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Forum Index : Electronics : Perfect Toroidal for the OZ Inverter ??
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fillm Guru  Joined: 10/02/2007 Location: AustraliaPosts: 730 |
For Lithium batteries and really FLA and any Battery should be LV protected I would think, and a conservative setting that does not destroy. I use average 200Ahrs+ @ 48V every night cycle and sometimes 300 when the youngest is in the equation , even though the house is still connected to the grid @ 3 phase I use 3 latronics change over switches that switch to inverter ( when power is sensed) then the 3 phases are changed to single phase and really circuits. The main 3 phase load being a 10kW AC is left permanently grid connected. We have many loads and during the day when the Lithium batteries are full the pool pump is used to use excess. And then there is the 3 phase grid connect system as well with 8.5kw of solar and the Battery system has a further 5kW + 1 or 2 Turbines. So the system is a kind of DIY Grid Battery Hybrid system and it is easier to put extra solar on than try and teach how to not use power. Also the shed and all its loads are easily catered for as well a large Mig. With the 3 change over switches I can deselect a phase ( Really circuits when inverter connected ) and have it on the grid. They are on SSR relays as well as CBs and soon the pool pump will be auto / wireless connected. I would put battery protection as paramount in an inverter that if left unchecked can wipe years of batteries. Oh, forgot about the 12V x 700ahr FLA Ennersuns that I rescued & running as a small 12V system with a string of outdoor LED lights that are on 4 ~ 5hrs. My eventual plan is to go down the path of an on demand generator DC high power Gen as Lithium can easily soak up C2 if it can be supplied. Its on the bucket list . PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
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Clockmanfr Guru Joined: 23/10/2015 Location: FrancePosts: 429 |
The OzInverter is just an Inverter that gives 220vac 50HZ from 48vdc. It can backcharge the batteries from the 220vac side ie GTI's. I control the backcharging buy using the OzInverter ac voltage slight rise to knock the GTI's off when the batteries start to fill. I then finish the batteries with 5kW of DC controllers. I am using the GTIs as slaves to my OzInverter Mini Grid, I need power, the Mrs has the Kettle on, my boy is drying his hair, the battery voltage drops slightly the AC voltage drops slightly, the GTI sees this and starts up again producing power for the loads. I use the OzInverter back charging as an absorb/bulk mode for my GEL batteries, then as I have said finish the batteries with the DC controllers on separate DC PV. I also have 3off Hugh Piggott design 3.7m diameter wind turbines, these are direct connected to my 48v battery bank. I have 4off Tristar diversion controllers to divert excess voltage to 8kW of heaters. These diversion controllers will dump any excess voltage over and above what the batteries require. So another safety feature for my sensitive batteries charging parameters. If I had Grid tie option to the Main utilities grid then I would install auto changeover relays on the GTI Ac side. Batteries full AC GTI output shut down/off, then change/switch the GTI to Utility Grid connection and back feed the grid. Definitely need break before make connector. Just a thought. The OzInverter is just a simple robust Inverter, control your AC side source when its back charging through the OzInverter. Everything is possible, just give me time. 3 HughP's 3.7m Wind T's (14 years). 5kW PV on 3 Trackers, (10 yrs). 21kW PV AC coupled SH GTI's. OzInverter created Grid. 1300ah 48v. |
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| fillm Guru Joined: 10/02/2007 Location: AustraliaPosts: 730 |
Yes completely understand the principal of back feeding and charging through the H-bridge that was most likely the brain child of one of our exiled comrades. My query is about battery protection in the inverter and switching it of at a predetermined voltage ( Low Voltage cut-off). Most crappy inverters will go as low as 10.5V / 42 - 44V and I am sure I do not need to rabbit on with the associated damage this does. Then to stop load bounce as the battery voltage rises again under no load the inverter output is held / stopped by the reconnect voltage setting and needs to be high enough to stop it connecting and disconnecting. Then allow it to operate again ONLY when battery voltage indicates that charge ( solar wind or Gen ) has commenced. PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
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oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686 |
OriginallyI uses the temp as on/off just to get it working. The EGS002 board has a comparator that controls the drivers as well as the inhibit pins, and this ,means o/current would kill the fets due to wave pulses out of sync on shut off. The 8010 boards I did have no evil driver inhibits, so the pin 6 ... normal way to shut it off is used in the final boards. It can be switched off on loads up to 7kw ( tested thus far) without problem. The temp is now used for temp only, and will trigger a shut down if useing 10k@25c thermistors at around about 75C... very high for my taste, but a good thing to shut off before destruction if the fan fails. The current shut down works fine too now, as the unit controls only the inhibit switch, which is soft start after 16 seconds and then shut down and another 16 seconds, the full shut down after about 3 tries. I have not tested the short circuit capability yet, but that will be a product of the cap on the current limiter and set point.. user does this, so watch out. The short will have to be serious, not just a flash of wires, as it can start up with in excess of 10kw peaks that I have run so far ( meter topped out at 40 amps@ 240v).. so the short needs to be serious... but not tested yet. Under voltage and over voltage is on the chip in most cases, but that is AC not DC. You need an arduino or simple comparator to do that separately I'm afraid, and shut down pin 6 or the temp if you wish. If you felt moved to do so, you could use a comparator to drive the ac sense down, to fool the unit into under voltage AC mode, and that would then allow the status led to flash for undervoltage or over voltage to give you the correct indicator on the indicator LED.... will also give you excessive volts for a few seconds too on under voltage now I think about it. 
I have just found the thing to work stupidly well for such a bare bones system.. and yes fillm, it handles loads better than the victron, and the selectronic ( upon the hill with the AWP mill).. not sure about the newer selectronics though.... they should have solved those problems by now surely.... seems the front loader washing machines confuse them badly...no problem for these or the PJ or the W7's.... all the cheapies.... ..........oztules Village idiot...or... just another hack out of his depth |
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| oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686 |
Interesting, I assume they are different sizes?... if so probably to try to get down the idle currents but still use cheap transformers ( EI types). .............oztulews Village idiot...or... just another hack out of his depth |
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Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
Hi Oz, They are EI's, one big one, one medium and one baby one, 4.5 KW Inverter is too heavy for me to lift, around 70KG, I used an endless chain to get it on the wall by myself. They are actually a very efficient Inverter, designed by boB who has popped on one of your Inverter topics on another web site and Robin Gudgel. Same guys who then went to Outback and now Midnite Solar. By driving the appropriate windings or combination of it forms the sine wave through a series of steps, here is something I found on the web, "I've been looking at inverter designs (with a view to building my own 'clone' and was trying to understand how the trace SW works; I think I understand that it has 3 transformers in ratios of 1:1, 1:3 and 1:9 and drives each one with H-bridges (I assume +ve, -ve and shorted, like a standard MSW) to give +V, -V and 0V. Having jotted a quick truth table I can see how this can give 27 steps (13 +ve, 13 -ve and 0V), but Trace claim 34 to 52 steps out of the 3 transformers; can anyone tell me what I've missed?" Problem I have with the 2 of them I have is they where made last century and Trace was taken over by Xantrex and then Schnider, when Schnider came on the scene all the SW series inverter support/parts was completely cut. This why I have been keen to build my own, I am in control, so long as we don't run out of EG8010 chips the Inverter can be kept running forever. Even then I see you said that part could be done by other means that yourself or someone equally as capable will bodge together a few parts and perhaps a bit of fencing wire and we can invert for eternity. Another BIG benefit is it so much cheaper than commercial Inverters out there, this could even become a project to help third world population get off grid power. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
thanks Oz I was under the impression that when the soft start was enabled on the eg8010 (5v to pin 21) that it was only the enable (pin 6) and the temp shutdown that had access to it. Sounds like there is a good chance that all the triggers are soft start capable. I still think that the AC voltage limits is a handy feature, maybe not for the big inverters but for the pip-squeaks. A 600w-1800w inverter in a brand name can be $1000-$2000 and they still pull 300-350 amps on surge. They are handy for 240 volt on the go. The elcheapo's dont last, this drive board and power board with a much smaller toroid is still going to be good value. I'm confused, no wait... maybe I'm not... |
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| oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686 |
Mad, I find it very difficult to believe that they used three transformers to make a sine wave between them. They are different sizes so i have to assume three units in parallel. By driving only the size combination needed for the expected power, you can cut your iron losses hugely. Using different duty cycles, you can have as many steps as the programmer wishes, but your 70kg unit is so heavy because they used EI. For the same power, they must be at least twice the weight as a torroid.....so twice the magnetising current to start with, and the EI will have thicker plates, so worse eddy currents too... just another reason torroids are preferred for this application.... except the cost is outrageous normally. Note how thin the layers you had to removed were.... thats how they cut eddy losses much better than EI, as they can be very very thin, but require no mechanical properties like the EI require to retain structure and assemblability. If you look at the C core inductors in the aerosharp, the layers are very very very thin...... they are just torroids cut in half. I expect the 54 steps are because of the course programming of the three parallel inverters. The jump tables will be different perhaps, and this will give you another overlay of variables, and your scalars will be different too. Without the three transformers, and just using one 50 kilogram one, your idle losses would be in the 5wkh/day range.... much like the power star ones are and for the same reasons. Buy a hundred chips for $150, and you should never ever run out of these things. Frackers I think will write a program for a dedicated chip apparently too. Yahoo, yes the over under AC voltage part works on most chip variants, I had some that did not...... 350 amps at what voltage? I only use 48v, so thats in the 17kw range, which is not difficult to get in these things either. 70 amp(240v) surges are more than possible if you do the surge maths for the output stage, and your torroid is big enough. Pulsed drain max current on the 4110 is in the 600 amp range... each... or 3600 amps per leg... serious stuff.. cannot even begin to imagine it really. I ran a test unit using a EI 2kw transformer, and it is capable of HZ movement without damaging the fets.... in fact used that ot trouble shoot the O/current shut down issues on the original egs002 board... as it could not kill the fets. It does not need to be torroid for transient uses, but for 24/7 it is a big bonus. ..............oztules Village idiot...or... just another hack out of his depth |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
Hi Oz, The Trace is not a conventional Inverter, all the service information is tightly held and due to agreements that had to be signed those who have it will not release it. Transformers are not used in the conventional way like your inverter. I believe the secondaries are in series across the 3 transformers and each transformer is switched in combination to produce every sine wave. Maybe one day one will come into your possession as they have been around since late nineties and time will be catching up with them. A lot where sold with BP panels, they where one of the first inverter chargers, has 2 transfer switches built in. Can do generator support, also can sell to the grid, although not approved here to do that. Anyway does matter any way, time to move on to DIY and be in control. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686 |
Ok I found the description, and it is as you stated... three in series. Interesting arrangement.... they must have been smoking something to come up with that. To get the zero volts, they must be fairly tight coupling units so that shorting the primary yields a short secondary for 0v .........oztules Village idiot...or... just another hack out of his depth |
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| fillm Guru Joined: 10/02/2007 Location: AustraliaPosts: 730 |
Hi Oz , so it sounds doable but not done, anyway I will put that on the back burner and cross those bridges when I get to it ( If and When ) I will wait for the book and PCBs from Clockmanfr and time permitting with all the rest of the bucket list I will get to it. By then who knows there might be a tested solution after someone drains away the life out of an expensive battery set. But as you have outlined there is a start point. Thanks .. Phill PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
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| yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
Hi Phill, the concept of this is based around reliability and repair-ability, so everything is modular and autonomous. Most (all?) of the integrated features have been ditched and replaced by something that is more flexible or suitable and wired separate from the inverter board/chip. I have been retro fitting battery management to older systems, in some cases just a relay driver and big gigavac contactor and some bits and pieces. so far it has saved three systems from total destruction when mosfets shorted. I am pretty chuffed about that, one of the lessons learned from working with lithium's I guess. I'm confused, no wait... maybe I'm not... |
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| fillm Guru Joined: 10/02/2007 Location: AustraliaPosts: 730 |
Hi Yahoo, Yes I grasp the concept but In my mind I would think that reliability repairability is important but if you are shelling out 15 ~20K on a decent set of batteries I know what I would prefer to be protected as paramount as the inverter. Every thing usually goes hand in hand in system design and I am sure the Vac or spring loaded contactors would be suitably rated and a costly addition. As you would well be aware of is that these inverters are for the more DIY of the DIYers and what happens in main stream systems needs all the associated approvals and suitably qualified installers these days( voltage dependant ). As far as autonomy I am in agreeance there and it all may be as simple as a suitable sized AC relay and a basic turbine controller circuit keeping it latched, but I merely asked the question in relation to DC/LV a which has been given a solution. I am sure there are other ways to do it where the user can set what they feel is the best level of DC LV protection. PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
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| yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
that is what I was writing about, DC protection. eg http://www.gigavac.com/sites/default/files/catalog/spec_sheet/gx16.pdf I'm confused, no wait... maybe I'm not... |
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| fillm Guru Joined: 10/02/2007 Location: AustraliaPosts: 730 |
Hi Yahoo, Yea nice looking little units, what sort of price is on them. PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
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| yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
it was $160-170, but the Au$ was up and I got on the end of a bulk buy. I mostly used the GX14 (350A) and that was nearly half that price. As you can see from the specs its overkill for most systems, provided its not switched regularly under massive loads. I'm confused, no wait... maybe I'm not... |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
If this is an automated safe guard then isn't there a likelihood it will be shutting down with a load and larger loads will tip it it into low voltage. As you say the life span reduce drastically with larger loads at time of disconnect. With the Oz Inverter it is easy to turn off the inverter on the control board with out the big DC switch. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
that is your choice, the world that Phill and I live in, we need both options. Its not about what can be done its about avoiding risk. if a fault that drains or overcharges the battery bank occurs once in 30 years, I may never see it on my personal system on the other hand it may happen the first day it is installed. If I have 100 clients I will likely see that fault 3 times a year, it changes your perspective. if I calculate that it will handle 8000 cycles @ 50 volts with a 30Kw load and it only cycles under full load ten times in 15 years. Have I wasted my money? not if there is a workshop with 80 amp fuses on the machines. Charge controller failure-Lithium battery damaged Have a read, I am not singling this Guy out, he took a chance and was unlucky, I used to get between 5 and 15 calls a year from DIY owners with cooked or flattened batteries. it happens. I'm confused, no wait... maybe I'm not... |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
I see, you are a lot more experienced than myself. I am one of those DIY types you talk about, although I would never be calling in any outside help. What you are saying makes sense now, you don't want someone chasing you for the cost of replacing batteries when you set up the system and something went wrong that was out of your control. Better to have no power for a little while than be up for $10K plus for battery bank. Still you could shut down the inverter at a level slightly higher than the battery disconnect. Then you have a fail safe and less wear on that device. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
Yep! then you can use a smaller cheaper contactor as well. And you fit a big red button and a sign saying cycle contactor every 2 months to check it is functioning and 30% of people wont even do that. 
I guess it is story time. when I was about twenty, I was working up a ladder and dropped a 3/8 open ender, it bounced off the mirror of a truck and under the open bonnet of a Valiant ute. Wedging itself across the solenoid and positive terminal of the starter motor. 
Ute was in gear, it hit the wall of the shed with enough pace to bend the roo bar. 
Not much shocks me 30 years later! If I haven't seen everything I have probably heard about it.  I'm confused, no wait... maybe I'm not... |
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