Looking for small inverter with low stand-by current

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_OS_
_OS_ Solar Expert Posts: 207 ✭✭✭
I my solar system I have a Victron inverter that has an idle power of 8W and I am looking for a small (150W give or take) inverter with smaller idle power to use at night. Hopefully one with an idle/stand-by power of 1W or better.

I searched the net and found a 500W Studer unit that has a stand-by consumption of 0.3W and no load consumption of 3.8W when on. This inverter has a true sine output but is more expensive than modified sine wave inverters of the same wattage.

I do not need a true sine wave since it will only be used for lighting. Any ideas?

EDIT: I checked the Mornigstar SureSine 300W and it seems like a good choice. The price is around half that of the Studer and the stand-by current is pretty good: 55mA.

OS
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,478 admin
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    Re: Looking for small inverter with low stand-by current

    What is your battery bank voltage?

    The Morning Star 300 watt (600 Watt Peak) TSW inverter is a nice 12 volt unit. It is ~$260 from NAWS.

    It has a 55 mAmp (0.66 watt) no-load standby current--so the Studer you found is even less.

    Samlex and Exeltech have some less expensive inverters (and 24 volt versions too)--but their standby currents are still in the 6 watt range (at 12 volts, 24 volt standby is even greater).

    For off-grid use--I would really recommend staying with a TSW if you can justify the costs. Things just run better, cooler (more efficiently), and sometimes quieter on TSW inverters vs MSW.

    -Bill

    See you found the Morningstar... The couple of people here who have one seem to really like it.
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • _OS_
    _OS_ Solar Expert Posts: 207 ✭✭✭
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    Re: Looking for small inverter with low stand-by current

    My system voltage is 12V.

    I noted that the SureSine has a meterbus connector so the big question now is: Can I wire the SureSine together with my SunSaver MPPT and share the same PC meterbus adapter?
  • 2manytoyz
    2manytoyz Solar Expert Posts: 373 ✭✭✭
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    Re: Looking for small inverter with low stand-by current

    I tested my inverters to determine their idle current. I posted the data here: http://2manytoyz.com/noload.html

    One of the best ones was an old Vector inverter. 1.8 Watts/hr. The newer version has a similar model number, but draws 6.36 Watts/hr by comparison. Details at the link above.

    I'm using two Vector inverters for lighting at my home. Rather than leave the inverters running all the time (parasitic load), each only runs when lighting on their circuit is required. One circuit is for exterior lights, and is switched on/off via an automatic lighting circuit built into a MorningStar 10L charge controller. The other circuit is my living room lighting. I'm using a 12V remote control circuit and relay to turn this inverter on/off. Works very well. Details on this setup are at this link: http://2manytoyz.com/gridless.html

    FWIW, the CFL lighting connected to each of these inverters operate as if on the grid. There's no fluttering, humming, etc. MSW works well for this purpose.
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
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    Re: Looking for small inverter with low stand-by current

    I love my suresine 300. You can even wire a remote switch to turn it 100% off at night,, with the switch located somewhere you are likely to need emergency light at night. (bedside?)

    The last time I checked,,, (a couple of years ago!) the mod bus metering was "in development" and wasn't useable. I don't know if that has changed since,,, since I use a Tri-meteric, metering the inverter is no needed.

    Tony
  • _OS_
    _OS_ Solar Expert Posts: 207 ✭✭✭
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    Re: Looking for small inverter with low stand-by current

    Hi Robert!

    Thanks for the information. I have spent the last hour reading everything on your web site! Very interesting read! Much of the stuff you have done I will do in my cabin system as well.

    As I wrote above, my Victron inverter uses about 8W of stand-by power that is a total waste at night when the only power we need is when we turn on a light in the bedroom. The Victron has a power save mode that reduce the power to 5W. I tried it but the problem is that the lights "blinks" once every 5 seconds or so. This was so annoying that I turned it off.

    I will install a relay that switches in the small inverter at night either automatically or on my command.

    OS
  • _OS_
    _OS_ Solar Expert Posts: 207 ✭✭✭
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    Re: Looking for small inverter with low stand-by current

    Hi Tony,

    Can you switch it 100% off using the on/off connector on the unit itself or do you need to disconnect it from the batteries mechanically? The reason I ask is that the spec. says that the power when switched off is 25mA.

    OS
  • _OS_
    _OS_ Solar Expert Posts: 207 ✭✭✭
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    Re: Looking for small inverter with low stand-by current

    I have now made up my mind and will order a SureSine inverter. I have e-mailed wind-sun and a couple of others for price but have not heard anything yet.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: Looking for small inverter with low stand-by current

    the suresine was shoved in with the exeltech inverters. Discounted Price: $259.00. i'm not sure what the shipping and handling would add to that.
  • _OS_
    _OS_ Solar Expert Posts: 207 ✭✭✭
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    Re: Looking for small inverter with low stand-by current
    niel wrote: »
    the suresine was shoved in with the exeltech inverters. Discounted Price: $259.00. i'm not sure what the shipping and handling would add to that.

    I got a reply from wind-sun now and the shipping is $111. I will shop around a little bit more before I pull the trigger.

    OS
  • n3qik
    n3qik Solar Expert Posts: 741 ✭✭
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    Re: Looking for small inverter with low stand-by current

    If this is for just one light, why not use a 12v CFL or LED lamp ??????
  • 2manytoyz
    2manytoyz Solar Expert Posts: 373 ✭✭✭
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    Re: Looking for small inverter with low stand-by current
    _OS_ wrote: »
    Hi Robert!

    Thanks for the information. I have spent the last hour reading everything on your web site! Very interesting read! Much of the stuff you have done I will do in my cabin system as well.

    As I wrote above, my Victron inverter uses about 8W of stand-by power that is a total waste at night when the only power we need is when we turn on a light in the bedroom. The Victron has a power save mode that reduce the power to 5W. I tried it but the problem is that the lights "blinks" once every 5 seconds or so. This was so annoying that I turned it off.

    I will install a relay that switches in the small inverter at night either automatically or on my command.

    OS

    Glad you found some of the info useful!

    My Prosine inverter also has a stand-by mode. It draws less than 1.5 Watts in the standby mode. It sends out a pulse every couple of seconds to determine if a > 20 Watt load has been applied. If so, the unit comes up to full power. That pulse isn't enough to flash an incandescent, but it sure will flicker a CFL bulb. An X-10 lighting control module will do the same thing unless it's modified.

    I managed to capture the small pulse on a scopemeter...

    1614.jpg

    Nice feature, but doesn't work well with CFL bulbs!

    Good luck on your cabin project.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,478 admin
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    Re: Looking for small inverter with low stand-by current

    Different CFL's may behave differently too... I installed a lighted wall switch (little 1/8 watt neon bulb)--and we had a couple CFL's that would flicker once every 5-10 seconds as the accumulated charge from the neon bulb leakage current. I had to remove the lighted switch as it was so irritating.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • 2manytoyz
    2manytoyz Solar Expert Posts: 373 ✭✭✭
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    Re: Looking for small inverter with low stand-by current

    One problem I discovered, while testing how a MSW waveform would hold up after a 100' of extension cord, is the two 50' extension cords with neon bulbs built into the female end, would cause the inverter to fault. I could plug one 50' cord in, then the load, but two cords, with no load, would cause the inverter to shutdown. Weird.

    dscn3344.jpg

    I did successfully complete the 100' extension cord test, but I had to use a 50' section that didn't have a neon bulb. This is something GOOD to know if you ever plan on using extension cords during an outage!

    Waveform at the inverter:

    dscn3347.jpg

    Waveform at the end of 100' of extension cord:

    dscn3353.jpg


    Another issue that can occur is having a purely inductive load. A friend on another forum tried stringing 10 CFL bulbs on a MSW inverter. The string would light up, power down, then light up again.

    He discovered that it would power up a few fine, and if he added one at a time, he could eventually light up the entire string.

    The booklet that came with my inverter talks a bit about this issue. They said to avoid it, make part of the load resistive, and the inverter will work fine.

    Since I'm only powering a couple of CFL bulbs on each of these two inverters, the problem doesn't occur.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,478 admin
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    Re: Looking for small inverter with low stand-by current

    You may try and add a resistive load (xx watt filament bulb for example) to provide a non-inductive/capacitive load for the inverter to be stable.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • _OS_
    _OS_ Solar Expert Posts: 207 ✭✭✭
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    Re: Looking for small inverter with low stand-by current

    I have experienced a related problem with my 2KVA generator: when I attach a 1200W Devalt Milter Saw and start the saw the output of the generator shuts off at once the saw starts rotating. If I attach a long extension cord between the saw and the generator everything works fine.

    OS
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
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    Re: Looking for small inverter with low stand-by current

    Ole,

    The suresine 300 draws (according to the book) 25ma switched off, and 450ma idle. I just kill mine at the breaker when I leave for a while.

    Tony
  • BB.
    BB. Super Moderators, Administrators Posts: 33,478 admin
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    Re: Looking for small inverter with low stand-by current

    If I understand the MorningStar inverter correctly...

    25 mA "off" (external switch)
    55 mA "searching" (called "standby mode")
    450 mA "idle"...

    I would guess if you have too much capacitance (lots of wiring and/or phantom loads)--it may take the unit out of "standby" and go into "idle" mode--which is full 120 VAC (or 230 VAC for European version) inverting mode.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • _OS_
    _OS_ Solar Expert Posts: 207 ✭✭✭
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    Re: Looking for small inverter with low stand-by current

    So far I have only heard from wind-sun about the price and shipping charge. I guess this is because the solar businesses are doing very well in the US and they have bigger customers to take care of.

    I have also e-mailed a couple of dealers in my country and they can order it and the price from one of them is a little less than the price I got from wind-sun but the delivery time is 4-5 weeks.

    OS
  • BB.
    BB. Super Moderators, Administrators Posts: 33,478 admin
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    Re: Looking for small inverter with low stand-by current

    Windsun earlier has posted about issues with shipping problems ("lost" items, things signed for but never received, problems with higher loss rates to out of US destinations, etc.).

    I would guess that they are, unfortunately for you, protecting themselves from excessive losses that they have experienced in the past.

    -Bill

    PS: I am not speaking for Windsun / NAWS--I have no connection with them other than what you see here. -Bill ;)
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: Looking for small inverter with low stand-by current

    2manytoyz,
    i like that scope. set you back much?
  • SkiDoo55
    SkiDoo55 Solar Expert Posts: 414 ✭✭✭
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    Re: Looking for small inverter with low stand-by current

    I like them too, can't afford one yet. Listed on the internet at about $2900.00 for that unit. Keep up the great support work in helping people out.
    GT3.8 w/4600W Trina 230W, TX5000 w/5000W ET-250W, XW4024 w/1500W ET-250W, 4 L16, 5500W Gen. (never had to use) Yet!!
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: Looking for small inverter with low stand-by current

    ouch, a bit too much for me.:D
  • _OS_
    _OS_ Solar Expert Posts: 207 ✭✭✭
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    Re: Looking for small inverter with low stand-by current
    _OS_ wrote: »
    My system voltage is 12V.

    I noted that the SureSine has a meterbus connector so the big question now is: Can I wire the SureSine together with my SunSaver MPPT and share the same PC meterbus adapter?

    I got an answer from Morningstar tech support today:
    Each device requires its own Meterbus adapter for PC interface.

    So much for using Modbus that are designed to handle more than one unit on each bus.

    OS
  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
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    Re: Looking for small inverter with low stand-by current

    You can use a single adapter

    1) You need to use the MS-View tool to change the modbus ID of the SunSaver, they both have a default address of one ( SureSine and SunSaver )

    2) Just wire all three devices together, pin for pin, keep in mind, there is no isolation between the inverter and charger doing it this way!!, so never,ever have the modbus wires connected and NOT the battery negative to both the inverter and charger

    3) Your PC application can send/receive one request at a time only. Once data is received ( or timeout of > 200ms ) the can address another device.

    I Talked with MS about this, we both agree this can be done with the understanding your at risk having the communications of the inverter and charger hardwired and not isolated. It makes allot of sense having a second isolator/adapter, but this is for safety, not a modbus thing
  • _OS_
    _OS_ Solar Expert Posts: 207 ✭✭✭
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    Re: Looking for small inverter with low stand-by current

    Thanks for clarifying this!

    Now, If I only can find a place to order the SureSine...

    OS
  • _OS_
    _OS_ Solar Expert Posts: 207 ✭✭✭
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    Re: Looking for small inverter with low stand-by current

    I have now ordered the SureSine from a dealer in the US. They had the 220V version in stock so I will get in two-three weeks.

    OS
  • 2manytoyz
    2manytoyz Solar Expert Posts: 373 ✭✭✭
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    Re: Looking for small inverter with low stand-by current
    niel wrote: »
    2manytoyz,
    i like that scope. set you back much?


    Nah, not much. I have 4 of them. Okay, my 'employer' has 4 of them. I sometimes will field test one. Really like that it displays volts/freq as well as waveform. Painfully easy to use, unlike the previous model (same brand) that we had.

    Well beyond my personal budget. I have an old Sony/Tek 2 channel o-scope that I can call my own. Nothing fancy, but works.

    dscn3094.jpg

    One thing better than buying expensive toyz, is being able to borrow them. ;-)
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
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    Re: Looking for small inverter with low stand-by current
    2manytoyz wrote: »
    Nah, not much. I have 4 of them. Okay, my 'employer' has 4 of them. I sometimes will field test one. Really like that it displays volts/freq as well as waveform. Painfully easy to use, unlike the previous model (same brand) that we had.

    Well beyond my personal budget. I have an old Sony/Tek 2 channel o-scope that I can call my own. Nothing fancy, but works.

    dscn3094.jpg

    One thing better than buying expensive toyz, is being able to borrow them. ;-)


    Just don't back up!

    T
  • _OS_
    _OS_ Solar Expert Posts: 207 ✭✭✭
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    Re: Looking for small inverter with low stand-by current

    The SureSine that I paid for three weeks ago is still not sent from the US dealer I ordered it from. So far I have got three different excuses from them. Two days ago I asked for a refund if they did not send it this week. This is a pity since I have ordered a lot from this dealer and I trusted them. Maybe they are hit by the financial crisis. I don't know.

    Ole
  • 2manytoyz
    2manytoyz Solar Expert Posts: 373 ✭✭✭
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    Re: Looking for small inverter with low stand-by current
    icarus wrote: »
    Just don't back up!

    T

    LOL!

    Wouldn't be so bad if the wife would let me buy a new Fluke scopemeter, but that's not going to happen!