question

jakudo avatar image
jakudo asked

Choose correct MPPT

Hi,


I have 8x 260Wp panels. Can you please advice the best mppt regulator?

I guess that the best would be 2x SmartSolar 100/20

https://mppt.victronenergy.com/#djE7Y3VzdG9tLDIsMiw1NCwtMTAsNzAsNDgsOC42NiwwLjA1NCw5LjAyLDI2MCwzMC4wMiwtMC4yOSwzNy43OCwxMCw2

it has PV power ration 90% and it would be cheaper than 1x 250/60 with 60% PV power ration

https://mppt.victronenergy.com/#djE7Y3VzdG9tLDQsMiw1NCwtMTAsNzAsNDgsOC42NiwwLjA1NCw5LjAyLDI2MCwzMC4wMiwtMC4yOSwzNy43OCwxMCw2

What do you thing? Any advice what is better?


Thanks,

Jakub

MPPT Controllers
3 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Alexandra avatar image Alexandra ♦ commented ·
@jakudo

We would also need to know your system voltage. 12/24/48?


0 Likes 0 ·
jakudo avatar image jakudo Alexandra ♦ commented ·
It should be 48V as far as I know. 3x Pylontech US3000C
0 Likes 0 ·
Herve RV Nizard avatar image Herve RV Nizard commented ·
you cannot put 2 panels or series of panels on parrallel in a 100/20 as you will probably exceed the other (the hard one) 20a max input.


0 Likes 0 ·
1 Answer
christianf avatar image
christianf answered ·

Strongly recommending to use the XLS for your calculation, which gives much more details than the web calculator. Can be found here: https://www.victronenergy.de/upload/software/VE-MPPT-Calc-4_0.xlsm

7 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

jakudo avatar image jakudo commented ·
So I've tried that excel sheet, however, since I'm a noob in photovoltaics, it didn't give me more information than the web calculator because I don't know how to interpret the details...
0 Likes 0 ·
nickdb avatar image nickdb ♦♦ jakudo commented ·

It escapes me why people insist on first buying panels and then worrying how they will make it all work. The components should be matched properly.

For a 48V system, I wouldn't consider using anything under a 150v MPPT.

There isn't much to go on here but your panels seem to be near 37V, so that would be max 2 in series (on a 100v MPPT) which is a bit close to the where the batteries will want to be, it will work, most of the time, but isn't optimal.

A 150/35 (or 45) would be better but that would want 3 panels in series, so you'd actually want 9 panels.

If you are stuck on the 8 panels, then for 4 in series you would need a 250V MPPT which is actually bigger than you need for those small panels.



0 Likes 0 ·
jakudo avatar image jakudo nickdb ♦♦ commented ·
I agree, it is not the best solution to buy the panels first, however, the price was great (70 EUR/panel - it was from my friend). Yes, 9 would be better from what I calculated. I believe I can buy one more from other friend, ho has 16 of them (they both bought it at the same time in one order), so for him it would be better to have only 15 of them (3*5). It would make sense to buy one from him and then use:
  • 150/45 for installation 3x3 panels in my installation and
  • 150/70 for installation 3x5 panels for my friends installation

Am I right?


0 Likes 0 ·
nickdb avatar image nickdb ♦♦ jakudo commented ·

"Am I right?"

Your maths is sound.


1 Like 1 ·
klim8skeptic avatar image klim8skeptic ♦ jakudo commented ·
A 60 cell 260w panel will have a Vmp of around 31v. 2 series might be enough to charge a Pylontech battery.


A 96 cell 260w panel will have a Vmp of around 50v. 2 series will be enough to charge the Pylontech.

Panel specs are important. If you dont know count, then measure..

0 Likes 0 ·
jakudo avatar image jakudo klim8skeptic ♦ commented ·

Yes, I know the data of the panels. It's 60 cell 260w panel. So I entered them in the calculator and I believe 3 series will be better. The panels have Vmp 30.02, so the calculation will look like this:

https://mppt.victronenergy.com#djE7Y3VzdG9tLDMsMyw1NCwtMTAsNzAsNDgsOC42NiwwLjA1NCw5LjAyLDI2MCwzMC4wMiwtMC4yOSwzNy43OCwxMCw2

All values are taken from datasheet:

GTEC - Poly 6X10 Module Datasheet - Viessmann PV panely.pdf

0 Likes 0 ·
gtec-poly-6x10-module-datasheet-viessmann-pv-panel.pdf (639.1 KiB)
nickdb avatar image nickdb ♦♦ klim8skeptic ♦ commented ·
I was working off the mppt sizing links sent in the original post which have Voc at 37V.

Post the links into a browser and you will see what specs were used to size.

0 Likes 0 ·