LFP Battery Bank runs the air conditioner!

[rich2468]

Hey Rick,
Can you confirm your inverter no-load power usage? The 70 watts sounds a lot higher than I'd expect.

I can't recall what you shared was the continuous and peak rating of your inverter, but I thought most 3000W/6000W pure sine wave inverters used about 1/2 those watts under no-load now.



Rich and Lynn
2021 2922KB

[Wavery]

Originally Posted by rickst29

This one is the best choice for a "30 Amp" trailmanor:
https://www.bestconverter.com/PD-510...010Q_p_28.html

That's the same ATS that Will Prowse suggested, under a different name.

[Shane826]

Can someone explain why an inverter uses ANY watts under no load?

[rickst29]

Originally Posted by Shane826

Can someone explain why an inverter uses ANY watts under no load?

The entire DC side charges up, and the AC waveform generation gets done and provided at the outputs. Al the control circuits are active, and all the monitor interface signals are activated as well.

[Bill]

[QUOTE=rickst29;157446]
[T]he AC waveform generation gets done and provided at the outputs. All the control circuits are active.[QUOTE]

In addition to Rick's points, all inverters start by generating a stairstep approximation to a sine wave. The more stairsteps, the closer the approximation, but don’t let the hype about “pure sine wave” fool you - it isn’t quite true. There are still steps. Then at the output, there is a filter circuit that smooths the steps by passing the current associated with their edges directly from the hot side to the ground side. This “edge current” is wasted, but it gets the approximation still closer to “pure”. And the filtering happens even when there is no load on the inverter output. I would bet that this “edge current” is part of the static load.

Engineers and audiophiles will recognize the term “harmonic distortion”.

Bill

[Shane826]

That seems kinda wasteful…

[rickst29]

Originally Posted by rich2468

Hey Rick,
Can you confirm your inverter no-load power usage? The 70 watts sounds a lot higher than I'd expect.

I can't recall what you shared was the continuous and peak rating of your inverter, but I thought most 3000W/6000W pure sine wave inverters used about 1/2 those watts under no-load now.



Rich and Lynn
2021 2922KB

IIRC, my coulomb counters showed a a total change in current of about 5A between 'Inverter ON' and 'Inverter OFF'. (Voltage was about 13.3V). But there may have been other factors at play - variable loads from the DC powered fridge and perhaps some variability in current being supplied from the Solar Controllers.