shading question

[BruceB]

It is the default, so if it has not been changed then yes it is correct. Note that you also have to select 'installer' when you log on for that code to be useful.

 

[babba]

It would be safer to ask your installer as he may blame you if things go wrong and to go messing may void your guarantee...

 

[moggy1968]

I've not used the SB3600TL, but am rather suprised a dual tracker inverter doesn't come set up for dual tracking, that does seem to rather defeat the object!

 

[Gavin A]

I've not used the SB3600TL, but am rather suprised a dual tracker inverter doesn't come set up for dual tracking, that does seem to rather defeat the object!

that's not what we're referring to.

It will automatically do dual MPPT if something's plugged in to both the A and B inputs. Optitrac global peak is an additional function to help it cope better in shaded conditions. Essentially it just means the inverter will sweep fully up and down the voltage curve ever few minutes to check if there are any better peak points away from the point on the voltage curve it's occupying. In shaded conditions the peak point can suddenly move to being further away on the voltage curve from the current position than the standard MPPT with track, meaning the inverter can get stuck at a false peak point on the voltage curve.

or f that didn't make sense, SMA have a couple of decent info sheets about it on their website.

 

[moggy1968]

ah, ok, thanks for that.
Why would you not want that as the default action though?
Surely then it would cope better with changeable shade due to cloud etc?

 

[Gavin A]

it also causes losses in the system while it's doing it's searching up and down the voltage range thing. IIRC it's of the order of 0.1% or so losses, but still not worth it in situations where there's no shading.

eta and it's not fast enough for clouds, it only does the sweep every few minuts (we usually set it to every 15mins) it's aimed at stuff like hard shading from chimneys etc. And basically enables the system to operate with the bypass diodes more effectively.

btw, I suspect this is why it works in solving the apparent compatibility issues between Sanyo panels and SMA HF inverters, as the voltage on the Sanyo panels is so much higher than standard, that one string of cells (or certainly 2 strings at once) being knocked out by the bypass diode would take the MPP outside of the MPPT's standard tracking range.

 

[moggy1968]

top info chaps, cheers:grouphug:

 

[wstevew]

BTW Global Peak can be enabled/disabled in User mode on Sunny Explorer, but there is no setting for the cycle time in User Mode

 

[Gavin A]

BTW Global Peak can be enabled/disabled in User mode on Sunny Explorer, but there is no setting for the cycle time in User Mode

I had a feeling that might be the case, but almost never log in as user. Thanks for the info.

 

[provr6]

Is it possible to switch between user and installer or are you stuck with what you login in at first use? I've read the password for users is 0000 and that the default scan time is every 6 minutes.

I do have chimney shading for a few hours. Is there likely to be any difference between a 6 min and 15min scan?

As the sun goes off the panels at the end of the day it shadows them one by one, would it benefit this situation?

Finally is it possible to set a time range for the optitrac to be on as you wouldn't want in on in full sun but equally you don't want to have turn it off manually.

 

[babba]

Stupid question time... MPPT on the power one resets every couple of seconds I cant remember off hand how many would this make any difference or is it on the same subject we are talking about...???????

Does anybody how often SMA MPPT resets itself..???

 

[screwdriver]

Probably but the inverters rated efficiency is likely to include this and so at least you can compare the overall efficiencies.

The power one has a user selectable scan interval, so I am not quite sure how that relates to the claims about very fast tracker changes ' The high speed MPPT offers real-time power tracking and improved energy harvesting. The transformerless operation gives the highest efficiency of up to 96.8%.'

unless this setting does nothing useful!

 

[babba]

I had a data sheet on power one mppt reset something like every 1.5 seconds to cope with moving clouds and was wondering if optitrac was just another name for the same features. I know sma have mppt but it all seems to do the same thing makes the most of incoming light and allows the inverter to reset to make the most of it...I dont know how often the sma MPPT resets..
Seems hard to get hold of that info and they dress it up to make one inverter sound better than the next..