Pinning down the best system for us?

bbbuddybbbuddy Solar Expert Posts: 125 ✭✭✭
I keep going back and forth over what would be best for us in the long run.

Most of the time our use runs at about 150 watts (computer), with fridge and freezer going on and off at 150 watts each, plus surges.

Without surges that's 450 watts running at once, once in a while.
We have been going along just fine with mod sine wave.

I would like in the future to run small washer off inverter.

I would like to have the ability to run a 1hp 240v 2 wire well pump (water level 80 feet) for 1 hour, 2 to 3 times a week. Everything else could be off during this time. We already practice load control...

I can see using about 1200 watts at once, once in a while in the future, if I do laundry using inverter and the rest (not well pump) is on at the same time...

I go back and forth over getting:

2 smaller stacked mod sine wave inverters
2 smaller pure sine wave inverters (not sure I need this),
or one BIG sine wave inverter.

Also stacking for 240, or getting a 120/240 booster.

If we stacked for 240v, can one inverter be turned off and everthing else just run at 120v off the first inverter (like using just one leg of 240v) but when wanting to run the well pump, turn on the other inverter.

Second inverter would only be wired just for the pump, so you would not accidentally send 240v to the house wires.
Main inverter would have a circuit for the well pump for one leg.
Or does the software inside mean settings would need changing each time?

I hate to run a big inverter all the time when it would only be needed 2 to 3 hours a week...

This is bothering me, I can't seem to decide what is best.
Magnum4024PAE, 2 Midnite Classic 150s, 3100watts solar, 432ah lifepo4 battery.  Off grid since 2004.

Comments

  • mike95490mike95490 Solar Expert Posts: 8,470 ✭✭✭✭✭
    Re: Pinning down the best system for us?

    Gotta run the 240V well pump on pure sine, or risk toasting it.

    Have you already bought the pump ?

    What's the duty cycle of the pump, on 1x for the pumping, or off and on many times to build pressure?
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
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  • RCinFLARCinFLA Solar Expert Posts: 1,280 ✭✭✭
    Re: Pinning down the best system for us?

    1 hp well pump will take 4-5kW inverter to start up.

    Frig's and freezers also have defrost cycle that take about 1 kW for short periods. Peak power is usually compressor start up surge.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Pinning down the best system for us?

    You can not "pin down" your system without first pinning down what you plan to run from it.
    If you are going to run motors such as 'frige, washing machine, and/or well pump you will need pure sine wave. It is foolish to risk trying to run them without.
    If you are going to run that big well pump, you must have inverter capacity capable of taking the start-up surge.

    In my opinion, you either go with a small "lights only" system or go whole-hog and buy the big inverter. Trying to stack inverters to save money probably won't, because stackable inverters like the OB series are expensive per unit. Even though you might save 20 Watts stand-by, some of the bigger inverters don't use 2X what 1 OB FX does.

    There's probably not much sense in buying 1 small inverter for lights now and then having to buy a big inverter later to run the "big stuff".
    Do you have a budget in mind? Could you swing one of these:
    http://store.solar-electric.com/maenms4444wa.html ?
  • bbbuddybbbuddy Solar Expert Posts: 125 ✭✭✭
    Re: Pinning down the best system for us?
    mike90045 wrote: »
    Gotta run the 240V well pump on pure sine, or risk toasting it.

    Have you already bought the pump ?

    What's the duty cycle of the pump, on 1x for the pumping, or off and on many times to build pressure?

    Yes, the pump is in place and has been used for 7 years now.
    Duty cycle is once to twice a [email protected] 1 hour each to fill a 3000 gallon cistern.

    I plan to pump 2 to 3 times a week in the future as garden expands.
    Magnum4024PAE, 2 Midnite Classic 150s, 3100watts solar, 432ah lifepo4 battery.  Off grid since 2004.
  • bbbuddybbbuddy Solar Expert Posts: 125 ✭✭✭
    Re: Pinning down the best system for us?
    You can not "pin down" your system without first pinning down what you plan to run from it.
    If you are going to run motors such as 'frige, washing machine, and/or well pump you will need pure sine wave. It is foolish to risk trying to run them without.

    But we already do run the fridge and freezer on mod sinewave. I used to run the washer on the ms inverter sometimes, until my batteries got so bad....

    If you are going to run that big well pump, you must have inverter capacity capable of taking the start-up surge.

    In my opinion, you either go with a small "lights only" system or go whole-hog and buy the big inverter. Trying to stack inverters to save money probably won't, because stackable inverters like the OB series are expensive per unit. Even though you might save 20 Watts stand-by, some of the bigger inverters don't use 2X what 1 OB FX does.

    Well, I was thinking of going with 2 Xantrex TR series...like 2 2424s
    So, how about the stacking? Can you use one for 120v, then turn the second one on for 240v if the second one is only hooked up to the well pump?
    Wouldn't that give me the equivalent of one 4824?


    There's probably not much sense in buying 1 small inverter for lights now and then having to buy a big inverter later to run the "big stuff".
    Do you have a budget in mind? Could you swing one of these:
    http://store.solar-electric.com/maenms4444wa.html ?

    Yeah, that's what I thought I wanted, until I started thinking about it being used the majority of the time for 150 watt loads...
    thanks for your reply!

    edit: I forgot to add, we can "in a pinch" run the well pump from a gennie as small as a cheap Champion 3500/peak4000watt .
    I know this because I have done so. So my well pump will start with 4000 watt surge, which is why I "think" a 4000 watt inverter with higher surge capacity would be ok...for an hour at a time.

    another edit:

    One of the reasons I keep coming back to the idea of 2 smaller inverters stacked, is in case one were to fail, we would still have one to run all the loads except the well pump....
    if one big inverter fails nothing works, unless gennie is on...
    Magnum4024PAE, 2 Midnite Classic 150s, 3100watts solar, 432ah lifepo4 battery.  Off grid since 2004.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Pinning down the best system for us?

    This is very much the situation I was faced with: most of the time my 3.5 kW inverter loafs along providing less than 500 Watts, which makes it an utterly silly choice. But ... When the refrigerator starts, you need 1000+ Watts (not to mention defrost). No choice. Water pump? Only 6 minutes a day, but 850 Watts running plus a near 2000 Watts to get started. Digester pump; same, only worse. And if everything comes on at once ... 3.5 kW is good to have.

    Don't think that just because your 'frige is running on MSW now doesn't mean it isn't drawing more power than it should and shortening the life of the motor. When I switched mine over, I noticed right away that it didn't make the rattling noise on start-up. And the power use from the batteries dropped the first day because 20% wasn't going to sine wave incompatibility.

    So your down to picking either two PSW 2kW inverters that are stackable, or one 4 kW inverter. You'll have to compare idle power on both and see if it's worth it. The third option is a small inverter for 'frige and everything else, and a big one or the genny for the well pump. Since you can't get down below 1kW and still run the 'frige, I don't think that option is very attractive.

    I wouldn't worry too much about inverter failure. It's very rare. I've got a StatPower here that's been abused and mis-used for ten years and it still works. Nothing fancy about it, of course; that helps.
  • bbbuddybbbuddy Solar Expert Posts: 125 ✭✭✭
    Re: Pinning down the best system for us?

    Odd that your fridge rattled on startup, ours is as quiet as can be.
    It's only a 10 cubic footer, but seems huge after 7 years with an 8 cf propane fridge!
    Magnum4024PAE, 2 Midnite Classic 150s, 3100watts solar, 432ah lifepo4 battery.  Off grid since 2004.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Pinning down the best system for us?
    bbbuddy wrote: »
    Odd that your fridge rattled on startup, ours is as quiet as can be.
    It's only a 10 cubic footer, but seems huge after 7 years with an 8 cf propane fridge!

    Mine's full size: 16 cubic feet.
    This is one of the problems with the recurring question "will this motor run on this inverter?": motors aren't all equal. Usually people only have "refrigerator" or "1/2 HP" to go by. Within those wide descriptions are thousands of different specific motors any one of which may or may not work.

    Take a deep well pump, for example. On the one hand, it's a small-frame motor and it's submerged in water so it can handle MSW and dissipate heat better than an above-ground pump. On the other hand, it's higher HP, has greater start-up current, and is doing more work so it's not a good choice for MSW. :confused:

    Some motors have better Power Factor than others. Some have start and run capacitors, some have "soft start" systems. So very many varieties.

    But the most sure-fire way to get any motor to run from an inverter is to be sure the inverter is pure sine and that its run capacity exceeds the motor's start-up needs. It may be over-kill, but it'll work.
  • Dave AngeliniDave Angelini Solar Expert Posts: 4,842 ✭✭✭✭✭
    Re: Pinning down the best system for us?

    There seems to be quite a few good questions and some big missing answers?
    Budget and your goals now or over a time period. Another question is the trace an SW or DR? The SW is a sine type inverter and the DR's were modified.

    You are running the well with a generator right? So do you want to run it with solar in the future? Are you married to Outback? Magnum and xantrex build spilt 120/240's that are all in one box.

    It seems like you should take some time and go read the posts in this thread and regroup a response. Good Luck! Where in Az?
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • bbbuddybbbuddy Solar Expert Posts: 125 ✭✭✭
    Re: Pinning down the best system for us?
    There seems to be quite a few good questions and some big missing answers?

    Budget and your goals now or over a time period.

    Hi Dave, goals were stated in my first post...

    Another question is the trace an SW or DR? The SW is a sine type inverter and the DR's were modified.

    What Trace, I never mentioned any make or model inverter...

    as I stated in my first post, I was trying to decide which way to go, 2 small stacked MSW, 2 small stacked SW, or one big SW....

    You are running the well with a generator right? So do you want to run it with solar in the future?

    Yes, as I stated in my first post...

    Are you married to Outback? Magnum and xantrex build spilt 120/240's that are all in one box.

    I never mentioned Outback....I know anout the split 120/240 inverters, that is why I mentioned going with one big inverter, and answered Cariboocoot that, yes the Manum AE series is what I had originally though I wanted

    It seems like you should take some time and go read the posts in this thread and regroup a response. Good Luck! Where in Az?

    We're in NE AZ, White Mountains area...I have been answering the posts in this thread, perhaps you will clarify what you mean???

    Actually, I still would like to know the answer to this question:

    "If we stacked for 240v, can one inverter be turned off and everthing else just run at 120v off the first inverter (like using just one leg of 240v) but when wanting to run the well pump, turn on the other inverter.

    Second inverter would only be wired just for the pump, so you would not accidentally send 240v to the house wires.

    Main inverter would have a circuit for the well pump for one leg."

    Can stacking be done this way? If each inverter was, say 2,000 watts, would I not get two 2,000 watt legs for the 240v well pump, or 4,000 watts 240 total?

    I know there is a way to stack and synchronize for 240, but wondered specifically about only using the second inverter as directly wired to well pump for one leg...
    Magnum4024PAE, 2 Midnite Classic 150s, 3100watts solar, 432ah lifepo4 battery.  Off grid since 2004.
  • Dave AngeliniDave Angelini Solar Expert Posts: 4,842 ✭✭✭✭✭
    Re: Pinning down the best system for us?

    Does it not say "old Trace 2012" at the bottom of your post?
    The reason I asked this is you may not know what you have right now!
    In the old days we did things like switch on and off inverters and use transformers, MSW outputs, and make kludges that were hard to explain to wives, girlfriends, and even boyfriends! The standby loss of modern inverter chargers is easily overcome by a single extra solar panel. I try and make these system simple for people. It does not have to be simple!

    I have friends in your neck of the woods! A beautiful place!
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • bbbuddybbbuddy Solar Expert Posts: 125 ✭✭✭
    Re: Pinning down the best system for us?
    Does it not say "old Trace 2012" at the bottom of your post?
    The reason I asked this is you may not know what you have right now!
    In the old days we did things like switch on and off inverters and use transformers, MSW outputs, and make kludges that were hard to explain to wives, girlfriends, and even boyfriends! The standby loss of modern inverter chargers is easily overcome by a single extra solar panel. I try and make these system simple for people. It does not have to be simple!

    I have friends in your neck of the woods! A beautiful place!

    Yes, it is! We are not in the pines, but further north in "high plains" with a huge view.

    We did this because we lost everything in a southern California wildfire in '03 (we were in Lake Arrowhead, San Bernardino mtns), and decided at that time to just start over in a new place away from "Kalifornia".

    After being burned out, we didn't want to relocate right into more forest - There was a huge fire here the year before (Rodeo-Chedeski)

    :roll:Of course I know what I have right now, lol, but I can see that you have run into people that do not know...;)

    If I knew THAT little, I wouldn't be trying to make these decisions on my own...:D

    I "think" we have been doing ok for 7 years off grid, and only now needing new batteries. Our first set have lasted that long, AND only got ruined by the old (20yrs?)Trace charger acting up.

    The reason I am weighing choices is because needing a new inverter AND batteries all at once, I'm thinking of getting a MSW first to replace the 2012, so I can get MORE battery and solar!

    Thanks for any input you may have!
    Magnum4024PAE, 2 Midnite Classic 150s, 3100watts solar, 432ah lifepo4 battery.  Off grid since 2004.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Pinning down the best system for us?
    bbbuddy wrote: »
    The reason I am weighing choices is because needing a new inverter AND batteries all at once, I'm thinking of getting a MSW first to replace the 2012, so I can get MORE battery and solar!

    Thanks for any input you may have!

    1). Forest fires are not fun. :grr
    2). MSW inverters are a waste of money these days. :roll:
    3). Always design your system around the loads. :D

    Well, you did ask. :p
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