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Everything posted by phil.g00

  1. I have been considering something similar for a while now, so please report back on your progress. Longi is apparently the world leader in bifacial panels, and are (or becoming) partners with ZA's Artsolar. I predict if I ever do this, it will not be in the very near future. The reason I say this is I had a paid calculation done which relied on a high bifaciality factor. The bifaciality factor I chose was higher than mainstream values, with a view that when I got around to doing this, it would approximate a realistic value not a historical one. That said, let me try and explain what and why I did what I did. I am a believer that an MPPT should within its threshold be optimized. Because of the bifaciality factor of theses panels one side is more productive than the other. This means if your N-S vertical panels have their best side facing E then the morning peak will determine the MPPT size necessary. The afternoon peak will essentially underutilize that same MPPT capability. So I thought, what if I didn't line up the panels exactly N-S, but offset them so that the sun's arc favoured the afternoon peak (at the expense of the morning peak), so that both peak's were the same size. That way I could use a smaller (read cheaper) MPPT that was fully utilized at both the am and pm peaks. My thinking was that at noon production would be low, so I could possibly also add a north-facing string and achieve full utilization throughout the day. OK, so far so good. Except that knowing that this offset must exist, is quite different from trying to estimate what it is. So I contracted Charles Landau at solarpaneltilt.com and posed him with this question ( for a fee). This is an extract from his reply and I hope it helps in your own quest: Based on your information: Latitude 28.746 degrees South Panels mounted vertically (fence) Bifaciality factor 83.5% Calculation for the summer solstice The two sides of the fence will produce the same amount of power if the good side is oriented 315° from North, which happens to be exactly Northwest. Your situation is unlike any I've encountered previously, so unfortunately I don't have any intuition of what the result would be at a different latitude or different day of the year. To determine that would require a new calculation, and a new fee. This latitude approximates Kimberley or Ladysmith (KZN), the bifaciality factor I assumed was at the pinnacle of what could be achieved at the time, with the idea that this value would be commonplace by the time I got around to doing this. I chose the summer solstice as I figured this would be the day of the year that the peak disparity would be at its greatest. If this information is helpful good luck to you.
  2. From the website sales warranty:
  3. No. The combined positive and negative cabling length of parallel batteries should be the same so that voltage drops over cabling is the same. Which in turn means that parallel batteries are equally charged/discharged at the same rate. The same logic would apply to other parallel devices that are likely to draw high current during operation.
  4. Municipality authorities won't know what is out there or what meters do what. So they'll read forums like this one to find out. Be careful what you post, you may be very lucky, don't advertise it. Get a 500W elcheapo chinese grid-tie inverter hook it up to single pane that you lean on your fence next the meter box. Trip your feed in breaker and watch the disc. If you are lucky keep shtum and don't tell the neighbours and switch off your inverter well before the meter reading dates.
  5. This is the COCT bylaw. I am not a lawyer but it seems that if they supply you with a service they can get access to inspect that service. It also say they can seek information from you. I do not see this as a blanket right to invade your right to privacy, but limited to the provision of their service. However, my non-legal opinion after reading this is: It would be a stretch to interpret this bylaw to mean that COCT authorities can demand off-grid registration legally. Sure they can inspect their connection to ensure it's off-grid and they could ask you if you are connected to the grid. After that though, the details are not their business, no more than they could compel you to register if you were HIV+. It is a private matter that does not affect them. In fact, I would argue that is illegal under some or other information/privacy act for authorities to compile a database of people for things that have nothing to do with them. Electricity Supply By-law.pdf
  6. Thank you for the data. I am not sure about this conclusion. In the light of this: but this does seem to be an issue: Please can you justify your conclusions.
  7. Sorry, I'll have pass on this. This info will be needed by other people interested anyway.
  8. Thank you, that tallies with what I have already. I'll have to have a think.
  9. That's the Version of VRM or something it'll be the first 4 digits of the number on the chip inside either 2654 or 2655. All your units will be the same FW, they have to be to be in the same system. Look at the inverter product Id in the device list tab in VRM.
  10. May I ask the FW version and where you are based?
  11. If you can show you have enquired and shown the diligence of a reasonable man and you still can't find out, there isn't, even if there is.
  12. If you feel intimidated, go ahead and comply. I am just saying my stance would be, unless it's a law, they can huff'n puff and then go swivel.
  13. Nearly 30 years ago, there was a big hype about registering boreholes, fire and brimstone and imminent woe if you didn't. I was about to have mine dug at the time, so I phoned in. Without getting my name, I was told that I may be expected to provide water for any surrounding rural community. I said fine, what were they willing to subsidize my costs, they said not a cent. We left it at that. I didn't register, and nothing happened, I am not sure anything would have happened if I had. But I'd as soon as not be on a database somewhere. I think the same principle applies.
  14. @gooseberry I understand your logic. Batteries won't save you money the costs are not on your side. So that leaves a grid-tie inverter. Legalities aside, some practical economic considerations: If your array is uniform all your power will be delivered in about one 4-5 hour mountain sometime during the day. If your tenant is at work no-one will use it and your inverter will throttle. (No sales) If your tenant is home and doesn't need it at the time you produce it your inverter will throttle. (Minimal sales) When a user uses his/her own solar he/she has an incentive to schedule his/her loads to match production to save money. What incentive does a tenant have for scheduling their usage to make you money?
  15. Equalization voltage are a higher voltage that cause the plates to bubble, and gas (water vapour) is lost, but it is easily replaced in a non-sealed battery. The reason it done reverse acid stratification, it is a "shake up" of the electrolyte to remix it so there is an equal acid concentration throughout. The bubbles on the liquid lead acid plates easily float to the top, if they remained on the plate they would make the plate effectively smaller by reducing electrolyte contact area, but they are un-hindered by the non-viscous acid. this action stirs up the thin electrolyte. To a lesser degree if bubbles remain in suspension they would also make the battery less effective. Yes. a byproduct of this process is the battery bank is top-balanced, but batteries can be balanced numerous ways without doing this. So, noting the the limitations of a sealed battery vs an unsealed battery. Let us consider a full jar of water (the liquid Acid mimic) and a full jar of honey (the Gel mimic). As gently possible put a drop of food colouring on the surface of both jars and fit the lids. The food colouring mimics a high concentration of acid that must be mixed throughout the liquid. Now shake both jars (the equalisation process) until the food colouring is mixed at an equal density throughout the water and the honey. During this mixing process it will become clear to you how the viscosity of the electrolyte plays a role.
  16. The right direction is not to ask why we don't equalize gel batteries, but why we do equalize liquid electrolytic lead plate batteries (i.e standard lead acids). Then you'll see why it is applicable (even harmful) to gel batteries.
  17. Balancing and equalization are not strictly the same thing and not really done for the same reasons. The short answer: All batteries types can be balanced, but not all equalized. Don't equalize gel batteries. For the long answer: Spend a while reading up on things.
  18. I've seen recommendations of 6 inches minimum (Type L copper) vertical loop height within the first horizontally 6 inches of the cold water inlet and hot water outlet.
  19. Overheating generally happens for 2 reasons: 1. The cross-section of the cable is too small for the amount of current you want it to carry. 2. A loose connection. For 1.) There are a host of current capacity tables on the www. for 2.) It is normally localized heating at the poor connection. ( It's always nice if someone can lend you a Flir).
  20. Read the specs of your panel, there is a temperature coefficient for voltage, meaning the Voc will rise as it gets colder. If it gets cold enough the Voc will exceed 50V, meaning that 5 panels in a string will exceed 250V. You may get away with it on the coast, but generally in the low minuses it exceeds 50V.
  21. No, you will exceed the voltage rating of the MPPT if it gets cold. Normal slope I am referring to your roof pitch slope, vertical is self-explanatory. Not many people go vertical. Probably in this ballpark, but I think you are being slightly optimistic with these numbers.
  22. I once looked at pool heating and I was surprised how effective this was, from memory it was something like the heating capacity could be down-scaled 25-30% with one of these. Definitely, first stop when considering pool heating or just keeping it warmer longer.
  23. From graphs I am going to go with a daily peak power from PV as 150V @35A, say a nominal peal power input of 5250 Watts. (In line with what you said). I'll guess your charging voltage is say 55V and you have 100A at that voltage, so you are capable of handling a peak of 5500W'ish. So you have around 250Watts of headroom in your present configuration. Which isn't much. Essentially you can't add any panels (N or normal slope E/W) that add to your noonday peak. You won't have problems, but you won't reap a whole lot of benefits either. So your options to harvest more power in a day without buying a second controller are: A) Add vertical or near vertical East-West arrays which won't contribute to the noon peak. (You could add many strings of 4 x 405W panels E/W if they were vertical). B)Reconfigure your North facing array to just normal slope E/W arrays. Then you could add about 30%-50% more panels and still stay below the peak of your controller. This just be using E/W panels at your available roof gradient (normal slope), without using vertical panels. (Although you could still add vertical as well on top of that).
  24. You cannot exceed the voltage rating of the MPPT, this is a hard limit. In your case I believe 4 panels in series will be the maximum length of string. Exceeding this voltage will damage the MPPT. The number of strings is a different story, this is the current output limit superimposed on you by the MPPT. It is not a strictly a power limit but depends on your battery voltage. It might be known as a 48V system, but the charging voltage may be 10V higher. It is a current limit, in your case it is 100A. If you added another North-facing string that peaked simultaneously with you existing panels you would experience "clipping". In other words you'd hit your ceiling output and the peak would be a flat line. Exceeding this limit shouldn't damage anything. Indeed it may be worthwhile having a number of strings so that most of the year you don't clip, and only clip on great days. I am a proponent of not having North-facing panels, and rather having E/W panels. This way I can get a lot more panels for the same noon peak. More panels are better when it is overcast.
  25. You will need to add matching strings if you want to use the same controller.
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