to that video?
If by above you are referring to the below quoted text, then that text is not correctly formulated and it should read, as a few paragraphs above in the same manual is mentioned, that the relays are closed because of an EXTERNAL fault (not internal fault), and are closed to prevent further damage to the inverter MPPT input. Manual quote: “When the relays are closed, the PV array is short-circuited to prevent PV power from entering the SmartSolar MPPT RS.”
Usually those relays will close when a thunderbolt is striking close to the panels. The momentary very high voltage induced will make those relays to trigger/close and therefore the fuses close to the relays will blow and forbid the high voltage to reach the internals.
But all this, IMO, is just wishful thinking and there for the rules to be followed.
No installation will survive. Not even a close event, not to mention a direct strike…
I am indeed referring to that text. As long as Victron does not correct it, My customers will point me at it.
This has nothing to do with what I am afraid of. You are being warned (even if this is a faulty text)
That relays are NOT for surge protection!
As far as I know the text in the manual is correct and the relays close in case of an INTERNAL failure.
The relays short the PV input to prevent further internal damage.
I think that assumptions are not the road to follow. What can be the reason to stop manufacturing and implement a safety that is not resettable? Also no explanation is given orher than contradictionary.
I believe that victron should at least indicate what harm a solar panel can produce that can be kept external by this device. Why are they being so vague?
Personally I have a hard time working with statements that are not founded. We are technicians here, aren’t we?
Please excuse my sharp tongue. I love most things they produce. I will not however take everything for granted. Victron points my customers at me as their reseller, so I need correct and clear information
Then follow the manual, and the advice from one of the distributors, and not what you find on a youtube video, which mainly are at best slightly correct or at worst, wrong.
There are official avenues available to get formal answers.
The production stopp had another unrelated reason, the safety relays where already implemented before that.
The (as far as I know) the relays are NOT triggered by an external event.
An internal issue will trigger the relay to prevent further internal damage.
I already asked for more information about that.
Oh I do not follow the expressions on youtube, that is why I came here with my question.
I am however now a bit further away from understanding the situation. I went to see distributor, I called Victron and I even went to their booth in Munich last month on the topic, but I am still no step ahead.
Did you have the chance to look at the schematic?
And to the part number of the “relays” to know what they really are?
This could clarify all our guesses… 
Because, if they are there to prevent the grid from reaching the PV inputs - which is a distinct possibility according with the type of hardware topology, then there is a real problem and their presence there is just to mask and/or avoid another big problem…
Thank you! Would be great to have it cleared up.
Why should Victron name them “safety relays” instead of “surge protection” if they are actually a surge protector?
A surge protection needs to be installed externally because it needs to be replaced after it has engaged.
But I will take a look at it tomorrow if I have some time.
No one said that.
PV and battery are galvanic isolated → the safety relays only apply to the high voltage side of the MPPTs.
PV and battery yes.
But there is a direct line (OK, not direct, but through some IGBTs) between AC-OUT and PV.
So if the IGBTs fail in shortcircuit, then it’s possible that grid reaches PV inputs. And vice-versa.
So depending where the PV input fuses are placed in the PV line, before or after the relays - this could also be clarified by looking at the schematic - the relays could also “protect” from grid leak, by forcing fuse blow.
This could be the sole justification for using relays that are SHORTING the PV input to protect from INTERNAL malfunction.
Thank you Alex. This is exactly what troubles me. The design is not galvanicly isolated (we know that, none of the HF are) and apparently not fail safe, if I may conclude that from the various messages. Adding such protectors in this stage, implicates assumption of incidents which makes me feel unsure.
Hope Matthias digs up some good news
Don’t worry.
The design seems to be unsafe, but in reality almost ALL all-in-one inverters manufacturers are using it.
No problems until now, if normal safety measures are taken and the installation rules are followed.
If I’m not mistaken, these relays are associated with the function of monitoring the internal & external integrity of insulation PV-in.
