TonyT Posted January 24, 2021 Share Posted January 24, 2021 Have a look at plyontec batteries. outside is fine as long as the IP rating of the inverter and associated components are suitable for the environment. Link to comment Share on other sites More sharing options...
BartW Posted January 24, 2021 Author Share Posted January 24, 2021 12 minutes ago, TonyT said: Have a look at plyontec batteries. outside is fine as long as the IP rating of the inverter and associated components are suitable for the environment. thought Pylontech ones were strictly to be kept in a din rack, but LG storage looks like the correct IP rating: https://midsummerwholesale.co.uk/buy/storedge/lg-chem-7hv I think there is an overall premium to it being incased into an enclosure that is good for the outside, though. Link to comment Share on other sites More sharing options...
ma9mwah Posted January 24, 2021 Share Posted January 24, 2021 5 hours ago, BartW said: Assumed 10no 445W panels along the pitched roof (South - tiny-bit-East roof), and 6no 445W panels on the flat roof. All connected up using individual microinverters. No shading. Total 7120W @ 20% panel efficiency x 70% realistic efficiency due to weather, etc gives me 996W per h. If I average 7 hours a day in beautiful Oxfordshire, then there is a potential for 7kWh of energy. 3 hours ago, ProDave said: My 4kW with a LOT of shading generates way more than that, so you must have done something wrong for 7kW I think there is double counting of the efficiency happening. A 445 Watt panel doesn't produce 20% of its rate value, it is the 20% of the ~2000W insolation energy (clear summer day). So 7120W at 70% summer day is 4980 Watt per hour Link to comment Share on other sites More sharing options...
BartW Posted January 24, 2021 Author Share Posted January 24, 2021 I am struggling to understand (being thick obviously ? ). Can you please elaborate? 1 Link to comment Share on other sites More sharing options...
Russdl Posted January 24, 2021 Share Posted January 24, 2021 @ma9mwah what @BartW said. That was a bit over my head as well! 1 Link to comment Share on other sites More sharing options...
TonyT Posted January 24, 2021 Share Posted January 24, 2021 1 hour ago, BartW said: thought Pylontech ones were strictly to be kept in a din rack, but LG storage looks like the correct IP rating: https://midsummerwholesale.co.uk/buy/storedge/lg-chem-7hv I think there is an overall premium to it being incased into an enclosure that is good for the outside, though. sorry that was 2 replies not indicating that the pylontec batteries were IP rated 1 Link to comment Share on other sites More sharing options...
ma9mwah Posted January 25, 2021 Share Posted January 25, 2021 11 hours ago, Russdl said: @ma9mwah what @BartW said. That was a bit over my head as well! 11 hours ago, BartW said: I am struggling to understand (being thick obviously ? ). Can you please elaborate? Sorry it was late, so probably didn't make too much sense. In your calculations for the best day generation you are timings the result by 20% because that's the efficiency of the panel. But that's already been taken into account of with the panel rating of 445W. (a 445W panel is around 2m2 which if 100% efficiency give you ~2200W so (2200 x 20% = ~445W)). So on a theoretical summers days with no cloud cover at midday (for an hour) you would get 7120W * ~85% (as the sun wont be directly over head) = 6kWh generated in that hour. Link to comment Share on other sites More sharing options...
SteamyTea Posted January 25, 2021 Share Posted January 25, 2021 (edited) 12 hours ago, ma9mwah said: 2000W insolation energy (clear summer day) 15 minutes ago, ma9mwah said: ~2200W so (2200 x 20% = ~445W)). Where are you getting this 2000 to 2200W figure from. The solar constant for Earth is ~1.36 kW.m-2 Module, that use the standard test condition are tested at 1000W.m-2, at 25°C and an air mass of 1.5 kg.m-3 For annual yield in the UK, work on 1 MWh/kWp installed (assuming you don't have a system has shading, and is less than optimal azimuth i.e. North facing. Edited January 25, 2021 by SteamyTea Link to comment Share on other sites More sharing options...
ma9mwah Posted January 25, 2021 Share Posted January 25, 2021 The only 445W panels I could find online were ~2.2m x 1m in dimension. So I just did 2.2m2 x 1000W.m-2 x 20% panel efficiency gives 445W. Link to comment Share on other sites More sharing options...
BartW Posted January 25, 2021 Author Share Posted January 25, 2021 1 hour ago, ma9mwah said: The only 445W panels I could find online were ~2.2m x 1m in dimension. So I just did 2.2m2 x 1000W.m-2 x 20% panel efficiency gives 445W. I was under the impression that the quoted 445W is output per panel, which you then work out the 20% efficiency, no? Link to comment Share on other sites More sharing options...
SteamyTea Posted January 25, 2021 Share Posted January 25, 2021 3 minutes ago, BartW said: I was under the impression that the quoted 445W is output per panel, which you then work out the 20% efficiency, no? No. The 445W is the peak power the module will make under standard test conditions. Very rare day you actually get that from the module. Link to comment Share on other sites More sharing options...
BartW Posted January 25, 2021 Author Share Posted January 25, 2021 6 hours ago, SteamyTea said: No. The 445W is the peak power the module will make under standard test conditions. Very rare day you actually get that from the module. In that case matters look a lot more optimistic, and we would be able to technically generate 6000KW per year. That is 16.4kW per day, which means that a 10kWh battery, would be well suited for our needs Link to comment Share on other sites More sharing options...
SteamyTea Posted January 25, 2021 Share Posted January 25, 2021 53 minutes ago, BartW said: That is 16.4kW per day Only for a few days, the rest of the time it is lower, or higher. Probably lucky to make 6 kWh/day in December. Link to comment Share on other sites More sharing options...
BartW Posted January 25, 2021 Author Share Posted January 25, 2021 5 minutes ago, SteamyTea said: Only for a few days, the rest of the time it is lower, or higher. Probably lucky to make 6 kWh/day in December. Yes, I am working on an average. 6000kWh per year is basically a combination of highs and lows. All in all, if the calculation is relatively true, (I actually increased the losses to 20%), then I would be very happy. Link to comment Share on other sites More sharing options...
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