When the protection relay is triggered, will the solar panels also be short-circuited?
Only the 250/100 has a protection relay that can short the PV input
A 250/70 does not have such a relay
The 250/70 v3 also has a protective relay, but the question is whether it shorts only the controller’s front (it has a shifting contact group), or will the solar panels also be short-circuited?
Are you sure? Ive just reread the manual and datasheet and theres no mention of a PV input shorting relay. Chapter 8.10.5 is missing in the 150/60 to 250/70 manual
I’m so sure because I have a version 3 controller and it has a relay and a reset mode, it’s just that the instructions haven’t been updated yet, so I’m interested in the mechanism of operation of this relay, this is a question for Victron specialists!
For devices with the PV relay it will short the solar panels, this is why its important to keep within the max input current.
This procedure outlines the reset process for the internal protection mechanism, known as the PV Short Relay, in the Smart Solar Charger 250/100.
The manual specifically refers to the 250/100
And to specific models
SmartSolar VE.Can MPPT 250/100 - The PV Short Relay was introduced from serial number HQ2150 and newer.
Other models have a PV input shutdown, so do still have protection. Just a different method.
Thank you, the procedure for resetting this error is known to me. That is, inside there is a relay with one contact group, which shortens the input and at the same time the panels connected to it, thereby creating a fire hazard, why not ask the tilting relay a question to the developers, because in this design this controller is dangerous?
Have you opened it?
Did you note there is an input rating?
If the operational rating is not exceeded the relay will be fine.
Considering the 10’s of 1000’s of units that ship and the decades they have been building these products, it is unlikely they would produce an unsafe product, nor that you have found something they have not already considered.
Every device has clear specs and if you adhere to them there is no risk to the product or you.
If it is sufficient for certification standards, it should be fine for you.
It’s all good, but the situation, this “protection” is triggered, shortens the array of panels of 4500 KW (two strings of 2250 W), the short-circuit current of the panels is 14 A * 2 A = 28 A, the voltage of one string is more than 200 V, the fuses are 15 A for each string, then the entire short-circuit power will be dissed on the Schotkey diodes (which are in the panels) on the connectors, on the cables, on the relay contacts, and where it will be the weakest will overheating and God forbid the fire, and the system works remotely and autonomously, no one will be able to turn it off quickly in the event of such a situation, in addition, long-term short-term short-circuit-circuit of the panels will drastically reduce their service life!!!
Neither the current nor the voltage of the modules are a problem for the MPP. A shortend Input is the best way to shut down the output current or output voltage. The cables, connectors and the bypass diodes are made for this current.
Why? If the modules are at Voc the full short current flows though the cells because the are diodes too. And the normal MPP-currrent ist almost the same as the shortcurrent of a module.
The mppt doesn’t short it panels every day, it is only under specific conditions and usually to prevent damage to the battery.
If it is doing that every day then there is something drastically wrong with the set up and the installer/owner needs a smack on the back of the head for not paying attention.
The problem is not in the installer or users! MultiPlus II charged the battery at night with BMS Seplos ver3, the battery had a SOC charge of 100%, the BMS periodically turned on sharply from the charge, because of which the voltage rose sharply to 60-65 volts, at four in the morning the solar panels began to give out somewhere around 60 volts, and the MPPT controller thought that there was an emergency situation with recharging the battery and turned on the protective relay, shorting the input from the solar panels.
So they were paying attention. Excellent.
What i am referring to is a situation where it is left to get to this point. I have seen too many people just reset the error and carry on and never look at why it happened or how to prevent it in future.
Troubleshooting is what is supposed to happen.
Problem identified. So now a solution must be thought of and implemented to prevent any damages.
Since the overvoltage happened at night, it is overcharged from the grid, why did that happen?
This is completely the wrong question to be asking then. Worrying about a fire and other issues, when there is actually a totally different problem (battery overcharging or triggering protection with grid charging) and would ultimately be the root cause of any faliure.
Panels are not damaged when they are short circuited unless there are too many in parallel with no protection between strings (and there is actually a faliure in the panels themselves). Short circuiting panels will definitely show up shortcomings in the connections and installation - this will also not a fault of the mppt operation to protect the system but a problem in the the installation practices.
The inverter’s charging characteristics settings were made according to the recommendations of the battery manufacturer’s instructions: https://www.nkon.nl/novat/amfile/file/download/file/1750/product/5842/ but I see that the upper limit of the charge voltage needs to be reduced.
Is the bms connected to the GX?
If it is then cap the voltage in DVCC on the GX. It is a useful tool for such situations especially when diagnosing bms upper charge limit problems. Particularly those to do with high cell, battery balancing and overcharging
Yes, the BMS is connected to MultiPlus-II 48/5000/70-50 GX, the system works in Dynamic ESS mode
Ok. It may be worth using the cap rather than reprogramming (i asume you used the guide and copied it exactly). (Check that the system is obeying it - it does not always work as expected with some BMS)
But you still need to investigate why the bms is disconnecting.
With vrm advanced Widgets if the bms is sending this information, it is possible to see if:-
It is high battery voltage
Or a high cell voltage that is causing the issues
Check the battery graph for bms charge and discharge limits.
So I will additionally turn on this mode, but it is unlikely that it will help when there is a charge and the BMS is sharply released, the induction output will remain and the voltage will jump up evenly, I am inclined to the idea of slightly lowering the upper limit of the charge voltage.
DVCC will do it, it is the only way to override what the battery is requesting with the can connection to the GX. (This is if the battery is compliant with Victrons system, which it is not officially so we are now working together to find out how to manage it)
Even if you program lower the system will ignore that and follow the Charge Voltage Limit send by the battery. That is why it is important to know what it is asking the system to do.
Although i must admit the 57.4 v shown in your document link is quite a high voltage.
A further thought, are the batteries daisy chained or individually connected to a bus bar?