inverter power consumption

[fabricator]

What model is it?

[defed]

sorry, i thought they only made one mppt charge controller.

xw-mppt60-150

[fabricator]

Cool thanks.

[zvizdic]

This one is 1.5w in Saving Mode

http://www.psui.com/pdf/75-1000-0001.pdf

[ChrisOlson]

15-18 seconds to bring it out of "sleep"?  So in the middle of the night my wife turns on a light and stands there tapping her foot on the floor waiting for the inverter to boot up?  That would go over like a lead balloon.
--
Chris

[wooferhound]

the list of parasite draws is as follows:

phone:  2w
clock radio:  1w
dvr:  5w
vcr:  3w
dish receiver:  10w
OTA tuner:  5w
tv:  1w
cable modem:  5w
router:  5w

You should run a DC line from the battery . . .
I have a 150 watt solar power system and I don't use an inverter at all with many of the things in your list being powered straight off of the battery at voltages ranging from 11.5 to 14.7. The equipment doesn't seem to mind running that way at all.
My list of 12vdc appliances is . . .
Portable TV
OTA Tuner
4 port LinkSys router
Cable Modem
Amp for Computer Speakers
Cell Phone Charger
Room Fans
4 individually switchable lights
Clock Radio

I also have a 9vdc regulator that is running my
Cordless Phone Charger
Police Radio Scanner, or anything else that little 9v plug will go into

Many of these things are only turned off when we are asleep. I realize this will not eliminate parasitic loads to use this DC method, but you will remove the losses caused by running these items through an inverter, and the loses caused by the WallWart transformers they need to operate.

[ChrisOlson]

the list of parasite draws is as follows:

phone:  2w
clock radio:  1w
dvr:  5w
vcr:  3w
dish receiver:  10w
OTA tuner:  5w
tv:  1w
cable modem:  5w
router:  5w

A lot of those parasitic draws could be simply eliminated too, and this is one big difference between off-grid folks and people that have grid power.  Another big difference is like what happens when the power goes out like it did in California, but that's another story.

For us, we have zero parasitic loads.
Phone - don't have one
Clock Radio - runs on AA batteries
DVR - don't have one
VCR/DVD player - turned off with power strip unless we're using it
Dish Receiver - turned off with power strip unless we're using it
OTA tuner - don't even know what it is, so we don't have one
TV - turned off with power strip unless we're using it
Cable Modem - satellite modem for us but turned off with power strip when we're not using it
router - turned off with power strip unless we're using it

Total parasitic draw = zero watts.  The inverter goes into search mode unless the 'fridge, freezer or furnace blower (winter time only) is running.  Folks with grid power think they can't do without this stuff.  Then when the power goes out their whole life comes to a grinding halt.  Folks who don't have grid power live without this stuff every day (for the most part).  If you really want to use less power and are concerned about inverter power consumption, then get rid off this stuff.  Believe me - life itself does not depend on having all this electronic stuff sucking you dry and your quality of life may actually improve once you get rid of it.
--
Chris

[defed]

i've tried clocks running on AA's and every one i tried is a battery hog.  i'd rather pay 12 cents a kwh than keep buying/recharging batts.  now, if i want to run it off of my solar/wind...i should figure something else out.

realistically, the TV, vcr, over the air (OTA) tuner and dish could be switched off w/ a power strip when not being used.  the DVR will lose it's memory if powered off too long.  don't ask me how an electronic device in this era can't keep a memory.  i sometimes record when i'm not home, so obviously needs power to do so...the phone obviously stays on, and the router/modem need to stay on because i have a wireless network to my parents house.  so even if i'm not using it, they might be.

can i live w/o this stuff?  i'm sure i can, and if i HAD to i would.  i've already cut my power usage by at least 30% in a year.  i'm sure i could cut it in half from the original if i really had to.

[defed]

i'm having trouble finding a small (1000 ish watts) inverter that is hard wired on the AC side.  they all have receptacles.  i'd like something a little less expensive than the xantrex prosine, as i may grid tie in a year or 2, but pickings look slim.

[ChrisOlson]

i'm having trouble finding a small (1000 ish watts) inverter that is hard wired on the AC side.  they all have receptacles.  i'd like something a little less expensive than the xantrex prosine, as i may grid tie in a year or 2, but pickings look slim.

That's because a 1,000 watt inverter is 8 amp output and manufacturers typically aren't going to bother with hard wiring a 8 amp service
--
Chris

[defed]

i figure it would be cheaper for the mfg to offer hard wiring, but as you say, it's probably not a very common application for a small inverter.  even at 8 amps, that's still about 3x more amp draw than i would have at any one time...which is why it's not really practical for me to go for a bigger inverter.

[pyrocasto]

Why not just use a plug cord and hard wire yourself? That's what I figured I'd do to start off a few breakers on my 2500w inverter which also has plug outlets.

[defed]

i'm not sure that routing a wire from the receptacle on the inverter to the transfer switch is NEC compliant.

[WindriderNM]

Most of these inverters can not be hooker to be NEC approved. If you try to connect to a grounded system you will let out the magic smoke and it won't work any more. Keeping the magic smoke inside electrical equipment is very important.

[ChrisOlson]

i'm not sure that routing a wire from the receptacle on the inverter to the transfer switch is NEC compliant.

NEC has no problem with that.  It's nothing but a backup power source like a generator.  Most standby generators have a power cord with a plug that is hard-wired to a transfer switch.  Whether or not the inverter is UL Listed and compliant with NEC is another matter, if it don't have hard wire capability.  There are mobile inverters and residential.  Mobile inverters have plugs and no hard wire capability.  Residential inverters always have hard wire capability.

Do not use an inverter designed for mobile use for a residential application.  There is no inspector I've ever met that will pass one if you live on-grid.  If you're off-grid you can get away with anything.
--
Chris

[rossw]

Most standby generators have a power cord with a plug that is hard-wired to a transfer switch.

Here's how my "house" plugs in. This socket is on the wall in the generator room:


With the plug plugged in:


The end of the plug:


(Eagle-eyed readers may notice 2 cables comming out the back of the connector in my hand - that's because the photographed connector is actually for my backup diesel generator. It is 8KVA but only has two 10A sockets. A 10A socket can only (legally) supply 2.4KVA  In the event I need to use this backup genset (I never have yet), BOTH cords will be plugged in and turned on, which should let me safely take 20A (5KVA) which I couldn't do up just one cable/connector)

There is no inspector I've ever met that will pass one if you live on-grid.  If you're off-grid you can get away with anything.

My place was all done to all local and national codes. There are a lot of things that were not necessary but that were done purely in order to ensure total compliance, even though not connected. Part of that was for insurance - even though it wasn't grid connected, we didn't want to give them any loopholes for things "they" considered were "wrong".

[ChrisOlson]

We have similar setup, although we have a Ronk manual transfer switch



The house and shop service panels are connected to the load lugs in the transfer switch.  The inverters normally feed 240 volt power to the load with the switch in the "On Line" position.  The inverters control the generator and start it as needed to meet heavy loads, exercise it once every 30 days if it hasn't run in the previous 29 days, or it starts if the batteries get below 24 volts for more than 2 hours.  The inverters have auto-transfer switches inside them that switch the loads over to gen power, plus it then uses the internal chargers in the inverters to charge the batteries.  When the charge cycle is done it shuts the gen off and switches back to battery power.

The transfer switch, when switched to "On Aux" disconnects the gen power to the inverters and switches it over directly to the load.  The only reason the transfer switch is there is to completely bypass the inverters, allowing me to disconnect the DC power and service batteries or inverters without loss of power to the house and shop.

Our generator is a Generac EcoGen and it has a plug to hook it up.  It's a four blade twist-lock plug.  It has two "hot" legs (120/240 split phase), the neutral and the ground.  The inverters have the same output with two "hot" legs, neutral and ground.  The service panel is where the ground rod is driven and the neutral/ground bond is at the service panel so neutral and ground are separated at both the inverters and the genset.

This is also done all to code, and has been inspected and signed off by a Certified Master Electrician.  But all this stuff is UL Listed and if you try to power a residence in the US that has a grid service with a non-UL Listed inverter it will not pass inspection.  For off-grid you can probably use one if you don't have to pass a code inspection.  But even off-grid, if it has to be inspected, it won't pass.  But the plug part does not make any difference other than the fact that you cannot run the average residence on 15 amp wall plugs.
--
Chris

[defed]

my setup will be installed the same as a backup generator.  i forgot about the fact that many of those are 'plugged' in.  i will have a transfer switch, so technically, the solar is still 'off-grid'.  i am (trying) doing everything per NEC, and i've already talked to the inspector to clarify some things that i can and can't do.  i don't believe that i need an inspection for what i am doing, but i am getting one because if i grid tie in the future, it should make things easier that everything i already did was inspected.

i have an small inverter i was messing around w/ on my temporary setup.  the chassis and ground on the AC outlet show continuity.  the negative battery cable and the chassis do not.  this is the configuration that you wish to avoid?  the chassis should be isolated from everything, correct?  in my system, the negative cables from PV and battery are not grounded themselves.  the controller has a GFI, so it gets grounded there and only there.  i still have to bond all metal boxes, the controller itself and inverter chassis on the DC side, but nowhere should the negative cables themselves go to ground.   so this is where i see the inverter chassis and AC ground terminal being bonded internally being a problem.  i certainly don't want to let out any magic smoke.

while i can't run my entire house on a 15 amp receptacle, with what i am doing at this point, 4 amps is actually enough.

[ChrisOlson]

so this is where i see the inverter chassis and AC ground terminal being bonded internally being a problem.

I don't see where that's a problem, as that's normal.  If it was a hard wired inverter with no outlets on it that's where the ground goes - to the grounding bar on the chassis in the AC conduit box.  Just like this - you can see the green wires going to that grounding bar and the white wires go to the neutral bars.



--
Chris

[defed]

i guess what i am getting confused on is what you referred to earlier as 'floating neutral'.  i had read in a cpl different places that if you don't have the inverter grounded properly (something is bonded to chassis that shouldn't be, etc) it wouldn't be good.  in my case, i know i don't want my negative on the DC common to the chassis, as i need to keep the negative ungrounded (gets grounded in the controller only).  then i got to wondering...NEC wants the DC grounding conductor and the AC grounded conductor using a common grounding electrode...so if the chassis is not common to the DC negative, but is common to the AC ground, it all goes to the same ground electrode anyway.

 

[ChrisOlson]

i guess what i am getting confused on is what you referred to earlier as 'floating neutral'.  i had read in a cpl different places that if you don't have the inverter grounded properly (something is bonded to chassis that shouldn't be, etc) it wouldn't be good.  in my case, i know i don't want my negative on the DC common to the chassis, as i need to keep the negative ungrounded (gets grounded in the controller only).  then i got to wondering...NEC wants the DC grounding conductor and the AC grounded conductor using a common grounding electrode...so if the chassis is not common to the DC negative, but is common to the AC ground, it all goes to the same ground electrode anyway.

That is correct - the DC system ground is connected to the same ground as the AC system ground so all the grounds in the system have the same potential.  The inverter chassis is connected to that same ground.

Where the issue comes in with a floating neutral is in the neutral/ground bond.  There can only be one in the system, and that is at the service entrance - in your case, the grid service.  You can not use and inverter with a floating neutral because it will blow and let the "magic smoke" out of it if you hook it up to meet code for a residential backup or prime power unit.  This is because the neutrals of the system are connected to the ground at that bonding point.  Power flows in the neutral under normal conditions.  Power never flows in the ground unless there's a fault.

You can't hook a floating neutral to the ground ANYWHERE or the inverter will blow.  The other issue is that if you wire a service for an inverter with a floating neutral you can't use a single pole breaker in the service panel for 120 volt.  If you do you can flip the breaker off and all it does is kill one 60 volt leg - the neutral leg is still "hot".

Inverters with a floating neutral are for mobile use only.  They are designed that way because you can accidentally come in contact with a "hot" conductor, or use a power tool standing in a mud puddle, and you won't get a shock because there is no path to ground thru you.  However, in the US the four wire split phase power is the only thing that meets code for a single phase residential service - two "hots", a neutral and ground.
--
Chris

[defed]

ok, let's see if i have this straight...

AC main service panel has neutral and ground bonded.


main panel to transfer switch:
white and green from transfer switch go to the neutral and ground bars in main panel.  red and blacks of transfer switch go to main panel breakers and loads.


inverter to transfer switch:
input to transfer switch has 4 wires, 2 line (240v capable), white and green.  since the inverter is only 120v, i will have 3 wires out.  tech support for the transfer switch said i could pigtail my 120v from inverter to both lines of transfer switch to give 120v to all its breakers (has 2 bars of 120v where some of its breakers can be 240v if wired from a 240v source).  so, hot from inverter to 1 (or both) line of transfer switch input, neutral from inverter to white transfer switch input, ground from inverter to green transfer switch input.  ground on inverter not bonded to neutral as there can only be 1 bonding point (which is in the main panel)...so ground wire on inverter is from chassis.