Computer keeps shutting down after plugging freezer into inverter

Hello.

I have an off-grid system I've been running for about five years. Have a Magnum pure sine MMS1012G Inverter that is not hardwired. Just has 2 outlets on the inverter itself. This system is set up in my RV with solar panels and golf cart batteries and I bring it into the house with extension cords, mostly to run a Mac computer system (all day, work at home) TV and a light or two. Not an ideal situation I know.

This weekend I bought a Kenmore freezer. By the way, anyone looking for a super efficient freezer, this thing is great. It is 5.1 cu.ft and runs on less than 1 amp and around 67 watts. Rock solid food fast. $200, so much more economical than a DC freezer. Quite the find.

I hooked up the freezer on Saturday and worked on the computer for about 3 hours on Sunday with no issues. This morning, I turn on the computer and within 20 minutes the computer just shut down and it has been doing this all day. After awhile it was just shutting down after about a minute. Spent the day looking on Mac forums and trying different things, but nothing worked. Finally decided to hook up my generator and run the computer on it and it is not shutting down anymore.

So I'm thinking the issue is with the inverter in conjunction with the freezer and computer running at the same time. I have the freezer on one outlet on the Magnum and everything else is on the other outlet. My question is, could there be some sort of interference from the freezer that is affecting my iMac even though it is running on a separate outlet? It is not affecting anything else on that outlet, printer, Macbook Pro laptop, TV, lights, all working fine with the freezer plugged in.

And if there is some sort of interference is there a fix of some sort, aside from disconnecting the freezer during the day?

Any help would be appreciated.

Teri


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Comments

  • PhotowhitPhotowhit Solar Expert Posts: 5,804 ✭✭✭✭✭

    Do you have a simple meter to check the voltage? Check for a drop/change in voltage.

    It might be shutting down when it sees a quick drop in voltage as the compressor starts up and shuts down to protect the equipment. Can you track the shutting down to when the compressor engages? BTW - this would happen pretty quick and not be readable on most meters.

    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • BB.BB. Super Moderators, Administrators Posts: 32,601 admin
    First question--Is the computer going through normal shutdown, or is it just like you pulled the plug?

    It sounds like the battery bank is not getting charged fully/correctly (problem is getting worse).

    It is also possible that your DC wiring is not heavy enough to give good surge current to the DC input of the inverter.

    If the inverter+battery bank+DC wiring is OK--It is possible that the inverter simply cannot manage the high surge current of starting the freezer (very short brown out/AC failure). If so, buying a second AC inverter to run your "critical electronics" (like this 300 Watt TSW AC inverter) may be workable option.

    But as it stands right now--I think your battery bank is not getting charged (not enough solar panels/sun/charging current) with your new freezer load. Look at that before you take your battery bank "dead" and ruin your battery bank.

    Also, what is the AH size of your battery? Induction Motors for refrigeration can take a fair amount of starting current (600-1,000 VA or more). A small battery bank (less than ~200 to 400 AH @ 12 VDC) may simply not be able to drive the surge current (especially if the bank is getting old/not getting fully charged).

    Have you check the specific gravity of your bank lately?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • iabteriiabteri Solar Expert Posts: 45 ✭✭
    Hi and thanks for the replies.

    It is definitely not a system issue. I have 8 golf cart batteries wired (#4 welding cable) for 12V and 5 135-watt Kyocera solar panels and live in the hi desert with plenty of sun in the summer. I’m also in the habit of monitoring the battery charge many, many times throughout the day. The freezer is running right now and the Magnum remote is showing that I have 14.6V in the batteries at 3:00 p.m. Most days they hit float with just the solar panels in the summer, even while I’m running the computer equipment. I use very little energy over here. I had the freezer running all night last night, the TV was on last night for a few hours, and when I woke up I still had 12.2V in the batteries and they started charging up as soon as the sun came out again.

    Yes, I did check the voltage on the the outlets on Monday nite and it was fine.

    Today I called Magnum and after some time, the tech over there concluded that the computer must be very sensitive to noise because it appears to shut down (just like it would if you pulled the plug) as the freezer is going on and off. The freezer is pretty efficient so once it reaches temperature it shuts down. I monitored it quite a bit yesterday and it shuts on and off a lot during the day, pulling nothing, then a slight surge as it comes on. I wasn’t able to tell if the computer was shutting down when the freezer came on or shut off because the computer, remote and freezer are all in different rooms. And the freezer is super quiet so I can’t really even tell when it is running. I have to look at the Magnum remote.

    The computer being affected is an Apple iMac desktop. I also have an older, not so efficient desktop Mac Pro, which is a CPU tower computer and separate 23” monitor. This computer draws a lot more energy than the iMac. Today I turned that on and ran it for about an hour in conjunction with the freezer and it was fine, it did not shut down. Also, everything else is fine running with the freezer. It is just the iMac that will not run with it.

    But here is what I don’t understand. I had the freezer plugged into a surge protector on Sunday when I first brought it home and had the iMac running for about 3 hours in conjunction with the freezer and the computer never shut down. After I shut down the computer myself, I took the freezer off the surge protector to do something with it and forgot to put it back on. So when I turned the computer on Monday morning the surge protector was not on the freezer when the iMac started shutting down. Monday nite I noticed it was not plugged into the surge protector so I plugged it back in. I was thinking that was the issue and that it would be fine Tuesday morning. Well, the iMac shut down Tuesday morning after 15 minutes. Ugh.

    Monday I had done a bunch of resets and all sorts of stuff to the iMac because I thought there was something wrong with the computer at first. Now I’m wondering if there is some sort of software conflict in conjunction with the power surges from the freezer and all the shutdowns I encountered on Monday. I’m just a little confused because the computer ran fine the first day I hooked up the freezer and the surge protector was on the freezer. I have no idea what affect a surge protector on the freezer would have with the iMac hardware or software, but the surge protector on the freezer is what was different the day the iMac ran okay with the freezer.

    So, right now I either have to turn off the freezer while I'm running the iMac or I have to run the iMac with a generator while the freezer is on the solar system.

    I’m considering wiping my hard drive clean and reinstalling the system software to see if this clears up the issues. It’s something I’ve been wanting to do anyways, since I’m having some issues with a couple programs. But could software even be an issue, I have no idea? I’m thinking of calling Apple, but that’s usually a nightmare so I’m still thinking about it!

    Today I started reading about Online Uninterruptible Power Supplies and I’m wondering if this would resolve the problem. I noticed that under ENERGY SAVING on the iMac there is a setup for a UPS. Apparently, the Online UPS allows the computer to run through it's battery constantly so it resolves the fluctuations as they occur. Don’t know too much about how they work, but it sounds like it could be an answer? So I would be going from DC to AC via the battery bank and then from AC to DC to AC via the UPS. Anyways, that's what it sounds like will happen.

    What do you think about all this?

    Thanks.

    Teri

  • VicVic Solar Expert Posts: 3,145 ✭✭✭✭

    Hi iabteri,

    When reading the following,  in your first comment,   "...  I have an off-grid system I've been running for about five years. Have a Magnum pure sine MMS1012G Inverter that is not hardwired. Just has 2 outlets on the inverter itself. This system is set up in my RV with solar panels and golf cart batteries and I bring it into the house with extension cords, mostly to run a Mac computer system ...   "

    That part about Extension Cords,  is a bit concerning.   How long is the cord that runs the freezer,  and do you know what wire gauge is that cord?

    It does seem (to me,  like many others commenting here)  that the Compressor start surge  is causing the issue   ..   This could be caused by a number of things,  each contributing its own part to make the issue too much for the iMac.

    It is possible that the batteries might not be in great shape,  some of the battery connections might not be too great ...  it is possible that the Inverter does not have enough surge current capability to start the freezer,  and so on.

    The sum of all the resistances in the system are probably not helping,  either,  and resistance can make the compressor start take considerably longer,  and extend the surge,  to the extent that the iMac does not have enough "ride-Through",  but perhaps the other computer's power supply might ...

    FWIW,  my drive-by thoughts,    Vic


    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X[email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • mike95490mike95490 Solar Expert Posts: 9,571 ✭✭✭✭✭
    Could be the fridge has poor power factor, and the inverter can't manage it, allowing the voltage to sag.   But I don't know why the computer is sensitive to that.
    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
    gen: http://tinyurl.com/LMR-Lister ,

  • iabteriiabteri Solar Expert Posts: 45 ✭✭
    Thanks for your comments.

    The batteries are actually in really good shape. Just replaced them about 1.5 years ago. I check the water around the 1st of every month. Honestly guys, it isn't the system. It is well taken care of and well put together. I really depend on the electricity I have because I am totally off-grid and work at home on a computer all day.

    I know the extension cords are not the best way to do this and it definitely could be the issue. All the manuals on these appliances say not to use them, so it is a bit concerning and I need to do something about it soon. But I've been using extension cords all along. Use them for the washer and dryer, also, in conjunction with a 7000 watt generator.

    I bought a new extension cord and surge protector when I bought the freezer, so the extension cord is 12 gauge and 50'. I'm not sure if it would help to get a shorter extension cord, I could probably get by with 25'.

    But whatever is happening isn't affecting the freezer, it is affecting the computer, so that is really weird. I think the iMac must be super sensitive to power surges, so I'm thinking that I need to get something on the computer to absorb the surges. Sounds like a UPS might be the answer.

    Also, I think the inverter can take the surge. It is 1000 watt inverter and the freezer seemed to have about a 400 watt surge when it is first turned on, but it doesn't surge that high now that it is cold.

    Is anyone familiar with UPS? Today I'll be checking into that to see if I can find something to put on the computer.

    Thanks again.

    Teri

  • BB.BB. Super Moderators, Administrators Posts: 32,601 admin
    A 1,000 Watt AC inverter may not be large enough... The standard recommendation today is 1,200 to 1,500 Watt minimum rated inverter to support starting surge.

    And, in some cases, extension cords are your friend here. Using a longer/smaller gauge extension cord for the freezer will actually reduce starting surge current (to a degree) and has helped others with "undersized" AC inverters/battery banks ride through startups.

    Using a smaller gauge/longer extension cord on the freezer is worth a try (make sure that the compressor actually starts and does not stall).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • VicVic Solar Expert Posts: 3,145 ✭✭✭✭
    edited April 2016 #9

    BB Bill said   "   ... And, in some cases, extension cords are your friend here. Using a longer/smaller gauge extension cord for the freezer will actually reduce starting surge current (to a degree) and has helped others with "undersized" AC inverters/battery banks ride through startups   ..."

    Yes,  the added R of the cord can help reduce the magnitude of the surge,  but will also increase the duration of the surge.

    Had wondered if the iMac had very little "Ride Through",  as,  believe that there were essentially no optional items that could be added into that computer,  so the power supply had almost no provisions for optional peripheral devices,  so there might no added ability to ride through a surge.  Thought that perhaps the other computer referred to might have considerable extra power supply capacity for options that may not be present,  and that this could add significantly to Hold-Up time in the PS.

    AND,  completely agree that that inverter may well not have enough capacity for the freezer's  surge,  as noted by Bill,  the standard Rule-of-Thumb  is about 1200 - 1500 watts of inverter capacity for modern high efficiency  120 VAC Refers and freezers  --  all depending on the Surge capacity of the inverter.

    Also,  12 V systems surge more poorly than do 24 and 48 volt systems,  primarily due to the high battery currents,  and the inability of the inverter power electronics to efficiently handle these larger DC currents.

    Teri,  as was noted before,  your batteries may not be getting fully-charged every or most every day,  and one might not know this,   until a new high-surge appliance is added.

    Battery voltage readings are often not a good indication of State Of Charge (SOC),  or battery health.

    Believe that you are using Flooded batteries.   What does your Hydrometer read on each cell of the battery when you have entered Float?
    And,  are you using a Remote Temperature Sensor on all charge sources?

    FWIW,  continually guessing,   Vic

    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • solar_davesolar_dave Solar Expert Posts: 2,389 ✭✭✭✭
    My Mac mini computers have some tolerance to a glitchy line but not much.  

    I worked for USWest phone company as a Unix Sys Admin about 20 years ago.  We had 3 HP machines in the development lab and one largish SUN.  The HP machines would cruise through most power line issues but the Sun would "crash" power off on very little disturbance in the line.
  • iabteriiabteri Solar Expert Posts: 45 ✭✭
    Well, it’s good to hear extension cords are my friend!

    Today I moved the iMac and connected it to another 14 gauge (I incorrectly said it was 12 gauge that I had) and ran it for an hour and it didn’t shut down, so now I’m thinking I have an extension cord issue. The one I've been using is a higher gauge, it’s old so not sure what it is, but I ordered a 100’ 14 gauge extension cord today and I’m going to give it a shot and see if the iMac runs okay with it. Unfortunately, it is a ways to the office, so I had to get something longer than 50’. Since the freezer seems to be happy, I’m just going to leave the 50’ on there for now and will switch it out if the new cord for the iMac doesn’t resolve the problem.

    I do have a temperature sensor on the 8 battery setup and I have the Magnum digital remote. It is always the DC volts I tend to look at on the remote, it seems to give me a really good gauge of what I have left in the batteries, whether I need to shut something off to get thru the nite, etc., so I’m not quite sure why this isn’t a good indication that the batteries are charging well? Why is this?

    Insofar as testing the cells with a hydrometer, I do have one of those things, but I don’t use it sorry to say. Probably because I don’t have a very good one.

    It doesn’t appear that the freezer is too much for the inverter. If it was, it would just shut down the inverter, wouldn’t it? I put the Kill-O-Watt on the freezer and it is drawing around .89 (AC) amps and hovers around 67 watts when it turns on. I do have a mini fridge here that is 1.5 amps and I tried to put it on my 1000 watt Honda generator once and it knocked it out. I was pretty surprised but the surge is about 800 watts on that little fridge. Still I was surprised the Honda couldn’t handle it. But this new freezer really is super efficient. I believe it surged at 400 watts when I first turned it on. Nothing else was on at the time, so the inverter seemed to handle it fine. It's not surging that high at all now that the freezer is cold. When I was monitoring it, I saw surges of about 89 watts at the most.

    That’s also interesting about the iMac not having optional items so there is not a lot of ability to ride out a surge. My other computer is actually an old Mac G4 (the computers change so fast I forgot what it was called) and is a tower with the ability for many additional options along with 3 or 4 internal hard drives. I’ve always had towers before, been through a bunch of Macs, but I got the iMac this time because it is so energy efficient.

    Thanks so much for the replies. I really appreciate your input.

    Teri

  • VicVic Solar Expert Posts: 3,145 ✭✭✭✭

    Hi Teri,

    Sounds like you are making progress.

    Battery voltage can be an OK,  but often an approximate indicator of State Of Charge (SOC) of batteries.  One issue with voltage vs SOC,  is that the voltage will vary,  based on charging or discharging that has occurred in the previous number of hours,  AND,  battery temperature has a fairly large impact on battery terminal voltage.

    However,  as we become very familiar with our system,  and any loads and charging that has occurred,  and also the present battery temperature,  it can be an adequate,  but a bit approximate indication of SOC.

    It is good that you do have a battery temperature sensor,  and hope that every charge source has one,  ie,  one on any Charge Controller that you have,  and probably also on the inverter/charger.

    Good Luck with your system.   Thanks,   Vic

    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • zonebluezoneblue Solar Expert Posts: 1,218 ✭✭✭✭
    What makes you so sure the surge is only 800W? How did you measure it? The fact that the Honda is also not coping supports what others are saying above. If you are off grid, sounds like time to sort out our wiring, proper hard-wire, load center, sub circuits, GFIs etc. And probably... a bigger inverter.
    1.8kWp CSUN, 10kWh AGM, Midnite Classic 150, Outback VFX3024E,
    http://zoneblue.org/cms/page.php?view=off-grid-solar


  • PhotowhitPhotowhit Solar Expert Posts: 5,804 ✭✭✭✭✭

    "
    It doesn’t appear that the freezer is too much for the inverter. If it was, it would just shut down the inverter, wouldn’t it?"

    Perhaps not! I know my exeltech will change wave form, From Exeltech manual;

    If Output power is exceeded for more than 3 seconds, output voltage is reduced to a level which will provide the inverter's rated power to the load by clipping the tops of the waveform. The inverter can operate safely in this mode indefinitely.

    Not sure what is happening but your statement of;

    I put the Kill-O-Watt on the freezer and it is drawing around .89 (AC) amps and hovers around 67 watts when it turns on.

    Doesn't make much sense, .89 amps at what voltage? Amps x Volts = watts so are you at 75 volts? something is hinky here.

    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • mike95490mike95490 Solar Expert Posts: 9,571 ✭✭✭✭✭
    A kill-a-watt meter CANNOT record peak surge readings.  You might get lucky and record a part of a surge, but never the true surge and it's doubtful you could even catch 1/4 of the surge, the averaging is so slow.
    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
    gen: http://tinyurl.com/LMR-Lister ,

  • ThomThom Solar Expert Posts: 196 ✭✭✭
    zoneblue said:
    What makes you so sure the surge is only 800W? How did you measure it? The fact that the Honda is also not coping supports what others are saying above. If you are off grid, sounds like time to sort out our wiring, proper hard-wire, load center, sub circuits, GFIs etc. And probably... a bigger inverter.

    Yes time to correctly wire your system. Could try a smaller inverter for the Mac. I ran mine on cheep inverter for years. 

    Off grid since 1984. 430w of panel, 300w suresine , 4 gc batteries 12v system, Rogue mpt3024 charge controller , air breeze windmill, Mikita 2400w generator . Added [email protected] 100w panel with a midnight brat 
  • BB.BB. Super Moderators, Administrators Posts: 32,601 admin
    Measuring current, voltage, and Watts is a bit of a "problem" with AC circuits.

    Watts = Voltage * Current for DC systems (more or less)
    Watts = Voltage * Current * Power Factor = Voltage * Current * Cosine of the current vs voltage phase angle for AC systems
    VA = Voltage * Current for AC systems

    The short answer is that VA is either equal to Watts (if PF = 1.0) or greater than Watts (if PF ~ 0.5-0.80 typical for induction motors).

    For standard non-commercial AC inverters, the maximum Watts  is usually equal to the maximum VA measured. Induction motors tend to have "very poor power factor" when starting and PF~0.7 or so when running at speed.

    For example--Your 67 Watts, 0.89 Amps, and ~120 VAC would indicate PF:
    • Watts* 1/volts * 1/current = 67 Watts * 1/0.89 amps * 1/120 volts = 0.63 Power Factor running reasonable number
    • Watts* 1/volts * 1/current = 400 Watts * 1/1.5 amps * 1/120 volts = 2.22 Power Factor starting does not make sense PF>1.0
    • Watts* 1/volts * 1/current = 400 Watts * 1/6.0 amps * 1/120 volts = 0.56 Power Factor starting guess starting VA
    In the end, as said before, the Kill-a-Watt meter is about useless for trying to capture starting current.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • iabteriiabteri Solar Expert Posts: 45 ✭✭
    Thank you all for your replies.

    The problem lingers with the new extension cord, although I don't know why it worked for an hour with the 50' cable. So, this morning, I turned on the computer, planted myself next to the freezer cord with the Kill-O-Watt and watched it until the freezer surged. Yikes, it was a big 951 watt surge for just a millisecond, would've missed it if I'd blinked, then fluctuated to about 850, before it went down. Went into the office and sure enough, the computer was off. Mike, if the meter isn’t really accurate, maybe the surge was even higher, I’m not sure?

    I looked online and the inverter can handle a 1750 surge but, apparently, the computer cannot. The TV does not have an issue with it at all.

    Zoneblue, it was actually a different mini fridge that I set up on the Honda, not this particular freezer. I haven’t tried to put this freezer on the Honda.

    Vic, I have a Magnum temperature charger which hooks up to the batteries from the inverter. I don’t have one on the controller, which is a TriStar MPPT with a Morningstar digital meter.

    Photowhit and Bill, I need to monitor that watt meter again insofar as the amps and volts. I sort of wing it with this stuff. I didn’t even know how a generator worked when I moved out here, so it has been a learning experience. I did install the system myself, but I’m good at reading and learning things and I was very careful and I do believe I did a good job. I also had a lot of help on this forum and you guys are really great.

    I know I need to upgrade this system. It was set up in the RV as a temporary sort of thing and, as things usually go, I’ve been milking it for longer than I should. I’m going to be figuring out how big I want to go on a new hard-wired system, but I need a temporary fix aside from shutting off the freezer in the morning and then running the computer on a generator in the afternoon.

    Do you think it is worthwhile looking into a UPS system on the iMac to handle those surges, or should I set up a small system just for the iMac? I'm not sure I like the idea of another interim solar system, but I may not have a choice.

    I'm going to try with that 50' cable again, too. Maybe the freezer didn't surge for that hour and that's why the computer didn't shut down, but I'll have to try it again to see what happens.

    Bad timing, I have company coming today for the weekend, so I can’t investigate today, so will have to look into this further on Sunday afternoon or Monday.

    Thanks again for your help.

    Teri






  • VicVic Solar Expert Posts: 3,145 ✭✭✭✭

    Hi Teri,

    "...   Vic, I have a Magnum temperature charger which hooks up to the batteries from the inverter. I don’t have one on the controller, which is a TriStar MPPT with a Morningstar digital meter   ..."

    In general,  it is more important to have the Remote Temperature Sensor (RTS) on the Morningstar Charge Controller than on the Inverter/Charger,  as,  usually there is daily charging from Solar,  and much less often from a generator & inverter.   You should really get an RTS for the CC,   IMO.

    AND,  it is correct,  that the Kill A Watt (KAW) meter cannot really catch surges,  and what you DO see is only part of the surge.

    But,  it seems that you have done pretty well with your system,  and the self-install.

    Good Luck,   Vic

    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • BB.BB. Super Moderators, Administrators Posts: 32,601 admin
    edited April 2016 #20
    Inverters are not perfect... And some have better voltage control than others during surge conditions. Installing a second, small AC inverter (like the MorningStar 300 Watt) just to power your electronics is not the worst thing in the world.

    The only other things you have control over... Exactly how is your DC cabling wired? What length and AWG are you using between the batteries and batteries to AC inverter's DC input?

    Otherwise, trying a different brand/model of your main AC inverter is about your only other thing you can try--Short of designing a larger system (24+ volt battery bank, new AC inverter).

    Magnum has been reported to have less than ideal AC voltage control (voltage changes during changes in current loading). Is this your problem? I really do not know.

    The Kill-a-Watt meters are nice--But they are not great pieces of equipment. I would use their surge display with a grain of salt. Even their steady state readings have been called into question at times--Usually good enough for basic sizing of a solar power system--But not a substitute for a Fluke meter with peak hold, or an oscilloscope.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • 2twisty2twisty Solar Expert Posts: 199 ✭✭✭
    The power supplies in the iMacs are tiny and can't handle brownouts as well as the power supply in your older Mac Pro.

    I suggest that you pick up a small UPS unit that can help your iMac weather those surges.  Maybe even spend a little more on a unit that can filter your power, too.  Even though I have an Outback VFX3648 inverter, I still have my NAS and other sensitive electronics on a UPS.  For me, the UPS is needed because my generator doesn't produce perfect 60Hz all the time (varies by a few Hz) and my NAS doesn't like that much.  When my generator is on, I sometimes hear my UPS click over to battery to regulate the power.

    My MacBook Pros are just plugged in directly, since they have batteries internally that act as their own UPSes. 

    I'm using an APC BackUPS Pro 1300.
  • iabteriiabteri Solar Expert Posts: 45 ✭✭
    Vic, I may actually have a temperature control on the Controller. It does have a temperature readout on the digital meter, but I’m not sure what that temperature is from. I assumed it was the outside, but I’m not too sure? I put this system in quite a while ago, and really can’t remember all the details, but it has been running quite smoothly.

    Bill, my DC cabling is wired with as short a cable as possible and I used #4 welding cable. The batteries are in one of the RV compartments, and the inverter and controller are in the RV just up from the batteries, so everything is a very short distance and actually a pretty good setup for the 12V system. I am going to start designing a new system, either 24 or 48V, and was planning to leave the Magnum 1012 on the computer system (and bring it into the house) since it is pure sine and I may not get a pure sine inverter for the house. But it will be quite some time before I can get this set up. When you talk about installing the 300 watt inverter, you are talking about a whole new solar system, correct? I can’t add that small inverter to the system I already have, can I?

    2twisty, I looked up that APC on Amazon and am wondering if it will be okay with the iMac since it is not a pure sine UPS? I called APC and the sales rep recommended the SMX1500RM2U. At $762 (ouch!) I don’t think I want to do that. His less expensive recommendation was the BR1500G, which appears to be pretty much what you have only 1500 watts instead of 1300. The 1500 is actually a little cheaper so I’d probably get that, but I’m concerned it isn’t pure sine. It will only be a second that it needs to pick up that surge, but since the iMac seems to be more sensitive than other Macs, do you think this will be okay?

    Thanks again.

    Teri
  • BB.BB. Super Moderators, Administrators Posts: 32,601 admin
    I would just get a MorningStar 300 Watt TSW inverter for much less (~$240+shipping). And run all of your small/critical loads from that inverter (has remote on/off, and "search mode" power saving--Sould work nice for your needs).

    The backup UPS probably puts AC mains power through when available. And only switches to MSW during outages (a few cycles to a few minutes for you)--Probably not an issue for your machine.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • iabteriiabteri Solar Expert Posts: 45 ✭✭
    Bill, I don't understand how that is going to work. Can I use the MorningStar in conjunction with the Magnum so I can still run the freezer on the Magnum or would I would have to set up a whole new separate system (panels, batteries) to run this smaller inverter for the computer?

    Teri
  • BB.BB. Super Moderators, Administrators Posts: 32,601 admin
    Just bolt the 300 Watt AC inverter to the battery bank (behind a breaker/fuse on the + lead). And "plug in" your iMac and other loads to this second AC inverter.

    Assuming your battery bank is not "sagging", this will isolate your iMac from the voltage variations on the Magnum inverter.

    At the cost of ~6 Watts when the 300 Watt inverter is "on" and invertering. (during standby and remote off, it uses much less power).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • iabteriiabteri Solar Expert Posts: 45 ✭✭
    This sounds like a really great solution, Bill. I downloaded the manual and will look it over to be sure I understand how to install this and how this is going to work in my system.

    Thanks very much for the info.

    Teri


  • iabteriiabteri Solar Expert Posts: 45 ✭✭
    Bill, just wanted to let you know that I purchased the SureSine from NAZ Wind & Sun and installed it on Friday. Everything is working great and this was a perfect solution. Thanks very much for your help.

    I'm planning to move the system into the house this summer and get it off the RV, but I just wired the new inverter into the RV for now since everything else was in there. The solar setup will be an issue for me in the winter, not enough sun to power everything, so I'm debating a course of action this summer to handle this next problem.

    As an aside, I also purchased another freezer from Sears, bought a Johnson Controls Freezer Temperature Controller and turned it into a refrigerator to run along with the freezer on the 1000 watt Magnum inverter. The controller works great and it is amazing to have both a freezer and refrigerator in the house. Refrigeration has been a big issue for me, I had actually been using an old piece of junk Dometic in the RV so very inconvenient and horrible refrigeration in the summer, and I had been looking at propane refrigerators. Very expensive, along with the continual propane costs, so this has been a great find for me.

    Thanks again.

    Teri
  • BB.BB. Super Moderators, Administrators Posts: 32,601 admin
    Teri,

    Very happy to hear this is working out well for you... Now to add some complexity--Now that you added a second re-freezer to your setup.

    There is the possibility of both units trying to start at the same time--It is questionable if the Magnum can support the surge of two starting at once. Likely, the Magnum will brown out or shut down/restart when this happens--And it could damage your freezers and/or the Magnum--And you could lose your food (if you are gone for a day or two when this happens).

    A suggestion. Get a NO/NC relay and connect it to your Johnson thermostat. When the "refrigerator" is off, the relay sends AC power to the Freezer. And when the thermostat is "on", the relay directs power to the refrigerator (and cuts off the freezer). This will prevent both starting at the same time.

    It is a simple setup--And as long as your freezer and refrigerator run at less than 50% of the time (for each)--The shared power timing should not be an issue.

    Also--Look at getting a freezer and refrigerator audible alarm--Always nice to know about problems "early" before your food goes bad. Solar power systems are "complicated" and there are many wild and wonderful ways they can fail.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.BB. Super Moderators, Administrators Posts: 32,601 admin
    I should add--You are now getting to have a "medium sized" off grid power system... Battery bank capacity, solar array size, amount of power you use daily--You may need to look at adding more solar panels before you over discharge your battery bank some cloudy day.

    Some helpful tools:
    http://www.solar-electric.com/midnite-solar-battery-hydrometer.html
    http://www.sears.com/craftsman-digital-clamp-on-ammeter/p-03482369000P

    And some optional equipment that you might like:
    MidNite Solar MNBCM Battery Capacity Meter (cheap, easy to understand)
    Trimetric Battery Monitoring System (more complex and accurate--But need to understand weaknesses too)
    Blue Sea Digital Volt & Amp Meter with Alarms (not cheap, but need with programmable alarms)

    You are now "hooked" with the solar bug--And the system is "growing". Each new load needs to be evaluated against system capacity (now you have lots of sun)...
    http://solarelectricityhandbook.com/solar-irradiance.html

    Las Cruces
    Average Solar Insolation figures

    Measured in kWh/m2/day onto a solar panel set at a 58° angle from vertical:
    (For best year-round performance)
    Jan Feb Mar Apr May Jun
    5.08
     
    5.62
     
    6.50
     
    6.75
     
    6.57
     
    6.26
     
    Jul Aug Sep Oct Nov Dec
    5.83
     
    5.60
     
    5.79
     
    5.72
     
    5.27
     
    4.75
     
    "No Surprises" is what we aim for here.

    Good luck,
    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • iabteriiabteri Solar Expert Posts: 45 ✭✭
    Bill, I had thought about what happens when both the fridge and freezer come on together and I believe they have in fact been on together and things seem to be working okay when that happens, maybe because they are just not surging exactly at the same time? I agree it could be an issue if they do surge together, but I don't understand that NO/NC relay. Can you direct me to one that would work for me? I have the freezer and fridge plugged into a common surge protector (which is plugged directly into the Magnum), but I don't understand how the 2 units would connect via the Johnson thermostat since it is only being used for one of the freezers?

    I will look into these links you mention also and appreciate the info. I am in the California Mojave desert and the sun is potent out here in the summer, but I've always had issues in the winter…even before the fridge and freezer were added, so it will be even worse this winter. Since I work at home as a graphic designer I have the computer on all day, so I have to find an economical solution this summer to prepare for the winter to cut down on generator usage.

    The panels are maxed out for the controller on the system I have now, so I'm thinking of adding a totally new system so I don't have to trash anything I already have. I actually only have 4 135 watt panels on this system. I have 2 solar systems on the RV and the 5th solar panel is on a separate system to keep the 2 RV "house" batteries charged. I bought the 2 house batteries and the 8 system batteries at the same time, so now I'm thinking of moving the 2 extra batteries onto the 8 and just replacing the batteries for the RV house system. This way the batteries will all be the same age and I'll have 10 instead of 8. I think it will help a little bit to have that extra bit of battery storage.

    First thing is to get that system out of the RV, something I will probably start on the end of June. I have a spare bedroom in the house and I'm planning to use it to house the batteries and all the equipment, so I am just now in the planning stages to figure out how to set this up safely in the house. I also have an 8' x 20' storage container on the south side of the property, a good 35 feet from the spare bedroom in the house, not including the way up to the top of the container and the bedroom wall, so hoping this will work with the panels this far away on a 12v system. I'll be starting a new thread when I tackle this because I do have a lot of questions about how I can set this up!

    Teri
  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    edited May 2016 #31
    I would look at the 2,000 and 3000W Honda Inverter generators as possible solutions, both gas sippers...
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
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