Energy Matters Forums

[poida]

Hi Kev

I too have a Tristar 60A MPPT. The printed manual that came with my unit (bought about 15 months ago)
shows "MS-ZMAN-TSMPPT-01 v02 12/2009". This printed manual applies for the 45A and 60A models.
It has the same values in fig. 8-7 as yours, 60A to 140V input.

In the past I have downloaded two different versions of the manual for the TS-MPPT-60
one "MS-000946 v05 12/2013" has 60A cut off at 115V (manual applies for 30A, 45A and 60A models)
the other "MS-ZMAN-TSMPPT-01 v04 03/2010" has 60A cut off at 140V (manual applies for 45A and 60A models)

I suspect that recently Morningstar have changed the design of this product to allow the addition
of the 30A model. I have no idea what year my unit was produced and also wonder if it's going to be effected by the 115V max current cut-off.
The unit's website (live data) shows "TriStar-60 MPPT Controller v1.1.12
Serial #13460057 Server v5.19" How does this compare with yours?

Peter

[kemills1]

Hi Peter,
mine's showing

TriStar-60 MPPT Controller v1.1.12
Serial #12281058 Server v5.19

It seems mine in an earlier unit than yours looking at the serial number...

What Voc are you seeing and what power is your array. I'm assuming you don't get the alarm.

Kev.

[Gordon-Loomberah]

It might be worth contacting Morningstar about firmware- there may be a version that is suitable to make it work as desired.

[poida]

Hi Kev

today in Melbourne there is sun. No really, there IS sun today.
My system details:
3 kW array, wired in 4 strings of 3 panels in series. Panels are Suntech 250W 60 cell units
Panel specs:
Vmp 30.7V
Imp 8.15A
Voc 37.4V
Tristar 60A mppt of course
a worn out 48V battery @ 200Ah running a 3kW Victron inverter/charger

Today at 9:30 I am getting 20A at 90V DC from the array, this is converted to 32A at 54V at the battery
by the Tristar. Voc is 110V, and Vmp is 90V. So no problems from any over voltage.
I have never seen Voc over 110V or so. Last December for instance I saw typical values of
37A at 72V (Imp and Vmp respecively) with Voc peaking at 108V at the array and this was converted to
47A at 53V at the battery. No alarms raised by the Tristar.

See http://poidapie.ddns.net/mppt/m10.php for live data (all my own work, custom hardware, php and C code)

Peter

[Ray]

Hi Kev,

I have the same problem as you i think and i was wondering what the outcome of your array rearrangement was ?

I have a 48V system with 3 strings of solar and i see about 1100W max if i am lucky with a Voc of 128Vdc. I see the fault almost every day and i am not able to see why, since i am lucky to ever see close to 20amps going into the battery i don't see how this should be even happening ?

My understanding is get the input voltage as high as possible so it performs at max efficiency ?

My panels should put out about 1600 watts but they a very sad (mixed sizes and one is broken) so i was not to unhappy when the best i have seen is 1100 watts but if the charger is derating then maybe the panels are not that bad after all ?

Thanks
Ray

[Gordon-Loomberah]

Maximum efficiency with MPPT charge controllers happens when your rated PV input is ~10V above your maximum charging voltage. It decreases significantly if you go too high, near the CC's limit (assuming a relatively low battery voltage), and drops off even more if you exceed the max input voltage and suffer de-rating.

[Ray]

Sounds like i would definitely benefit from lowering my 128Voc down to 85Voc (2 panels instead of 3 in a string)

But still does not explain why i get the fault (High Array Voltage Current Limit) ?

Ray

[Gordon-Loomberah]

What panels do you have, and how are they arranged?

[Ray]

It is a bit of a mess but i have 3 strings

String 1
3x200 Watt 45.53Voc

String 2
3x175 Watt 44.5Voc

String 3
3x175 Watt 44.5Voc(1 panel in this string has smashed glass)

Has been a long time since i looked at the specs and must say that is a lot higher than i remember,

so maybe the voltage i am seeing in the tristar is the result of being derated hence why i cant pinpoint a common cause of this fault.

Has been a few years now but i remember this fault occurring when i had only String 1 connected.

Ray

[Gordon-Loomberah]

You could be applying 140V or more to the Tristar on cool sunny mornings.

Can you hook them up as 4 strings of 2, and leave out the broken panel?
200-200
200-175
175-175
175-175

It will mean one of the 200W panels will only put out as much as the 175W it is in series with, but that wont be a huge loss.