March 27, 20179 yr 12 hours ago, SilverNodashi said: welcome to the forum. How did you find it? Awesome, I see that you have taken on my request for a bunch of seperate questions to push up my post count - thanks for the assist. I came across the forum as a Google result to several of my queries relating to PV installations.
March 27, 20179 yr 12 hours ago, SilverNodashi said: which inverter do you have? I have just received my 2x Axpert MKS 5k inverters which I am planning to run in parallel.
March 27, 20179 yr 12 hours ago, SilverNodashi said: how many solar panels do you have? Currently 12 because I was planning a single inverter with 4x3 strings, but I have since decided on the 2 inverters in parallel so will increase to 18 panels - 9 per inverter in 3x3 strings.
March 27, 20179 yr 12 hours ago, SilverNodashi said: which batteries do you have? Currently running 4x Vision 100aH AGM on a 5kVA backup inverter, but I dont intend using this equipment at all going forward (maybe sell here on the forum?) I am leaning towards the OPS260-12 from Sinetech - the marketing hype of up to 4200 cycles at 20% DOD has me intrigued.
March 27, 20179 yr 13 hours ago, SilverNodashi said: how many batteries do you have? I think I will go with 8 x OPS260-12 being 4 per inverter (hence the 2x HA02 ordered from Chris-R), but I am still working through the calc's on various scraps of paper scattered around my office so this may still change.
March 27, 20179 yr 13 hours ago, SilverNodashi said: Is your system off-grid, grid-tie or hybrid? I am going with grid assist (no feed back into grid at this stage of my planning) - so I plan to shift load as much as practical to sunlight hours and then use battery to supply a reduced load at night to 20% DOD, after which grid will take over load but hopefully not charge batteries which I would like to do via solar. This is all theory which I hope can be accomplished with the Axpert program - which is why I wanted access to Chris Hobson's document in the hope that it will steepen my learning curve.
March 27, 20179 yr 13 hours ago, SilverNodashi said: what was your Eskom energy consumption before, and after going solar? My daily consumption currently ranges from 30 to 50 kWh/day (summer/winter). I would like to reduce this by around 30 kWh/day and use grid to take up any shortfall.
March 27, 20179 yr 13 hours ago, SilverNodashi said: Do you have fuses on your battery bank? I am an electrical contractor and circuit protection is close to my heart - I plan to install DC circuit breakers on the battery bank.
March 27, 20179 yr 13 hours ago, SilverNodashi said: Do you have fuses or isolators on your solar panels? Each string will have a DC breaker at the combiner box.
March 27, 20179 yr 13 hours ago, SilverNodashi said: Do you have a COC for the installation? Ummm...No.
March 27, 20179 yr 13 hours ago, SilverNodashi said: Did you do your own installation, or was it done by an installer? IF done by installer, was it done to your satisfaction? I plan to do my own install and it will definitely be to my satisfaction (unless something goes wrong then I will need someone to blame).
March 27, 20179 yr 13 hours ago, SilverNodashi said: Does your whole house run off solar, or just some of it? I will leave the oven and 2x geyser elements fully on grid - I have a gas hob and both geysers are solar heated, one via flat plate collector and the other via 4x 260wp panels supplying 900w DC element with 1.2kw AC element as backup. The rest of the house will be on inverter with grid backup as mentioned earlier.
March 27, 20179 yr 13 hours ago, SilverNodashi said: Do you know much about solar energy, DC power, power factor, etc? Or do you still need to learn a lot? I know a bit, I have a diploma in electrical engineering and been an electrical contractor for 30 years - but this is my first foray into the solar field and will always take advice from those with more experience and better information.
March 27, 20179 yr 13 hours ago, SilverNodashi said: Did my posts help? Immeasurably I am not sure that the rest of the forum will be as pleased as I was to see all your questions and I am sure that they will fall asleep half way through the answers, but you pushed my post count right up there which is exactly what I asked for (jokingly!) Thanks for your effort, and thanks to Chris-R and Chris Hobson for prompt response to my queries yesterday.
March 27, 20179 yr 52 minutes ago, pilotfish said: I think I will go with 8 x OPS260-12 being 4 per inverter Hi @pilotfish, welcome to the forum. Just one small correction, you only have one bank of batteries, connected to both inverters. 38 minutes ago, pilotfish said: My daily consumption currently ranges from 30 to 50 kWh/day Damn, that is a lot. Do you have a small factory in your back yard?
March 27, 20179 yr 2 minutes ago, Don said: Hi @pilotfish, welcome to the forum. Just one small correction, you only have one bank of batteries, connected to both inverters. Damn, do you have a small factory in your back yard? Hi Don, yes I saw the single bank requirement mentioned in the install documentation - I was thinking more of charge capabilities with 9 panels per inverter supporting 4 batteries each. I wish I had a factory in the back yard then I wouldn't have to tackle Joburg traffic each morning! But seriously I heard that 40kWh/day is about average for suburban household, I have pool pump, borehole pump, pressure pump which adds a bit and then run underfloor in the lounge in winter and A/C in the bedroom year round (greedy I know)
March 27, 20179 yr 1 hour ago, pilotfish said: Currently 12 because I was planning a single inverter with 4x3 strings, but I have since decided on the 2 inverters in parallel so will increase to 18 panels - 9 per inverter in 3x3 strings. What capacity panels are you planning to install? With 18 x 300/315 watt panels you should be able to generate 20-25 kWh on average. Batteries are useless things, you can probably add another 5 kWh for them running from 24h00 till sunrise (no aircons allowed to run during this time though). That takes care of about 60% of your daily requirement.
March 28, 20179 yr 7 hours ago, pilotfish said: 7 hours ago, pilotfish said: I am going with grid assist (no feed back into grid at this stage of my planning) - so I plan to shift load as much as practical to sunlight hours and then use battery to supply a reduced load at night to 20% DOD, after which grid will take over load but hopefully not charge batteries which I would like to do via solar. This is all theory which I hope can be accomplished with the Axpert program - which is why I wanted access to Chris Hobson's document in the hope that it will steepen my learning curve. You probably aware that the Axpert is not a hybrid inverter and cannot do grid assist. It is either grid or solar/batteries. The Infinisolar V series is exactly like an Axpert and has full hybrid capability. FCS sell them and their pricing is marginally more than that of an Axpert. For your PV strings have solar fuses in the combiner box and DC CB or isolator near the inverter. On the battery feed use fuses too. I have a Mersen battery disconnect which is fused which I really like.
March 28, 20179 yr 8 hours ago, pilotfish said: Immeasurably I am not sure that the rest of the forum will be as pleased as I was to see all your questions and I am sure that they will fall asleep half way through the answers, but you pushed my post count right up there which is exactly what I asked for (jokingly!) Thanks for your effort, and thanks to Chris-R and Chris Hobson for prompt response to my queries yesterday. It was fun reading your answers, nonetheless
March 28, 20179 yr 8 hours ago, Don said: What capacity panels are you planning to install? With 18 x 300/315 watt panels you should be able to generate 20-25 kWh on average. Batteries are useless things, you can probably add another 5 kWh for them running from 24h00 till sunrise (no aircons allowed to run during this time though). That takes care of about 60% of your daily requirement. 18 panels will fill up my unshaded roof space, if I slip over the fence and give a small diesel injection to one of my neighbours trees then I might be able to squeeze in the extra 6 panels to max out the MPPT capabilities.
March 28, 20179 yr 1 hour ago, Chris Hobson said: At the time of purchasing the Axpert I wasn't aware of the Infini at all, which I am now thanks to this forum. I was never planning to provide for grid tie, but in retrospect it would have been nice to have the facility available in the unlikely event that proper grid tie with sell back becomes available in Joburg. I will follow your advice regarding fusing of the strings etc.- thanks.
March 28, 20179 yr 6 minutes ago, pilotfish said: At the time of purchasing the Axpert I wasn't aware of the Infini at all, which I am now thanks to this forum. I was never planning to provide for grid tie, but in retrospect it would have been nice to have the facility available in the unlikely event that proper grid tie with sell back becomes available in Joburg. I will follow your advice regarding fusing of the strings etc.- thanks. It is available in Johannesburg already: https://www.citypower.co.za/customers/Documents/City Power Booklet_Tarrifs_2016-2017.pdf But it may, or may not make financial sense at this stage, yet
March 28, 20179 yr 9 hours ago, pilotfish said: ... run underfloor in the lounge in winter and A/C in the bedroom year round @pilotfish the above made me sit up. It is not about the average household consumption, it is about your consumption. Our household was at that load per day, am down to 16kWh per day in summer. Working the magic still to get below 10kWh - but it gets very tricky and expensive now. Solar is all about NEEDS and WANTS and WANTS in solar costs a LOT - where batteries are involved. So first steps in solar is to reduce the load to efficient NEEDS - that costs a pretty penny itself. Then you solarize. If you cannot, that is your load, from what I have learned the last few years, I would seriously look at grid tie, move as much of the load to daytime, evenings on grid. SMA has the products that can grid tie and feed nothing back at all. Because with batteries with the above 2 loads is just a problem waiting to cost you a lot of money and batteries are NOT cheaper than Eskom, and if you borrow monies to buy them batteries, it does not make any sense at all.
March 28, 20179 yr 3 minutes ago, SilverNodashi said: It is available in Johannesburg already: https://www.citypower.co.za/customers/Documents/City Power Booklet_Tarrifs_2016-2017.pdf But it may, or may not make financial sense at this stage, yet I believe that they have no intention to allow it to make financial sense now or in the future. The problem being that Joburg Metro makes a huge amount of money from reselling electricity - once Grid Tie becomes financially viable then all those that can afford the capital outlay and are currently paying their bill will make the move (because you would be dumb not to!) which will create a giant headache for the Chief Financial Officer.
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