grid tie inverter for small 120w solar array

[cypher007]

i need a grid tie inverter for my current setup, ive got two:

http://www.maplin.co.uk/Module.aspx?ModuleNo=223250

[tange179]

Hi,

I do not belive that there are any manufacturers producing a G83 UK inverter for such a small array.

John

[climber]

SWEA 250W inverter?

[ecogeorge]

Hi,

I do not belive that there are any manufacturers producing a G83 UK inverter for such a small array.

John

I agree SWEA do , rated at 250w max with volts in 24-55 dc. Stackable up to 1000w. G83 approved I believe.
pm me if you can't obtain one , -may be able to help.
rgds George.

[tange179]

Found the manual for the inverter:

http://www.swea.nl/PDF/ExtensionkitManualEng.pdf

It appears that a UK G83 version is available, whether your panels will work using this inverter, is a different matter. Prehaps another forum member can help you out.

Do not forget that you cannot plug this inverter into a UK 3 pin plug outlet, it needs to be wired in directly to the distribution board using an approved electrician and then informing your local DNO that you have connected a small solar generator to the grid.  If you search the forum there is plenty of info' on this process.

John.

[cypher007]

what about the steca's? i may want to hook up a small wind turbine as well at some point.

[davebodger]

what about the steca's? i may want to hook up a small wind turbine as well at some point.

You would have to use a StecaGrid 300 and rewire your panels into two parallel sets of 4 panels in series connection, to get enough input voltage and current for the Steca (minimum 45 volts).
The StecaGrid 300 MPPT only works between 45 - 100 volts, so you could not put all 8 panels in series (too much Voc).
The Steca 500 has a higher minimum input voltage (75 volts) so is probably not such a good idea as with it you would have to run all 8 panels in series to get sufficient voltage.
Or you could use a Soladin 600 which would give you greater expansion potential, as it has a similar minimum voltage operating area to the Steca 300 but with more headroom.

[cypher007]

what would be the best way to run them? also i have a couple of 15w 12v panels could they be used as well or as they are a slightly different design/manufacturer would they upset the whole array? ive seen a swea inverter advertised on ebay for £199 is this a good price or should i buy a steca at about £270?

[cypher007]

anyone?

[RichardKB]

Well from the Maplin picture it shows 4 panel so they will be 15W also, so if you wire your spare panels in series you will get 6 x 22V as the string open circuit voltage.

MPP voltage will be approx 6 x 17V so you will need a grid tie capable of  more that 132V with an MPP range around 100V.

Rich

[cypher007]

ive actually got two lots of the maplin kit. also the spare panels are the same size but different in appearance there made by icp.

[davebodger]

what would be the best way to run them? also i have a couple of 15w 12v panels could they be used as well or as they are a slightly different design/manufacturer would they upset the whole array? ive seen a swea inverter advertised on ebay for £199 is this a good price or should i buy a steca at about £270?

Assuming they are similar panels (i.e. amorphous, like the Maplin ones) then they should have similar output as they seem to be rated the same voltage and power.
So put one in series with each of your 4 panel units and wire those in series.
You then have two strings of 5 panels in series. Those strings can then be connected in parallel to double the current.
The voltage will be about 5x 18v = 90v on load.
Off load it could rise to around 110v.
You 10 panels would then total about 150W of PV.
This would suit both the Steca and the Soladin (both max operating voltages and MPPT voltages).
Which is best depends on if this is the final design or if you intend to add to it later and how much difference in price there is.
If you intend adding a wind turbine later then you need further expert guidance - I have no practical wind power experience myself.
If you wait long enough a wind expert may be along, or just put a post in the wind section.

All the best.

Dave.

[cypher007]

thank you for the reply Dave. the icp ones have more layer connects, as when you look at them they have more lines down them. they look the same as these:

http://www.maplin.co.uk/Module.aspx?ModuleNo=217850

i think icp rate there panels at 15v not 17v like the maplin ones, hence the 15w rating icp have given what is probably a 12w panel. but im guessing it wont matter if there connected in series. also would it matter if some of the panels suffer from shading depending on the time of day? and last but not least can a soladin 600 run a wind turbine as well as panels? i thought the grid tie inverters were source specific?

[davebodger]

thank you for the reply Dave. the icp ones have more layer connects, as when you look at them they have more lines down them. they look the same as these:
http://www.maplin.co.uk/Module.aspx?ModuleNo=217850
i think icp rate there panels at 15v not 17v like the maplin ones, hence the 15w rating icp have given what is probably a 12w panel. but im guessing it wont matter if there connected in series. also would it matter if some of the panels suffer from shading depending on the time of day? and last but not least can a soladin 600 run a wind turbine as well as panels? i thought the grid tie inverters were source specific?

It's the current the panels can produce that's important when you are putting them in series.
This is normally listed as "Optimum Operating Current".
You want them to be fairly similar otherwise the odd panel could act as a limiter if it's a lot smaller than the other four.
The voltages won't matter as they just add up. As long as the strings are balanced (same mix of panels, i.e. one of one type, four of the other) then you should be OK putting the strings in parallel.
As long as they are all the same technology (i.e. Amorphous - which they look like) then they should be fairly resistant to shading.
You really need to speak to Outtasight who has significant experience in this area - you might like to read his thread as it talks many times about mixing various types of panel.
http://www.navitron.org.uk/forum/index.php/topic,8368.0.html

As I have said, I am no expert on wind energy, but I think that there is a way of connecting wind turbines to solar inverters but it is quite technically complex and I would not like to advise you on that route.
It would almost certainly be a compromise. The correct way is to have a separate inverter for the wind turbine. That will give you maximum output from both.