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Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 71
Posted: 04:25pm 10 Jul 2024
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Hello I just joined this forum and this is my first post. I have been following Wiseguy and KeepIS posts on the 6 KW Nano inverter. I have to admit it’s very impressive what an open hardware design can do. Only one problem I need a 12 KW version. I like the idea of just not only having parts that I can swap out but having the ability to repair the thing itself. You can’t do that with Victron and I would need 2 X 10000VA to equal a 12 KW continuous unit. That’s 9000 Euro with tax and shipping included that is crazy expensive. The reason I need the 12KW and just not use 2 X 6 KW is because I want to continue to use my MIG welder and that uses 6 KW to 11 KW of 230v single phase power. Batteries is not an issue I just need an inverter that can put out that power. I am planning to use 2 X 6 KW transformers and put them in parallel as building 2 x 6 KW units is much easier.
There are 2 ways which a 12 KW inverter can be built.
Method 1 Firmware Modification Use 2 x 6 KW units in parallel mode this would seem the easy method but it would require perfect sync between a master and slave unit. The firmware code would have to be perfect and it would be connected via serial to rs232 or serial to rs485. There would have to be much firmware code work to be done and I don’t even know if the nano has the compute power to do this. I believe this is not the best option. Podia and KeepIS can answer this one.
Method 2 New Power board and capacitor board This would require a new power board and capacitor board. The power board would have to be longer and perhaps wider it would have 8 mosfets per channel for a total of 32 mosfets. It would have 4 battery terminals one set per transformer. I believe the gate drivers has enough power to drive 8 mosfets. It’s also requires a new capacitor board to hold 8 capacitors vs for 4. Even if the cost of the pcb is double thats a non issue. The best part is that it does not require any major firmware changes to be done. Only wiseguy can say if this can be done and if he is willing to do this project.
I believe having a single 12 KW continuous inverter is more than enough power to power any small home a large boat or RV and pretty much any off grid anything.
I hope the 12 KW design can be done as I will take 3 complete units.
Thanks for taking the time to read my post.
Godoh Guru Joined: 26/09/2020 Location: AustraliaPosts: 435
Posted: 09:50pm 10 Jul 2024
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Most inverters of that size are 3phase. You may be better off to create your own Micro Grid, and use a 6kw battery inverter and one or more Grid Tie inverters to get the output you want. Pete
KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1624
Posted: 10:18pm 10 Jul 2024
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First, welcome to the forum
This is just a heads up, this is wiseguys design and his can advise you if this is possible. He designed his controller to drive two of his power boards, so sync should not be an issue, hopefully when he gets time he will answer your questions.It's all too hard. Mike.
noneyabussiness Guru Joined: 31/07/2017 Location: AustraliaPosts: 510
Posted: 11:15pm 10 Jul 2024
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if you want a turn key commercial one, have a look at growatts sph 12kw ... low frequency ( so you can attach GTI's to it ) and is well featured and reasonable price...I think it works !!
Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 71
Posted: 11:39pm 10 Jul 2024
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Thank you KeepIS for the kind welcome. First I would like to state I am not in a hurry if I was I would just purchase 2 X 10000VA victron inverters which are rated to 6000 watts continuous at 65 degrees celsius. So basically they are a 6 KW continuous inverter. However at 4500 Euros a piece that crazy expensive and still leaves you with a unit that you cannot service or repair yourself. I am planning on a expedition on my 49 foot aluminum catamaran so having the ability to swap and repair is needed. Battery power is not an issue as I will have over 200 KW of lithium batteries on board with just over 10000 watts of solar on board so power is a non issue.
I want a 12 KW system because it’s the largest single phase inverter at 230v there is and I need a simple low frequency design that I can service and or repair in the middle of nowhere. I did not know that wiseguy had a design that could drive two 6 KW inverters however I still believe a single design mainboard would be a better option only wiseguy could answer that question.
I need a 12 KW single phase inverter or two 6 KW in sync. Either solution works for me. I need my MIG welder onboard if I ever need to weld anything also having a 12 KW onboard I can pretty much run anything at the same time well except for the MIG welder of course.
In the past I have built a few OZinverters but they have their issues and are only rated at 6 KW as well. I would rather have a wiseguy design inverter running the nano code. The latest design is vey impressive. I hope we can have a 12 KW design in the future.
Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 71
Posted: 11:56pm 10 Jul 2024
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I do not want a turn key solution. I want a DIY solution that I can swap and repair myself. KeepIS blew his DIY inverter with a changeover switch and he was able to repair swap his system that is what I want I want to carry all the spare parts so that I can replace repair at will. Also all my systems are DIY if you can build it then you can fix it. Also I do not want any Chinese junk that I can’t fix myself.
Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 71
Posted: 12:39am 11 Jul 2024
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Sorry no 3 phase or grid tie for me as it is to be used on a boat. I need the 12 KW due to having a MIG welder onboard. As I do not have a AC generator but a 42 KW DC generator which is used to charge the large lithium DIY battery pack onboard. Also I want the KISS approach Keep It Simple Sailor so only one 12 KW single phase 230v inverter is needed or 2 X 6 KW inverters in sync. Either solution works for me.
wiseguy Guru Joined: 21/06/2018 Location: AustraliaPosts: 1127
Posted: 12:40am 11 Jul 2024
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Hello Cpoc, I still have pleasant memories of Faro and Castro Verde, nice part of the world you live in (I was visiting the Somincor Mine).
The inverter design I created can easily drive 2 power boards and your application is exactly why I created it this way. You will have to either buy or wind two transformers with exactly the same turns for primary and secondary and have the secondaries (230V) in parallel. Each of the 2 primaries are driven by 2 x 16 FET power boards which are both driven from the one controller which has 2 x 8 way connectors, one for each power board.
On the latest power board I included 2 connectors in parallel so the second power board can also be just daisy chained from the first Power PCB instead of a second 8 way cable back to the controller card. The drive signals are just a handful of milliamps, there can be no synchronising issues as they are driven from a common drive signal. So the only difference between a 6KW & 12KW version is an extra 6KW transformer, a second power Choke, a second Power PCB (with 2 x capacitor PCBs) and an extra 8 way ribbon cable and assorted Power cables etc to wire the input DC power to the second PCB.
This I believe is the easiest and most foolproof way to build a 12KW inverter using 2 x 6KW modules, It is essentially the same reasoning that you are planning to build 2 x 6KW transformers, to design a single PCB that can handle ~250A is bloody difficult and very expensive. If the 2 x 6kW units are fused or overload protected separately should help minimise damage if a part was to fail.If at first you dont succeed, I suggest you avoid sky diving.... Cheers Mike
Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 71
Posted: 01:13am 11 Jul 2024
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First of all thank you for responding so quickly. I live in central Portugal in the Algarve. It has at least 300 days of sun per year. Every day is a day in Paradise you get used to it. Being born in Canada and moving to Portugal you get used to the heat. It’s great to live on a boat here as there is no hurricanes or crazy weather to speak of. However the cost of food has risen a lot it’s not as cheap as it used to be.
I had no idea you had a 12 KW solution. It seems that your solution is a hardware one and not software. I did not think that was even possible. I know building a pcb that can handle 300 amps was going to be expensive but I did not know there was another solution. That is why I have stated a larger mainboard solution was the best solution but your solution is even better. So there is no change in the nano code or there is some change in the nano code to run the two 6 KW units in sync. As for the transformers my specs are the same as my Ozinverter design. OD=240mm ID=100mm H=100mm Which gives me a cross section of 7000mm2 perfect for a 6 KW continuous unit. The secondary is 10 AWG or 5.26mm2 and the primary is AWG 2/0 or 67.4mm2 the math works out perfect and you have 1 layer of secondary and one layer or primary.
All my electrical work is always fused or breaker. Anything connected to the lithium batteries is always fused with a class T fuse for the high AIC protection. All my DIY lithium ion batteries have 4 layers of protection. The insulated sealed aluminum case with external DIY BMS. Each battery pack is 28KW and protected with a Bluesea 200A breaker and each cell is fused with a 4.5a fuse wire that will melt at 7 amps. I have been using this design for many years it’s simple solid safe and plenty of power. I have switched to 5 amp high cycle life 21700 cells. My latest design will have a life cycle of about 20 years.
I prefer DIY design where I have control. As I have said before If you can build it you can fix it.
wiseguy Guru Joined: 21/06/2018 Location: AustraliaPosts: 1127
Posted: 07:34am 11 Jul 2024
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There is no software changes required for the controller card's ability to drive 2 power boards. There may be a few minor component value changes required to rescale the AC output current metering. With regard to the synchronising the Power boards, because the exact same drive signals are being applied to both power boards they cannot be anything else but in sync.
I need to say though that you will be the first person to run two power boards from a controller, but that is not to say it would cause any unexpected issues, just that no-one else has required that much power to date. There is no technical difficulty in driving and paralleling the power outputs as long as they are phased correctly it will just work.
There may be an option to run half the inverter ie a total of 6KW and when running the welder is required throw a switch and contactors etc to bring the other half to life. It just sounds a bit extreme to run a 12kW inverter to run a toaster for a few minutes or and boil a jug and have a few lights running. The idling power might be as high as 30 odd watts for the 12kW unit but if you have plenty of battery storage and it does not bother you it will be less complicated to just run the whole 12kW.
With regard to the transformer design please rely on others here or Clockmans bible re flux density and power handling capacity - I am remaining willfully ignorant for now as I have not needed to know (ok I did run the sums once). If a core and winding was rated for 3kW I don't bother reworking the figures. I determine the volt per turn by placing a temporary 10T winding on the transformer, leave the 230V winding intact and after winding my new primary I just use it - lazy yes I know....If at first you dont succeed, I suggest you avoid sky diving.... Cheers Mike
Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 71
Posted: 08:02am 11 Jul 2024
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I use Clockmans bible so far I have not changed the design however now that I will parallel 2 transformers I will have to adjust the design a bit. Going with OD=250mm ID= 110mm H=100mm Core is still 7000mm2 however I will go with 9 AWG for secondary and AWG 3/00 for primary. When you add the mm2 for the secondary it now gives the correct values I need. I will leave it at 12KW continuous as the idle power of 30 watts would be fantastic I was expecting 50 watts. Having 10000 watts of solar and a 42KW DC generator and a sh*t ton of lithium batteries as they are needed as the sailboat will be electric powered by 4 X 10KW motors. The batteries can put out up to 1500 amps at 50volts for a couple of hours so power is not an issue. Also having the 12KW is going to be good as the water maker consumes 4KW and I will have several AC fridges and freezers. Why AC and not DC well it comes to cost. I can get 4 to 6 AC fridges for the cost of one DC fridge. This is why I need an inverter that I can fix myself because I will have alot of food that could go to waste if I have to wait for an RMA and send it back to the manufacture. You can’t do that if you’re in the middle of nowhere.
How do the chocks work do I need 4 of them 2 per transformer. The Ozinverter only used one choke. What are the specs for the chocks and how many turns do I wrap them. The chocks would have to be a bit large to handle 3/00 wire I’m sure of that.
Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 71
Posted: 08:08am 11 Jul 2024
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Ignore as this was a double post. Edited 2024-07-11 18:13 by Cpoc
rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 835
Posted: 11:38am 11 Jul 2024
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Welcome Cpoc, it's good to see someone new ... and someone with out of the ordinary requirements.
Looks like you've put a lot of thought into what you need and how it can work with what you've already got. That's a lotta lithium power.
I've been interested to see how wiseguy's design might work with two transformers to get the power level up there and it has always made sense that with one controller providing the drive signal for everything ... that you should be able to safely parallel up the output transformers ... and not have to worry about trying to synchronise two seperate drive boards.
I have built a Warpverter which is good for 15kW ... but is physically quite large and very heavy. I suspect if you can put two 6kW wiseguy systems together that you'd come out less than half the weight of what mine ended up.
One thing I have learned after running mine for a while is that having a good solid inverter running and providing my own personal "grid" ... that it is easy to add a cheap secondhand GTI with its own set of panels to add to our power generation.
In my case, I added a 5kW Growatt GTI with an additional 6.6kW of panels. It has proved to be a very simple way of increasing our total power output. Of course if the Growatt fails, I'll probably have to throw it away and find another cheapie to replace it. Unlikely to be easy to fix ... especially in the middle of the ocean.
And while I don't really see the need for more power ... I could easily add another one or two GTIs to our system.
One other thought came up too regarding using a Warpverter in your situation ... it may be easier to build a higher power system if you start with a much higher supply voltage than the 48v I'm using. Eg. Warpspeed the guy who designed it used 96v ... but there's no reason you couldn't go well above that. In fact I have a feeling that Haxby (another backshedder) used around 200v from a Toyota Prius battery.
The other change I would probably make if I was starting again ... epecially if using a higher supply voltage, would be to use IGBTs (at least for the bigger two transformers) ... rather than mosfets for all of them like I did.
Though using modules like I have makes it very quick and easy to swap one over if you have a failure.
Anyway, good luck with your build and I am looking forward to seeing a 12kW Wiseguy Inverter ... it's likely to be the beginning of a new trend. Cheers, Roger
Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 71
Posted: 01:31pm 11 Jul 2024
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I hope so because 12KW seems to be the perfect size inverter for single phase that can pretty much run all you need at the same time. For me the large devices that use a lot of power are the MIG welder 6KW to 11KW. The water maker 4KW. The dive Compressor at another 4KW the chiller/heat pump at another 4KW and all the other devices. the induction stove, washer dryer etc.
My current boat does not have any of these things but as we get older the luxury things matter. My current catamaran has no AC no washer, dryer and is 39 feet long buts she is fast and can do 22 knots sailing. That comes at a price and the price is payload. She can only carry 2 metric tons. Her light displacement is 5.5 tons and fully loaded she is 7.5 metric tons. On my new aluminum 49 design she comes in at 13 metric tons light displacement and fully loaded at 6 metric tons. That’s almost 3 times more payload. She can also carry 2000 liters of fuel and 800 liters of water. So yeah I want my power and my solar and my luxury. She still can do a top speed of 18 knots and is classified as a performance crusier expedition vessel. I hope so as most of the design is all mine as she is custom build off a known aluminum design with heavy modification on my part. I know what works and does not work on a boat and I want my dam power.
In Europe a self built boat has its limitations one of them is length which is 15 meters maximum hull length. Mine comes out to be exactly 14.98 meters. Also another limitation is on the DC side you cannot have more than 65v DC and 230V on the AC side. So the warp internet was out also it’s a very good design but to dam big and heavy for a boat. The good thing with a self made boat is no need for CE certification and no need for inspections. However the boat can never be a commercial vessel and you cannot sell the boat until 5 years have passed adapter it has been splashed.
To keep the cost down everything I can build I will build myself from the electric propulsion system to all the electrical and plumbing system. As much as I can with open hardware designs. I don’t care for the open source part as I am not a programmer buts some projects are open source like the navigation system and the DiY BMS system. Budget to build under 300k for everything and I mean everything. If you would ask a yard to build this they would ask 1.8 to 2.2 million euros. I know I have asked that’s crazy expensive.
Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 71
Posted: 01:34pm 11 Jul 2024
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I hope so because 12KW seems to be the perfect size inverter for single phase that can pretty much run all you need at the same time. For me the large devices that use a lot of power are the MIG welder 6KW to 11KW. The water maker 4KW. The dive Compressor at another 4KW the chiller/heat pump at another 4KW and all the other devices. the induction stove, washer dryer etc.
My current boat does not have any of these things but as we get older the luxury things matter. My current catamaran has no AC no washer, dryer and is 39 feet long buts she is fast and can do 22 knots sailing. That comes at a price and the price is payload. She can only carry 2 metric tons. Her light displacement is 5.5 tons and fully loaded she is 7.5 metric tons. On my new aluminum 49 design she comes in at 13 metric tons light displacement and fully loaded at 6 metric tons. That’s almost 3 times more payload. She can also carry 2000 liters of fuel and 800 liters of water. So yeah I want my power and my solar and my luxury. She still can do a top speed of 18 knots and is classified as a performance crusier expedition vessel. I hope so as most of the design is all mine as she is custom build off a known aluminum design with heavy modification on my part. I know what works and does not work on a boat and I want my dam power.
In Europe a self built boat has its limitations one of them is length which is 15 meters maximum hull length. Mine comes out to be exactly 14.98 meters. Also another limitation is on the DC side you cannot have more than 65v DC and 230V on the AC side. So the warp internet was out also it’s a very good design but to dam big and heavy for a boat. The good thing with a self made boat is no need for CE certification and no need for inspections. However the boat can never be a commercial vessel and you cannot sell the boat until 5 years have passed adapter it has been splashed.
To keep the cost down everything I can build I will build myself from the electric propulsion system to all the electrical and plumbing system. As much as I can with open hardware designs. I don’t care for the open source part as I am not a programmer buts some projects are open source like the navigation system and the DiY BMS system. Budget to build under 300k for everything and I mean everything. If you would ask a yard to build this they would ask 1.8 to 2.2 million euros. I know I have asked that’s crazy expensive.
Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 71
Posted: 01:59pm 11 Jul 2024
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As for the Solar I cannot use anything higher than 65 volts so I will use solar mppt boost controllers. Shade on a boat is a big problem so putting solar panels in series is a no no. You can put low current panels in parellel but not series due to the shade. Most of all my solar panels will be 300 watt panels and a few of them 50 watts. So one controller per panel for the 300 watt and 1 controller per 2 50 watt panels. The EU is very strict about their rules for self made boats and you may be inspected boarded anything anywhere in the EU and if you are not up to code you will pay a large fine and the boat may be forced to go to land until it complies with the law. That is why all boats that are sold in the EU after 1998 manufacture date must have the CE certification documents. My current boat is a 93 model so CE rues do not apply. If it were to be inspected it would not pass inspection. On my current boat I have a total of 400 watts of solar and it sucks. So going from 400 watts to 10000 watts will be like night and day. I will feel like Tim Allen.
400 watts of solar no ac very limited hot water no chiller heat pump no induction stove no washer dryer dishwasher no luxury anything. You get used to it but it still sucks. Right now it’s 32 degrees no clouds in the sky and no wind and yes my balls are sweating. So I think it’s time for an upgrade.
Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 71
Posted: 02:09pm 11 Jul 2024
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Sorry I forgot to make this clear on non CE certified equipment you can only go to 65v DC and 240v AC on a non certified self made boat in the EU. If you have all CE certified equipment on the solar side you can go up to 250v DC and on the battery side you can go 65v max on self made boats. On a CE certified boat will all the CE certified equipment there is no limit as long as you have all the CE documents to prove that. I have seen 800v DC systems on a boat. All CE certified and you don’t want to know the price of these systems.
Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 71
Posted: 02:10pm 11 Jul 2024
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Double post again. Edited 2024-07-12 01:10 by Cpoc
wiseguy Guru Joined: 21/06/2018 Location: AustraliaPosts: 1127
Posted: 04:50pm 11 Jul 2024
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I know I said it to you in a PM but for the public record the idling power will be closer to 50W than my initial 30W guess, my 3kW unit idles at 13W so the total will be at least 3-4 times my idle power.
With regard to the chokes, you can either use 2 chokes for each transformer (total of 4) they only have a handful of turns each or larger choke cores with split windings so 1 larger choke per 6KW toroidal transformer, I am not sure which will work out more economical, it needs a bit more investigation.
Dex has a supplier in Europe somewhere (maybe Poland) for iron dust type choke cores. Just had a look, I think this is the site; https://sklep.feryster.pl/en/ or https://sklep.feryster.pl/en/10917-toroidal?page=1
So worst case you can just purchase what you need new from Feryster, maybe they have an outlet closer to Portugal ?If at first you dont succeed, I suggest you avoid sky diving.... Cheers Mike
Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 71
Posted: 06:41pm 11 Jul 2024
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I figured that 30 watts was a bit low for idle power. For my past OZinverters I have purchased in the UK as I could not have any suppliers in the Eu. I will check out that site in Poland as it seems like a good place for chokes.
The UK supplier makes made or order size and are of very high quality. I will have to find the link. When I do I will post it.
Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
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