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Forum Index : Electronics : Inverter building using Wiseguys Power board and the Nano drive board
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| jakesea Newbie  Joined: 30/09/2023 Location: United KingdomPosts: 19 |
Yep, room temperature beer - I wouldn't have it any other way...😋 @KeepIS, thank you very much, Mike - the kilovac on the way and the choke cores already at home. Getting closer  |
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| mab1 Senior Member  Joined: 10/02/2015 Location: United KingdomPosts: 280 |
that's fine by me.  |
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KeepIS Guru  Joined: 13/10/2014 Location: AustraliaPosts: 2134 |
Some interesting observations with regard to Load switching and currents. With fast transfer, in this case < 20ms. Mains AC to Inverter AC switching under any load is basically the load current, with no abnormal phase difference spikes, even 40ms seems to make little difference. It's interesting that we have have discussed the possible need for syncing when switching between Mains and Inverter under load, but in my real world testing, the real problem is when switching cold loads, either to Mains or Inverter. This became even more apparent when I reverted back to a Manual Mains - Generator switch. There are a few reasons I did this, but that's for another post if anyone is interested, the Auto switch is great, but without Street power it won't be needed, and the Auto switch needs a separate housing as they are about 5mm deeper than standard DIN rail RCBOs and AC breakers etc, the manual switch is a perfect fit, and looks almost like 4 AC breakers, same size, unobtrusive and very neat in the din rail cover housing. These Manual switches usually have a centre off position, the one recommended and supplied by the Sparky is the a HAGER SF263, apparently this seems to be the favourite when installing an Emergency Generator backup facility, which I'm informed, is happening quite a lot lately. The SF263 is rated at 63A, Sparky had the data sheet and it's very good, especially the build quality when compared to the lower cost unit he had, and the cost itself is quite reasonable. The Fuse box Main AC breaker/disconnect is a 100A unit, so the SF263 as per the data, should have a 63A-C breaker between Mains and the SF263, and the same for the GEN Input, or lower depending on the Gen output and wiring. The easiest generator input is an isolated output type, which the Inverter Toroid transformer is, that means everything back from the GEN AC output is also isolated from the House AC Supply. The SF263 data sheet and typical install labels for changeover switches indicate that the loads should be removed before switching. Loads then switched back on, usually via the circuit breakers in the Fuse box for the loads required, since this is obviously where the changeover switch is located, it only takes a few seconds. I monitored the loads as the circuits were switched, and there are up to 400A peak DC inputs on the Inverter when switching circuits that have Inverter supplies, like Fridge and Freezers, SMPT devices like Computer and screen Plug packs, TV and other device standby loads, I would imagine a large number of incandescent lights and older fluros would also present high initial cold surge currents. So dumping the lot at one go can see a peak DC input of around 580A, in my case that's less than half of the Inverters capability. But why stress it when it's easy to just switch the load circuits one at a time, worst case is then around 300A, which happens to be what two LCD monitors and a NUC-PC plug pack can draw on cold power on. BTW a 2.7kW restive load powered first can reduces these SMPT cold start currents by around 30% to 50%. . Edited 2026-05-14 10:42 by KeepIS NANO:Inverter V 8.2ks - Linux AvrDude GUI script V4.1 |
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| KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 2134 |
I've finally got some accurate power readings for the Inverter conversion efficiency, this is the efficiency to convert DC input power to AC output power and does not include Inverter idle power. The efficiency is very high, with a prominently resistive AC load and a PF of 0.98, the conversion efficiency is close to 98% to 99% @ loads around 1.8kW and above, I have not measured much above 5kW, where wiring losses will lower it slightly. Below 900 Watts, the AC load PF is incorrect, the HOIKI Power Analyzer won't calculate PF or power below 900W, and Standard AC power meters suddenly show a PF dropping down to 0.54 as power starts falling below 900 Watts, I could be wrong, but AC power may be incorrect, as I don't know if the calculation is based on an incorrect PF of 0.54. Obviously the overall efficiency "with Idle power" is less at lower power, however at higher power the efficiency still gets up to 98.3%. On Another subject, I've touched on this before with battery technology comparisons, and it seems to be continually ignored, one major advantage of LiFePO4 is the power Input/Output efficiency. The efficiency for the amount of power needed to replace the power used in LiFePO4 is above 95%, and translates to less Solar power and shorter recharge times, which really becomes apparent in poor solar conditions. Another forgotten parameter is the voltage drop with current and State of Charge, the lower the voltage drops, the more current is required to generate 230Vac, things start to sag fast, LiFePO4 after charging finishes (no solar), runs at around 53.4V under load, and drops 400mv overnight to 53v under low loads, and 600mv at 52.8V under a few kW at an SOC of 52%, depending on battery size and build quality. BTW, some of my LiFePO4 batteries are almost 6 years old now. I'm now currently running 11kW of panels as two arrays are off line while changes are slowly being made, getting old sucks, two of the "Poidas and wiseguy and others" Solar Charger design and PCB's, are being made, with another four to be made for future spares. FYI: I made the mistake of looking at some AU forums discussing commercial installations and new rules and ripoffs, and there seems to be a religious belief that you cannot fully run "off the grid solar" on a 600sq block as there is no room for required panels, especially if the Home is all electric, as it could only last a few days, irrespective of where you live, they get quite agitated if you dare even suggest otherwise, "their calculations cannot be challenged." Perhaps they also believe that panels only work if facing the correct direction and angle, I guess they also believe that Flat or East and South facing panels (roof slope) can't possible be of any real world use. It's a clown world  . Edited 2026-05-14 12:21 by KeepIS NANO:Inverter V 8.2ks - Linux AvrDude GUI script V4.1 |
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phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 3202 |
Have seen that too. A blanket statement like that does not account for the wide variety of circumstances. On a block covered in trees (like mine) it holds up but for others without trees and with a large garage or shed enough panels can be installed. And they don't all have to face the sun as in overcast conditions (which is when you need the extra input) almost any direction will do. Another point is the definition of "fully run off the grid solar". Just as the grid uses gas fired generators to plug occasional gaps in renewable energy supply, a small generator to top up the batteries occasionally does not invalidate the idea of off grid solar. |
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| KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 2134 |
Yes agree totally, you likely know my solar situation, one tree on the east side, but makes very little difference, 30% of the arrays are south facing, 30% flat, 30% north and the rest face West, in the future, another 6kW West facing will be added. Two big advantage with 48V systems, just two panel series strings, and many sets of 4 panel arrays, with 2 series strings paralleled per array, and one 4 panel array per 60A Solar regulator. Seven low cost Solar regulators, each panel array is only running at a maximum of 60% of the Solar Regulator capacity for a 4 panels array. The result is low stress and zero failures with lots of redundancy, and this panel configuration is also incredibly resistant to partial array shading and individual panel drop off, especially when compared to HV strings with many series panels. This also allows instant indication if any panel in an array is under-preforming. We have been running 100% electrically off grid for over a year, and previously 80% off grid for a few years. Never once needed mains in any weather, including many days of rain and gloom, and that's while still using off grid AC like it was Mains AC. I really feel for anyone confronted with trees and/or two story buildings around them. I must stop posting long winded replies  . Edited 2026-05-14 18:38 by KeepIS NANO:Inverter V 8.2ks - Linux AvrDude GUI script V4.1 |
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Revlac Guru Joined: 31/12/2016 Location: AustraliaPosts: 1249 |
From Other Thread I have the Digitech powerpoint Earth leakage tester QP-2000, Its been a great tool for checking power points, found one with a missing earth. Exactly, I find that testing the entire circuit to see if it is actually wired correctly instead of been misled into thinking its all good, tested my friends setup, he said the safety switch works pressed the button yeah see it trips, I said plug this in and try again....no way the switch would trip even at 100ma, I asked where was the neutral bond? blank face....I guess I shouldn't have asked that.  I did find one safety switch on the house wouldn't trip either, had that sorted since. Perhaps one of these should be in everyone's tool kit , I don't get nuisance trips anymore like when it was connected to the grid except for the odd gecko triggering them. Thats much better than the old Rotary Cam switch I have, its obsolete now as it only switched the 2 active's from grid power and linked the 2 together on the gen side to run the 2 lines on the house and shed. I'm sure my friend will be getting a switch like the HAGER SF263 one posted above, though I couldn't see any way to turn the power off after or before the Meters...the sparky will charge more to pull the fuse at the street pole I guess. My first LiFePO4 batteries build (manufacture) date are 7/2019. powered up to use on 1/2021 Interesting, didn't know it would have that much affect, I have quite a few of those little SMPS. Edited 2026-05-14 19:35 by Revlac Cheers Aaron Off The Grid |
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| KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 2134 |
Some of the small SMPS supplies are ok, I find the larger LCD monitor adaptors and Laptop / Mini PC adaptors have the highest cold inrush currents, likely larger cap values and lower circuit impedance, the largest cold inrush is from big SMPS Chargers and Bench supplies. With the manual GEN-Mains switch, the centre OFF position, even though it has a very positive centre Hold Indent, is clearly stated as to not be used as a Safety OFF or Isolation position. Sparky said the specs require a breaker for Mains and GEN inputs before the Changeover switch Active terminals, with both located in the Fuse box with the Changeover switch. With breaker values at or below the 63A rating of the changeover switch, and obviously the GEN breaker lower to match the Generator rated capacity and the GEN cable rating, which in my case, the cable run calls for a 63A breaker, but we decided on a 45A-C for the Inverter output, although I think I could go lower. I've had a 25A-C in the shed for years and only tripped it once on startup current, and that was with a really Big VARIC. I'm sure you know the deal with Trip Time graphs for load and temperature trip conditions for those. Besides the AC or DC Over-Current sensors in the Inverter always trip before any of the mechanical breakers I finally found some metal 16 Cell battery boxes at a reasonable price, I only have to pick them up and then get down to transferring the Cells and BMSs etc, should look really neat when all done.   . Edited 2026-05-15 11:11 by KeepIS NANO:Inverter V 8.2ks - Linux AvrDude GUI script V4.1 |
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