glendouglasza Posted October 5, 2017 Share Posted October 5, 2017 Hi all. I am interested to know how popular solar tracking setups are on the forum? Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted October 5, 2017 Share Posted October 5, 2017 @Don has one and there may be one or two DIY setups. The general consensus is that the gains achieved by trackers is more cheaply achieved by just adding extra panels. Clint, ___ and SilverNodashi 3 Quote Link to comment Share on other sites More sharing options...
DeepBass9 Posted October 6, 2017 Share Posted October 6, 2017 What can achieve a similar effect is 2 panel arrays, one pointing more east and one pointing more west to maximise the morning and afternoon sun respectively. This should give a more constant power production with less of a midday peak. You will need two MPPTs though. Is there any solar modelling software that allows you to model non- true north panel orientations to simulate this? All the ones I have seen assume north pointing arrays. Quote Link to comment Share on other sites More sharing options...
Sidewinder Posted October 6, 2017 Share Posted October 6, 2017 I feel that a 25% East, 25% West & 50% North setup to be optimal, especially if your roof construction limits North exposure. But that then requires 3 (or 4, if inverter has dual) MPPT's. I would even split the north panels over two MPPT's. The next time I go to solar Version 4, that would be my end goal. E.g. if the MPPT can handle 3kW each, then with 2 MPPT's, the optimum setup would be 50% North1 (3kW) & 50% North 2 (3kW), for total of 6 kW, if only North is available 2 MPPT's, the optimum setup would be 50% East (3kW) & 50% West (3kW), for total of 6 kW, if no North is available 3 MPPT's, the optimum setup would be 33% East(3kW), 33% North (3kW) & 33% West (3kW), for total of 9 kW 4 MPPT's, the optimum setup would be 25% East(3kW), 25% North 1 (3kW), 25% North 2 (3kW)& 33% West (3kW), for total of 12 kW This kind of setup would only be beneficial when the total size exceeds 6-12 kW, but depending on the rating of one's MPPT. Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted October 6, 2017 Share Posted October 6, 2017 32 minutes ago, DeepBass9 said: Is there any solar modelling software that allows you to model non- true north panel orientations to simulate this? All the ones I have seen assume north pointing arrays. There is but the licence costs about €900 a year. From the little bit of reading I have done The orientation of east/west arrays is not that critical as what you may lose on one array you gain on the other (on the two opposite sides of a roof for instance). I am still not sure whether there is any advantage of a NE facing array and a NW facing array versus purely East and West facing arrays. A JHB install that I was reading about had East/West arrays at an angle of 15°. Anyone wanting to do something like that I would just copy that as obviously on a large install they have done their homework. Quote Link to comment Share on other sites More sharing options...
___ Posted October 6, 2017 Share Posted October 6, 2017 24 minutes ago, Chris Hobson said: whether there is any advantage of a NE facing array In my experience, leave the NE bit unless you run out of space. Point them North and North West as much as you can. SilverNodashi 1 Quote Link to comment Share on other sites More sharing options...
DeepBass9 Posted October 6, 2017 Share Posted October 6, 2017 Why? Surely you would want charging to start as soon as possible in the morning? Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted October 6, 2017 Share Posted October 6, 2017 24 minutes ago, DeepBass9 said: Why? Surely you would want charging to start as soon as possible in the morning? I think it has to do with morning mist. Interestingly enough solar engineers in Germany are recommending East West arrays to increase self consumption and there is only about 4% loss not having panels face North. Quote Link to comment Share on other sites More sharing options...
ibiza Posted October 6, 2017 Share Posted October 6, 2017 Very interesting! Any link to that article, please Chris! Quote Link to comment Share on other sites More sharing options...
___ Posted October 6, 2017 Share Posted October 6, 2017 2 hours ago, Chris Hobson said: I think it has to do with morning mist. At least where I live, it is very common to have clouds on the horizon, probably because I have the Overberg mountains to the North East too (and clouds tend to stick around those areas). It means the NE array starts making power around the same time the North array does. It might differ from installation to installation, but I find that I make more gains from the late afternoon sun than the early morning sun. Better to have the arrays "heavy" towards N and NW. Might be a Western Cape thing though, YMMV as they say. Quote Link to comment Share on other sites More sharing options...
maxomill Posted October 6, 2017 Share Posted October 6, 2017 just 2 cents worth of useless info my 2nd array on our L shaped house is a west facing array and in jhb it works for me in the afternoons but works super in mid summer when the sun is really high, also anyone have reasons for wanting 2 mppt s (or pwm) for having east and west panels , my little brain says if they are parallel then 1 mppt is still good. , or am I missing something cheers Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted October 6, 2017 Share Posted October 6, 2017 5 hours ago, ibiza said: Very interesting! Any link to that article, please Chris! I have been doing some research and these are the articles I found. https://www.solarquotes.com.au/blog/an-eastwest-spit-of-solar-panels-on-a-single-string-can-work-well/ http://www.telegraph.co.uk/news/earth/energy/solarpower/10996273/Most-solar-panels-are-facing-the-wrong-direction-say-scientists.html http://soltra.co.za/the-benefits-of-east-west-solar-pv-installations-for-the-sa-market/ https://youtu.be/0esRftZ3qdw https://www.solarpowerworldonline.com/2016/10/happens-east-west-solar-array-isnt-perfectly-east-west/ 2 hours ago, maxomill said: also anyone have reasons for wanting 2 mppt s (or pwm) for having east and west panels , my little brain says if they are parallel then 1 mppt is still good. , or am I missing something The is somewhere (don't ask because I will never find it again) info where in certain instances a single MPPT can be used for a due West due East array. What the circumstances were escapes me. The reason for 2 MPPTs is each is going to behave differently and you asking the single MPPT to hit the sweet spot somewhere between the two. It can be done (as I have mentioned) but it is not plain sailing. Quote Link to comment Share on other sites More sharing options...
ibiza Posted October 6, 2017 Share Posted October 6, 2017 Tnx Chris Quote Link to comment Share on other sites More sharing options...
Mr_Nickolay Posted October 9, 2017 Share Posted October 9, 2017 On 06.10.2017 at 8:39 PM, Chris Hobson said: I have been doing some research and these are the articles I found. https://www.solarquotes.com.au/blog/an-eastwest-spit-of-solar-panels-on-a-single-string-can-work-well/ http://www.telegraph.co.uk/news/earth/energy/solarpower/10996273/Most-solar-panels-are-facing-the-wrong-direction-say-scientists.html http://soltra.co.za/the-benefits-of-east-west-solar-pv-installations-for-the-sa-market/ https://youtu.be/0esRftZ3qdw https://www.solarpowerworldonline.com/2016/10/happens-east-west-solar-array-isnt-perfectly-east-west/ The is somewhere (don't ask because I will never find it again) info where in certain instances a single MPPT can be used for a due West due East array. What the circumstances were escapes me. The reason for 2 MPPTs is each is going to behave differently and you asking the single MPPT to hit the sweet spot somewhere between the two. It can be done (as I have mentioned) but it is not plain sailing. Thank you! Very informative! Quote Link to comment Share on other sites More sharing options...
___ Posted October 9, 2017 Share Posted October 9, 2017 On 10/6/2017 at 7:39 PM, Chris Hobson said: certain instances a single MPPT can be used for a due West due East array. What the circumstances were escapes me. I think we speculated about this in the past. What should happen is that the MPPT looks for the optimum voltage at which the most power is harvested, and that should cause it to push the voltage up to a level where the second array (the one in full sun, assuming the other one is not in full sun) works better. The first array (not in full direct sun) will still make some power but it won't be able to really deliver it because it needs to overcome the "system voltage" to push current in there. So you'll be losing power on the array that is not in full sun. How much, that is the question... and at what point does it make financial sense to add another MPPT. If you consider an east/west array at exactly noon, both arrays make the same power. Then as you move to around 2PM, one makes 60% and the other makes 40%, and then 70/30, etc... and basically by 3pm your second array (which might still make significant power) simply can't push the voltage up high enough to compete and it is all lost. So my gut feeling says... get the second mppt. DeepBass9 and Chris Hobson 2 Quote Link to comment Share on other sites More sharing options...
SilverNodashi Posted October 27, 2017 Share Posted October 27, 2017 My North facing array works quite well as-is. But then again, where I live it's quite flat and we get Gauteng sun shine from as early as 6am Quote Link to comment Share on other sites More sharing options...
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