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Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1513
Posted: 06:39am 15 Aug 2025
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I do suppose this is really a question for Keepis, now as Mike did point out to me when I got my first aerosharp toroid that 7 turns was needed to be on the primary to match the secondary.
Now using Co Pilot the advise I got unless the 2 separate turns are exactly matched expect major problems.
I did find this out the hard way when I coupled both on my first inverter project.
So with stacked toroids is the secondary only used or is the gamble of adding extra turns worth it.
Well some may say why go with the Madboard when Mikes inverter is the bee's knees well on reading the best I saw was around on the Madbaord was around 4Kw with not all fets that are available used using a single toroid.
I do intend to put 24 HY5608 on this first board and with me getting 2 aerosharps and making that toroid from my variac will give me 3 toroids to stack.
I have bought all the components for the Madboard so may aswell go ahead with this project of 3 stacked toroids and a fully populated Madboard just to see if I can get 6Kw out of it or more.
Regards Bryan
Godoh Guru Joined: 26/09/2020 Location: AustraliaPosts: 549
Posted: 06:57am 15 Aug 2025
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Bryan the way to use stacked torroids is the wind the low voltage winding around the whole stack. I don't understand the first question about needing 7 turns on the primary to match the secondary. The primary is the low voltage winding the secondary is the high voltage winding on an inverter. There is no need to match them they are different guages and turns.
If you are still going to be using 24 volts then I very much doubt that you will get 6kw out of the inverter. Unless your cables are massive and the battery bank is also massive. 6kw is 250 amps from the batteries not taking any losses into account. I have got mine to around 4kw but that is about it. The best way to get the sort of capacity you are talking about is to have some GTI inverters AC connected to the battery inverter. I can charge my car ( in full sun) at 5.5 kw by using the battery inverter and 2x GTI inverters together. There is no way my battery inverter would do that level of charging. Don't believe AI. I saw a picture where scientists asked AI to draw a picture of the average Australian dad. Well he was out in the outback, cattle yard in the background, checked shirt, pitchfork in hand and holding an Iguana in another hand. If that is the sort of answers you want stick with AI. Otherwise ask Roger
Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1513
Posted: 08:46am 15 Aug 2025
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Well Pete the first thing I use forklift batteries for storage so with the big amps needed yes they will handle any current needed.
In a forklift battery they are designed to take 800 amps for 8 hours so as far as the current needed it isn't a problem.
The question I do want ask is only the secondary used on the aerosharp toroids used and on stacking are fewer turns needed to work off 24 volts.
I do have 6Kw of solar to to use and a couple of 5Kw grid ties.
Now back in the day when I made 2 ovens for this 1850 oven I got I went thru 2 box's of 2.5mm TC16 welding rods and my kipoint inverter did handle the current but I reckon I broke the surge.
I just want to point out I can run a distillery off the grid where 6Kw is used just to heat the mash to please the tax dept as they don't believe me. I do want to prove them wrong.
So a 3.6Kw element and a 2.4 Kw element for heating and to date a 3.6 Kw voltage controller isn't invented so for a 100 litre boiler 3.6Kw is needed to provide the heat.
Godoh Guru Joined: 26/09/2020 Location: AustraliaPosts: 549
Posted: 09:20am 15 Aug 2025
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Hi Bryan, I can't answer about aerosharps, never used one, I have used a few cores from dead inverters and just other cores I got and unwound.
I would be concerned that the size of the low voltage winding you would need for that sort of current will be difficult to fit through the cores centre. To carry 250 amps you need a cable around 150mm squared which is around 30mm diameter. That is big cable
I opened my cores out to have a 100mm hole and only just fitted my windings in , and that was for a 4kw transformer. Remember to make the windings large enough in cross sectional area to allow for the heating too. For 6kw you are going to need at least 6.5mm diameter wire for the high voltage winding. This could be made up of a number of lighter parallel wires but you need at least that to do the job.
Maybe if you have two elements as you say in the distillery then two separate inverters would be easier to run.
wiseguy Guru Joined: 21/06/2018 Location: AustraliaPosts: 1216
Posted: 11:18pm 15 Aug 2025
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Hi Bryan, for the 2 Toroids I had there was a 17 turn difference between the input and output windings. I cannot remember the number of turns different for your toroid but it is no doubt in my thread somewhere - 7 might be the right number but it did not ring any bells to my aging memory…
It was not imperative to have them both in parallel but if the primary for 48V could fit leaving the existing windings on there the AC output would cause minimal heating being doubled up. However I think it would be wise to remove one of the windings to give yourself the largest space for the beefiest 24V winding that can fit.
Pete’s comments re adding a grid tie inverter is one of the easiest and best ways to inject energy into your home grid without it all having to come from the inverter and could provide some back feeding to the batteries if there is any excess energy not required by the load.
You might be able to do a Roger and just lean the gti string against the shed ? Edited 2025-08-16 09:20 by wiseguyIf at first you dont succeed, I suggest you avoid sky diving.... Cheers Mike
mab1 Senior Member Joined: 10/02/2015 Location: United KingdomPosts: 254
Posted: 10:29am 16 Aug 2025
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question:-
1/ Do you know what size the aerosharps are? 2kw? 3kw?
The 3kw aerosharp I have is similar to the the one Wiseguy referred to: it has 230v : 250v windings, and there's 17 turns difference between them.
The ones Keepis used for his triple stack were 2kw I think, and were wound 90v : 230v I think.
If you are planning to follow Keepis's plan (I'm assuming so) you would remove the 230v outer windings, but keep the 90v windings, wind a similar 90v winding onto your bare 2kw(?)core. It wouldn't have to be an exact match as you're going to connect the 90v windings in series, and use the nominal 270v output from all three as your 240v output. You then stack them and wind a single primary around the whole lot. If Keepis wound 13(?) Turns for a 48v battery, then 7 would be about right for 24v.
If you have the 3kw aerosharps, you can still do a stack, but your options are a bit different.
wiseguy Guru Joined: 21/06/2018 Location: AustraliaPosts: 1216
Posted: 11:14am 16 Aug 2025
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I believe the toroids were all from 3KW Aerosharps but one toroid (Bryan’s) was a slightly different turns ratio to the other 2. The other two are being used in my 2 stage inverter. Edited 2025-08-17 07:55 by wiseguyIf at first you dont succeed, I suggest you avoid sky diving.... Cheers Mike
Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1513
Posted: 11:30pm 16 Aug 2025
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I don't know the size of the aerosharps yet and I will be going over to get them on the 13th of next month so plenty of time to ponder. Edited 2025-08-17 09:30 by Bryan1
rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 929
Posted: 01:42am 17 Aug 2025
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From the photos, at least one of them is a 3kW Aerosharp ... so hopefully both are.
And then there are two different versions of 3kW ones with slightly different physical size and windings.
I saw another over in Melbourne Bryan, but it was only a 1.5kW ... and only $15.
There are others on there too ... but $350 brand new!!!Cheers, Roger
Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1513
Posted: 03:41am 17 Aug 2025
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Roger I did message my mate this morning at this arvo he will let me know what size they are off the nameplate on them.
I did get in touch with that guy who wants $350 and told him what they are really worth so offered a $100 and he won't budget under $300, so I told him my offer stands.
Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1513
Posted: 05:03am 17 Aug 2025
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Ok got a photo of the aerosharp from my mate
Model HR-INV-X01-030 Nom DC Power 3500W Max DC Power 3750W Dc volt Range 150-400V Max Current 10+10
Also just confirmation both gridties are the same so matched. Edited 2025-08-17 15:06 by Bryan1
Godoh Guru Joined: 26/09/2020 Location: AustraliaPosts: 549
Posted: 06:06am 17 Aug 2025
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Hi Bryan, it will be interesting to see just how big those cores are, 3500 watt cores should be fantastic stacked. The weight will certainly do something for your strength while you wind them good score pete
Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1513
Posted: 06:28am 17 Aug 2025
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Hi Pete, well mate I reckon the pair of them would be enough so double stacked and I will measure both of the secondaries with my Fluke meter to ensure there are the same Ohm's or very close. Then there will be no rewinding needed and by double stacking the primary for 24 volts should be guessing 10 turns so I can use nice heavy gauge wire for the primary
now as far as trying to lift them I will will be using my old 2 tonne engine crane as I don't feel like forking out to go see a bonecruncher after trying to lift them
So still a few weeks away from getting them and for the choke I will go like that one I have on that inverter I made. 10 turns on each side of the big choke after removing the wire so it becomes a dual choke and yes that idea did come from Tony many moons ago.
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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