Inverter energy usage when idle

[sailorchic34]

Originally Posted by a64pilot

How do you increase DC voltage? I thought that took a transformer, and DC will not transform, .

DC to ac inverters work by using circuits to generate a sine wave (or MSW). At that point it's no longer DC though it starts as DC. then it's transformed to 120V (60v each leg) via transformer or a buck converter.

More manufacturers are going to non-transformer inverters as it saves a few dollars. BUT from a what works best and safest, the transformer type inverter will prevent more transients and will protect both the 12V and 120V sides far better. This as the both sides are decopled at the transformer.

[TheThunderbird]

Having weak batteries, I switch it off by night

[alley]

I just installed the Xantrex 1055 in my own boat. Love it.

Yes, it draws power with no load attached. Not much, but some. I haven't measured mine under no-load conditions. At the very least, you're powering up some LEDs in the display along with the logic and control circuits inside the unit. I would guess that the "snooze" mode is something less than 1 Amp and that the idle mode (inverter on and no load on the output) is somewhere around 2-4 amps. The only sure way to turn off the unit is to disconnect both the DC and AC input.

Yes, transformers with no loads on the output also draw power. Again, not much, but enough to measure.

According to the manual, the Xantrex 1055 has a maximum efficiency of 87%. Maximum efficiency is usually around 90% of full load. Below 50% of full load, inverter efficiency drops off sharply, sometimes getting as low as 30-40%. The good news is that the output is a pure sine wave, making it much kinder to the AC loads you plug in downstream.

One unfortunate feature of the Xantrex 1055 is that if AC power is suddenly available, the unit will turn on and try to charge the batteries (if connected), and then if the AC power turns off, the unit will remain on until the battery voltage drops below the limit that you can program in. This could be an issue if you leave the boat unattended for a long period (days or weeks), as this mode of operation virtually guarantees that you will have dead or deeply discharged batteries when you get back. For this reason, I would strongly suggest that you have an on/off switch for the AC supply to the unit, along with a disconnect in the positive line going to your battery bank.

[Pizzazz]

Originally Posted by donradcliffe

Which is why I use a 150 watt inverter to run the computer and charge the cell phone, and only turn on the big inverter when I need big power.

I do exactly the same. TV, laptop, phone charging all comes from the small inverter as it is more efficient and silent. For example, my 32" TV draws 6A DC through the 1500W Xantrex and 4A from the 140W solid state inverter.

Interestingly, I cannot power my stereo through the 140W inverter. When the subwoofer kicks in the inverter cuts out.