PIP-5048MK inverter

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Re: PIP-5048MK inverter

Post by affer »

kmsj13 wrote: Sun, 06 Dec 2020, 04:33
Hi, what display firmware version you used?
2.49 afair.
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Re: PIP-5048MK inverter

Post by sergea »

bloubul7 wrote: Thu, 15 Oct 2020, 14:10 Another option might be to intercept the RS485 communication and alter the requested charge voltage before it reaches the inverter.

Although this would require additional effort, it does keep the warranty of the Pylontech intack as the battery software is not modified.

HEllo, did you capture, the message send by the inverter to the pylon, ? I'm interessted to get a copy :-)
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Re: PIP-5048MK inverter

Post by atomi »

Hi all,

I have read this thread but I can't seem to get the answer to my question.

I have a limited power (2kW) mains line and I want to be able to pull up to 5kW for short periods of time. I am thinking that a pip5048mk seems like a good candidate (double conversion and all) but I am not sure if you can turn off bypass.

What I need is a mains charger, current limited to, say, 40 amps and an inverter that outputs 5kW from battery (and/or solar). Mains cannot be converted to DC directly on the common high voltage DC bus because it wouldn't be limited, I guess, or is it?

So the flow would be: mains connects to pip mk charger, it charges the battery, the max power it delivers is limited to 2kW by the charger, the battery is inverted to 220Vac. Thus, for short periods of time, I can get up to 5kW (2kW from charger and 3kW from battery) and, when the power needed is lower, the battery is getting charged full. The mains shouldn't be connected to the load at any time, not directly, not through DC bus (if it is not current limited).

Is it possible, does pip mk do that?

Thank you.
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Re: PIP-5048MK inverter

Post by coulomb »

atomi wrote: Sun, 27 Dec 2020, 16:22 I have a limited power (2kW) mains line and I want to be able to pull up to 5kW for short periods of time. I am thinking that a pip5048mk seems like a good candidate (double conversion and all) but I am not sure if you can turn off bypass.
Yes, you can. There is a setting, setting 23 (Bypass Function), that can be set to byF (BYpass Forbidden).

I'm guessing you are on a Single Wire Earth Return system (SWER line).
What I need is a mains charger, current limited to, say, 40 amps and an inverter that outputs 5kW from battery (and/or solar). Mains cannot be converted to DC directly on the common high voltage DC bus because it wouldn't be limited, I guess, or is it?
Battery charging can certainly be limited to 40 amps, no problem; there is a Maximum Utility Charge Current setting (setting 11). The problem is that powering loads in "line mode", which you would normally be in, doesn't count. Setting 11 is about not wasting too much utility power when you might be able to charge for free later or even right now.

What you would want to do would be to lock the inverter into battery mode, never allowing it to enter line mode:

Axpert King bypass mode.png
Note that the PIP-MK / Axpert King, different to all the other models, behaves differently in line and bypass modes. In bypass mode, a relay connects directly from AC-in to AC-out.

I was hoping that setting 10 (Operation Logic) would have a setting to force battery mode. But it seems the assumption is that AC-in is a powerful grid, or at least a powerful enough generator to handle all loads. But it doesn't, at least in the manual I'm reading. It's a shame; all the hardware is there to do what you want, but the firmware doesn't have any way of selecting that configuration.
Is it possible, does pip mk do that?
I can't think of a way, but perhaps you cam if you download the manual and study it carefully. If you're keen, check out the manuals for the other models. For example, the PIP-MAX can set a maximum battery discharge current limit. See the MPPSolar downloads page.

So to do what you want, it looks like you'll need an external 2 kW battery 48 V charger, and leave AC-in unconnected. That will force battery mode. You won't need a PIP-MK model; any model with suitable ratings will do (other models may well be cheaper than the PIP-MK, because they don't possess an AC-DC converter).
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Re: PIP-5048MK inverter

Post by atomi »

Thanks so much.

I don't really know the SWER system, I know for sure it's called TN.

I was afraid that this would be the answer (separate charger + inverter), not the best solution due to the fact that although there may e cheaper inverters a high power charger is quite expensive.

I have read pip5048mk's and pip max's manuals and to my understanding there is no such mode of operation. I was just hoping I was wrong.

Thanks again for your quick response.

PS: I know that this is a pip mk thread and the moderators can edit this out if it's not ok. I have found a possible solution (although an expensive one) to this problem. Victron multiplus does exactly this, it limits ac power, calculates the needed supplemental power and provides it from the battery, all this, apparently without injecting power into the grid.
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Re: PIP-5048MK inverter

Post by solamahn »

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Re: PIP-5048MK inverter

Post by atomi »

Wow, thanks!

My problem was that I didn't know which charger is better (or not so bad). Where I live a new voltage source is in the high hundreds of dollars up to a thousand, I can't begin to understand why. Because of this pip mk was an affordable solution.

This is much cheaper (not THAT cheap if you factor in the shipping cost) but still a long way from what I knew. It's power is a bit high but it's a very good start.

Thank you.
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Re: PIP-5048MK inverter

Post by executivul »

@atomi
Buy a second 5048MK and use it as a grid +/- PV charger only.
I'm from Romania (Eastern Europe) and to me this was the logic option (600Eur from Ebay) since I needed more than the rated 4kW PV array MPPT and a locally sourced 4kW MPPT was near 500Eur for that power rating, but the PIP also has the grid charger, inverter, logic.
You can add more panels to it too and by using some clever wired manual/automatic switches you get some redundancy too, if the main one blows up sometime you use the other one.
I've already developed a nice Arduino based controller for the PIP/Pylontech combo and integrating the second would be a breeze.
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Re: PIP-5048MK inverter

Post by affer »

So for this year expansion.

go from 3s3p to 3s5p, that will though increase total wattage to about 4600 watt, and the inverter says the limit is 4000w (i will still be under maximum amp)

what are your thoughts about this? i hope the inverter will just use what it can, and in more hours of day i can draw the 4000w from my panels.

or should i be more careful, and keep the total wattage under 4000 watt. the panels is installed on a 5 degree roof pointing west. so no optimal south 20 degrees here (what is recommended for my lat-long)

thanks.
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Re: PIP-5048MK inverter

Post by coulomb »

affer wrote: Fri, 22 Jan 2021, 17:19 the panels is installed on a 5 degree roof pointing west. so no optimal south 20 degrees here (what is recommended for my lat-long)
I suspect that will save you from too many overshoots. And hopefully for the sin of 3S panels (assuming 72-cell). Does it ever get near freezing where you are?
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Re: PIP-5048MK inverter

Post by affer »

coulomb wrote: Fri, 22 Jan 2021, 21:11
I suspect that will save you from too many overshoots. And hopefully for the sin of 3S panels (assuming 72-cell). Does it ever get near freezing where you are?
Its only 60cell panels. so well below VoC. highest peak ive seen is around 105-110v afair, and the inverter is 145 maxium. But yes, we have dipped to -10 celcius this year.
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Re: PIP-5048MK inverter

Post by vibromaxx »

"I've already developed a nice Arduino based controller for the PIP/Pylontech combo and integrating the second would be a breeze."

Hi,

i am from Germany can i have your software and an quick Guide which hardware did you use?

with best regards

Marco
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Re: PIP-5048MK inverter

Post by executivul »

I've uploaded an archive with my software here: https://www.dropbox.com/s/4nlquub71zo0v ... er.7z?dl=0

I'm using an Arduino Mega 2560 which has 4 UARTS (serial ports), you must use some level converters: RS232 for PIP and RS485 for Pylontechs, the modules are cheap (Ebay/Aliexpress) and simple to wire in: VCC, GND, RX, TX and DIR for RS485 which is simplex, plenty of tutorials online.

The main.h file has basic initialization, port configuration, leave the baud rates as they are.
Main.cpp is the core program, there you can customize what automation you want to do, I've left some simple examples to work with.
The libraries are in their respective h/cpp files.

Note that my system is integrated via mqtt so I left the publish examples in the files, I recommend to edit the commented out sections to suit your communication library accordingly.
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Re: PIP-5048MK inverter

Post by atomi »

Hi, all, again.

I am still looking for a solution to my 2kW max grid power. A got a good suggestion for a power source right here. Still, if I add VAT and transport I get a not so cheap power source, used and with some tinkering needed. I'm not too clumsy but the solution I'm looking for is for a permanent setup of a whole house. The least amount of "customizing" is welcome. If there is some work to be done I'd rather go for low cost.


So, regarding the use of PIP 5048mk for my setup (given that it has solar charge, grid charge and inverter functions), I would have to disable every possible way of having the grid connected without control to the load.

The questions are:

- Is it possible to open the grid to DC bus path (physically or software)? Is the charger linked to the HV DC bus? I was thinking that I might keep the charger maxed at 2kW and pull all the energy needed from battery exclusively.

- Also is it possible to completely disable the bypass?

Without relation to the above, is there a workaround for the premature float bug? I read this thread but I understood there is only a software hack that reduces the chances for this bug.

Is this doable? Is there a better suited PIP inverter for this job?
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Re: PIP-5048MK inverter

Post by executivul »

@atomi
You can use a simple 220V contactor (big relay) to cut the grid for the first inverter and also disable ECO mode.
You can get the second PIP as a charger only, solar up to 4000W and grid 2A or 10A (the amps are at battery voltage) and 10A at 52.5V are about 2.3A at 230V grid. No connection to loads so inverter never gets used and grid is used only for charging at low current.
The premature float bug only affects Pb, the LFP ones are not affected in any way since you don't bulk/float them.
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Re: PIP-5048MK inverter

Post by atomi »

Wow, thanks executivul for such a quick answer! (by the way, Romania too)

First, thanks for clarifying the premature bug thing. Such a relief.

I think I understand what you say but this adds up the costs. I can get an expensive 2kW 48V, high quality, current limited, quiet (no fans) power supply at the same price (or even less) as a not so powerfull MPP inverter. Set it to a reasonable voltage (something like 53.6V for 3.35V/cell) and get the full 2kW from the grid. I can add any mppt controller to this setup (maybe with some automation to disable power supply if I have PV). Also, the power supply would draw something like less than 1w, according to the specs vs 50W for 5048mk. Unfortunately half power pip's don't cost half the price.

Also, for the price of 2 PIP's I can (almost) get a Victron Multiplus 5KVA which, in theory solves my problem (well, I still need the permits for an on grid device).

If I could hack a PIP I could lose the power supply altogether.
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Re: PIP-5048MK inverter

Post by coulomb »

atomi wrote: Mon, 08 Feb 2021, 00:59 - Is it possible to open the grid to DC bus path (physically or software)?
Yes, you should be able to ignore grid input with software, and if not, as mentioned above, a simple contactor will do the job.
Is the charger linked to the HV DC bus?
On the MK/King, yes. High SCC voltage models, yes. PIP-MS models, no.
I was thinking that I might keep the charger maxed at 2kW and pull all the energy needed from battery exclusively.
That would be ideal for your situation. Alas, I don't know a way of doing it as yet. You want a sort of "utility balance" setting, like the solar balance setting (that I could never think of a use for), but for utility charging. The MK/King doesn't have the solar balance setting anyway.
- Also is it possible to completely disable the bypass?
Setting 23 has a ByF option, Bypass Forbidden. Assuming it does what it suggests, yes.
Without relation to the above, is there a workaround for the premature float bug? I read this thread but I understood there is only a software hack that reduces the chances for this bug.
Weber and I hope to provide a fully (or nearly fully) patched MK/King firmware in the next few months. It may be possible to add a generator power limit (most people don't have to limit their grid power, no promises.

executivul wrote:The premature float bug only affects Pb, the LFP ones are not affected in any way since you don't bulk/float them.

Mmmm. I would say not quite. Most people actually want a float function, i.e. when the LFP battery is fully charged, you'd prefer to run the battery at a lower voltage, to extend life. This becomes especially important if (like @atomi) you are probably going to be utility charging for many hours of the night, as well as PV charging during the day. If you left the float voltage equal to the bulk/absorb voltage, it would spend most of its time near the bulk/absorb voltage, which is not ideal.
Is this doable?
Yes, I think so.
Is there a better suited PIP inverter for this job?
Not that I'm aware of. The Axpert MAX (PIP-7248MAX) has a maximum discharge power, sort of the opposite of what you want. When the limit is exceeded, it goes into bypass mode (presuming that the utility is stronger than the battery). So that suggests to me that they might implement a generator power limit one day, but it may never come.

In the interim, a contactor that disconnects the utility (preferably with software) when the AC-in load becomes excessive (or the line voltage sags excessively) would be a start. Unfortunately, when the load is high and utility is available (just power limited), that's when you'd like to be drawing maximum power from the utility, not zero power.

I say preferably with software because the PIP-MK AC-DC converter is a boost converter, as are most power factor corrected chargers. But disconnecting them under load may lead to problems. There is considerable energy in the PFC inductor, and when the input is disconnected under load, that energy has to go somewhere. Usually there is protection circuitry, but that circuitry may degrade over time from the repeated surges of energy it has to absorb. For that reason, I try to avoid disconnecting power to my EV when charging. So a controlled source (one that might switch off at 5am when I may sometimes still be charging) is something I'd like to avoid. If the AC-in is disconnected by software, the power can be ramped to zero in a tenth of a second or less, before the AC-in relay is opened. This is much easier on the electronics.
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Re: PIP-5048MK inverter

Post by atomi »

Thanks!

Well, I was more like ignoring AC input for the bypass or the load but not for the charger... Doesn't seem possible right now. The manuals of all pip's say that, while in battery mode, charging from grid is not possible, only solar.

So I'm left (apparently) with (maybe, if I'm lucky) some desoldering/shorting of circuits. But I doubt that pip mk can be modified like this, having the charger on the HV dc bus (I suppose it's something like 330V that come from rectifying and filtering the AC grid). Perhaps another pip is suitable for some hacking? pip ms? or some other pip that has separate charger?

I don't know if "utility balance" would be necessary as long as the charger is powerful enough. Set the charger to 40A max, set absorb voltage to 3.35V/cell or even lower set float voltage=absorb voltage to mitigate the float bug. AFAIK LiFePo4 is not bothered by floating at a lower voltage, that is, lower than 3.65 which I suppose is a typical absorb voltage. Yes, you lose 5-10% of LiFePO4 battery capacity but it's healthier like that anyway (that and max 85-90% depth of discharge).

If I could trick the pip to charge while on battery without passing the grid to the load... There must be some transfer relays inside that could be set to take only from inverter. I don't believe that the inverter is turned off during AC bypass so if I could set the AC circuit path (by physically locking the relay) to inverter only the pip might be fooled into thinking that it's getting power from the grid and not fault... Maybe not the MK but perhaps another model?

Of course, the best situation would be a software mod that includes generator limiter...

This limited power function could be quite useful for the marine world where the shore power limited. Victron has this and I think they have it for a reason.
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Re: PIP-5048MK inverter

Post by coulomb »

atomi wrote: Tue, 09 Feb 2021, 02:40 Well, I was more like ignoring AC input for the bypass or the load but not for the charger... Doesn't seem possible right now.
Preventing bypass is possible with setting 23 (Bypass function = ByF), but preventing the AC-in from blending with battery power to provide the load, I don't know. If you
The manuals of all pip's say that, while in battery mode, charging from grid is not possible, only solar.
Yes. For all models apart from the MK/King, the reason is that utility charging uses the inverter proper (the DC-AC converter) in reverse (as an AC-DC converter). So the only way to power the loads while that is happening is with the utility. But the MK/King has a separate AC-DC converter, so it's the only one that could do what you want. If only the firmware would allow it.
So I'm left (apparently) with (maybe, if I'm lucky) some desoldering/shorting of circuits.
I don't think that will be necessary.
But I doubt that pip mk can be modified like this, having the charger on the HV dc bus (I suppose it's something like 330V that come from rectifying and filtering the AC grid).
To clarify, utility charger (the AC-DC converter) connects via the HV bus. I was confused in an earlier post, and said that the PV charger also connects to the HV bus; it does not.
The MK/King Solar Charge Controller is the same as the one on the MK/Axpert MKS models; it connects directly to the battery. Sorry for the confusion. I'll correct that post.

But I don't see any way to separate the utility charger from powering the loads. The utility charger is in fact two converters in the MK/King: the AC-DC converter to the DC bus, and the inverter working in reverse to charge the battery (if power is flowing towards the battery). But "all you need" is a limit on the AC-DC converter's power, in addition to limiting the charge current into the battery (if any; the battery may be discharging).

Presumed block diagram.png
Presumed block diagram.png (18.55 KiB) Viewed 318 times
Perhaps another pip is suitable for some hacking? pip ms? or some other pip that has separate charger?
No. All the others have the problem of a single DC-AC (or vice versa) converter. You need two: one to power the loads, and one to draw power from the utility. The first one will be operating in the forward or reverse direction depending on the instantaneous power of the load. With a 3 kW load, 1 kW will be discharging from the battery (DC-AC converter operating forward to power ⅓ of the load; ignoring losses for simplicity). The remaining ⅔ of the load (2 kW) will be provided by the DC-AC converter running in the forward direction. With a 1 kW load, the utility will provide all of the load, and 1 kW will be left over to charge the battery (if needed), and the AC-DC converter will be working in reverse (power flow will be from the AC "output" to the DC "input").

I hope I'm correct in my assumption that this can be achieved without reconfiguring the inverter proper.

Actually, the above is not quite true; some of the smaller (< 5 kVA) models do apparently come with a utility charger (utility in, battery out). But you'd be limited to about 3 kVA output (and possibly 2.4 kW output, maybe not all the smaller models are PF1.0 as yet). Would a smaller model work for you? Perhaps two smaller ones? Often the smaller models can't be paralleled, so you'd have to split your loads, with all the hassles that that entails.
I don't know if "utility balance" would be necessary as long as the charger is powerful enough.
You seem to be assuming that there is a separate utility charger. It's actually more complicated, as I try to explain above.
If I could trick the pip to charge while on battery without passing the grid to the load... There must be some transfer relays inside that could be set to take only from inverter.
As above, this will not be possible.
I don't believe that the inverter is turned off during AC bypass so if I could set the AC circuit path (by physically locking the relay) to inverter only the pip might be fooled into thinking that it's getting power from the grid and not fault... Maybe not the MK but perhaps another model?
I don't follow this, but I don't see any way to do what you want.
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Re: PIP-5048MK inverter

Post by atomi »

Great schematic. Thanks.

As I understand it, the "only" thing needed is a limit on the output of the grid AC/DC converter (as the bypass forbid is already in the software settings). I saw some pages ago that there is a serial communication protocol in the pip. might there be a command to do this?

Still, the fact that there's a software AC charge limit means that the pip knows and can control the amount of AC power that goes to the battery (doesn't seem to result so from the schematic but I do understand that the schematic is am over simplification). It doesn't make any sense to me why inverter cannot operate simultaneously with AC charge since you say the charger is separated.
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Re: PIP-5048MK inverter

Post by atomi »

I'm still trying to understand the two inverters strategy. You say that (something like @executivul said?):

- I connect one 3kW inverter to AC, battery (+maybe solar) and loads and set it to charger + line mode
- I connect other 3kW inverter to battery (+maybe solar) and load and set it to inverter mode.

Then parallel them (?)

_IF_ this is possible then what happens when battery is full and I have an instant load of 5kW or bigger? The first inverter gets to supply 2.5kW from the grid...

I don't understand how the 3kW (in your example) get split conveniently between battery and grid?
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Re: PIP-5048MK inverter

Post by coulomb »

atomi wrote: Wed, 10 Feb 2021, 01:56 I'm still trying to understand the two inverters strategy. You say that (something like @executivul said?):
...
Then parallel them (?)
His proposal as I understand it is to have a 5 kW and a smaller (say 3 kW) inverter. The load remains on the 5 kW inverter, and has no AC-in; the smaller inverter has no load, but connects to your limited AC-in. The smaller inverter is set for utility charging with a maximum of 40 A utility charging (setting 11), and possibly a higher total charging current into the battery (if it has PV). Both inverters could have PV connected.

If you have a load greater than 5 kW for more than a few seconds, the larger inverter trips out due to overload.

This seems very wasteful, since you don't use the AC-out of the small inverter, or the AC-in of the larger inverter.

My proposal was two smaller inverters, if you can find suitable models. Preferably 48 V models, but they must have small stand-alone utility chargers built in (ideally 2 kW). These would have to be parallelable, or the loads split across the two small inverters. Only one of the small inverters has AC-in connected to the utility, unless the utility charger is rated at 1 kW or less, in which case both AC-ins are connected. The utility charger has a maximum power rating, ideally 2 kW, and that's what limits the utility power.

Say they are 3 kW inverters. If paralleled, any time the total load exceeds 6 kW for more than a few seconds, they trip on overload. If not paralleled, then any time the load on either of them exceeds 3 kW for more than a few seconds, that inverter trips on overload. If it's the one with the utility charger, then you lose utility charging as well. My proposal still wastes the AC-in of one of the small inverter-chargers. Plus, I'm doubtful that you can find a 48 V model with a 2 kW utility charger.

A quick look at the various Axpert MKS model specifications shows that none of them limit utility charging to 40 A (2 kW @ 50 V). So it looks like you'd be stuck with two Axpert MKS 3K-24s, each of which has a maximum utility charger power of 30 A (@ 25 V). So that's 750 W each, or a combined 1500 W max (using both AC-ins). You'd have to reconfigure your battery to 24 V nominal. And you'd still have to confirm that there are separate utility chargers in them (that power only the battery). [ Edit: And also confirm that they can utility charge while operating in battery mode, and that bypass mode can be prevented somehow. ] They aren't parallelable, so you'd have to split your loads, with never more than 3 kW from either circuit (either half-load). Not very attractive, I'm sure you'll agree.

Edit: so as you say, a MK/King with generator power limiting would be by far the most attractive option, if only it existed. I highly doubt that a software command already exists )in factory firmware) to perform this function.

Edit 2: Patching the firmware to achieve generator power limiting will not be trivial. I've just had a quick look, and I can't even figure out which PWM channel controls the boost (PWM, AC→DC) converter. Three PWM channels seem to be involved.
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Re: PIP-5048MK inverter

Post by atomi »

Indeed, these are suboptimal solutions to this problem.
I realize that software modding is difficult and I realize that it is not feasible to do it for such a small niche. Thank you for even considering the idea.

But, after all the doors closed I had an "epiphany".

What if grid could be rectified and filtered to get some 350V DC (not too difficult I presume, some oversized diode bridge and some big capacitors, perhaps, or just the rectifying stage of some power supply) and fed directly to... solar input of the inverter? the inverter would see grid as solar input and would be able to limit charging from what it sees as solar panel. Grid input would be disconnected and battery connected to battery input. It should be an inverter with high voltage solar input (450V).

The problem that I can think of would be the voltage ripple of the rectifier.
executivul
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Posts: 13
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Re: PIP-5048MK inverter

Post by executivul »

@atomi
You can build a simple system: a contactor, some current sensor and an Arduino which controls the contactor, EMON library is free, and making a program (sketch) is trivial, you just read the current value and cut the power if current gets over the threshold value leaving the solar system in completely off-grid mode. The way it alters you and the way you reactivate the grid feeding is your choice.
I still can't figure out what kind of grid you can possibly have with such low current limiting, maybe if you can shed some light we can find a better/cheaper/more reliable sloution.
atomi
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Posts: 11
Joined: Sun, 27 Dec 2020, 16:07

Re: PIP-5048MK inverter

Post by atomi »

Yes, I understood your solution but as I understand from coulomb it isn't good for the inverter to cut AC when under load. Plus, I need something that is as simple as possible (not the building but the functioning). Your solution, while good for my situation, involves at least 2 current sensors (1 on the grid and one on the inverter output) some small programming (prone to human error) and the constant on-off shock on the inverter.

As for my grid, it's an old house with the grid line passing through neighbors' house and they wouldn't let me in, not even to change a fuse in the main panel. If the main fuse burns I'm left without power. Don't think I can see any way around this.
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