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Inverters in Series/Parallel

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  • Pemba
    replied
    Originally posted by tc0nn View Post
    Kinda along the same lines.. I have 3 5KW Solis inverters tied to my 120v legs but nothing on my 277v leg (three phase power here). I didn't notice much if any gains on the power bill even with the 15KW Texas sun. I'm about to add 10KW more (panels are up) but I'm considering getting a 277V rated inverter. Trying to decide if that would be what makes the 25KW solar suddenly put a dent in my power bill. Or maybe I get rid of the 277v altogether. Not sure having three phase power adds any value if you aren't using it.
    Suggestions?

    I have a 5 KW off grid Growatt inverter that I'm basically playing around with. The inverter comes with this app that allows you to monitor "everything". Initially I had connected one circuit breaker line that had the computers connected to it, a small fridge and a fan. It was also practical since it was acting like a UPS. What I noticed is that my PV panels were producing up to about 500W max with a "load consumption" of around 200W. Load consumption is quite constant throughout the day and at any point less than 500W. Some produced power will continuously go into keeping the batteries topped up, but once they are "full" that becomes little. So while "import from grid" was mostly zero throughout the day, I noticed that while there was lots of sun, I wasn't able to use my full (max 500W) capacity. So I thought, I'd add a circuit that has an airconditioner connected to it, also wanting to see how the inverter would handle the power spike, but thinking at least I will be continuously using or benefitting all PV power that I am producing. But that doesn't seem to be happening.. It have noticed two "funny" things:
    1. It seems that at times the inverter ignores (reduces) solar input, I'm guessing because load consumption is a lot (15 times) higher than PV input. I have measured that to confirm. Solar input can go down 1 or 2 W for a long time when it should be much higher. Then when I switch off AC input (forcing the inverter to pay attention to solar) and back on again, solar input goes up again to say 200W.
    2. While my consumption is now typically around 3 kw, and my PV panels produce around 200W (varying between 0 and 500), my "import from grid" is ALWAYS (app reports in 5 min steps) higher than my "Load consumption". Whether my PV panels produce 50 W, or 500 W, import from grid is always around 100 W higher than load consumption. You'd think there might be a difference between 50W and 500W PV input but there isn't.

    Leave a comment:


  • PVAndy
    replied
    If you email these guys they will tell you compatibility. We use them a lot to start AC Condensers on Powerwalls

    http://www.hypereng.com/

    Andy

    Leave a comment:


  • tc0nn
    replied
    Kinda along the same lines.. I have 3 5KW Solis inverters tied to my 120v legs but nothing on my 277v leg (three phase power here). I didn't notice much if any gains on the power bill even with the 15KW Texas sun. I'm about to add 10KW more (panels are up) but I'm considering getting a 277V rated inverter. Trying to decide if that would be what makes the 25KW solar suddenly put a dent in my power bill. Or maybe I get rid of the 277v altogether. Not sure having three phase power adds any value if you aren't using it.
    Suggestions?

    Leave a comment:


  • Ampster
    replied
    Originally posted by Pemba View Post
    Newbie here.
    ................. Connecting them in series (AC output of one as AC input to the other ?) wouldn't make any sense to me.
    I agree. To some, AC coupling may seem like series connection but in reality it is parallel. I don't know what the OP was referring to in the title.

    Leave a comment:


  • Pemba
    replied
    Newbie here.
    I understand that some of these "types" of inverters (charger/inverter with PV input and AC and battery in and output) can be linked parallel to increase output. I have a Growatt SPF 5000 TL HVM for which I understand this is possible although I haven't tried it. But not all. You'd need to check with the supplier. I might be wrong. Connecting them in series (AC output of one as AC input to the other ?) wouldn't make any sense to me.

    I sell submersible (borehole) pumps, it sounds a bit as if you are talking about the control box which often has capacitor specifications written on it. But it has nothing to do with a soft starter as written above. There is also a "solar inverter" which takes DC input and produces 3 phase AC output and I think often has a soft start. If input is low, then the pump will start but it will run slow and at some point (depending on how you adjust it) switch off.

    Leave a comment:


  • fw12
    replied

    oregon_phil and Mike90250
    Thanks for the info. I'm waiting to obtain the controller and test the pump.
    The controller I'm getting is made by the same company as the pump. 1.5hp pump + 1.5hp controller.
    The only thing I'm waiting to find out is whether the controller is hard start capacitor, or run capacitor.

    It is exciting to learn new things I never knew before about pumps. I've always used DC solar pumps. But the cost of DC pumps is cost-prohibitive.

    Leave a comment:


  • oregon_phil
    replied
    I have a soft start variable speed 2hp three wire well pump. For my 2hp well pump, pentek recommends a 5800 Watt minimum to start it up; 5300 watts for 1.5 hp pump. And this is for a soft start system. Mike902550 numbers are in the same ballpark. 2500 watts isn't enough.

    Leave a comment:


  • Mike90250
    replied
    Originally posted by fw12 View Post
    Thanks SunEagle. I have been doing research on pumps, and I came across info about pump controller. Apparently it reduces the surge at startup.
    Perhaps with the controller, just one 2.5kW inverter can handle the pump.
    The pump controller is labelled as having 45uf. I'm assuming that is micro farad. So it is a capacitor.

    Thanks again.
    All 3 wire pumps have a starting capacitor in the control box. The capacitor is no the same as a Soft Start module

    I suspect there is not an easy way for a small inverter to reliably start a 1.5hp pump motor - either 120V or 240V
    All pumps will be in this general range. Add in the Power Factor PF that a large motor imposes, and it's unlikely a 4kw will manage it.
    1.5 hp needs 62A @ 120V for about 2 seconds for starting. that's 7.4Kw and your battery cables (needs to be 48V battery) have to not
    wimp out and undervolt the inverter [ 48V = 155amps to start ]

    Well Pump Motor Specs.jpg

    Leave a comment:


  • fw12
    replied
    Thanks SunEagle. I have been doing research on pumps, and I came across info about pump controller. Apparently it reduces the surge at startup.
    Perhaps with the controller, just one 2.5kW inverter can handle the pump.
    The pump controller is labelled as having 45uf. I'm assuming that is micro farad. So it is a capacitor.

    Thanks again.

    Leave a comment:


  • SunEagle
    replied
    I could be wrong but I would say that it will be impossible to use 2 of those inverters to run a single load. You might want to look into some type of reduced voltage starter for the pump because it seems the pump draws more power than a single inverter can provide.

    Leave a comment:


  • fw12
    started a topic Inverters in Series/Parallel

    Inverters in Series/Parallel

    I need about 4KW to start up a 1.5hp AC pump, according to https://thesolarstore.com/what-size-...umps-n-56.html

    I have two 2.5KVA inverters. A single one of them could not start the pump.

    So I'm wondering if one could combine both to give 5kva. Should they be in series or parallel?

    Here is the specific inverter http://www.famicareindustry.com/prod...--38758--.html

    TIA.
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