Ask a renewables installer...

tunnel

grahamc2003 wrote: »

I'd see if you can get the software upgrade for their Optitrac system on your Inverter model. All it is is a better tracker, which searches for all the peaks in the Power v Voltage curve instead of stopping at the first local peak. If you have shading, then you have several local peaks (or rather points where dP/dV is zero), and Optitrac seeks out the peak peak, iyswim. Should give similar results to the solar edge system, without the expensive hardware and fitting. But you may have to go that way if Optitrac isn't available on your inverter, which it isn't on mine (SB1800). I decided not to go down the solar edge route due to the risk of increased problems in the future, but it depends on how much generation you are losing due to the shading.

Thanks, i'll check out my inverter this afternoon,do you know if this would work with the progressive shading i get or would it be limited to occaisional shading?

Tunnel

Martyn1981

tunnel wrote: »

Thanks, i'll check out my inverter this afternoon,do you know if this would work with the progressive shading i get or would it be limited to occaisional shading?

Tunnel

I suspect Graham means OptiTrac Global Peak, as I think all SB's have OptriTrac. Your HF (if it is a HF) should already have this, so a great idea to check if it's got the best update.

This system will try to find the optimum level for the string, and exclude 'damage' from the shaded panels. SE PO's attempt to maximise each individual panel.

The SE route won't be cheap, as an afterthought add-on, due to call out and scaffolding. Perhaps £300 for PO's, £500 for inverter, then perhaps £500 each for installer and scaffolding. Even if you got £2-300 for the inverter, you'll still be down £1,500.

You need to look carefully at the numbers, what you'll gain, is it 2kWh's for a month either end of the summer, or 3kWh's for 2 months either end. Also the efficiency differences in the inverters. You'd probably need to clear £150pa (approx 300kWh's) to breakeven.

You might also value the monitoring available and the 12yr inverter warranty. But remember, you'll have 8 extra bits, albeit with 25yr warranties, on your roof.

If you're still considering another extension, then maybe wrap the jobs together, additional scaffolding will be minimal, and labour (whilst they are there) shouldn't be too much.

Just a thought, but there is a SE add-on box to allow PO's to work with other inverters, I think it might be £200, but can't recall (hope I'm not making that up), also I think SE are due to launch a new PO that'll work with any inverter outright, but now I'm really stretching my memory.

Mart.

tunnel

Martyn1981 wrote: »

I suspect Graham means OptiTrac Global Peak, as I think all SB's have OptriTrac. Your HF (if it is a HF) should already have this, so a great idea to check if it's got the best update.

This system will try to find the optimum level for the string, and exclude 'damage' from the shaded panels. SE PO's attempt to maximise each individual panel.

The SE route won't be cheap, as an afterthought add-on, due to call out and scaffolding. Perhaps £300 for PO's, £500 for inverter, then perhaps £500 each for installer and scaffolding. Even if you got £2-300 for the inverter, you'll still be down £1,500.

You need to look carefully at the numbers, what you'll gain, is it 2kWh's for a month either end of the summer, or 3kWh's for 2 months either end. Also the efficiency differences in the inverters. You'd probably need to clear £150pa (approx 300kWh's) to breakeven.

You might also value the monitoring available and the 12yr inverter warranty. But remember, you'll have 8 extra bits, albeit with 25yr warranties, on your roof.

If you're still considering another extension, then maybe wrap the jobs together, additional scaffolding will be minimal, and labour (whilst they are there) shouldn't be too much.

Just a thought, but there is a SE add-on box to allow PO's to work with other inverters, I think it might be £200, but can't recall (hope I'm not making that up), also I think SE are due to launch a new PO that'll work with any inverter outright, but now I'm really stretching my memory.

Mart.

Luckily this system is garage mounted and i can lend my builder mates tower scaffold so one less expense i suppose.

I'm reckoning on at least 6-8 months of "lost" generation due to the shading,when i had it installed late september,i noticed straight away that next door would lose me some generation. It was when i checked what my generation was before and with shading that i realised i may be losing more than i first anticipated. 1600w down to 100ish with the loss of less than 1 panel in late september.

As a comparison,this system is shutting down roughly the same time as my ESE system,when in reality(if i had no shading) it should continue for probably another 2 maybe 3 hours in peak summer.

Your last paragraph makes interesting reading though and makes me wonder if i should sit tight a little longer and suck it up. Guess i'll have to see what the "expert" says.

cheers

Tunnel

Energetic_2

Ok, not got much time so excuse the brevity of my reply...

So starting with Marts neighbour. IMO PV with the immersun is a better option than ST. If he has no gas he's likely on E7 and the immersun can be programmed to boost during off peak hours. The technologies completely overlap in terms of seasonal operation and PV is a lot simpler to maintain with a lot less to go wrong. That said, a diy thermal system would have a good payback as PV does at current prices. Since the immersun and the wooldridge units came out we have not done any Thermal and will probably let our MCS for it lapse at our next assesment.

Moving on to SMA inverters, if you have the SB2000HF a simple firmware upgrade will give you optitrac if it is not pre installed, the original ones didn't have (pre autumn 2011 roughly). It can be activated in Sunny Explorer in the 'DC side'. While it cannot eliminate the effects of shading it will get the best performance possible from a shaded system.

The PO's or micro inverters will work that bit better with shading but i don't have an enormous amount of experience with them. I doubt its worth changing the inverter but keep an eye on it. We tend to design around shading issues where possible. Most panels have 3 parallel strings within them with a blocking diode in each to stop reverse current if one single whole panel is shaded the rest of the system will be limited to the current flow of the shaded panel. Constant hard shading such as a chimney resulting in regular operation of the diodes will likely cause a reduced life of the diode and if unnoticed the cells will degrade without their protection.

Tunnel did your installer model the system up to give you an estimate of the effects of the shading? it's easy to do with the right software and all good installers should be designing this way.

simplewanderer

Hi
Newbie here, live in NI, so think the whole FIT thing doesn't apply to me.

I live on a small farm, with a nice windy hill. Was considering a wind turbine, however the low maintenance/minimal planning of solar PV is tempting.

Grateful for any advice from those who know more than me [i.e. everyone]

Thanks

[had originally posted in the thread which has been hijacked]

Fruit_and_Nut_Case

simplewanderer wrote: »

Hi
Newbie here, live in NI, so think the whole FIT thing doesn't apply to me.

You're right. That seems extremely mean.

simplewanderer wrote: »

I live on a small farm, with a nice windy hill. Was considering a wind turbine, however the low maintenance/minimal planning of solar PV is tempting.

Grateful for any advice from those who know more than me [i.e. everyone]

Thanks

[had originally posted in the thread which has been hijacked]

Without a FIT it may not be financially viable.

Energetic_2

simplewanderer wrote: »

Hi
Newbie here, live in NI, so think the whole FIT thing doesn't apply to me.

I live on a small farm, with a nice windy hill. Was considering a wind turbine, however the low maintenance/minimal planning of solar PV is tempting.

Grateful for any advice from those who know more than me [i.e. everyone]

Thanks

[had originally posted in the thread which has been hijacked]

Hello. Not familiar with the scene in NI but it's possible that if you can do a 'cheap' PV install and use everything that you generate that you would be looking at payback in roughly 10 years. Thats not as easy as i have made it sound by the way.

Call a local installer if you have one or find someone with a PV system and ask their advice. A quick goggle turned this up, No FiT but a NIROC instead which appears to be higher than britian, and a higher export tariff: http://powerni.co.uk/saving-energy/renewables/sell-your-electricity/

Wind can also be viable depending on the location without subsidies but you can get NIROC for that too. Worth looking into i reckon if you have 5.5m/s average windspeed or better.

I'm not looking anymore, you've depressed me...

scotsblood

Hi
Just starting to collect quotes for an install after lurking for some time building up knowledge!
3kw will fit on west facing 35degree roof.
First quote arrived today with SMA SB2500HF as recommended inverter, haven't had chance to speak with installer yet so was wondering why this model.

Have done a fair bit of reading and looked at Sunny Design this evening and it seems to suggest SB2500TL would be marginally more efficient. Also noticed 2500TL is also slightly cheaper at many outlets!

Any thoughts on HF v's transformerless choice?

Energetic_2

scotsblood wrote: »

Hi
Just starting to collect quotes for an install after lurking for some time building up knowledge!
3kw will fit on west facing 35degree roof.
First quote arrived today with SMA SB2500HF as recommended inverter, haven't had chance to speak with installer yet so was wondering why this model.

Have done a fair bit of reading and looked at Sunny Design this evening and it seems to suggest SB2500TL would be marginally more efficient. Also noticed 2500TL is also slightly cheaper at many outlets!

Any thoughts on HF v's transformerless choice?

Interesting choices, nice to see quality products still being quoted with all the cheap stuff around these days...

The TL will be slightly more efficient as you have noted, the HF is a little bit more flexible to install. It's compatible with 30mA RCD's which the TL isnt, so if you have an existing board with RCD's in and no options to add other boards the HF will make life easier for the installer. The 2500TL is only a single string inverter unlike its bigger sibings so not suitable for split systems, similar to the HF. Both will come with Optitrac, bluetooth as standard, pretty similar really.

Both great inverters and we have installed plenty of both. I like the Sunny Explorer, theres still nothing out there quite as good for a tech...

jimjames

In relation to the questions about inverter sizing vs panel output we have 3kWp panels and SMA 3000HF inverter. We have only very briefly hit 3kW output for a few minutes after clouds cleared to bright sun.

You can see the max output per month here

http://solar-panels-review.321web.co.uk/monthly-pv-solar-panel-generation.php

I'll have a look to see if I can show how many 5 min periods were over a certain level last year which might show that you won't lose much output with a smaller sized inverter. Between Oct and Mar the peak output was only 2700kW so well below the inverter max.