Wetkit

Right, so I have been running the 5kw MicroCare invertor now for a week. In all honesty, I am a bit in 2 minds about this unit. The 48V to 220V conversion is about 80% effcient. My old invertor used to run untill 23:00 before the battries runs low, but the Microcare unit kills them around 20:00 The changeover between AC and battries is seamless now, so at least that is a plus point.

What a great system. Must have cost a packet!!! Could you post some picks please? For just another R2k you can buy a Victron Battery monitor. Using just voltage for such an expencive install is not really the way to go. The initial high voltage is your "bulk" charging cycle. After a couple of hours of bulk charging, it will change to "float" which will be a lower voltage. This is like a "slow soak" or absorbsion charge. It is extremely important for your installer to program the MPPT according to the correct battery specifications!!! If this is not done correctly, you can destroy a very expencive battery bank in no time

Never heard of these "power Optimizers". Could you perhaps post some details?

Hi Clouble, Do you need to have all 3 phases on back-up power? What 3 phase equipment do you currently have? Converting 3 phase to single phase will work out cheaper in the long run. Point 3 you say your usage will increase, why is that?

@superdiy, sounds fair, thanks.

Here is a pick of what I could get on the net. Problem is there is no way that you can do 2 seperate earthing systems if you do everything according to the law. For now I will do Equipment grounding only.

Right, so you doing a solar system, but what is the correct and legal way to do your earthing??? So far I have looked, I came across 2 words, Equipment and System grounding. Equipment Grounding: This is standard practice where each metal part of your installation is grounded with a suitable conductor. The common eathing point of your solar system is then connected to your main home earth. According to law, each metal part on your PV installation must be earthed. This means each and every solar PV panel must have its own earth point. It is not acceptable to just ground the mounting rails. System Grounding: Now here is where it becomes interesting. According to EU, USA, AUS and NZ laws, at least one of the DC conductors needs to be grounded as well. What this means is that your negative coming from the PV array needs to be grounded and your negative DC on the batteries needs to be grounded. I have done the Equipment grounding, but still too scared I blow something up to do the System grounding. Anybody done this before? What does our local regulations say?

So I have been snooping around the interwebs and asking quotes from installers. My ideal system would be a 5kva bi-directional invertor, 48V battery bank with a MPPT controller on the solar array. Most of the installers is happy to quote me on the above, but all of them say my battries will not last. According to them the battries will cycle at least 3 times a day, reducing even the most decent battery to jelly in a year or less!!! They reccomending I go 5kva bi-directional with battery bank, but to connect the solar array to a gridtie invertor. Supposedly the battries will now only be used when Eksdom is down and the gridtie does not deliver enough power to keep everything running. Thing is will the gridtie invertor be able to re-charge the battries backwards through the bi-directional invertor? Now all of the above is sort of true, but are they, these installers, not trying to make more sales by pushing gridtie invertors? Surely if your battries cycle 3 times a day, either your solar array is too small, your battery bank is too small, or both?

Hi Willem, You have it 100% correct. I am still using my 60Amp Microcare unit and very happy with it. Price around the R8k mark. Another way could also be with a grid-tie invertor. The 230V from the grid-tie supply the bi-directional invertor with power to charge the battries. But this type of set-up can become extremely complex. See options 5 to 7 here... http://microcare.co.za/tech-support/microcare-wiring-options/ I am currently aiming for Option 2.

Ok, so some time back I was planning to upgrade my existing solar system. The units Mike is selling do look great, but there was no news on the 5kva unit, so a 2nd hand MicroCare Bi-Directional invertor jumped at me. I got a great price on a nearly new unit, so I will be going that way. At least now I can remove my contactors and the installation will be looking way more profesional than what it currently does. I am still looking to get a qualified electrical guy to move all the required circuits from my main DB inside the house, to the garage, where I will be installing a new DB. For now I will be looking at dividing up my house circuits up into 4 parts: 1. Eskom powerd directly, no backup - Ovens and Air-conditioners. 2. UPS Powerd - This is directly from the Bi-Directional invertor. This will be for lights and my TV+computer stuff. 3. Bi-Directional Powerd but disconnected when Eskom fails - Geyser backup element, normal house plugs. 4. Bi-Directional Powerd but disconnected when Eskom fails + Solar power is low - Kitchen, Pool and Irrigation systems. Yes, it does look overly complicated, but this way I do not overload my solar system and still run most equipment from it as well. The other way is to run everything off the invertor, but then stand a good chance of overloading it, or running out of battery capacity during a power failure. This way I can also still run everything from my existing battery bank

Ok, just to clear up a couple of things here... Bi-Directional, Hybrid and UPS have to be connected in-line to the load and the supply. (Physical break in the line) So, if you have a 3kva unit, the max load you can run through it is around 3kva. Also, some UPS units, is not on-line, meaning they only switch on and run from battries and solar when the mains supply is off. These units will not save you power, like a hybrid or by-directional unit can. Gridtie can be connected anywhere on your system. The unit can only deliver according to its size, say 3kw, or how much solar is available at any given moment. So, if your house draw 6kw and your gridtie deliver 3kw, you will only draw 3kw from Eksdom.

@slayer69 - Great work there on your own PV pannels!!! Care to share a little bit more with us on how you got to this stage?

The micro invertors is a great idea and concept. Biggest problem is the cost The only units I have seen function like a grid tied invertor, so no battery backup if you looking for it. The main aim of such a system is max power back onto the grid.

I was looking at new Trojan J185HAC battries. The specs say Absorption charge at 14.8V, so 59.2V for 48V bank. As this is way higher than the 57V volt max on the unit, will my battries charge ok? Equalise charge is 62V !!! Would it be possable to request the manufacturer to do a software update for Flooded/wet Lead Acid battries???

So, any feedback as to how good/bad the unit is running....?

Great photo's there Willem!!! How is the blades fixed to the centre hub? I mean, once one blade is installed, how is the remaining blades or the hub rotated to make them easy to lift and install? Lifting a blade at 45 degrees does not really sound plausable to me? Can one of these fit in my garden

Hi Mike, Any picks yet of this new unit installed and running? Some other units can combine battery and supply input to give higher output than rated, for short durations, like with starting big motors. Can this unit do it? According to my log of the past years, my power peaks around the 5kw range. Will this unit cope if I remove the oven? Does this unit have any programmable outputs, like to switch off certain loads if there is no AC power on the input? Thanks

@Willem, if you like cost and features, please have a look at the MLT Powerstar. With it's integrated remote monitoring system, 2 x AC inputs and 2 x AC outputs it is a clear winner for me. Also locally made!!! Next would be MicoCare, also local, but they still a bit lacking in remote monitoring software. Lastly, Victron. Looking at them they seem very simple, but once you start programming them with software, it gets way better. Problem here is cost and then extra added cost for remote monitoring. Yes, it is possable to import directly from overseas, but who carries the warrently and support for you then? If you happy to accept the risk then by al means, go for it. For myself I planned big first, then divided it up in smaller chunks. Working on the smaller chunks now. My first step was to run the pool pump directly from solar. Now I can expand as money become available or I have the time. Good luck!!!

Not sure about the steam release valves??? Do you have more info on these? I do have vacuum breakers on the inlet and outlet pipes. The is also a T&P valve on the geyser. (Temp and Pressure release valve)

Hi Mike, please call me so I can come and have a look. Problem with these "grey" imports is proper english manuals and backup support. Another reason for the changes, is my pool pump. Just before I went on leave, the current 750w pump packed up. I go to the shop and see the cash diff between 1100w and 750w pump is very small, so best bang for buck is the larger pump, correct? Well, yes and no. Yes, for more bang for buck, but NO when running on solar. The extra 350w is an extra 8 Amps on DC. This is causing by invertor to overload when starting the bigger pool pump, when the 750w irrigation pump is already running. It is also draining the already weak battery bank way quicker.

Hi Willem, Thanks for the info. What cranes do you use to lift 76 tons to about 80m high? Especially at Hopefield where the soil is just pure sand! What does the tower foundation look like? Funny enough, I actually drove past the Sere windfarm this Dec, again on my way camping. Seems like I pick all the windy spots...... Guess it is the only way to avoid the crowds.

RIght, so winter performance was very good, but still had to use some power during rainy days, as to be expected. I am busy increasing my PV footprint, so need some more roof space. This means I am going to have to relocate both geysers as to cast less shade on the roof. Currently the units is facing North West. The plan is to get them facing true North. This would mean shifting the stands 45 degrees. My current roof slope is 20 degrees. Lets see how this comes out....

Ok, just an update on this one for now. System been running pretty stable now at around 17kwh per day. My main aim of keeping my monthly Eishkom consumption below 600 kwh is ok for summer, but in winter I struggle to get it below 1000kwh Right, so now due to all this Eksdom issues, I have been re-looking my complete system. At some stage I was looking to go Gridtied, but this is not worth it anymore due to return on investment and all the red tape involved to get such a system approved. So how do I utilize ALL my available solar power without too much hassle, AND still run some stuff while Eksdom is plodding along in the dark? Going Hybrid would have been the ideal, but I have not really found a unit that match what i would like to do, or the supplier that is importing the unit, knows nothing about it Anyway, for now I have settled on Bi-Directional. 1. Increase current PV capacity from 12 x 235W to 18 x 235W. Total then 4230W. 2. Keep current 60Amp MPPT. Output will be limited, but at least I will be getting max amps even if conditions is less than ideal. 3. Get current house wiring sorted and routed through garage to allow invertor connection. 4. I should be able to still use my old invertor, but once I have some spare cash again, install new invertor More to follow later....

Bloody hell, you going to need a big fat genny or fill your roof with PV panels!!! Was going with normal solar heating panels on the roof not an option?

Sorry for the late reply, but induction and instant water heaters all have the same issue, HUGE power. Most of them require 4kW to 7kW of power to function.