120v LED vs CFL vs 12v Lamps Results
Following up on another thread discussing using inverter and 120v lights with LEDs or CFLs. I have been using a CFL for a reading lamp for some years, but now have an LED bulb to make a comparison. ...
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It does make a difference which inverter you use, but it also makes a difference if you use it "whole house" to get at the 120v circuit the lights are on.
I have my 3000w inverter up by the batteries and I plug the shore power cord into it to get whole house. There are other ways to do all this, but I don't know if another way would be any better for DC draw. I tried having two inverters with one small one for smaller loads, but it turned out that it was a much easier set up to just use the one big one for everything.
I have some figures to show what is really going on with the draws on the battery with the 3000w inverter:
Trailer at home, not plugged in, nothing on except LP alarm and stereo memory. Trimetric used as the ammeter:
- base amount- -00.2 amps
-turn on the 3000w inverter, but no load--Tri says -00.4 amps, so the inverter added 0.2 amps
Now plug in the shore power cable to the inverter, but no 120v things on in the trailer.
- Tri says -00.7 amps. So the power centre itself is a 120v load on the inverter by 0.3 amps DC ( I did one breaker at a time and it went up with each breaker. In other testing I believe I found that GFCIs are "live" even with nothing plugged into them, so that might be part of it--there are two in the trailer.)
So the inverter itself is only 0.2a of the 0.7a before turning on a light. I did the same with a 150w inverter and got the same results except it was only 0.1a itself.
So yes, the 150w inverter was only half the draw of the 3000w inverter--but half of what? 0.2a. Using the big inverter "costs" 0.1 amp. I can afford that! :)
Next issue is how the inverter is connected to the batteries. The 3000w is up by the batts on short, fat wire. The 150w inverter goes in the Winegard 12v socket in the trailer on long, thin wire.
The result is that with more of a 120v load, you get more DC current draw, and line loss with the small inverter as connected shows up.
In that test (not the same as the test in this thread which was while camping so the standing DC draws are more--but the lamps came out the same of course) the CFL lamp added 1.0 amp to the DC draw in each case. (Tri measures to only one decimal place though)
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EDIT--- (for those paying attention) Not quite--the CFL added more to the 150 than for the 3000 even for that small load's current due to line loss. Both showed total 1.7 amps, which means the 150w at 0.1 less itself, made the CFL 1.1 instead of the 1.0 with the 3000. Then---
------
But with a 60w regular bulb in the 120v light, that made the total DC draw 5.8 amps with the 3000w and 6.5 amps with the 150w inverter. Line loss more obvious there.
So there is more to it than just the inverter size!
(If the 150w inverter were installed up front next to the batteries, I imagine there would be little difference since there would not be such line loss as when using it from the Winegard 12v socket way inside the trailer.)
I have my 3000w inverter up by the batteries and I plug the shore power cord into it to get whole house. There are other ways to do all this, but I don't know if another way would be any better for DC draw. I tried having two inverters with one small one for smaller loads, but it turned out that it was a much easier set up to just use the one big one for everything.
I have some figures to show what is really going on with the draws on the battery with the 3000w inverter:
Trailer at home, not plugged in, nothing on except LP alarm and stereo memory. Trimetric used as the ammeter:
- base amount- -00.2 amps
-turn on the 3000w inverter, but no load--Tri says -00.4 amps, so the inverter added 0.2 amps
Now plug in the shore power cable to the inverter, but no 120v things on in the trailer.
- Tri says -00.7 amps. So the power centre itself is a 120v load on the inverter by 0.3 amps DC ( I did one breaker at a time and it went up with each breaker. In other testing I believe I found that GFCIs are "live" even with nothing plugged into them, so that might be part of it--there are two in the trailer.)
So the inverter itself is only 0.2a of the 0.7a before turning on a light. I did the same with a 150w inverter and got the same results except it was only 0.1a itself.
So yes, the 150w inverter was only half the draw of the 3000w inverter--but half of what? 0.2a. Using the big inverter "costs" 0.1 amp. I can afford that! :)
Next issue is how the inverter is connected to the batteries. The 3000w is up by the batts on short, fat wire. The 150w inverter goes in the Winegard 12v socket in the trailer on long, thin wire.
The result is that with more of a 120v load, you get more DC current draw, and line loss with the small inverter as connected shows up.
In that test (not the same as the test in this thread which was while camping so the standing DC draws are more--but the lamps came out the same of course) the CFL lamp added 1.0 amp to the DC draw in each case. (Tri measures to only one decimal place though)
------
EDIT--- (for those paying attention) Not quite--the CFL added more to the 150 than for the 3000 even for that small load's current due to line loss. Both showed total 1.7 amps, which means the 150w at 0.1 less itself, made the CFL 1.1 instead of the 1.0 with the 3000. Then---
------
But with a 60w regular bulb in the 120v light, that made the total DC draw 5.8 amps with the 3000w and 6.5 amps with the 150w inverter. Line loss more obvious there.
So there is more to it than just the inverter size!
(If the 150w inverter were installed up front next to the batteries, I imagine there would be little difference since there would not be such line loss as when using it from the Winegard 12v socket way inside the trailer.)
