Hi,
I am wondering how much power the inverter takes to run itself?
and as such how much extra power a SMA 2500w inverter takes to run itself compared to a SMA 1700w inverter?

I say this because Im wondering whether to buy the SMA 2500w inverter incase I want to possibly add extra pannels in the future.
I cant afford the extra pannels at the moment but maybe in the future I may, but if the inverter consumes alot of extra power
it may not be worth it. I am not sure when or even if I will add more pannels and ,maybe even I wont, so is it going to be a problem if I have the 2500w inverter and only have 1640w going into it from the pannels?

Ive tried to look at the spec's on the inverters but its not clear what power they actually consume themselves to run....

Any help greatly apreciated....cheers

good inverters should consume 2watts up to 5kw

.25W standby, 0W night time.

Bigger unit, more efficient than smaller unit, even at 1/2 power. Get the bigger one.

Most grid tied inverters run off your solar DC supply, thus they will consume no power at night. Whilst operating, they will generally consume 0.5 - 2 watts as mentioned above.

I would be cautious about trying to add panels in the future. First off, panels are changing all the time, and you would need to ensure that you could add the same panels later. Mixing and matching won't work. Second, the panels de-rate over time, so the characteristics of new panels versus old panels (assuming they are the same model) could be different enough to make them incompatible. I would suggest oversizing your array versus your inverter (about 125%), and adding a new system later with a separate inverter. Good luck and enjoy the sun.

TonyB wrote:Most grid tied inverters run off your solar DC supply, thus they will consume no power at night. Whilst operating, they will generally consume 0.5 - 2 watts as mentioned above.

Actually, they run off the AC--that is why the status light can stay on all night. Notice that when you can turn the DC off the display etc will still be on. This allows the inverter to be troubleshot in the event there is an issue.