AC300: inverter efficiency threshold, no-load consumption

I read a few topics and external articles so I understand an inverter with no load connected still draws power.

Not complaining here, just getting to understand my device better to use it in a more predictable/educated way.

My questions are specific to AC300 as I only found topics about AC200.

Test conditions today: full sun, PV input reading on average 100-120Watts, no load, AC inverter on.

  • 11am, battery is at 50%
  • 2pm, battery is still at 50%

In 3hrs, that’s at least 300Wh generated.
B300 is 3072Wh, so ignoring all laws of physics, my unit generated about 10% of battery equivalent charge.

With AC200’s no-load inverter in mind (forum admin mentions 23Wh), the AC300’s no-load consumption seems higher. Is it correct that it drains about 2-3% of battery equivalent per hour, which is about 100Wh?

Also, the inverters’ 86% efficiency seems quite good. Considering the truck-vs-moped analogy where a simple burger needs to be delivered, I wonder: from what AC load is the AC300 inverters’ efficiency at its top?

Use case: fridge + other 24/7 appliances in a future offgrid configuration.

Ideally a few data points like « efficiency at 50W, 150W, 300W, 1000W, 3000W » would really help me.

Last question: does DC have the same « no load draw » ? I didn’t test the « DC out on with no load » yet.

Thanks in advance for the help!

When performing calculations, do not rely on the Display meter. It is an estimate only and not considered fully accurate.

It is all but impossible to directly measure the inverter power consumption with no load, but yes, assume that all else being fairly equal a 3000W inverter will use more standby power than a 2000W inverter.


Any idea where the sweet spot is to reach a decent inverter efficiency?
It’s more an order of “150W is too low, 600 is close to the max efficiency” than an accurate figure of course.