Our new Solar Hybrid-System & Grounding/N-G Bonding Special Introduction
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- Опубліковано 3 жов 2024
- Hi, in this video I am showing you the now completed new storage system in the garage. This is an A-Z video series of an Solar Hybrid-System installation. As always, we are going to take a deep look into earthing concepts of such systems.
Inverter: Deye SUN-6K-SG03LP1-EU
Battery: UNISUN Vss, LiFePo4 48V/200Ah
This is the website of the Chinese equipment supplier (non-affiliated):
unisunsolar.en...
Contact: Ms. Shu Zhang
On our property, all energy systems (PV, Powerwalls, etc.) are DIY. Please check my Playlists for other content. Thanks
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Great, I love your understanding of electrical hardware, good job
Great video as always :)
I believe Deye manages this problem via internal relays. However to be safe side with all these inductive issues, it is better to use an external bonding.
Only the 3 phase inverters have internal relays as I was told
Hello Roland. I was engaged in a conversation with another viewer on this uploaded video, which reminded me how common the misconceptions are about polarized DC circuit breakers. Might be a good idea to upload a future video that explains in more detail about DC double pole and single pole breakers, specifically explaining why polarized DC breakers are directional and non-polarized DC breakers are non-directional. There are still a large majority of DIY and "expert" solar installers whom do not understand this. The common confusion amongst most users and installers is that polarized DC breakers are still non-directional, so long as you wire the Positive Line input into the (+) terminal and Postive Load output into the (-) terminal, and Negative Line input into the (-) and Negative Load output into the (+). Most people do not realize this polarized DC breaker type is still directional (i.e. the breaker is designed to trip with current flowing in one direction only). Whereas, a non-polarized DC breaker does not matter whether the Line or Load is either top or bottom of the breaker since it will safely trip (without risk of fire) in either direction in an over-current scenario. Most people familiar with either type of breaker assume both the polarized and non-polarized is non-directional, so long as "correctly wired" with the Line (+) and (-) and Load (+) and (-).
Suggestions in future video can explain the differences of terms between polarized and non-polarized, directional and bi-directional protection, reason to use double pole instead of single pole types. Which type of breaker is suitable for which scenario. How to understand the terms and symbols used on breakers, such as Line, Load, (+), (-), ratings etc. Difference between AC and DC breakers. There is much conflicting and confusing information online about polarized and non-polarized DC breakers (especially the misinformation about polarized DC breakers are designed to be bi-directional).
I have read much about this topic of polarized and non-polarized DC breakers, and the majority of uploaded UA-cam video content and online forum content is filled with incorrect understanding and knowledge. It is no wonder that most people are not aware. Most people falsely assume that a polarized DC breaker is still protecting conductors in a bi-directional scenario (i.e. any direction flow of current).
Scary to think that many people are still using polarized single pole or double pole DC breakers between the inverter hybrid and battery bank or solar strings in parallel. They have a false sense of security that just because you can manually trigger the breaker to disconnect the circuit that it will do exactly the same thing by itself when the current is flowing in reverse direction in a polarized DC breaker. Yikes.
I personally use the double pole non-polarized DC breakers throughout my two solar systems (12V and 24V). I avoid all polarized DC breakers.
Here in Australia, there are only three reputable proven manufacturer brands of double pole non-polarized DC breakers that are available on ebay and most solar product retailers. The brands are Suntree, ZJ Beny and Noark.
Yes. I actually made a finished video which should have gone online next week but must scrap it as it is not digging deep enough into the matter. I just realized that this topic is very tricky to correctly communicate in a way that the common DIYer will make the right thing. Especially as you say, when using this with batteries where current flow is reversed when charging or discharging, this sort of breaker cannot be used. I am not even sure if I understand every aspect of it. I personally do not use any type of DC MCB in the high voltage PV circuit due to safety concerns, and that would also have been my recommendation in the video that won't be shown :)
@@RolandW_DIYEnergyandMore Hence why it is less complex and safer for the majority of people to understand and install fuses, rather than DC breakers. Believe me, I must had spent hundreds of hours learning everything there is to know about AC and DC circuit breakers, even tear downs of the inside of each type of breaker and how it works in different scenarios. I even bought a HikMicro thermal camera to visually inspect the heat signatures of different types of breakers in various fault configurations, then teared down a few breakers myself to inspect the internal damage. Hence why I only ever use or recommend to others rated double pole non-polarized DC breakers, or Class T fuses (if the latter is connected to Voltages greater than 32VDC) or fast blowing MRBF (marine rated fuses).
@@Matthew_Australia maybe you can tell me something and help me to clarify this. On my typical Chinese DC breakers there is no +/- marking next to the screws as i know it from breakers which are shown on many polarized DC breakers from Australian videos. I also know from my Tomzn 2pole DC breaker teardown that there was no magnet built inside the breaker. But still the Chinese breakers all have the same pictogram printed on the front where they are showing a +,- symbol for the top terminals.... I've now learned a bit more. The Chinese call polarized breakers "solar breakers", they show +,- and -,+ on both ends of the pictogram, and the non-polarized they call "battery circuit breakers", which show plus/minus in a circle only for the upper end, but that looks like to mean that it actually doesn't matter...
You see, the deeper you dig the more questions you have.
The new video will be totally different. Nobody who sees it will ever consider to use DC MCB anymore. Haha
@@RolandW_DIYEnergyandMore You are not alone there. It has been demonstrated by some of us that some Chinese breakers (typically rebadged or relabeled) can be fake news.
All quality non-polarized DC breakers will instead use an electromagnet solenoid coil with a small plunger that is typically contained within its own mini enclosure, and not a permanent magnet. As you know, an electromagnet is only energized with a magnetic field if there is current present. Most good quallity AC breakers also use an electromagnet coil, and not a perm magnet. However, a dedicated non-polarized DC breaker will have a much larger electromagnet coil to direct the DC arc.
The most obvious external tell signs if the DC breaker is a non-polarized type is the lack of markings and inscriptions indicating Load and Line side, and (+) and (-). However, some dodgy Chinese manufacturers have misled and omitted markings on a polarized breaker hoping to sell more units. In almost all fake cases, the polarized DC breakers do show to have a permanent magnet. Therefore, the internal tell signs if it is a NON POLARIZED DC BREAKER is the LACK OF PERMANENT MAGNET, the presence of a much larger arcing electromagnet coil and much shorter distance between dynamic and static contact points (to reduce arc distance and direct the arc from either current direction).
Rule of thumb, if the DC DIN type breaker has a permanent magnet, then it is likely a polarized type. If it has an electromagnet, then it is very likely a non-polarized type. Of course, you should also discern the pictogram and markings too to further verify what type of breaker you have.
My recommendation is to wave a ferromagnetic material near the breaker case, if you feel an attraction to a magnet then the DC breaker is likely a polarized type. Then, if you really want to make sure the breaker is a non-polarized type, start experimenting with loading an over-current in both directions, expect a small fire if the breaker is polarized and expect the breaker to trip and do nothing if non-polarized. Hope this helps you and others.
@@RolandW_DIYEnergyandMore My post got scrambled. So, I edited and fixed syntax to make it easier to read.
The problem with bonding the neutral conductor comes across relatively quickly if somebody want to learn more about solar technology by watching videos (but thank you anyway) , but professionals like you and Andy from the Offgrid Garage are unfortunately quiet about the problem with the polarized DC breakers (in Thailand they are still quite common). It was only by chance that a rather modest solar beginner made me aware of this, for which I am very grateful to him, because without him it would have resulted in a medium-sized catastrophe for me if I had turned off the breaker which the positive pole of the solar cells came from bellow on the same side where the plus symbol was printed at the top. To interrupt the 400 volts with this wrong connection would resulted in a huge fire of the entire fuse box within seconds.
It would be nice, Roland, if you could clearly draw attention to this in a separate video 🙏
OK, I think I have mentioned this topic occasionally in videos where I am showing my solar array builds, etc.
In my systems, for that reason, I never use breakers on the PV-DC side. Only fuses, Knive switches and the DC-Switch of the inverter. I have seen videos of people showing burning DC Breakers. Even if the problem might be avoided if make 100% sure that you have connect polarity correctly.
My channel with 2000 followers unfortunately doesn't have the reach to make much of a difference if 100 times bigger channels will show you that you need to buy those products because they will sell those to you in affiliate programs.
I will make a video about it in January. Thanks for the input!
@@RolandW_DIYEnergyandMore I was going to use fuses, but then Andy from Offgrid Garage show how hot they become and he replaced them with breakers, cause breakers producing less heat. Yes, even I am 100% sure i have connected them in the right way (+ from source comming from bellow on the same side where the - symbol on top is printed on the breaker) I am affraid to interrupt them under load. I will only do that at night when they aren't under load.
Also the fact that the battery connection to hybride Inverter should be never interrupted during solar power is still connected is quite tricky and user manuals do not point out this fact enough. It will destroy the Inverter when doing it in the wrong way. When connecting hybride Inverters always connect battery first and when disconnecting the inverter battery should be disconnected as the last final step.
@@topeye4202 to disconnect DC from the PV array you shouldn't use the breaker anyways. That should be built in somewhere hardly accessible in a junction box. My main means of turning of the PV is the DC switch in the inverter. But normally i would first disconnect the AC loads. That might not do much of course if the energy then is just rerouted to the battery :)
The simple knife switches are good interrupters as well as they have huge breaking gaps.
I don't know about heat issues of fuses. Never had any problems with them, but on the other hand i had a handful of molten , overheated MCBs...
@@RolandW_DIYEnergyandMore But the knife switches I know are open constructions right? Cause of the 400 Volts and the big electric arc I am affraid to use them. My Inverter have no build in switches, exept the on/off switch, whitch should interrupt the load as well I guess.
By the way, in another Video a guy say, solar panels do not need fuses or breakers, but he has breakers just to have a switch.
In a other Video one guy shows the interruption under 10A load and 200V and it works with just a little spark shining through the housing.... it seems to be possible... in other places we also trust in right connected polarization, why not here I ask my self... but I really understand You ; )
@@topeye4202 the reason why people with knowledge of the matter do have high respect of the PV-DC side is because we do know the stories of burned down houses because of isolator fails. It was a big thing in Australia where isolators where mandatory and cases where high compared to other parts of the world where DC isolators and utility disconnects are not really needed. So yeah, I do not install any device which is only opening a 1mm gap on a 500V DC circuit as a disconnect. No matter if it has magnets inside or not. haha
Roland, thanks for your videos - I have learned so much.I was a solar installer in California and I am still trying get my head around the neutral bonding differences in inverters here in Thailand. I am planning a 10kWp PV system in Northern Thailand and wish to import from China via Alibaba, as you did. I know I want a 3-phase Deye inverter, I can't decide on the brand of LifePo batteries - I don't recognise any of the brands or supply companies on Alibaba. Are you still happy with the Unisun battery? I have looked for Unisun company on line, but can't find them as solar supplier of small quantities. Would you mind sharing a contact name and email for the person you dealt with in Unisun, please? If you have any suggestions for other reputable Chinese solar suppliers, I would be most grateful. Thanks, Bruce, in Chiang Dao
Hi Bruce. Sure, it's probably easier if you send me an email to the address shown in my channel info. Then i can send you address, phone contacts, other info.
Unisun is sending in any quantity if you want 5o use them...
Great video as usual Roland. Can you kindly comment on the noise level of the inverter (if possible, in decibels) at full load? Any specific reasons why you bought this particular brand of hybrid inverter instead of the alternatives?
Hi. That inverter is passively cooled by a heatsink in the back. I have never heard any noise from it. I don't really know any suitable alternative brands which can do these features here in Thailand. These SUN hybrids are built under many brands anyways. I just took what i got here.
Little correct, all 3 phase inverter by deye/Sunsynk do have an internal relay
Ah, great. I thought that the higher powered, more expensive versions/series will probably have it. thanks
@@RolandW_DIYEnergyandMore I am not so sure if any of the single phase ones have this build in..
Just can confirm that my 12k 3 phases, and my friend's 8k 3 phase ones have it build in ;)
@@houseofancients well, it's simple enough the way it is.
@@RolandW_DIYEnergyandMore congrats on the new setup though..
Now make sure your battery addiction doesn't take over ;)
Hey Roland, thank you for creating such great content! I have a few questions regarding installation of this inverter:
-> If there is only a TN-C-S network available with earth and neutral separated in the distribution box of electricity provider, should I bond the inverter grounding to PE from the network? It seems to me that this connection is required to keep the low impedance path for GRID/LOAD ports when in on-grid mode. Otherwise, this setup will be working as TT which is only protected by RCD. What’s your recommendation?
-> As far as I understand, for both cases mentioned above, I would need a contactor to create N-G bond when in off-grid mode as only TN-C variant would allow to create permanent bond?
-> What do you think about an additional RCD on the GRID port? Would this increase safety of the system? Or rather this is something redundant?
Sharing some Deye tidbits:
-> The leftmost RJ45 port in the top row can be used to acquire some real-time data from the inverter/battery via RS485/Modbus. Alternatively, there is a lsw-3 datalogger, but I do not recommend it due to the delays (it is only useful when you want to upgrade firmware).
-> Enabling ‘Low Power Mode’ results in ignoring ‘Shutdown’ threshold. This can cause full discharge of battery if you not use Grid Charge.
Hi. If you are operating an grid interactive - ergo grid tied hybrid inverter behind the utilities TN-CS separation, I would use a bonding relay to provide a N-G bond when the inverter is in off-grid mode. The impedance in normal mode won't be different as in normal grid as the inverter is just overlaying its "magic" on the grid sine wave. This would avoid any double ground loops in your panel.
Technically you could use an upstream RCD at the grid input, again, because the inverter is just interacting with the grid, but in my opinion it is not required as the inverter as a power source is providing all protections by itself and will just shut down if it is faulty.
Thanks for the Deye tips. Greetings, Roland
Thanks for your feedback :) I've created a circuit diagram to confirm that I understood your suggestions correctly, but I'm not able to attach it to this comment (it seems that comments with links are automatically removed).
I'm still worried that in case of a neutral fault on the backup load side when in on-grid mode (bypass), the only protection will be the RCD as there will be no low impedance path via PE for MCB :(
@@kaspert0 there is an email address in the channel info. you can send it there and ill hava a look
Hello Roland. I have a 30 Euro for effort request. Please be so kind as to create a video about how to correctly wire up the AC SPD post inverter within a distribution breaker box and DC SPD before the solar controller (or inverter hybrid). I have reviewed your SPD related videos (using search feature on UA-cam), and the wiring was hard to discern. My understanding for AC SPD is; wiring from the Inverter AC output goes to main RCD input, then from main RCD output into AC SPD input, then piggyback power from the AC SPD input to all other breakers downstream (and not from the main RCD). My understanding for DC is; wiring from solar string goes into the input of double pole DC breaker (non-polarized) in combiner box (before solar controller or inverter hybrid), then from DC breaker output into DC SPD input, then piggyback power from SPD input to feed the battery bank (and not feed power directly from the DC breaker). Obviously the Earth output from either the AC or DC SPD to be wired to the Earth rod. Perhaps you can use a screwdriver as a pointer to follow each conductor into each input and output of device. I am aware that you use single pole fuses instead of breakers for your solar strings, but I presume the principle wiring connections will be the same for double pole DC breakers too. Thank you in advanced. Kind regards, Matthew from Australia.
Hello Matthew. SPDs in solar applications should always be as close as possible to the inverters input/output terminals. You would essentially connect AC SPDs right at the next point the inverter gets its AC from, or where it is feeding in. In my recent hybrid inverter installation the AC SPD is connected after the ATS output as there it is serving the inverter and grid, whatever source is switched through to ATS. But before the RCD-in and all subsequent circuits.
Similarly this is valid for the DC PV input. you could best connect the SPD just before the inverter PV input. But if the PV supply cables from array till inverter are more than 10m, then you should connect another SPD inside the combiner/fuse box at the array as well.
So, SPDs should be installed as far upstream to the power source/or sensitive device as possible, so that tripping of downstream breakers, RCDs, etc do not isolate them and make them ineffective when otherwise they still could have protected else.
OK, will make a detailed video of different examples. Cheers
@@RolandW_DIYEnergyandMore Great! I also bought a Geya branded AC double pole SPD, with same ratings as your triple pole version (Uc 275 with T1 and T2 protection). I also bought a few ZJ Beny branded DC double pole SPDs. Yet to wire up the AC or DC SPDs. Waiting for your advice and walkthrough. I am probably right on 10 meter length for the DC solar strings, might even be 11 or 12 meters for a few strings.
Thank you very much.. that's exactly my inverter and my problem, but I want to ask you ,I did the bonding in different way, I bring a contactor who has one point in NO and one point NC , then I have connected the Ground wire in Normally closed point and I have connected A1 and A2 points in contactor coil to Live and Neutral in utility , then when the inverter in off grid mode the ground is bonded to neutral and when I connect the utility the coil disconnect the point, is that way right?
So that way you let the grid-voltage take care of the bond. When grid is lost the bond will be open...Well, that works of course too. The better way is still to let the inverter take care the relay, as your grid might only have a low voltage condition where the inverter switches to off-grid but there is still enough voltage left on the relay coil to keep it working.
@@RolandW_DIYEnergyandMore Thanks alot for your precious help.