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Forum Index : Electronics : Wiseguy New Inverter Build Nano R6
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| rogerdw Guru  Joined: 22/10/2019 Location: AustraliaPosts: 830 |
Wow, fascinating background Mick and awesome location too. 1973 was about when I left school and started my electronics career. I'm with Aaron, I'd love to hear more too. Maybe start a thread in "Other Stuff" for motors and generators perhaps ... dunno what's best ... ... or the Solar section or the Electronics section depending on what you'd rather focus on. What are you working on specifically right now? It can be a bit overwhelming but there's no question there's some amazing talent here, with lots of support and encouragement which can make a huge difference in our progress. Cheers, Roger |
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wiseguy Guru Joined: 21/06/2018 Location: AustraliaPosts: 1106 |
Great reading of your background thanks for the information. While most of us have been looking for a source of dead inverters, it sounds like you have an ongoing stream of them in your own back yard, talk about lucky lol. I am surprised about the number of inverters that have been killed in your installation from just being in a similar environment to a lot of us. Yet either others don't volunteer the information or hopefully they have been having better luck than you. What do you think is different about your install that sounds like the panels are arranged in a target formation (sorry to sound flippant) but there must be something peculiar to your location/install ? I am thinking high up and very exposed. I understand perfectly well that lightning activity and semiconductors direct connections to mains wiring (otherwise known as trans-former-less GTI's usually with a TL somewhere in the model number) are bad news. I would have thought that a toroidal transformer type inverter would survive much better given your experience. Dont get me wrong if there is a direct hit to your mains supply all bets are off as to whether anything survives. Are there serious overvoltage surge arrestors installed on the mains side ? Are the runs from the cables to the inverters overly long ? I look forward to some further insight. I think that's enough questions to a two finger typist (edit I actually was using one finger when I started ~ 1985) a smarty walking past said "cant you use two fingers" my immediate two finger rude hand gesture showed him I sure could. Edited 2024-07-21 12:33 by wiseguy If at first you dont succeed, I suggest you avoid sky diving.... Cheers Mike |
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Revlac Guru Joined: 31/12/2016 Location: AustraliaPosts: 980 |
I would say the type of inverter (TL or proper transformer) makes ZERO difference when there is a direct or very close online strike, being grid tied or beside the grid as a backup if you need it, will give you the greatest chance of destruction, being full Off Grid will save you from all of the power grid strikes.  @Mick I started a thread long ago,Off Grid and lightning I need to update that soon as a lot has happened to neighbours And I have been running trouble free the all that time. Short and sweet is to be off grid with your own inverter and have some immunity from trouble the grid will give you. Edited 2024-07-21 18:31 by Revlac Cheers Aaron Off The Grid |
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| wiseguy Guru Joined: 21/06/2018 Location: AustraliaPosts: 1106 |
Hi Aaron, I did speak from some personal experience re the transformers giving the electronics a better chance of survival in electrical storm conditions. I also said above that for a direct lightning strike all bets are off. I designed and manufactured a robust rail crossing charger for a Rail authority in SA who shall remain nameless and the same unit is also used in Tasmania, there were well over 400 sites installed in total, in use to this day. Prior to this they had a brief experience with offline switch mode chargers that failed regularly and these were not direct lightning strikes, even a strike near to the supply wiring could induce enough energy to take them out. During the use period of these chargers, if there was electrical activity at Port Augusta or similar open and remote location it was almost a given that the charger would fail often with no charred or other evidence of lightning strike but dead FETs and fuse & no go. Galvanic isolation provided by the mains transformer design reduced these failures to essentially zero. From my experience I would not hesitate to isolate the mains with a transformer if that was determined to be the likely cause of killing my inverters. I also totally agree that being offline will definitely remove the mains as being the culprit. :) Edited 2024-07-21 19:26 by wiseguy If at first you dont succeed, I suggest you avoid sky diving.... Cheers Mike |
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| Revlac Guru Joined: 31/12/2016 Location: AustraliaPosts: 980 |
Hi Mike, Thanks for setting me straight, whats your thoughts on isolating the PV input to the solar system as well? I remove my solar input when there is a nasty storm approaching, some Anderson connectors are just pulled, I think its better to have done what you can, Only other problem is I cant remove it if I'm not home. Getting back to the inverter, whats the minimum size heat sink you would suggest, I guess something at least twice the size of the fet board? Cheers Aaron Off The Grid |
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| wiseguy Guru Joined: 21/06/2018 Location: AustraliaPosts: 1106 |
If I am aware of an approaching electrical storm or if travelling away for a few weeks I still turn off power points for most appliances especially big screen TVs etc to avoid a disaster. You raise an interesting point though, we have 13.5kW on the roof and I never considered disconnecting the PV input or mains to the inverter. We do have some hefty surge arrestors in the switchboard and I do get some comfort in knowing that there are taller structures (yes some are power poles  ) and even taller trees around us.I think if I was in a more remote location and relied maybe 100% on my off grid solar power your suggestion to temporarily isolate the panels from the MPPTs/GTIs for impending storms is a good idea. When I was in my early teens we had 2 decommissioned 32V Dunlite towers and I wanted a good antenna for shortwave so I fitted a porcelain insulator each end and ran a wire between them with a feed down to my workshop. One warm no clouds light breeze balmy afternoon I entered the workshop to investigate a weird buzzing sound, there were blue sparks in a few places on the wooden bench top and when traced out it came from the disconnected antenna feed and was discharging via odd bits and pieces to a ground point I could easily throw multiple continuous sparks 5-10mm long to ground. Needless to say when I realised the implications of lightning activity I quickly removed and dismantled the antenna which had seemed like a good idea at the time. The point of the story is that if steps have not been taken to ground the roof or and at least the rails for the Panels, you dont need a lightning strike, just atmospheric ionisation could cause a static build up and flashover. This is really only relevant to a handy man home install, if its setup on a wooden frame for instance, maybe grounding the panel frames might not have been considered. Re the heatsink I would be looking for something around the same size as the power PCB, the old Aerosharp 1.5kW is fine. Given the quantities of the GTIs they made, it always intrigued me why they chose horizontal fins for their heatsinks, when vertical fins would actually achieve better needed airflow, they certainly had the resources to specify something that would have worked much better for the same price but never did. Edited 2024-07-22 15:09 by wiseguy If at first you dont succeed, I suggest you avoid sky diving.... Cheers Mike |
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| Eddy C Newbie  Joined: 17/07/2024 Location: AustraliaPosts: 3 |
wiseguy, despite not seeing I cant see having sent PM??? Mick |
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| wiseguy Guru Joined: 21/06/2018 Location: AustraliaPosts: 1106 |
Message was received ok thanks Mick, will reply via PM. If at first you dont succeed, I suggest you avoid sky diving.... Cheers Mike |
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| Ziki_the Newbie Joined: 13/04/2023 Location: YugoslaviaPosts: 33 |
Hello everyone, I am slowly collecting components, looking at what I have and what to order. I found some igbt half-bridge modules. For a very decent current. They are Mitsubishi CM600DU-24FA, could I use them for inverter or vairiac? Would it be enough to change the gate drive voltage (12->15V)? Maybe a gate driver ic... I'm open to suggestions, no rush.. Thanks everyone. Pozdrav iz Srbije |
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| wiseguy Guru Joined: 21/06/2018 Location: AustraliaPosts: 1106 |
Hi Ziki, those devices are really meant for High voltage switching at high current. Whilst they could certainly handle the current required, their losses due to their inherent higher VCE when turned on would make them quite inefficient. For instance 6kW would be an input current of ~ 130A from 48V, these devices would be losing ~ 500W of power as heat, nearly 20% loss due to their ~2V C-E saturation for each switch. If your battery source was 200V instead of 50V then the losses would be ~120W. I have not tried IGBT's on the inverter. Whilst I encourage people to play my suggestion is to just build the inverter as presented, when it is working, by all means experiment as you then also have a working reference unit to compare to. If at first you dont succeed, I suggest you avoid sky diving.... Cheers Mike |
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| Ziki_the Newbie Joined: 13/04/2023 Location: YugoslaviaPosts: 33 |
Mike, Thanks for the detailed explanation. the components remain for some next project. When you look at the numbers, everything is clear.  Thanks for the help once again..Pozdrav iz Srbije |
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