Warning Beginner!! - 3KVA Solar Inverter overloading even though 'Bypass' is displayed

mbladenmbladen Posts: 20Registered Users ✭✭
I have began a small project that I have had on the back burner for many years, which is to provide a simple power back up for when we have the annoying powercuts here in Turkey. 

I had read the scant info on various Inverters and decided (mainly due to budget) to go for an MPP OEM 3KVA, I am starting to wonder if I have completely misunderstood its function.

Although it is wired to the whole house which occasionally peaks at around 6KVA my intention was that through using smart wifi sockets I would disable all major (>500w) loads when a power cut occurs and so 3KVA would be more than ample to provide the home with sufficient power (approx 300w load peaking at 500w with fridge/freezer)

I have installed my equipment and it is up and running but when I run anything above 2400W it overloads as though it is continuously using the Inverter rather than just when it is needed. 

Do I have to size the inverter for the maximum peak load even though this will only be used when there is main power? or should there be a setting/mode that I need to enable for me to 'by-pass' this load tripping circuit.



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Comments

  • mcgivormcgivor Posts: 1,750Registered Users ✭✭✭✭
    In order for anyone to answer questions you would need to provide more details, im assuming this could be grid tied with battery backup, responders would need as many details at possible, just trying to save you time as many are in a different time zone and the sooner the details are given, the sooner the responses will come. 
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

  • mbladenmbladen Posts: 20Registered Users ✭✭
    Mcgivor, many thanks for the heads up. you are correct it is a grid tied device with battery back-up

    This is the exact unit (TURKISH) http://urun.gittigidiyor.com/ev-elektronigi/3000va-24v-tam-sinus-akilli-inverter-ekranli-251876236?rcp_action=rceProductClicked

    but its an MPP OEM which can be seen here, http://www.mppsolar.com/v3/pip-hsemse-series/ 

    its basically a 3KVa 24v pure sine inverter, I am not currently using any Solar panels just mains and Battery  2 x Yuasa SWL2500fr 

    if there is anything else you may think would be useful please let me know.

    kind
    regards

    Marc
  • mcgivormcgivor Posts: 1,750Registered Users ✭✭✭✭
    edited December 2016 #4
    After checking Yuassa 2500fr, the results state that they are 90Ah batteries, is this correct? 
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

  • EstragonEstragon Posts: 2,314Registered Users ✭✭✭✭
    When running off grid power, the inverter should be simply passing current from grid to loads.  When grid drops, the inverter should cut over to battery power.  I'm not familiar with this particular inverter, but I'm assuming that's how it should work.

    I would first establish where the inverter is getting its power from when it overloads.  You may be able to use a simple multimeter to see if the voltage on the battery bank drops with loads on.  If the current is being passed through from grid to loads, battery voltage should stay the same or even increase (being charged from grid) with loads turned on.  

    I would also check the frequency and voltage of the AC grid power with the multimeter.  You mentioned you get a lot of outages, which makes me wonder whether the grid power, even when available, may be out of spec for the inverter.  This may be adjustable (within limits) on the inverter, but might be set to a narrow default value.

    The english spec sheet refers to a UPS mode with a 10ms cut over time and an appliance mode with a 20ms cut over time.  I don't know if the modes have any other differences that might be a factor, so maybe check the manual.      
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • mbladenmbladen Posts: 20Registered Users ✭✭
    Mcgivor - Yes Sorry I should of said that save you the hassle of checking :blush: 

    Estragon - I wish it did work in the way you described, the graphics on the front seem to show a nice clear bypass which would indicate that it was passing the current from grid to load, the grid voltages are in line with the inverter 235-245v is waht I see going in and out of the inverter.

    The manual is not good, I will change over to UPS mode as the manual states it is in appliance mode as standard and my V range is within 170-280 and see if this makes a difference.

    But at least you have confirmed that I am not going insane and that bypass should mean bypass i.e. whilst on grid it does not use the functions of the inverter at all other than to monitor the input, output of the attached sources.

    thanks

    Marc

     

  • EstragonEstragon Posts: 2,314Registered Users ✭✭✭✭
    edited December 2016 #7
    You may want to check the manual for a total AC input limit.  There should be one, but if it's around [email protected] (rated output) seems pretty low.  My outback (120V), for example, is 30A output, 60A input.

    You may also want to consider separating your critical loads (those to be supported during blackouts) from non-critical.  You would put the critical loads in a separate sub-panel connected to the inverter then on to an appropriate sized breaker in the main panel.  This way your non-critical loads are automatically off during an outage rather than using wi-fi socket relays.  I'm not sure how the wi-fi would work during an outage (does it have its own backup power?).


    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • westbranchwestbranch Posts: 5,024Solar Expert ✭✭✭✭
    you might find this interesting...  got it yesterday   http://www.kingnen.com/cpzxEC/list_52_cid_14.html
    there is a PDF somewhere explaining how it works

     
    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, Hughes1100 Sat Modem
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • mcgivormcgivor Posts: 1,750Registered Users ✭✭✭✭
    edited December 2016 #9

    mbladen said:
    Mcgivor - Yes Sorry I should of said that save you the hassle of checking :blush: 

    Estragon - I wish it did work in the way you described, the graphics on the front seem to show a nice clear bypass which would indicate that it was passing the current from grid to load, the grid voltages are in line with the inverter 235-245v is waht I see going in and out of the inverter.

    The manual is not good, I will change over to UPS mode as the manual states it is in appliance mode as standard and my V range is within 170-280 and see if this makes a difference.

    But at least you have confirmed that I am not going insane and that bypass should mean bypass i.e. whilst on grid it does not use the functions of the inverter at all other than to monitor the input, output of the attached sources.

    thanks

    Marc

     

    It would seem to me by your confirmation that the battery is 90Ah @ 24v, this is a very small reserve and may power your loads for a short period before the battery voltage drops to the low cut off shutting down the inverter. To add to this the higher the load, AC side, the lower the battery voltage would be, explaining why it cannot support  loads  larger than 2400W, 
    A calculation of all you loads during an outage is in order to establish a base, from that a calculation based on the average outage duration, inverter and other losses and depth of discharge, so as not to damage the battery, can be made. My opinions based on an educated guess and the focus is on the battery size only.
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

  • EstragonEstragon Posts: 2,314Registered Users ✭✭✭✭
    Mcgivor - agree the loads vs bank is worth looking at, but the issue at the moment seems to be getting grid power to pass through with normal loads.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • mcgivormcgivor Posts: 1,750Registered Users ✭✭✭✭
    True enough, didn't see the forest because of the big tree in front of it. Could be a setup error which would be hard to diagnose via long distance ping pong communication, attached is the manual I believe is for that unit for those willing to ponder.
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

  • mbladenmbladen Posts: 20Registered Users ✭✭
    Thanks both for your time and comments, The actual manual (slightly older 1.8 instead of 2.0) can be seen here http://www.mppsolar.com/manual/PIP-HS,MS,MSD,MST/PIP-HS 1-5KVA.PDF

    I can only find a breaker rating of 32A which would be more than sufficient for my Maximum load. currently it is acting as though it is running in invertor mode, which it definitely is not as the batteries are not being used and Bypass is displayed on the LCD.

    It is too problematic at this stage to isolate the heavy loads as the house (in Turkey) was wired in 1990 and so only had 2 circuits, even the Lights and power are currently on the same circuits, I have managed to isolate the A/C units in a previous project but still have wiring that would not be acceptable in todays standards.

    The Wifi units work well even in outage mode as the Inverter would only trip if 2 heavy loads or more were running (this is the same in line mode currently hense my problem) 

    We had a brief area power outage this morning and the inverter kicked in fine, no loss of power everything was amazing, now bearing in mind this Taiwanese unit can be bought for less than £250/300Euros and my 2nd hand Batteries cost me £40 each for less than £350 including cables/connectors its almost a brilliant back up.

    I am not worried about Battery capacity at present that will be phase 2, when I get this working properly, I hope to end up with a full solar system and realise that at this point I would need to upgrade my inverter to something with a little more guts, but at present other than the unit not giving me true bypass its amazing.

    I have emailed the original manufacturers (MPP) but may not get a response until next week, we are currently using the system in anger and other than forgetting about the 2 heavy load limit its great.

    Thanks for your time and patience

    regards

    Marc 
  • mcgivormcgivor Posts: 1,750Registered Users ✭✭✭✭
    Hi Marc, 
    Wonder about the quality of the grid power, in the trouble shooting section, ,third down, mains exist but works in battery mode, green led flashing, insufficient AC quality? If there are voltage fluctuations or phase drift, perhaps this could be the problem. There could be sag or swells that a digital multimeter is incapable of detecting, a power quality analyzer would capture them. 
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

  • EstragonEstragon Posts: 2,314Registered Users ✭✭✭✭
    I was wondering about mains power quality too, but the inverter apparently shows bypass mode. Also wondered if it was set to use solar input but that would show the flashing green you mention and also presumably wouldn't show bypass. I dunno.

    Looks like a nice inverter for 350 quid. Hopefully mfg support can help.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • mbladenmbladen Posts: 20Registered Users ✭✭
    edited December 2016 #15
    https://goo.gl/photos/E2v9fMAn1wBqn7Lc7

    mcgivor - the Lcd panel shows AC operation (Green static) and Charged Battery (Green static) I'm no Mains power expert but the display seems to fluctuate between 235 and 245, I think i have managed to upload a photo of the display.

    The Input V and Output V seem to be matched everything seems normal apart from bypass doesnt seem to mean bypass :-) we are living with it at the moment but I fear that we will have to ditch it if I cant solve this problem as the wife is not happy about only having one load on at a time :-)

    The unit can be had for £288 or $350 on the ebay uk and com sites, and would be an awsome unit if only there was a little more to the manual and support was more easily available, note to self, dont install a new toy on a friday and have to wait until Monday for support :-)

    I
  • mcgivormcgivor Posts: 1,750Registered Users ✭✭✭✭
    edited December 2016 #16
    Speaking of support has Taiwan responded yet? There must be an explanation, it has been the weekend so perhaps soon, there must be a logical explanation, it seems,despite the price, to be a sophisticated piece of gear. There must be a setting that was missed in the initial commissioning, I wouldn't give up, wait for tech support there may be a simple explanation. To add to that, what I would do is to default everything and start fresh.
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

  • mbladenmbladen Posts: 20Registered Users ✭✭
    Mcgivor, thanks for your patience I have been emailing everyman and his dog and have got no where other than to find out it is not an oem Mpp unit from Taiwan, although it seems identical in everyway even the software (that wont load) to the 2400va model they have on their website.

    They did reply, before telling me it wasn't one of theirs, and said that the rating is in fact the maximum throughput of the unit no matter which mode the unit is in as the power will still pass through the unit even if there is mains power.

    Initially I though this would cause me/family a massive problem and I was ready to rip the unit out, however we have now lived with it for 10 days and are loving it, we have had a couple of power cuts since the install and we have not been affected, the biggest change has been monitoring the way we use our power, which has been a good thing :-) so we cant have the Oven,Dishwasher,Washing machine,toaster and kettle on at the same time, in fact we cannot have 2 of the above on simultaneously.

    This was a little problematic initially but with most of the loads being in the Kitchen the TP-Link HS110 wifi sockets have help check if the water heater was on/off and so its been manageable, my wife has had to become a mini magician juggling the different loads in the kitchen when doing a more complicated meal.

    I am thinking about trying to isolate some of the Larger loads (Oven/Water Heater) and only have them run on the mains, then run everything else through the Inverter which would cut down on the inconvenience, 

    The reseller here in Turkey has not responded although I did only send it through in English, I'll try again in my Turkish and see what happens


  • mbladenmbladen Posts: 20Registered Users ✭✭
    I just wanted to finish off this post in case anyone else reads it in the future, I'd like to extend my thanks to Mcgivor for his help off forum.

    The system is now in place



    It took longer that initially thought as I had to change the main exterior meter box (middle), which involved getting a "real" turkish electrician in to make a mess, it took him 3 hours to change the box and then it took me 7 hours to clean up the mess and excess plaster!!!.

    So the system consists of a 3000va (2400w) smart inverter which can receive power through Main, Solar and Battery, there is also a generator auto start (green box at the bottom of the main Tommatech inverter) so it really does do a lot for its money (£290/$350/490AUD) it is connected to a 24v 360ah battery pack made up of 8 x 90ah Yuasa deep-cycle batteries.



  • mbladenmbladen Posts: 20Registered Users ✭✭
    Here is a very rudimentary schematic (Colour of the writing matches the colour of the lines)



    So whilst I am not able to run loads higher than 2400w while in Inverter mode I installed the switch as previously all electric paths went through the inverter and in the event of an inverter failure I would be left without any electricity, also if I know I will have large load demands (xmas dinner, or extra guests staying with us) I can decide to switch over to purely mains electric.

    I have since increased the battery bank to 360ah and my future plans include installing 2 x 265w Poly solar panels (£128/$158/217AUD each) I have been researching best practices and I think that I will construct an adjustable tilt frame to mount the panels on to give me maximum efficiency in each season.

    Many thanks for the support i received 

    take care

    Marc
  • mbladenmbladen Posts: 20Registered Users ✭✭
    Wanted to drop by and give a 3 Month update, 

    In short its awesome for what I paid. I have since installed another 2 panels which bring the solar up to 1kW. The Inverter's WatchPower software is a little kooky and doesn't always deliver the expected results after configuration and even sometimes it seems to take a few hours/a day for new settings to fully take effect even so I now have it running well.

    Spring has just started here in Turkey and we are experiencing sunrise around 07:30 and sunset around 19:30 so 12 hours of sunlight. The sun is still quite low on the horizon and my panels ended up being installed to fit in with my life rather than optimally, they are facing south east and run at around 30 degrees (probably more idea for summer) but that is how my roof lies.

    The inverter starts to take a charge (1amp) as early as 08:00, by 11:00 is 11a and between 12:30 and 16:30 can be as much as 26a which i guess equates to approx 70% of full potential, I would like to think that as we move towards Summer that will also increase, but even if it didnt i'd be happy.

    My system has cost approx £1300 ($1600/2200AUD) and is more than capable of running the normal load (500w inc fridge freezer) most of the sunlight hours. I have started to change some of my habits to heat water tanks at night so that the system is then used only to maintain that temperature, It can also deal with the daily use of heavy short term loads e.g. kettles and microwaves, I am a little concerned about these loads draining at a rate of 1/5th of the battery but its short term and I'm hoping that it can cope.

    I have seen the new range of Hybrid inverters similar to mine but with everything upgraded and also its the first one that I have found that deals with 5kW which would satisfy 2 simultaneous loads in my house, its approx £900 but i may just stick to the one I have as its working perfectly well apart from the load issue which we are managing.

    Thanks once again for all your help, it was really appriciated
  • mcgivormcgivor Posts: 1,750Registered Users ✭✭✭✭
    edited March 2017 #21
    Good to hear from you again,  things are working out and that is always good news, keep up the perseverance, who knows what summer will bring, you've come a long way, good luck! 
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

  • mbladenmbladen Posts: 20Registered Users ✭✭
    Alas today my system has hit a bump in the road, it appears the inverter has decided that it will no longer receive a charge from the Solar panels, I had been getting a comfortable 20amp average between 10am and 6pm. Occasionally the inverter would click to grid and reset the charge value (as though it had lost connection to the panels) but it was quite rare.

    Currently it says it is receiving power from the panels however it is 0amp, I have quickly disconnected the cables are re-connected (i have a 2 twin connections plugged into another twin connection then it is direct to the inverter about 7m away. I have 6mm cable.

    Tomorrow I will investigate and do a bit more searching, I guess what I need to do is somehow prove there is power coming to the inverter before I contact the manufacturure.
  • EstragonEstragon Posts: 2,314Registered Users ✭✭✭✭
    Can you check the voltage at the pv connection terminals on the inverter?
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • mbladenmbladen Posts: 20Registered Users ✭✭
    Main Control screen shows no PV Input log files show random 20v and 3-6 amps this doesnt make sense,  yesterday I was getting 28v etc and 0 amps.

    Can I disconnect the + and - PV Cable and test them with my meter?
  • mbladenmbladen Posts: 20Registered Users ✭✭
    If I put my multi meter onto the PV input (2 black cables, one red tape) it reads approx 21.5v, I'm wondering if I should disconnect these and test the actual cables themselves.

    I'm lost in all honesty, other than maybe testing each individual panel i'm not sure what else to do

  • mbladenmbladen Posts: 20Registered Users ✭✭
    Tested the panels on the roof, all reading approx 33.5, tested the parralel converter 4 - 1 again 33.5v, decided to remove the feed from the inverter and test that 33.5v !!!  at this point i'm thinking it has to be the inverter. 

    Re-connect the cables buck up to the inverter at which point the box clicked and kicked back into life, so maybe it was a simple cable connection issue at the Inverter or maybe disconnecting and re-connecting re-set something? 

    May cabling looks dodgy at best as there is only 3mm of cable showing as per the spec of the inverter, i've a good mind to strip it back a little more as it seems the plastic sheathing may be getting in the way? any thoughts?


  • mbladenmbladen Posts: 20Registered Users ✭✭
    Here is a pick of the dodgy cabling


  • mcgivormcgivor Posts: 1,750Registered Users ✭✭✭✭
    Looks like the PV cables have the outer insulation stripped of but still has a plastic wrap, the white material, can only zoom  so much, so not 100% sure if that is what I'm seeing, could have been a high resistance connection??
    Can you confirm if this is the case.
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

  • AguarancherAguarancher Posts: 268Solar Expert ✭✭✭
    "the outer insulation stripped of but still has a plastic wrap"

    i was able to zoom in and you are correct, the plastic coating is still there
  • EstragonEstragon Posts: 2,314Registered Users ✭✭✭✭
    In addition to the inner sheathing probably preventing a good connection - it's hard to tell, but that PV wire looks like it could be aluminum.

    Not necessarily a problem, but the wire should be 1 AWG size bigger than copper for the same current, and the connector should be al/cu rated. What can happen is the different metals react and the less noble metal (al in this case) corrodes. The presence of moisture, especially salty coastal mist, speeds up the process. As the corrosion advances, the connection resistance increases. Eventually, the deterioration of the wire loosens the connection enough to cause arcing an a fire hazard.

    This was a problem years ago in NA residential construction. AL was much cheaper than CU, so it got used for residential branch wiring with unfortunate results. It's now illegal unless special connectors are used for AL/CU interfaces.

    Maybe the wire is tinned copper or something, but it looks like it could be aluminum in the pic. If so, I would use a proper AL/CU connector to add a short copper lead to the PV wire and connect the copper lead to the inverter.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • mcgivormcgivor Posts: 1,750Registered Users ✭✭✭✭
    Estragon said:
    In addition to the inner sheathing probably preventing a good connection - it's hard to tell, but that PV wire looks like it could be aluminum.

    Not necessarily a problem, but the wire should be 1 AWG size bigger than copper for the same current, and the connector should be al/cu rated. What can happen is the different metals react and the less noble metal (al in this case) corrodes. The presence of moisture, especially salty coastal mist, speeds up the process. As the corrosion advances, the connection resistance increases. Eventually, the deterioration of the wire loosens the connection enough to cause arcing an a fire hazard.

    This was a problem years ago in NA residential construction. AL was much cheaper than CU, so it got used for residential branch wiring with unfortunate results. It's now illegal unless special connectors are used for AL/CU interfaces.

    Maybe the wire is tinned copper or something, but it looks like it could be aluminum in the pic. If so, I would use a proper AL/CU connector to add a short copper lead to the PV wire and connect the copper lead to the inverter.


    Doesn't look like aluminum, from what I can see, aluminum has a blunt dull finish, the pictures, from what I can see, look like sharp cuts, aside from that don't think that Europe went the aluminum route, but otherwise you're correct about aluminum, was a disaster in branch circuits, seen some house fires related to aluminum, it work softens,  you need to re torque, I use aluminum for longer high current runs, but understand the limitations and use an antioxidant on all connections.
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

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