This is the best video I have seen that fully explains the various inverter options in a concise, comprehensive and easy to understand manner. Thank you.
Phenomenal video. Thank you so much. I've just started down this road and only learned of AC vs DC coupling while ordering my Inverter on the last day of black friday sales. From how I imagined my system, I went with a Schneider XW PRO 6.8kW, which is a Battery Charger/Inverter, an 10kW of LiFePo storage. My priority is getting backup power online ASAP which run a well pump. I couldn't afford a full system, so I'll add solar later. During your whole video, my sweat intensified because I thought my concept was wrong, but then you put up your last schematic! Thanks! That's the model for me. Now I can start designing the rest of my system and use your image to show smarter people than me. Cheers.
Just make sure you know what the true inrush current is of your well pump. And good choice with the XW Pro because that inverter can handle a really large surge unlike some of the newer inverters. In your application I would definitely go DC coupled once you get your solar.
@@boblatkey7160 Thanks for the reply. I opened up my pump control box and put a current clamp on a hot lead for startup and got 17 amps. Since it's a 220v pump, I doubled that to account for the other hot, and got 35 amps inrush. 5 amps per leg once up and running.
You could probably look at a soft-start doohickey, they help with stuff like AC units too. I agree you got a good inverter! I am going to look at like 20kw ones though, I think the downside is price. It seems like batteries should have to step down to the loads instead of the other way around. I am thinking a Tesla battery from a car being stepped down to the loads makes more sense in my mind.
I am not a solar expert. I have a couple of Deye 8kw inverters. They have a CT that you can put on the grid line, and the Deye can be put in a mode to not allow any energy export to the grid. Its a hybrid inverter so the batteries and all connect directly to the inverter. It also has AC coupling modes to work with lesser inverters. Before I watched your excellent explanations, I didn’t realize how bad some designs are/were before hybrid inverters. Also I understand more about why Victron has separate charge controllers. The things I like about the Deye inverters are they can be configured to prioritize batteries first, grid first, even what times to charge the batteries first . . . it does so much. I have decided that complete and total overkill is what I want when it comes to solar. I eventually want enough battery to power everything and enough solar to recharge it all. I don’t have a battery car yet but I want to make it work with the solar when I do get one, so I can swap power depending on how far I will be driving. A battery car must have an awesome inverter in it because it needs to lay the power down when you stomp on it and the battery voltage must be like 400v DC, so charging that thing must take some bigger amps.
Thanks Glen, another good and informative video. I am down the road from you in Mt Evelyn and we have a 6.5kW solar array and an Alpha ESS 10kW batterwith inbuilt 5kW inverter, with the power backup option added for power outage. The backup power handles out lighting circuit and the power to our loungs dining area (fridges etc) When we upgraded I kept the old 1kW inverter and panels with the intention of installing them on the (large) shed roof. Adding a flow battery as you showed earlier and having this osolated from our mains connection and have it off grid to run basic tools etc. and the poo pump. I now realise this will not work with the old grid tied inverter, so I will have to decide what inverter to get and find where to get the redflow batteries, I have emailed them a couple of times a couple of years ago but got no response. Keep up the good work, I enjoy your videos !
Thanks Lindsey for the kind words. I too have an AlphaESS SMILE5 powering the circuits on my kitchen for the past 3-4 years. As for using Redflow off-grid, you will need at least two units as they alternate shutting down while self cleaning. Send me a message via my website and I’ll put you in contact with a Redflow installer smartenergylab.com.au
Hello, Thanks very much for this and your other very helpful explanation videos. In the UK, the most common use case is where people's houses are on-grid (230v) and then perhap add solar PV (say ~600v) and batteries. In that senario, surely HV batteries is on-balance a far better solution than LV? Are you able to do a video on the pros and cons of high and low voltage batteries, in this sort of senario? Let me know, many thanks. regards, Stewart Wylie UK
I noticed you have the BYD HVL batteries which are 120v dc to 400v dc. Those make more sense to me as the inverter would be stepping the batteries down to the load rather than the other way around. I am guessing this is really the way to go with solar. When you are reproducing the grid, you really have to think about what the grid brings to the table and what you need to build to replicate it. I’ve thought about a Tesla car battery and stepping in down with an inverter but you have to close contactors in the battery with can bus commands and some other janky stuff I don’t want to do. BYD makes a lot of sense and I think they would even be cheaper than the Jed Clampett system I imagined. You have me revisiting my battery choices. BYD is even supplying batteries to Teslas made in China now. They are becoming a force in battery cars and well . . batteries.
00:00 2:03 AC coupling System #1 07:46 AC coupled System #2 10:45 DC coupled System #3 12:44 DC coupled Hybrid with Switched Backup Circuit 14:47 DC coupled Hybrid wiht dedicated backup output 16:32 DC couped Hybrid with Virtual AC coupling #4 17:59 Diesel + Solar + Battery Hybrid System 1Φ or 3Φ 20:09 Diesel + Solar + Battery Hybrid System 1Φ or 3Φ DC coupled Charging with UPS functionality
Hi James, wind power is not my expertise but from my limited experience, the wind turbine will need it's own means of control for battery charging unless it is an a.c. coupled type that can be controlled directly. The solution will be very product specific.
Great explanations!! I have a question. In "AC Coupled System #2" could you in theory sell power back to the grid from the solar inverter and the battery's? Thanks in advance!!
Have a Fronius 6.0kW GEN24 PLUS and BYD 11kwh DC connection and Fronius smart meter at ATS... Question why does the system take 60 to 90seconds to switch over when multiple other brands are 20millseconds? Can it be made faster?
Very helpful, well explained. I have a situation that fits maybe your last scenario: Server rack that represents 24/7 load. Electricity is expensive and I want to optimize for cash saving. Clean slate, got just grid atm. Basically 100% reliable, very stable and clean grid. But: i can not do grid tied and I cannot backfeed / export. So: My backup is grid, my main is solar+battery. I have an ATS that will switch this with solar/battery as preferred source. Whenever there is not enough in solar+battery the grid takes over - until the solar does not provide enough to power the load (and store excess) or until weak solar does not charge batteries enough so that they can (maybe with help of overcast solar) power the load. No charging from grid (makes no sense as I dont care about UPS). So the question is: how to connect everything so that I maximize off grid production and at the same time have clean cutoff so that ATS can safely switch to grid if there is not enough? Will I need powermeter between ATS and load connected to Inverter? What kind of inverter should I choose for this? Is something like this viable?: Solar -> MPPT -> Battery -> Inverter -> ATS (with Grid as backup) -> Meter (info feeding to Inverter) -> Load. Tx.
Thanks for your detailed description. The arrangement that you require is totally possible with many multimode inverters. Some use internal grid switching to perform the function on an external ATS. They will be able to parallel the battery inverter's output with the grid and loads at the same time but with programming, only support the loads with zero export. Depending on what market you're in and what local regulations there are may determine which products you can select.
@@SmartEnergyLab Thank you for your reply and time. Thing is: To convince the property owner (the office building) to let me install solar at all I promised him it will be 100% sandboxed and will not have anything to do with the grid. I already got ATS (from APC). Inverter can not be grid powered at all, can not be connected to grid at all. Hence the relatively long device chain. I am just trying to understand how can inverter be "sure" it has enough juice to power the load 100% on its own.
As for scaling... the microinverter based system is easily scalable, neither solar panels nor windmills with the same characteristics are needed, in particular solar microinverters can be bought for $ 30 for a 300 watt battery moreover, the microinverter system is not critical to the parameters of the battery, it can be assembled from batteries with different parameters, well, of course, you need batteries + microinverter of the appropriate parameters . For example, I generally use used. solar panels, microinverters allow me to connect each panel independently.
That was extremely enlightening, thank you. However the way we use energy is changing radically. More and more of our systems use a USBc connector with a transformer converting AC to DC., all circuit boards are DC as well. Therefore the smart management of sensors and systems are DC in nature.. So why areal these LV and ELV systems in our homes AC, if we have solar and batteries? All lighting has transformer, all chargers, and most appliances. Only the three phase equipment or those with heavier loads needs AC and even those could operate on 380V DC. In fact modern factories and businesses of all types are run through a 48v and 380v DC bus. But the same is not the case for domestic solar especially if the home is being upgraded. I realize the electrical industry wants to drag their feet and no change, but no one seems to be discussing something that is very obvious to anyone with solar. I’ve got a 25kWp ground system and will rewire the home in the near future. It seems madness to me to put back an AC configuration? Thoughts please.
Thanks. So you don’t see an AI and energy future where all our systems are DC both industrially and domestically? Seems awfully logical to me when looking forward. The horse and cart got caught out as well. Is it as easy as I make out? The new industrial facilities seem to indicate that the technology is already available. Trouble is most industry participants don’t want to change. In fact all society has a proportion of it that is worried by change. Cheers
Great video thankyou. A question about the diagram DC Coupled 14mins into video. Why can't the ATS be installed between the original load centre and the energy meter. That would enable you to just use "normal" loads, depending of the battery capacity. The reason for the question is that I have a 16 kw (3 phase) solar system comprising of 3 x 5kw inverters. (There are NO 3 phase appliances in my home) I was contemplating installing batteries but everyone wants to sell me 3 batteries at a huge expense. My thoughts were to purchase say a 13 kw or so battery and install it on the phase that generates most power and install an ATS between the system and meter. The ATS on the house side could be wired so that when the grid is down, all the phases on the house side are wired together, making the house effectively 1 phase. Understand that the battery will drain quicker depending on loads. When the grid comes back, the ATS will disconnect and the house will have normal 3 phase. This configuration shouldn't interfere with the grid because as I understand it the ATS is break before make.
Thanks for your kind words. It is possible to backup just one phase on a three phase installation but the arrangement depends on the equipment used. If the solar inverter is a grid-tie three phase inverter then it can only work in phase synchronised mode, however, if it is a three phase hybrid inverter with unbalanced load support (think SolaX X3, Solinteg Hybrid, Fronius Symo Gen24) then when the grid fails it can support just one phase. In fact the Fronius Symo Gen24 has a special single phase load support called "PV Point" just for this arrangement.
@@SmartEnergyLab I'm a bit confused with your answer. I wanted to have a battery on one phase, but during a blackout, connect ALL three phases together via an ATS on the house side so I have power to all 3 phases.
Hi Paul, that makes two of us :) So you've got a single phase hybrid inverter with a battery connected and you want to move all the single phase loads in the house (currently configured as three phase) onto the single phase hybrid inverter when there is a blackout? I'd be most concerned by the maximum demand of the whole house exceeding the single phase inverter's peak power.
@@SmartEnergyLab I have 3 x 5 kw Grid Tie inverters. My thought were to buy 1 battery and an ATS. When the grid is down, use the ATS to connect the 3 phases on the house side together (Effectively making the house 1 phase) and the battery can be shared between the loads. When the grid comes back, the ATS would disconnect and I would have 3 separate phases.
SolarEdge inverters arene't grid forming so can't regulate frequency. They are grid following. However, Victron MultiPlus II is grid forming and can be programmed to provide frequency shift signalling for power control of a.c. coupled inverters.
The more I think about solar system designs, the more I question why the inverter has all the technology. It seems like the batteries are what need most of the brains because they are so sensitive to over-charging, over-use and all the monitoring they take to not get damaged. I am not sure what inverters are in the 6 200ah 48v batteries I have now but I am thinking I need to open a battery and see. I like the JK BMS, the new one anyway. it seems like I can have batteries of various capacities, link the BMS’s and they will manage the battery outputs and limits. I would like a system that works with Home Assistant. There seems to be room in the solar market for software to control and monitor these devices.
Great video! But I was thinking... Suppose you are using a bunch of micro-inverters, can a battery inverter with separate grid connection signal (by frequency) the micro inverters to scale down when batteries are full? And ramp up again when loads require it and/or the grid returns? I am still learning, so please be patient with me ;) Thanks!
Hi Michael, frequency control can only be enabled when isolated from the grid. When grid connected, simple export limiting is used the curtail solar inverter generation.
@@SmartEnergyLab The first part of your answer makes much sense. But how should I interpret the second part when the "solar inverter" is in reality a bunch of micro-inverters?
@@marcelvanlieshout3508 Depends on the micro inverter vendor. For instance, export limiting is controlled by the Envoy (separate device) if using the Enphase system.
Yes, when the grid is down and your batteries are low your inverter that is AC coupled to your solar array will allow the solar to come in full throttle. When the batteries become full the inverter will shift the ac frequency which will slow the power output of your solar array. Research frequency shifting and California rule 21.
Australia sounds like a bureaucratic nightmare. You can only have a 5 kilowatt inverter in some places? Why? This sounds like something the power company would want to limit people from going completely off grid among other reasons. Power companies are going to really start a war with people going completely off grid I guess. I wouldn’t sell power back to the grid anyway, I would rather invest in batteries. I like Jack Rickards take on it, selfish-solar! What do you really make selling power back? Disconnect and be free. No guns, only approved solar . . . yikes.
