Grid tie inverter with limiter? has anyone tried this?

jimmyazjimmyaz Registered Users Posts: 114 ✭✭

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  • jonrjonr Solar Expert Posts: 1,386 ✭✭✭✭
    edited August 2016 #2
    There is also:

    https://openenergymonitor.org/emon/mk2

    Useful if you have a an opportunistic load that is a better value than what the utility will pay (which might be positive, zero or negative).

    I am available for custom hardware/firmware development

  • vtmapsvtmaps Solar Expert Posts: 3,739 ✭✭✭✭
    jimmyaz said:
     and never suppose to back feed your grid...

    I looked at that ebay link:
    Note: The Grid Tied Limiter cannot able to limit power 100% accurate, It will have some excess power send to the grid or supplement by the grid. But in most of the time, it will supplement by grid.
    The "limiter" looks at the load and then tells the grid-tie inverter to reduce its output to equal the load.  As they explain, the purpose of the "limiter" is to get around a smart meter (which charges you for power you export to the grid), by greatly reducing the power sent to the grid.   The only reason to use the "imiter" is to hide an illegal system from the power company. 

    Also, I didn't see any UL or other regulatory listing for it.  Outback has safe equipment and a "grid-zero" feature which I believe can be se to not export power to the grid.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • jimmyazjimmyaz Registered Users Posts: 114 ✭✭
    vtmaps said:
    jimmyaz said:
     and never suppose to back feed your grid...

    I looked at that ebay link:
    Note: The Grid Tied Limiter cannot able to limit power 100% accurate, It will have some excess power send to the grid or supplement by the grid. But in most of the time, it will supplement by grid.
    The "limiter" looks at the load and then tells the grid-tie inverter to reduce its output to equal the load.  As they explain, the purpose of the "limiter" is to get around a smart meter (which charges you for power you export to the grid), by greatly reducing the power sent to the grid.   The only reason to use the "imiter" is to hide an illegal system from the power company. 

    Also, I didn't see any UL or other regulatory listing for it.  Outback has safe equipment and a "grid-zero" feature which I believe can be se to not export power to the grid.

    --vtMaps
    I agree that it make so much more sense to grid tie your system so if you produce extra power, it should be send to somewhere and not waste it.  But it's not like the power company is making that easy, between the new solar grid tie plan they are pushing out and try to prevent solar installation... does it still make sense?  Not to my understanding.  Can't you blame the people who looking for solution legally or illegally.

    Currently my system is completely off grid with it own subpanel and outlet.  But this has a lot of limitation on where and how I can use the power. 

    vtmap, you're saying the Outback inverter can be grid tie but not generating excess power?  I am not sure how that can work because how would it know without a way of measuring your entire house load?  I know that with the Hybrid Outback Grid tie, you can turn on or off selling power to the grid.... but not sure about the Grid Zero. 


  • Raj174Raj174 Solar Expert Posts: 795 ✭✭✭✭
    edited August 2016 #5
    Hi jimmyaz,
    I have a Radian GS4048A and use grid zero daily. It is also available in the newer FX series of Outback inverters. Grid zero is a mode that blends grid power with solar RE production. This is done by setting the amount of power you want to supply from the battery/solar and the rest of the load demand is supplied by the grid. Because the grid supplies any power beyond what you've designated from the batteries, the surge loads can be greater than one would normally be limited to by a given size inverter. As an example my system supplies my whole house except the clothes dryer and the range. The sub panel has breakers for 2 ton A/C unit, heat pump water heater, and all lighting, fans and outlets. It allows self consumption of the power that your system produces and is a backup system if the grid goes down. 

    This is an OpticsRE graphic of grid zero mode in operation. any black line above the red is solar self consumption.

    Rick



    4480W PV, MNE175DR-TR, MN Classic 150, Outback Radian GS4048A, Mate3, 51.2V 360AH nominal LiFePO4, Kohler Pro 5.2E genset.
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,028 ✭✭✭✭✭
    Other names for this are "self consumption" or "zero export"  Schneider does this on the XW and SW with modbus powermeters to throttle back your output to the grid.
    Hawaii is also doing this because there is too much solar for their island based power system that burns bunker oil. This was from a Hawaiian newspaper today.  Not the lousy wiring practice on a building inspected installation.


    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • jimmyazjimmyaz Registered Users Posts: 114 ✭✭
    edited August 2016 #7
    Raj174 said:
    Hi jimmyaz,
    I have a Radian GS4048A and use grid zero daily. It is also available in the newer FX series of Outback inverters. Grid zero is a mode that blends grid power with solar RE production. This is done by setting the amount of power you want to supply from the battery/solar and the rest of the load demand is supplied by the grid. Because the grid supplies any power beyond what you've designated from the batteries, the surge loads can be greater than one would normally be limited to by a given size inverter. As an example my system supplies my whole house except the clothes dryer and the range. The sub panel has breakers for 2 ton A/C unit, heat pump water heater, and all lighting, fans and outlets. It allows self consumption of the power that your system produces and is a backup system if the grid goes down. 

    This is an OpticsRE graphic of grid zero mode in operation. any black line above the red is solar self consumption.

    Rick



    Hi Rick,

    Thanks for joining in.  I understand how the grid zero suppose to work.  I know that it join your ultility power + Solar + battery (base on battery voltage).  What I don't understand is how it's wired and how it work.  So does grid zero = mean completely 100% no extra power is going back to the grid?  my smart meter should not be detecting anything?

    If this is the case, do i still need to notify my Power company?  Or can I just get a license electrician to do my wiring and since I do not feed the grid, I am not require to contract with my power company?

    Secondly, how does the sub-panel work?   Do you have to move all the load you're going to use to the sub-panel?  So basically you need to move all the breaker (load) you want to use to the sub panel?  Sound like it's going to cost a few grand to just re-do the wiring... The last time I had a subpanel added, cost almost 1k.... this sound a lot more work.

    attached image
  • Raj174Raj174 Solar Expert Posts: 795 ✭✭✭✭
    edited August 2016 #8
    Hybrid inverters are capable off selling to the grid and I would say most power utilities would require that they be informed of the connection. I would check with the local utility to be sure. However grid zero and mini grid modes do not send power to the grid.

    Your drawing is correct except, you will want a bypass switch to bypass the inverter to power the sub panel directly from the main panel if necessary.

    Yes, it is expensive if you can't do the work yourself. If you have room to put the sub panel next to the main panel it shouldn't cost that much. I installed mine that way and it took about 4 hours total. 

    Rick  
    4480W PV, MNE175DR-TR, MN Classic 150, Outback Radian GS4048A, Mate3, 51.2V 360AH nominal LiFePO4, Kohler Pro 5.2E genset.
  • jimmyazjimmyaz Registered Users Posts: 114 ✭✭
    edited August 2016 #9
    Hi Rick,

    Thanks for the info.  I have done all the work myself so far on my off grid and I know I can do the sub panel no problem.  But the issue here is... If I call the power company and ask them, then I would revealed that I am planning to do this... If they allow, good, but if not then they know what I am up to. :D

    Can you tell me what charge controller you are using?  I was using the Outback Flex80, it was good, until is pulled a stunt where it go into "charged mode" after absorb and just stuck there and let my battery die even when PV power is available.  Outback told me, this can happen randomly and not sure how to fix it... lolz.  How is that random, they blame my PV could be bad... but there was still input voltage was showing 70volts, just no amps out.

    So after that I bought a Mate3, figured I can use the OpticRE system to notify me battery low voltage in case it happen again... (OutBack technician told me with OpticRE it can send me an email if battery voltage is low.)  Then after I bought the Mate3 and got it going, I figured out that it can't do this.  It can only do the Battery SOC notification, required to add on a stupid FLEXDC or some sort... going to cost more money.

    600.00 for Flex80, 400.00 for Mate3 and now they want another 300 for the FlexDC crap... So I decided to buy a Midnite Classic 150 and be done with it... local application, online internet monitor.... never had problem so far.

    Can you tell me if this is right... To do your set up, you need the Mate3, Outback Hybrid Inverter (Radian or FXR) + Outback Flex charger (need to be on GT Mode?)


    My main power panel is on the side of my Garage.... and my system is basically right behind it inside the Garage... So litterally I can put the sub-panel back to back with the main panel...





  • Raj174Raj174 Solar Expert Posts: 795 ✭✭✭✭
    edited August 2016 #10
    jimmyaz,

    I have the Mate3 and the Radian, but I do not use the Flexnet DC battery monitor. I have a Classic 150 with a whiz bang jr.  to monitor battery SOC. For low and high battery voltage alert/alarm I use a programable JLD404AH amp hour digital meter that has built in NO and NC relays for alarms. It was 68 dollars. You can use 12 volt piezo alarms or relays to shutdown the system. Here is the link to the meter...

    http://www.electriccarpartscompany.com/ECPC404-Ammeter-and-Voltmeter-br-Intelligent-Digital-EV-Battery-Pack-Monitor-br-Amp-Hour-Counting-br-USA-Stock_p_425.html

    In my opinion, My Midnite and OpticsRE together make pretty effective monitor and management tools.

    It sounds like you have a good place to set up your sub panel. I used a small 125 amp GE sub panel with the half width breakers, really low cost, easily less than 100 dollars for panel and all 120v and 240v breakers.

    Rick     
    4480W PV, MNE175DR-TR, MN Classic 150, Outback Radian GS4048A, Mate3, 51.2V 360AH nominal LiFePO4, Kohler Pro 5.2E genset.
  • jimmyazjimmyaz Registered Users Posts: 114 ✭✭
    Hi Rick,

    Do you have picture of your set up, possibly wiring?  If you can share I would really appreciated...

    This is what I really should have done, instead of putting in a sub-panel and run 3 separate outlet to my home... dump idea. 

    So the Radian decide whether invert power from your battery or not depend on the DC Voltage you set?   Can you elaborate on this?  Let say 24v bank,  if there's no communication between inverter and charger, how can it know that the system has already go into absorb mode and battery is full?  If it's just base on voltage, say you set when battery get to 27v, start using for load, but if the load is huge, it will drag the battery voltage down and the charge controller can never go into Absorb mode.


  • Raj174Raj174 Solar Expert Posts: 795 ✭✭✭✭
    Hi jimmyaz,

    There are two settings for grid zero. DOD volts and DOD amps. DOD volts is self explanatory. The inverter will not take the battery voltage below this point. In my system that's 52 volts or about 40% SOC. DOD amps is the max amps AC you want the inverter to draw from the battery. The range is 1 to 15 amps at 240 volts. I usually use 5 or about 1250 watts. The Radians are a 48 volt inverter only. I believe the FXRs are 120 volt.

    Your question about the charge controller communicating with the system to let the Radian know when it can start is a good one, and very necessary if you are using a lead acid or AGM battery where reaching absorb and float is critical to the life of the battery. I can't say that I know the answer to that. I use a Lithium Iron Phosphate/LiFePO4 195 AH battery and it cycles between 40 and 90% SOC. If it is at 90% at the end of the day then that's great. The whiz bang jr. resets and battery will carry me to about midnight. I do try to reach float every few days to reset the SOC reading.

    I do know that when I leave the Radian in grid zero mode, it will start using power as soon as the panels supply it in the morning. I searched a bit but couldn't verify the requirement for charge controller communication, but I don't see how it could work otherwise.

    Anyway, here's a pic of the wiring during the install. 240 volt AC comes in to the Epanel from the main panel through the 1 1/2 inch conduit on top right, loops through the bypass switch, left side top, and back out through the same conduit. Both in and out using the buss bars. If the bypass switch is flipped then the inverter output goes to the sub panel. Battery bank below with high and low voltage disconnect relays not wired yet as of this picture.

    Rick   

     


    4480W PV, MNE175DR-TR, MN Classic 150, Outback Radian GS4048A, Mate3, 51.2V 360AH nominal LiFePO4, Kohler Pro 5.2E genset.
  • jimmyazjimmyaz Registered Users Posts: 114 ✭✭
    edited August 2016 #13
    Thank you so much for posting the picture.  Sorry for keep asking more and more question, but your set up is great, it seem like it's the ultimate set up and eventually I would have to go this route as well.

    So I call around to some of the Solar Contract around here to ask about the power utility company would require permission or not regarding Grid Zero mode.  One guy told me that he knew someone who's tried to use the Outback Hybrid in Grid Zero and it didn't do 100% good on the grid zero and it feed the grid and the power company came and force him to remove it.  Could you confirmed that your Radian never never feed even 1 watts to the grid?  Do you have a smart meter?  Does your ever show the reverse arrow and stay stuck there?

    I see more and more people use LiFePO4 ..... I use Lithium Polymer for Remote Control a lot and they are very easy to PUFF (Swell).... I have seen youtube video of LiFePO4 swell as well... Wondering if they are dangerous like Polymer? (explode, catches on fire).  I see people say LiFePO4 are A123 alike, but I thought A123 have the metal shell?  no explosion.

    Also, how much did your LiFePO4 battery cost?

    thanks again.
  • Raj174Raj174 Solar Expert Posts: 795 ✭✭✭✭
    Jimmyaz,

    Yes I have a smart meter and have never seen any evidence of sending power to the grid. The way grid zero works makes the name kind of a misnomer. It always takes at least 1 amp from the grid, so It will not feed the grid in that mode unless there is some kind of malfunction. Of course it will never zero out grid use either. The minimum grid use in grid zero would be about 5 kWh per day unless the load was less than that at some point.

    LiFePO4 can "puff" if they are severely over charged, but they do not explode or catch fire. A123 is a cylindrical battery as far as I know. These are large cell prismatic batteries. There are 3 or 4 Chinese manufacturers that make them.
    I paid about 3000.00 plus shipping, maybe 3100.00 total. They weigh about 210 lbs. There are a lot of advantages to them but 2 serious disadvantages. One is the cost. Two is that if they are seriously over charged just once it will kill them. The same for drawing them down too far, one time and they are done.

    Rick
    4480W PV, MNE175DR-TR, MN Classic 150, Outback Radian GS4048A, Mate3, 51.2V 360AH nominal LiFePO4, Kohler Pro 5.2E genset.
  • jimmyazjimmyaz Registered Users Posts: 114 ✭✭
    Really, are you saying in GridZero stand by mode it's using 230volts X 1 amps = 230watts? Why does it require that mad power? to operate?  5kw is half of what my system can generate a day...   Or are you saying that's how much you're GridZero uses + your load per day?

    Seem like 62volts X 195AH = 12000kw?   = 3k  is still way cheaper than what Elon Musk is promising...
  • Raj174Raj174 Solar Expert Posts: 795 ✭✭✭✭
    No, the inverter uses 34 watts. Grid zero mode always allows the load to get the first 1 amp at 240 volts. So, let's say the load is 480 watts. The grid provides the 1st amp AC and the batteries the 2nd. If the load is 120 watts, it all comes from the grid. If your away 24 hours and you leave a 240 watt load running then all of the load will be supported by the grid. Only loads above 240 watts are supported by grid zero.
    4480W PV, MNE175DR-TR, MN Classic 150, Outback Radian GS4048A, Mate3, 51.2V 360AH nominal LiFePO4, Kohler Pro 5.2E genset.
  • jonrjonr Solar Expert Posts: 1,386 ✭✭✭✭
    Raj174:  If you measure the voltage on each cell, are they all remaining at exactly the same voltage?

    I am available for custom hardware/firmware development

  • Raj174Raj174 Solar Expert Posts: 795 ✭✭✭✭
    Hi jonr,

    No, not exactly. They have been in service for almost 3 months and are all within .005 volts. They were all top balanced in parallel for about 24 hours. I check balance every couple of days. Initially much more often.

    Rick
    4480W PV, MNE175DR-TR, MN Classic 150, Outback Radian GS4048A, Mate3, 51.2V 360AH nominal LiFePO4, Kohler Pro 5.2E genset.
  • jonrjonr Solar Expert Posts: 1,386 ✭✭✭✭
    Interesting.  Do you think there is or will be any value to putting  a balancing resistor across each cell?

    I am available for custom hardware/firmware development

  • Raj174Raj174 Solar Expert Posts: 795 ✭✭✭✭
    No, I never charge the batteries to 100% and from reading all the various forum posts and all my research on LFP it believe they will maintain pretty good balance for many months charging and discharging at less than 1/3 C levels. 
    4480W PV, MNE175DR-TR, MN Classic 150, Outback Radian GS4048A, Mate3, 51.2V 360AH nominal LiFePO4, Kohler Pro 5.2E genset.
  • jimmyazjimmyaz Registered Users Posts: 114 ✭✭
    Hi Rick,

    I think you can buy balancer for them.... For Remote Control use, we all use lithium balancer, it hook into each of the cells and balance them.


  • Raj174Raj174 Solar Expert Posts: 795 ✭✭✭✭
    Thanks, but not necessary.
    4480W PV, MNE175DR-TR, MN Classic 150, Outback Radian GS4048A, Mate3, 51.2V 360AH nominal LiFePO4, Kohler Pro 5.2E genset.
  • jimmyazjimmyaz Registered Users Posts: 114 ✭✭
    Raj174 said:
    No, the inverter uses 34 watts. Grid zero mode always allows the load to get the first 1 amp at 240 volts. So, let's say the load is 480 watts. The grid provides the 1st amp AC and the batteries the 2nd. If the load is 120 watts, it all comes from the grid. If your away 24 hours and you leave a 240 watt load running then all of the load will be supported by the grid. Only loads above 240 watts are supported by grid zero.
    Hi Rick,

    Do you have any idea if the Radian is being power by AC or DC?  Meaning is the 34watts self consumption is coming from the Grid AC or your battery DC?

    thanks
  • Raj174Raj174 Solar Expert Posts: 795 ✭✭✭✭
    It's DC, just like any other inverter, because it requires the battery to power up. 

    4480W PV, MNE175DR-TR, MN Classic 150, Outback Radian GS4048A, Mate3, 51.2V 360AH nominal LiFePO4, Kohler Pro 5.2E genset.
  • jimmyazjimmyaz Registered Users Posts: 114 ✭✭
    edited January 2017 #25
    Raj174 said:
    It's DC, just like any other inverter, because it requires the battery to power up. 

    Hi Rick,

    Sorry to bring back this old topic.  But could you let me know how's your Radian set up? for 220volts?  Can you run a 120volts load off it?  Does it automatically balance the load if there's differences?




  • Raj174Raj174 Solar Expert Posts: 795 ✭✭✭✭
    edited January 2017 #26
    No problem, glad to help. The Radian is 240 volt and yes you can run 120 volt loads on it, however one would want to balance the loads between L1 and L2 for better efficiency. The manual states that 2000 watts per line should not be exceeded on the GS4048A. There is no automatic load balancing. So as you can see the Radian can tolerate a 50% imbalance.

     From the manual:

    IMPORTANT:

    •   The Radian inverter cannot support severe output load imbalance. The GS8048A can maintain no more than 4 kVA continuously on either the L1 or L2 output, regardless of the load on the other output. For example, it cannot maintain 8 kVA on L1, even if the load on L2 is 0.

    •   Similarly, the GS4048A can maintain only 2 kVA on a single output, regardless of the state of the other output.

    •   Any greater loads (at 25°C) will cause a Low Output Voltage error. 

    4480W PV, MNE175DR-TR, MN Classic 150, Outback Radian GS4048A, Mate3, 51.2V 360AH nominal LiFePO4, Kohler Pro 5.2E genset.
  • mike95490mike95490 Solar Expert Posts: 9,359 ✭✭✭✭✭
    Here's the imbalance spec for the   Conext XW+ 6848
       AC Output Current (maximum 75% imbalance between L1-N, L2-N) in Inverter Mode
    http://solar.schneider-electric.com/product/conext-xw-na-solar-inverter/

    page 124 of user manual









    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 ,

  • jimmyazjimmyaz Registered Users Posts: 114 ✭✭
    Raj174 said:
    No problem, glad to help. The Radian is 240 volt and yes you can run 120 volt loads on it, however one would want to balance the loads between L1 and L2 for better efficiency. The manual states that 2000 watts per line should not be exceeded on the GS4048A. There is no automatic load balancing. So as you can see the Radian can tolerate a 50% imbalance.

     From the manual:

    IMPORTANT:

    •   The Radian inverter cannot support severe output load imbalance. The GS8048A can maintain no more than 4 kVA continuously on either the L1 or L2 output, regardless of the load on the other output. For example, it cannot maintain 8 kVA on L1, even if the load on L2 is 0.

    •   Similarly, the GS4048A can maintain only 2 kVA on a single output, regardless of the state of the other output.

    •   Any greater loads (at 25°C) will cause a Low Output Voltage error. 

    So the 2000watts per a line is how much it can invert right?  Does not count the pass through power it can carry from the grid? 
  • WaterWheelWaterWheel Registered Users Posts: 340 ✭✭✭
    edited January 2017 #29
    Jimmyaz,     While Dave could probably explain this better I use a Conext XW 6848 usually off grid.    The breaker between the old home panel and the PDP (inverter's power distribution panel)  is usually off.        But if we have several cloudy days I flip the breaker on and allow the Grid power to go into the inverter.        I have the inverter set to "Sell to Grid" is off and "Grid Support" is on.      This allows the grid to protect the batteries from becoming drained if needed.

    When set this way the inverter will always accept about 80 watts from the grid so that the inverter can see the AC HZ the Grid is supplying.       The inverter must see this AC cycling so the inverter can match the hz exactly when the inverter supplies power.       Let's say I have a 400 watt load.     The grid will supply about 80 watts and the batteries/inverter will supply the rest as long as the battery voltage is above the set point (set point is adjustable).      When a heavy load kicks on (well pump kicks in while the mini split is running) the battery voltage may drop below the battery voltage set point.      In this situation the inverter will automatically accept more power from the grid but when the load is reduced and the battery voltage is once again above the set point the inverter will reduce the power accepted from the grid back to about 80 watts and the inverter will supply the additional power needed.       If the batteries get too low the grid will automatically take over 100% of the load protecting the batteries.

    If the inverter didn't accept a small amount of power from the grid the inverter would not be able to let the grid kick in almost instantly for heavy loads.       I have never seen the inverter produce more power than the house loads require so no power going back to the grid.     

    I had originally planned to sell to the grid so the XW 6848 is capable of sending power back to the grid but due to the local power company charging high meter fees for a 2 way meter I've never gotten the meter to sell back to the grid.       The local solar guy said that in my county I did not need to inform the local power company as long as I did not run the inverter in "Grid Sell" mode... but I live in a rural county and we never even had a building inspector until a few years ago so your power company and building inspector may need to be informed if you want to stay 100% kosher.       I installed the system myself but did bring an electrician out to run the subpanel final wiring so I remained in compliance with local codes in an effort to make sure my home insurance could never be denied if I ever had a claim.

    Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor

    21 SW280 panels on Schletter ground mount

    48v Rolls 6CS 27P

  • jimmyazjimmyaz Registered Users Posts: 114 ✭✭
    Jimmyaz,     While Dave could probably explain this better I use a Conext XW 6848 usually off grid.    The breaker between the old home panel and the PDP (inverter's power distribution panel)  is usually off.        But if we have several cloudy days I flip the breaker on and allow the Grid power to go into the inverter.        I have the inverter set to "Sell to Grid" is off and "Grid Support" is on.      This allows the grid to protect the batteries from becoming drained if needed.

    When set this way the inverter will always accept about 80 watts from the grid so that the inverter can see the AC HZ the Grid is supplying.       The inverter must see this AC cycling so the inverter can match the hz exactly when the inverter supplies power.       Let's say I have a 400 watt load.     The grid will supply about 80 watts and the batteries/inverter will supply the rest as long as the battery voltage is above the set point (set point is adjustable).      When a heavy load kicks on (well pump kicks in while the mini split is running) the battery voltage may drop below the battery voltage set point.      In this situation the inverter will automatically accept more power from the grid but when the load is reduced and the battery voltage is once again above the set point the inverter will reduce the power accepted from the grid back to about 80 watts and the inverter will supply the additional power needed.       If the batteries get too low the grid will automatically take over 100% of the load protecting the batteries.

    If the inverter didn't accept a small amount of power from the grid the inverter would not be able to let the grid kick in almost instantly for heavy loads.       I have never seen the inverter produce more power than the house loads require so no power going back to the grid.     

    I had originally planned to sell to the grid so the XW 6848 is capable of sending power back to the grid but due to the local power company charging high meter fees for a 2 way meter I've never gotten the meter to sell back to the grid.       The local solar guy said that in my county I did not need to inform the local power company as long as I did not run the inverter in "Grid Sell" mode... but I live in a rural county and we never even had a building inspector until a few years ago so your power company and building inspector may need to be informed if you want to stay 100% kosher.       I installed the system myself but did bring an electrician out to run the subpanel final wiring so I remained in compliance with local codes in an effort to make sure my home insurance could never be denied if I ever had a claim.
    Hi WaterWheel,

    Thank you for your reply... I've been looking at the Conext SW all morning and it's impressive for the price point.  I also called Conext tech and he said the SW can not sell back to the grid.  So that should be a good thing for me... Same situation here, we have two big power company here and I happen to landed into the greedy one, so they don't like solar.  I do understand that solar producer does put a lot of stress on the grid.  But soon all will have self battery storage anyway.

    My current situation of running a completely off grid system with a separate sub panel is I can not fully used all the power my system produce during high peak and often used too much out of my battery bank.  I did not know about this Hybrid features when I first decided to do a off-grid (not enough research from my side). 

    I see the great thing about Conext is they sell the AC box and DC box all set up, would be easy connect.  I was thinking if I go to this, I can maybe hook up one of my full size 3tons air conditioner to this and during summer time my solar can offset the usage more.... But the tech told me the pass through power is 60amps...  Can any of you guys confirm a 3 tons AC compressor would not surge more than this?  60A X 220= 13,000watts... I sure hope it doesn't sure more than this... :)

    I know it pull about 2,500 when running, hard to measure the surge.




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