help please reduced output on hot days

[billybee]

I believe the power 1 inverters use heatsinks and cooling fins rather than an internal fan so it would do no harm to get a large fan blowing on the inverter from early before it gets warm so to limit the heat build up. It may help. The inverter is not mounted in an enclosed space or warm loft is it?

yes its mointed in a loft bedroom, i didnt want it there as one its my daughters bedroom and two she has a pet ferret and we learned quickly that it wouldnt leave it a lone, so i had to build a ventilate box round it as well. i did bring up the t-boost issue with power one and there engernier said it wouldnt get hot enough to derate but i noticed the t-boost and temp once in may when looking at the display when it was down on peak.

this is the earlyer post i got. and it does sound the same as im getting but could be heat on panels same as mine.

Hi Billybee

I have a fairly similar system to you - Powerone PVI3000out and 13 250w suntech panels in 2 strings (these have a slightly better Temperature Coefficient than a-sun)

Have you noted the temp reading on the inverter when the power drops??

I have noted that as soon as the inverter temp reaches circa 54c the output power drops from 3300w to 2450w - the inverter display will also change from Tinv to TBoost.

Hope this Helps

Dave


i dont no why it changes from tinv to tboost at 54' and the system power drops the online manual only gives gerneral infor on it. i do think after the advice on here that even with out this at some stage on a hot day my powers going to fall by upto 20% but wonder if this is causeing reductions to happen earlyer than the panels need be. but hopefully power one will get back to me and explane more or finding a solution. the main question i had for them was if the 3.0 fell to 2450 because of this does that mean the 3600 would fall to around 2900 when the same affect happens. sadly no answer on this. i am going to get a thomitor on my roof and the next hot day i will see how hot the roof is when i stick at 2400w.


thanks again all

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[stavtoon]

Hello Billybee its my system you are comparing with and i like yourself in the early weeks of being up and running got a bit paranoid looking at other systems comparing them with mine.But later just let it get on with producing power for my household and are now enjoying EDF sending money to my bank lol.
For the other members here is my system.hilltopsolar 3.290kW | Monthly

 

[billybee]

Hello Billybee its my system you are comparing with and i like yourself in the early weeks of being up and running got a bit paranoid looking at other systems comparing them with mine.But later just let it get on with producing power for my household and are now enjoying EDF sending money to my bank lol.
For the other members here is my system.hilltopsolar 3.290kW | Monthly

probably am being paranoid a bit. but when you pay a lot for a system you want it 100% or and thanks for the info on your system the other week. and because i'm on the lower feed in tarrifs every kw counts. it might only feel like a couple of kws 50 days a year but it will add up over 25 lol. i was going to contact you and ask what data are you going off for your targets though. thanks

 

[stavtoon]

probably am being paranoid a bit. but when you pay a lot for a system you want it 100% or and thanks for the info on your system the other week. and because i'm on the lower feed in tarrifs every kw counts. it might only feel like a couple of kws 50 days a year but it will add up over 25 lol. i was going to contact you and ask what data are you going off for your targets though. thanks

PVGIS but not the climate version as i added the estimates before i found out about it.To be honest i dont take much notice of the estimates as March was 170% but it was a very unusual March even more so up here.I know what you mean about alot of money as its the kids nest egg (THEY DONT KNOW IT YET)

 

[matt25]

ktech.......... youve probably got the best solar related website ive ever seen, awesome!

 

[billybee]

just an update, ive had some feedback from power one, he beleives that changing the internal wiring on the inverter to one string will improve things somewhat. he sent me two data sheets on 2 strings and one string and while i dont fully understand what it all means. it will make changes to (Load Factor/MPPT [%])(Maximum Power/MPPT [kW]) and (Inverter Reccomended Activation Voltage [Vdc]) thus uping my performance. so i will of corse have these changes made which looks quite simple to do and see what happens. ive also now got a thomitor on one of the panels. and the last few hours now the rains stoped. my roofs around 33'c and i'm peaking around 2.8 to 2.9 kw. but as theres still a lot of clould and the room where the inverter is, 25'c its not going to tell me much till we get a very hot day again. on a normal hot day by 10am the system upto 1600w by 10am and today it its been merky out side till affter 1pm the roof and the inverters had no real heat. so i dont expect to learn anything

thanks all and i'll let you know of any changer after the modifications made.

 

[Gavin A]

did the aurora guy mean running the inverter on single string mode, but still with 2 inputs?

if so, that would make a minor difference, but running it in one string of 12 panels will make a much more significant difference. This is easily enough tested out, as the installer can simply alter the wiring at the isolators to switch it over to running in a single string. Long term it's obviously be better not to have the extra cable run happening, but if you want to test the difference it makes, then this is dead simple.

 

[jason121]

i didnt think you could alter the power-one to single string, i ask that question at technical and they said no. But wonder why they provideded the two cable links with the inverter

 

[billybee]

yes thats what he's suggesting, even sent me details and pics of how to do it, at this time he's just sugesting making minor changes at the isolatiors moving 1 black and red and adding 2 wires linking them. i'm guessing that way as to totaly restringing them would problably mean scaffold back up and getting on the roof again. or could the cables coming in already be used for one string, or would this cause issues with cable lenth.

so does that mean that you think runing 2 strings on a single string mode isnt going to make a big diffrence.

when i first discussed having the panels installed i didnt want the inverter in the loft for a few reasons, the origanal plan was to run the panel cable down the wall to the spair bedroom and then the ac cable back out the same way and back into the meter. as the panels spair room and meter are all at the front of the house, i thought that would be easyer than going through several floors. but i was informed that the lenth of the cable from the panels could make a diffrence on output and the closer the inverter to the panels the better. in the end being 2 strings theres a lot of cable anyway.

 

[billybee]

i didnt think you could alter the power-one to single string, i ask that question at technical and they said no. But wonder why they provideded the two cable links with the inverter

well he sent me the pics and it looks very simple to do move two wires one red and one black.



> 1, move my black input 6 to number 5 and then put a black link wire from input 2 to input 6
>
> 2, move my red input 8 to input 7 and then put a red link wire from input 4 to input 8

that was it

http://www.power-one.com/sites/powe...y/tech-manual/manuale_inst_2011_multiling.pdf

page 12

big question is how much diffrence will it make and if i get scaffold back up and restring will that make a much bigger diffrence.

 

[jason121]

Remember you playing with DC so be careful nasty stuff if it bites you

 

[jason121]

i cannot believe you have peaked at 3.3kw on a fine day on a 3.0kwp install according to you graph

 

[jason121]

Also if you have two strings identical installed on a Power-one inverter. On the display were its shows both string outputs in watts and they are both the same there is not a problem with the installation or design

 

[billybee]

i used to play with DC in my job and sadly through some one else being stupid i got a nip of it. funny the smell of burnt flesh lol. even though i could easerly do it ive had the system in for 2 months and the second i change wires without the installers consent theres my guarentee gone. so we will leave wire changes to the perfesionals i think thats best.

i am a bit curious about why i have the 2 strings is this because the aurora has 4 lots of inputs and makes it seem normal to use them all. if you were to have had just one string would two of the inputs be left unused.

 

[billybee]

ive peaked above 3kw on about 10 days but never on a hot day only mixed days, thats what my read outs say anyway.