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Forum Index : Electronics : Solutions for a shaded solar roof
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| nickskethisniks Guru  Joined: 17/10/2017 Location: BelgiumPosts: 458 |
Hi, Another episode for my off grid system, in an attempt to maximize solar production, I will (want to) swap my current 280W panels for 500W panels within a reasonable budget, there a Ja solar panels that have the best dimensions. This way I can increase production from 7840Wp to 11,2kWp on the best oriented spot of my property. The older panels will be placed on other places. I hope they are more efficient as well. At the moment my system has 14 strings of 2 panels in series. This works great with the nano mppt controller. But this could be improved if each panel potential would be maximized, there is a lot of shading on certain panels. Now with the new panels, orientation with 2 panels in series would be more terrible and I would probably loose a lot of potential. To make it worse, the new panels will be bigger, and Umpp will be around 37V, which is to low to charge my 48V battery bank. I will actually keep 6 panels and add 19 500W panels. The plan is to add another 15 to 17 panels on another roof as well. Normally there are only 2 solutions for this problem: Option 1 Grid tie inverters with optimizers, this would add a lot of money to the installation cost. Edit: are there for use with mppt charge controllers? Option 2 Micro grid inverters, this will probably more than double the installation cost. But I find there should be a diy solution, no? Option 3 DIY kind of optimizer, I guess these are just buck converters, which are probably with synchronous freewheeling mosfet for highest efficiency. Looks simple on first side but probably needs some kind of synchronisation for the mppt algorithm? Option 4 Provide each panel with a “boost “ mppt controller, this might be the simplest solution. These could straightly charge my battery or provide energy to a higher voltage “bus system” which can be used to feed my current nano controllers. What do you guys think about this problem? Not that a diy project is cheap, but this could be a cool project to accomplish. Edited 2023-10-07 07:17 by nickskethisniks |
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| Solar Mike Guru Joined: 08/02/2015 Location: New ZealandPosts: 1138 |
Wow, that's quite a lot of work and time; for DIY and to use your existing charge controllers, some sort of Voltage Boost converter fitted to each 500W panel output may work. Sort of subtracts efficiency in the conversion about 5% though. Simplest would be to purchase boost converters from Aliexpress that have current limiting, so you could set them to say 80V and allow paralleling up multiples feeding a common charge controller. These 1200W Ones rated at 1200 Chinese Watts should work ok without any fans. Looking at some of these online its difficult to know the quality of components used. Would still work out way less expensive than designing and building your own. Cheers Mike |
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| Godoh Guru Joined: 26/09/2020 Location: AustraliaPosts: 458 |
Do you have much land? If you do then a ground mount for your panels where they won't be shaded may be a better option. I have two large ground mounts, made from treated pine ( much cheaper than manufactured metal ones) I put them a little away from my house where the sun is unshaded all day. Pete |
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