StecaGrid 2010+

[Toonlad]

couple of questions on these, we just had a client drop these on me to install. Just reading the tech on them, im a bit unsure of the master slave scenario on them.

So far i see the master can have 2 strings fitted, to a max input voltage of 410 v DC. Now we have an array of 16 panels, so obviously i have split these into 2 x 8 panel strings. My thinking 410v per input.Or is it 410v for both combined.

My question is do i have to put one string in the master and other in the slave. Or do as i suspect use both on the master, and keep the slave disconnected.

Any help on this would be appreciated. Just not clear cut in my head. lol

stc below

235w panels x16
Voc 37.0V
rated voltage 29.5V

Isc 8.54A
rated current 7.97A

Regards
Steve

 

[VMan]

Do You have the 2010+ Master & Slave?
If so effectively you have 2 inverters, each with 2 Mppt.

When I used this setup on a 16 panles system before i had 8 panels on each string, and 1 string per inverter(1 on master, 1 on slave)

If i remember right you have to link both + inputs together if only using 1 string per inverter.

Make sure the AC is connected properly, its a right bugger on them inverters.

 

[VMan]

Heres a pic, ( Don't diss the connectors that can get knocked off, was a sub contractor job and they insisted on it!)

The +ve are linked together on both master and slave inverters

 

[Toonlad]

Thanks for the replys VMan. As you said it is a master and slave, it seems a bit of a faff on, which is not very clear in the tech manual. So i just put one string on each and put a link between the the positives only.

Would it work with master only and use both connections, or is the whole inverter whether it be master or slave limited to max input voltage. Or is it limited to max input voltage perinput on the invertor.

Looking at the photo im guessing its the invertor limited, hence the need for the slave also.

 

[VMan]

Just has a quick look at the datasheet, you have max 450V per inverter ( so 410 on the master and 410 on the slave) you will need 2 strings. (8 panels on each) once string on the master and one string on the slave with +ve(if i remember correctly) linked on both master and slave.


use the above to link +ve ( think its called a MC4 T splitter)

Think about the inverters as 2 separate inverters, each for 8 panels but sharing the same display & AC input (on the master) so the figures on the data sheet are for each inverter, i.e 450V Mppt for master and 450V mppt for slave also, same with current ect. This make sense??

They ae quite noisy too when they get going.

 

[Toonlad]

Now it makes sense use the two tees to link the positives up. Brilliant mate, that helps me loads i need to get some splitters tomorrow i guess, since i have one to do then. Just as well i asked or i would be in the 5hite when it wont work.

Cheers

 

[VMan]

remember to get the AC connected properly, it is seriously a bugger. apparently people end up shoving the cables in the terminals and think that right as they cant figure out how they go in. they do make a solid connection. i will pm you my number if you like and ill explain it when your doing it??

 

[Toonlad]

That would be handy mate, nice to have some reassurance even if its someone laughing at you, then you now its definately wrong lol

 

[newyear11]

Thanks for the replys VMan. As you said it is a master and slave, it seems a bit of a faff on, which is not very clear in the tech manual. So i just put one string on each and put a link between the the positives only

 

[Toonlad]

@ VMan big thankyou for the info you supplied me on here. The job went really well today. So thankyou very much.

ATB
Steve

 

[VMan]

No problem.

 

[sharpener]

Sorry it's a bit late, didn't spot the thread until now.

But you don't need the splitters unless you are (a) putting more than 8A into each inverter (which you are not) or (b) need to use the two separate MPP trackers provided in each inverter. No harm done though, by sharing the current between the inputs you are reducing the stress a bit => maybe slightly cooler running, longer life.

I have a very similar setup. Can thoroughly recommend the StecaGrid Connect web interface card.

 

[VMan]

When i was installing my first steca grid, i got onto there technical help and they said if you are not using both trackers on the inverter you must use a splitter, this is what i did and has worked since.

 

[sharpener]

they said if you are not using both trackers on the inverter you must use a splitter

I hesitate to differ but their own manual says on p. 38 the following:

"On each StecaGrid there are 2 positive and 2 negative sockets in total for connection

of the modules. Each input has its own MPP tracker.
When only one input on the inverter is used the module string must be connected to the right-hand sockets (input 1).
Mixing up the positive inputs (e.g. + from string 1 to + input 2) within the same inverter will not affect the operationability of the inverter. This is will however also cause the inverter input numbers shown on the display to be the wrongway round. To prevent possible confusion when looking for a problem the correct connection to both inputs should therefore be made.
When PV modules with a current of more than 8 A are used, both inputs can be connected in parallel using a special T-splitter, also called Y-plug (not included in the standard package). This way, modules with a maximum (MPP) current of 16 A can be connected. A T-splitter is not necessary for a negative connection because both inputs are already internally connected in parallel. Just connecting either of the two inputs with the module string will suffice.​

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