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Forum Index : Electronics : Inverter building using Wiseguys Power board and the Nano drive board
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| rogerdw Guru  Joined: 22/10/2019 Location: AustraliaPosts: 852 |
Haha ... the lengths some people go to to avoid winding a simple toroid.  Time to bite the bullet Mike. Add another string to your bow. Cheers, Roger |
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| Cpoc Regular Member  Joined: 28/05/2024 Location: PortugalPosts: 78 |
If I could avoid it I would as well. Winding those secondaries is not fun. For me it’s the worst part of the build process. |
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| Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 78 |
If I could avoid it I would as well. Winding those secondaries is not fun. For me it’s the worst part of the build process. |
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wiseguy Guru Joined: 21/06/2018 Location: AustraliaPosts: 1156 |
 I found an image of the mother lode but I dont know where it is sniff...  I just found the company, www.westernportmetalrecyclers.com.au (who would have guessed lol) maybe its worth a call next week ? Edited 2024-07-12 23:27 by wiseguy If at first you dont succeed, I suggest you avoid sky diving.... Cheers Mike |
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KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1679 |
Hi all: Yes Rodger I agree, but, and there is always a but, in this case there is no length to go to, Hack off the outer 230v winding and sit one on top of the other, wrap a bit of fiberglass tape around cores, put 14 turns of battery cable through - about 4 minutes to put the cable through, and one 3 stack Toriod transformer ready to go. It will take me some time to get it all set up, I have a sh*t load of work to do around the property, and I have to build the new cabinets. I have really learnt a lot from the first three builds, now I know exactly what works and all the unforeseen problems I had not considered - So it's only a time constraint at the moment as everything is already planned out and locked in. Mike, I visited a friend who had planned to build an inverter with my help over a year ago, he eventually found the three correct Solar inverters and had removed the toriods, sadly health issues have derailed his plans - a "relatively" low cost commercial system I helped him put together is still running fine though. So I came home with the three toroids. That picture makes me cry - A solar installer told me of the hundreds they literately threw in the tip over the past few years from school upgrades, these older SMA are getting as rare as hens teeth, and some people are still asking hundreds of dollars for one - crazy. Cpoc I have run close to 8kW for 20 minutes on the current inverter, these 3 stack toroids are good for about 5kW sustained running with some toriod cooling, I almost never have that load level, but I do have short high peak demands. With two of these 3-stack transformers and two power stages there is no doubt that it will run at 15kW, but not for long (toriod heat), but 8kW - 10kW should be a walk in the park, and way more than I would ever need. You larger Toroids, combined with a slightly heaver output winding should have no trouble with 6kw for one set - 12kW should be easy. The power limit really comes down to connection quality and loss (heat), you seem to have that fully under control and know exactly what you are doing from what I've seen in your posts, so keeping the Toroids and chokes at a reasonable temperature is likely the only limiting factor. EDIT Removing center plug: I have a large tool socket the fits in the center hole, I support the Toroid on four blocks of timber on a concrete floor, use a small sledge hammer to hit the center plug out. It really sticks to the wrapping tape, I haven't tried cutting the wrapping with a Stanley knife first, I think it would come away easier if I did, about 6 hard blows usually gets it moving. I might try cutting the tape and removing one of these new cores today. _ Edited 2024-07-13 10:35 by KeepIS It's all too hard. Mike. |
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| KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1679 |
I was correct about cutting the Mylar tape first, I also use a chisel to cut/break off the green plastic base plate, this allows two pieces of timber to sit closer to the plug and fully under the windings on the under side of the toriod. Only 1 medium strength hit with a "very small" sledge hammer and it popped straight out, the Mylar warp compressed between the windings and glued to the center plug is the only thing holding it in. So easy, and to think that I bashed the living sh*t out of the first three to get them out  It's all too hard. Mike. |
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| Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 78 |
The 110mm space ID core is perfect 9 AWG secondary at 104 turns and the AWG 3/00 at 13 turns. The math works out perfectly will a few mm to spare but needs to be wound very tight. It’s one layer each so copper loses and heat is very minimal. It should do 6KW at about 60 degrees which is perfect. The two Toroids and 2 power boards will fit nicely in a steel weatherproof box. The electrical box is 600mm by 600mm so everything fits in nice. 12KW continuous should not be an issue and can easily run my MIG welder. I am really glad that wiseguy design is able to run 2 power boards from one control board as I did not think this was possible. I am really looking forward to see you run 2 power boards at the same time and want to know your feedback how that works out. If you can do 10KW continuous that would be really good. Edited 2024-07-13 11:43 by Cpoc |
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| KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1679 |
Sounds good,  but it will be at least 4 to 8 weeks before I can get it done.It's all too hard. Mike. |
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| KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1679 |
No need to remove the green plastic, two pieces of timber against the plastic, not fully under the Toriod, one hit and it just popped out after scoring the Mylar tape. Tried one without first cutting the tape and 4 big hits later, not moving, cut tape, one hit and it popped out. All 3 are done. A 1.2kw toroid next to the 3 for comparison, plugs are gone.  _ Edited 2024-07-13 11:59 by KeepIS It's all too hard. Mike. |
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| Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 78 |
No problem about the wait time. Wiseguy had sent me a pm that some values may have to be adjusted in the hardware, so I will wait for your feedback first as I am in no hurry to build mine. |
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| KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1679 |
I thought it might be a good time to throw around some random thoughts on slight code modifications to monitor the use of two power boards. My first thought was physical adding the output of the two current sensors together and use that to trip the on board over current circuit latch. No code mods at all. Since ADC7 is no longer an issue in the Code, I now have the option to use ADC7 to display a second power board AC current. There is already a spare location on the LCD to display that, so both power board currents on the top line and the AC voltage output where the version number is. Almost no code change at all. In that case I would duplicate U5A+B circuit on a small PCB - nice clean and simple. Then there is a spare digital pin which could be used if needed. I'm getting this system ready for complete off grid running, so in that case I would not need the AC sync pin, and at the moment, switching currents are really quite low with the new ATS anyway. I also plan to use two of those small color full AC monitor modules, so perhaps there really is no need for AC current displays on the LCD at all. That would allow me to use ADC7 to monitor the Capacitor bank on the second power board, thinking about it, that may be more important in preventing and detecting any future fault/problem on the second PB. I'm also wondering about the use of two kilovacs, but as usual, I may be over thinking this, but just thinking out loud ATM. Perhaps when Mike (wiseguy) gets some time he may share his thoughts about the need for monitoring the second power board? Or shoot it down in flames  Any random thoughts from forum members most welcome. That feeling of an adventure is coming back again  _ Edited 2024-07-14 15:18 by KeepIS It's all too hard. Mike. |
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Murphy's friend Guru Joined: 04/10/2019 Location: AustraliaPosts: 648 |
The only LCD display I use here is on Poida's MPPT controller. I do notice it gets harder to read over time (or is it my eyes are getting old?  .Regarding capacitor bank voltage monitoring - why? They are at battery bank voltage level (after startup), connected with heavy cables, so monitoring the battery bank voltage is all I do. For my inverters I find the "colourful" displays perfectly adequate for AC voltage/ Amps/ Power etc. No programming required either .I use temperature controllers with their own display for the fans, ditto re programming .But I do see you like programming , something I'm not good at. |
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| KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1679 |
Sorry for Long answer I was in a similar frame of mind until I realized the simplicity of the Nano controller, trying to get dual stage fans running at exact temperature trip points with the correct overlap and hysteresis was an absolute pain, and I'm over twiddling pots on a PCB over an over to get it right. In the Nano, just 10 seconds to do that, works first time every time. Using the Nano was like a dream come true for that adjustment, same with calibrating the DC voltage displays, setting AC voltage enable, AC under voltage etc and no external control circuits needed, and all can be done with the inverter running. Monitoring the cap bank is important when Fuses or switches might be in the path and/or a Kilovac is used to automatically isolate the Inverter from DC input in the event of "ANY" fault, the reason I have never exploded a component with a failure is due to the DC current sense and AC over-current trip immediately removing DC input, much faster than the typical circuit breaker of fuse - IE the fuses never blow, the Kilovac and Nano always save them. The second reason to accurately monitor capacitor bank voltage is it allows the controller to wait until the capacitor bank voltage is within 200mv of the battery voltage before bypassing the per-charge resistor. Depending on the high value of capacitance, closing a pre-charge switch, either manual or automatically with more than 2 volts difference, will cause up to a 100A to 150A DC input spike - it does in mine. Input spike is now ZERO. These things annoy me and manual pre-charge and bypass will never work for my wife, or me, if one day I forget - and I have with manual pre-charge. As it is now, a complete Noob could switch the inverter Off and On, it's impossible under any condition to cause damage to the inverter, no matter how much you abuse the On/Off switch or disconnect and reconnect DC power cables or batteries in any fashion. Finally, as I will NEVER go back to a manual pre-charge system or a system without a Kilovac, monitoring the Cap-Bank voltage at the moment of pre-charge bypass confirms the integrity of the DC path from Battery input to Cap-Bank. During the inverter RUN state, it can warn you and also stop the inverter if it detects too much loss in that part of the circuit due to a sudden connection fault or other fault condition. I agree, those little color AC status meters are just brilliant, and so dam accurate. I have always loved programming since the early Pre-MSDOS days, mostly in assembler back then, once you get the programming bug you never get tired of it. . It's all too hard. Mike. |
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| Murphy's friend Guru Joined: 04/10/2019 Location: AustraliaPosts: 648 |
I take your point regarding other persons turning on your inverter, does not apply at my place  .For fan temperature controllers I use these: ebay No pot twiddling required .I do use a 500A battery switch to bypass the charge resistor, it gets switched on manually when, around 50V, a green light turns on. It never gave problems regarding switch spikes, I never bothered monitoring them either. The green light (and low voltage disconnect) is managed by a battery monitoring IC. AC over current is monitored by one of the little toroidal sensor coils, I use that to turn off the inverter ON switch electronically. It requires a manual reset - don't trust automatic re setting for that. There are just DC circuit breakers, no hi power fuses, in my inverters. Yes, this has possibly contributed RUD mosfets in the past but that prompted me to improve the design and, thanks due the input of our resident engineer, the inverter runs trouble free now. But that does not stop me from tinkering on one of them , mainly to make it more compact.You like programming, I understand why you get your Nano to take on many tasks about monitoring. I like doing PCB's and the mechanical aspect of inverter building. So we both have fun with it . |
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| mab1 Senior Member  Joined: 10/02/2015 Location: United KingdomPosts: 209 |
Just my thoughts on this: Personally i would want the inverter display to retain its volts, amps, etc: If you want an easy to read external meter that's fine, but in the event that something isn't working right, the inverter display showing what it 'thinks' the volts, amps, etc are, gives you something to compare with the external meter readings. On the subject of the sync input: well i rarely switch back to the grid with my existing powerjack anyway. I'm using a rotary centre off transfer switch, so when i do switch over i just wait in the off position for 40secs or so to allow the fridge and freezer to depressurise before putting the power back on. The risk of flash over has put me off the fast (manual) changover switches, plus the possible effects when running motors /transformers are suddenly 180° out of sync with their supply. But if the inverter could sync to the grid when it's there it would allow safe, seamless transfer without potential issues which would be a nice option even if i might never need it. |
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| KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1679 |
BTW: The Over current trip is always latching and independent of the Controller Nano. However the controller Nano remembers an Over current trip, so if power is cut to the controller, at power on the LCD indicates that over current trip had caused a shutdown. Yes I agree, what works best for us always wins out, and the big thing is that we enjoy the journey. I agree, it was only the AC current I was thinking about, all other LCD voltages and information is absolutely needed for monitoring Inverter startup and fault or error conditions. Which is why I think the second power board should have cap bank voltage monitoring at the very least. I'm lucky in that our fridge & freezers are Inverter drive, as are the Microwave and 5 small Reverse cycle AirCons, any induction motor running at power fail would instantly drop the NVR safety relays - So a manual restart would be required, which is why I have no need at this stage for sync. Agree with flash over, but that can't happen now with this new ATS. It's all too hard. Mike. |
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| Tribal Tronix Newbie  Joined: 14/09/2023 Location: NigeriaPosts: 6 |
Hello All, Please do bear with me, cause am about to ask a dumb question. 1)Is it possible to get the code for the wise guy board not just the hex( did read somewhere why that may not happen but, i still ask) 2) Can it back charge the batteries from grid? Rokai |
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| wiseguy Guru Joined: 21/06/2018 Location: AustraliaPosts: 1156 |
Sorry for the delayed response but I needed to find and refuel the flame thrower first  Remember that guy on here that really wanted to use the KISS principle well I have come to adopt that to a degree and it is quite sound. Just because we can do something doesn't always mean we should do it - I do often try to second guess myself and question why am I doing this as an ongoing self check. I do not really regard two Power Boards & Toroids as 2 x 6kW inverters I look at it as a 12KW inverter. As such I want to sum the outputs to have a common current output reading and voltage reading. Given that the Kilovac can switch 500A @ 900V I consider that it can briefly pass much greater than 500A which already is 25kW for start surges etc. Rather than have 2 Kilovacs, for simplicity and ease of determining contact/voltage drop issues I believe 1 is quite adequate. I created a suite of PCBs that are kind of plug and play and can meet the requirements that were intended from them, as is without (too many) modifications required. If anyone wants to extend on these and roll a new controller with new features and software I am fine with that and offer my best wishes in their endeavours. But for my own perspective I need to draw a line somewhere and call it finished & where we are at the moment is essentially it (for me anyway). Also I prefer to help with something that I understand and not a Heath Robinson contraption that someone has comprehensively modified from my original and then wants help with problem solving or adding more bells and whistles. I am still considering one last PCB that will mop up a few things such as DC input current monitoring with actual and peak readings, a method to monitor the output current and bring in the second Power Board & Toroid when the Power requirements exceed say 5 or 6 kW. This will not involve any High current DC switching, rather the second Bridge is always powered but the optical drive and Toroidal AC outputs are controlled with a soft start on the second toroid but from the 240V side not a primary soft start. IE soft start the second toroid from the mains on the first and then bridge the outputs and bring on the optical drive to make the extra power. Yes kind of 2 x 6kW inverters or maybe looked at as a 12KW unit with 2 stage power delivery and reduced idle Power for lighter loads. This project has burned me out a bit and I still need to build a finished final proper inverter and Variac for my own usage, so I will soon be taking a bit of a back step from the BS for a while, and there are also more imminent holiday plans etc in the wind. I'm still happy to answer questions and help with issues but a bit (lot?) less proactive whilst I recharge and finish some other home projects. Cpoc essentially has driven the high power inverter stage requirement so once he is underway and I send him some stuff to make his inverter, time for a rest. Edited 2024-07-16 02:05 by wiseguy If at first you dont succeed, I suggest you avoid sky diving.... Cheers Mike |
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| Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 78 |
I am very graceful for wiseguy podia and KeepIS hard work. I am in no hurry for this project so anytime taken for rest is well deserved. Having the 2X6KW inverters being driven off one controller is brilliant as I did not think this was possible but wiseguy explained to me not only is possible but will work perfectly. So I believe no code changes are needed as the code sees the inverter as one single 12KW unit. This way for most people 6KW would be enough but for other people that want to be completely off grid a 12KW unit is more than enough to run a home large boat or caravan pretty much anything off grid. Using ink open hardware design is not only a huge cost savings but you have the ability to keep spares and swap and repair if needed. For me when you are at sea in the middle of nowhere could mean life or death situation. This is why I am a huge fan of open hardware because when I was a kid we used to repair everything now we just throw it away and buy a new one. |
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| Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 78 |
I am curious how that second stage soft start function will work does that mean that the idle current when the second stage is not in use will be reduced and only come in when say more that 6KW is needed. Won’t that be complicated to design? I am still trying to understand exactly how it works. That would be really cool if that can be done. This way you have best of both worlds. Low idle current when low power demand is needed and have the full 12KW power available when needed. Am I understanding this correctly. |
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