Fronius minimum input power


#1

First post, so hope this is the right spot.

I’m looking to install solar in the near future and a few inverters ate being proposed - mainly Fronius. One point which was made about one inverter (ABB) what that it has a very low minimum power requirement before it would start operating (about 80 watts I think) whereas the Fronius requires around 240. Is this level of difference worth worrying about?

Thanks


#2

Hi, yes this it the right spot to ask.you may be confusing the start of the MPPT,s at 80 w with when the inverter starts producing 240 v power. the inverter starts at 1 watt A C power, and the max power point tracking starts at about 80 watts on my inverter.as you can see my inverter started on 15/7/19 at 3 watts please see in the PV ladder find box **Jims maxim jinkos 6625 for a view of my system so you can see what sort of data is averable from a fronius inverter, the live view will show you perhaps the best view of when the inverter starts etc and there is also the extended data for you to look at voltages from the panels in D C volts and watts for each array to see the inverter starting point look here for extended data right hand box Prev Day, date, next day,center under the chart the little square boxes under this ,right hand box is extended data, please feel free to ask any more questions you like about system size and design for your use, Jim


#3

FWIW my Primo starts recording generation data at 12w - my inverter doesnt shutdown completely tho as I have the Fronius Smart meter for recording grid import/export.

https://pvoutput.org/intraday.jsp?id=4988&sid=27734


#4

You are correct - inverters have a value (measured on the DC side) at which they will turn on. This is nothing to be concerned about - either value is just fine, they are not producing much AC power at those input values, but if that is something you want (to be able to produce tiny amounts of power) then the lower value is the one you want.
If you can post the model numbers of each inverter I can confirm the numbers for you… eg


shows the ‘startup voltage’ is 200vdc, but adjustable from 120-350vdc.

Ideally - get one which will allow you to get the most of your roof - dual mppt is ideal if you have multiple roof pitches which will get sun - allowing you to add more panels later…

my advice to you - is to make sure you have no shading of your panels. This is far more important than the startup voltage of your inverter.
Building a system with shading will gravely reduce the ability to produce power (unless you pay extra for sub string tracking devices).