SE SW split

[infinity]

didnt matter in the end, when i gave him cost for split 4KW system and he told me some 'electrician' his brother knew from screfix quoted him £5k... i said good luck and left

 

[Gavin A]

InterPV.net - Global PhotoVoltaic Business Magazine

problem is, that he's comparing a single inverter with 2 separate inverters, not a one string inverter with a dual MPPT inverter.

Also, relatively low roof slope, and erm, power one dual MPPT is the same price as fronius or cheaper, so why wouldn't we use a dual MPPT inverter?

 

[jupestar]

my dad has a install split round a chimney. he had a chinese something which cr£pped itself, they changed to a single mppt fronius, i advised him he should have got a dual mppt to allow for the chimney, so he kicked up and they changed it to a power one. he claims he gets less power now, and the fronius was pumping it out. he now has great pleasure in telling me i know nothing (which is fair).

anyway i don't have any hard data for this, as i've got better things to do then check his pv output everyday. but he checks it and is adament he wants his fronius back.

we both agree that the first chinese inverter they put in was a cheap piece of rubbish.

 

[poheZ]

well maybe the you have shading on both trackers now!

 

[finchy]

Use either a power one 3600 or SMA3600 both of these have 2 MPPT. You have to use two seperate strings. Even if you install in all the same orientation, if you have different roof angles you would need to do the same.

The start up for each orientation would be different.

 

[SolarCity]

my dad has a install split round a chimney. he had a chinese something which cr£pped itself, they changed to a single mppt fronius, i advised him he should have got a dual mppt to allow for the chimney, so he kicked up and they changed it to a power one. he claims he gets less power now, and the fronius was pumping it out. he now has great pleasure in telling me i know nothing (which is fair).

anyway i don't have any hard data for this, as i've got better things to do then check his pv output everyday. but he checks it and is adament he wants his fronius back.

we both agree that the first chinese inverter they put in was a cheap piece of rubbish.

What was the make of the Chinese inverter? For what it's worth, I've had Power Ones AND SMAs that have failed shortly after installing them.

I'm surprised that he is getting less power now - I'd be interested to know how he works this out.

 

[jerriais]

Has he got the Power One set up for dual independent MPPT tracking? Not all of them ship with that set as default, there's a tiny switch inside the front cover which I think can be set to IND or PAR (for parallel). It must be on IND in your case.

For the original question the new version of PV*Sol 5.5 can model split systems on dual MPPT inverters but you will have to stump up about £200 for the upgrade.

 

[Gavin A]

my dad has a install split round a chimney. he had a chinese something which cr£pped itself, they changed to a single mppt fronius, i advised him he should have got a dual mppt to allow for the chimney, so he kicked up and they changed it to a power one. he claims he gets less power now, and the fronius was pumping it out. he now has great pleasure in telling me i know nothing (which is fair).

anyway i don't have any hard data for this, as i've got better things to do then check his pv output everyday. but he checks it and is adament he wants his fronius back.

we both agree that the first chinese inverter they put in was a cheap piece of rubbish.

It could be that fronius have a point when you factor in the greater inverter efficiency from higher string voltage, if each array is a relatively low voltage array.

In fact I'm sure they must have a point in some circumstances, but don't agree in others, and we generally try to use higher voltage panels when doing dual string in order to get the system closer to the peak efficiency.

 

[poheZ]

fornius do have switch points at which the mppt efficiency works best but the losses when you are not at these points are very small

i believe these are 320v and 400v on the ig plus range