Another inverter question!

my library has an impressively low draw. The garden doesn't draw much either.

Just funnin' wicha!

Almot wrote:

Unusual approach to energy conservation, I have to say :)

I've been known to come up with all manner of craziness. :B

Whether you use LED or older incandescent, idle draw of inverter is additional to the lights, and can be rather substantial "addition". Idle 1800 mA = 43 AH in 24 hours.

I just turn mine off. No idle draw then.

Something I've wondered about. So if you plug in a 100w light which won't come close to loading either inverter, does the idle current still show and is it still the same as at idle? This is assuming the same efficiency on both.

mena661 wrote:
If you use your lights, don't worry about idle draw. Want to save some juice for the inverter idle? Replace two light bulbs with LEDs.

Unusual approach to energy conservation, I have to say :)

Whether you use LED or older incandescent, idle draw of inverter is additional to the lights, and can be rather substantial "addition". Idle 1800 mA = 43 AH in 24 hours.

Idle draw on your 2000W inverter is about the same as one standard RV light bulb. If you use your lights, don't worry about idle draw. Want to save some juice for the inverter idle? Replace two light bulbs with LEDs. Like BFL said, idle draw is NOT added when the inverter is in use. Idle draw is just that, draw when the inverter is idle.

MP soldier wrote:

So now I have a 2000w PSW inverter powering my LCD tv. Overkill much???

About 20 times overkill.

MP soldier wrote:

I'm just wondering if I should try and barter for a smaller inverter because the 2K watt may be wasting more of my battery than a 1,000 watt would.

If you want to run generator less often - yes.

More rated power almost always means more idle current. This idle current in 2000W inverter will cost you a lot of amp-hours in 24-hr period. You need to make sure that you turn it off when not in use. But sometimes you forget to turn it off or don't want to, because your DW says she'll be doing her hair "soon", or some other reason. Whether idle current adds 100% to the load current or not, it does consume energy when there is no load.

OTH, when there is a load, then efficiency of inverter comes into play, but this loss is more difficult to estimate because it depends on the load and you never know for sure how many hours and at what load you are using it.

If you can barter it for inverter that has both lower idle current and better efficiency, this would be the best solution.

Our TV has a 12V "brick" power supply so I made an adapter cord to feed it off a 12V power outlet in the TT. DVD's can be played on the TT radio and the XM radio is also 12V. DW can charge her phone off the USB port either in my truck or the TT. I don't have a 12V adapter for my laptop but it'll charge off a 75W inverter (barely) or during a generator run.

What @BFL13 said x 2.

BFL13 wrote:
I took some measurements a while ago from different size inverters and I thought we had it all sorted out that the "idle" draw means nothing for this question, which has to do with when loaded. The load is not "added" to the idle.

X2

I took some measurements a while ago from different size inverters and I thought we had it all sorted out that the "idle" draw means nothing for this question, which has to do with when loaded. The load is not "added" to the idle.

What counts is the efficiency curve of the inverter where they seem to peak at somewhere over half their watts ratings. If you max it out with load or underload you get poor efficiency, which translates into higher amp draw to run the same size load.

So to draw the fewest amps on a known load, you want that load to be say 3/4 of the inverter's watts rating.

TVs have a variety of load depending on your picture mode setting, which way overpowers any consideration of inverter size choice. Say you decide to go for the brightest picture on your 32" LED and that makes it 100w. (dull picture might be 60w)

So you would want 100 to be 3/4 of X so that makes X 133w as ideal. If you choose 2000 vs 1000 then obviously the 1000 is closer to 133 but in real life the "loss" in amps between the 1000 and 2000 won't be very much as both are far off that 133.

Which brings you to the time factor. The battery loses AH not amps. If the TV is on all day, a small "loss" can matter, but if you just watch the news and weather and shut it off, you can't get many AH no matter what the amps come to.