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Hi Guys

I’m looking to start my own solar install. I’ve been browsing this forum on and off for the last 3 years (I think) trying to better understand some of the concepts and to think about how I would like to implement a setup for myself.

When I first looked at this my daily usage was about 15KWh a day, with most of that in the evening, so due to low usage during daytime, it required me to have a battery setup which made the whole concept uneconomical for me, considering my monthly usage was only R500.

I kept on checking back every now and again to see if things have changed but kept getting back to the same answer that financially it doesn’t make sense (yet).

Recently my circumstances changed and started some cryptocurrency mining, and my electricity usage is up significantly, which also means that my daytime usage is now significant. This got me thinking that I should relook at the solar option. It also happened around the time that the Renesola Infinisolar 3KW inverter went on sale at Bonanzatech. I bought one of these and I am in the process of purchasing solar panels and the mounting brackets.

I haven’t decided on what I am going to do on the battery side yet. We have a weak substation that feeds our area, so the electricity trips every now and then, and some battery backup would be useful.

I’ve done a fair bit of research, but now that it is getting close to the execution, I’m finding that there a lot of details I am uncertain of or just need confirmation on. I think this is a long first post already so I’ll keep it limited for now and later add more to the thread as I progress.

Right, that was the intro, let me get to specifics.

My goal is to use as much of the PV power generated as possible.

 

Area: Fairland / Northcliff, Randburg.

Inverter: Infinisolar 3KW (Renesola branded)

Panels: 12x Canadian Solar CS6K-270P

Mounting: Renusol Metasole+

The way I’m reading the spec sheet for the 275W panels, I should put the 12 panels in series (Voc 38V x 12 = 456V, which is within the inverter’s max DC voltage of 500V.

 

Inverter:I guess most of my uncertainty is on how the Infinisolar works. It seems there are a lot of people with Axperts, but not Infinis, so information is thin. My understanding is that the Infini will combine PV and grid to supply the load (which I like, so there is less wasting of solar power if it’s insufficient to power the loads). My understanding is also that the max output is 3KVA / KW (13A at 230V). As mentioned before, I have some mining rigs in the house which gives my house a current baseload of approx 4.2KW (I’m using an Efergy monitor to track this and also on pre-paid). My thoughts are to split my DB to keep the Oven (Stove is gas), geyser, dishwasher and washing machine on the grid, and then to also move a mining rig or two to the Grid side to keep my baseload somewhere closer to 2KW – 2.5KW, so that I can selfconsume most of the PV generated during the day, but still gives me headroom when we start using appliances and lights in the house.

My uncertainty is how careful do I need to be on exceeding the 3KW rating and how much can the inverter handle for short periods of time, i.e. if someone switches on the microwave, would it cope for the 2 minutes or do I need to make sure the load doesn’t exceed 3KW ever?

Also, what does the PV power generation look like throughout the day? Will a 2KW baseload be able to consume most of it due to the “semi-bell shaped curve”, or will there be significant overproduction and wastage?

I’m also curious on whether anyone has experience with how nicely it plays with a Landis pre-paid meter? I see another thread on an Infini and a Conlog and it doesn’t sound very positive.

Thanks for reading so far. I’ll keep it limited to what I’ve written so far and add more later.

Regards.

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Welcome to the forum! I am sure someone will have more info on the Infini, but as far as I understand, it is similar to the Imeon 3.6. which means that it can feed back to the grid, a feature that you will have to block if you are using a pre-paid meter.

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22 hours ago, Analytical said:

max output is 3KVA / KW (13A at 230V).

This will really depend on your power factor. My house has a power factor around 0.8, and I'd expect the SMPS power supplies of those rigs to not have particularly good power factor, so your 3kva might only be good for 2.2kw. It is grid-tied however... what you can do (which isn't very nice), if the inverter even allows that, is pass on the reactive part to the grid. Chances are you can't do that, regulations usually require that the inverter ties at no less than 0.9, so it will attempt to compensate, and you will get out less than 3kw.

22 hours ago, Analytical said:

how careful do I need to be on exceeding the 3KW rating

It's a hybrid. It imports the difference from the grid. In general, you probably don't have to worry at all.

22 hours ago, Analytical said:

what does the PV power generation look like throughout the day?

See this histogram, which is of yesterday (today my batteries filled up at 2PM and wrecked production). Note that it only produces the top power (in my case around 1.5kwh per hour) between 12:00 and 14:00. The 11:00 and 14:00 bars are 1.3kwh high, the 09:00 and 16:00 are 1kwh(ish), that is around two thirds. But I have a second array pointing North West for a better spread. If you oversize the array by 30% you could probably get peak power between 9:30AM and 4PM... in summer... in Cape Town. YMMV.

I make a total of around 10kwh.

Selection_017.png.54661a2cf8f8183e0040b2564c2a1f82.png

(Yellow is direct consumption, blue is battery charging, red is what I accidentally push into the grid... it can be as much as 100Wh over an hour.

22 hours ago, Analytical said:

how nicely it plays with a Landis pre-paid meter?

@Wetkit ran into trouble with a Conlog BEC44. He suggested that the Landis are even worse, they don't only disconnect you, they go into tamper mode. I have no idea, and in most cases, the best people can do is try it and hope for the best.

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Thanks @plonkster. I appreciate the feedback

3 minutes ago, plonkster said:

I'd expect the SMPS power supplies of those rigs to not have particularly good power factor

I've got one of those efergy wall plug watt meters and it indicates that the power factor is between 94 - 97% on the mining rigs. Not sure how accurate the Efergy is though, but overall encouraging.

 

15 minutes ago, plonkster said:

It's a hybrid. It imports the difference from the grid. In general, you probably don't have to worry at all.

This is where my uncertainty lies. I've seen the Imeon 3.6 specify that it can go up to 6KW for short periods, and the Ingeteam Sun Storage can supplement with grid to way above its 3KW rated capacity, so it is pretty much install and forget, and no need to split circuits. (Ingeteam ISS 3TL 1 Play 3TL Spec Sheet) My brother in-law has the Ingeteam, but outside my budget for now. I cant imagine the Infinisolar having better features than the Imeon. I defiintely dont want to blow it in the first week :)

29 minutes ago, plonkster said:

See this histogram

Thanks, I was looking for some real world examples. I'll be putting my array on my corrugated roof, which seems to have a pitch of 17 degrees. Far from ideal for winter time, but I was also thinking that I'll just max the size of the array that I can fit on the roof and inverter instead of trying mounting structures or multiple strings (not that I have a choice with the infini).

 

38 minutes ago, plonkster said:

@Wetkit ran into trouble with a Conlog BEC44

I also read his post and I am / was very worried. After rereading it again last night, I noticed that he said in his first post that the system had been working fine for close to 2 years. It was only after a few re-reads that I realised he added a "modbus comms card" after which his problems started, so if I understand it correctly, he wanted to feed some power back to the grid side of the inverter so he could use more of his generated electricity, with the Modbus sensor then measuring the current and telling the Infini when to pull back. That is the most sense I could make of it, so I am hopeful that his issues arose after the modbus comms card. @Wetkit, I would appreciate if you could confirm whether this is the case, it would make me feel a lot better.

 

On the topic, I understand that these types of setups require a safety feature to prevent backfeed into the grid when the grid is out (anti-islanding). Is a separate device required for this? Would something as simple as this Hager do (ESC263)?

Thanks.

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46 minutes ago, Analytical said:

Is a separate device required for this?

The Infini complies with NRS097-2-1 as far as I know, no extra stuff is required. Check the Cape Town list (even if you aren't in Cape Town), if it's on there it complies.

Anti-Islanding is a bit more complex than just a contactor. There is a so-called NDZ (non-detection zone), basically if you balance your feedback exactly to your loads and the grid fails in a high-impedance manner so there isn't a huge voltage drop, the outage might go undetected. Anti-islanding employs a number of backup methods including change in voltage, change in frequency, rate of change of frequency (aka second derivative), and active measures where the inverter actively tries to create an imbalance, but the grid absorbs it. No cheap/simple device can do this. The Ziehl UFR1001e that I have goes even further, it has two independent detectors that back each other up!

54 minutes ago, Analytical said:

he added a "modbus comms card"

My inverter uses a modbus meter as well. There is quite a bit of lag, and the next version of the control loop (I'm already running it, my site doubles as a pre-release test site) has a low-pass filter to more accurately estimate use. The old version oscillated a bit, it went a bit like 1) meter says -600W, pull back, 2) meter says -500W, pull back, 3) meter says 300W, push back, 4) meter says -150W, pull back, 5) meter says 100W, push back, etc...

The trouble is that the comms are so slow that you work with stale values, you already pulled back by 600W, but you still see 500W going the wrong way when that was a second ago!

Messing with this control loop might well solve the problem for sensitive prepaid meters. You just need an adjustment loop that treats a negative value like an emergency, it should pull back as much as possible as soon as possible, and then approach the zero point from the positive side. But that's another topic... :-)

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You're right, I read that post again and it's full of technical stuff, such as high impedance and second derivative and low pass filter ... some of that is electrics/electronics, some is signal processing, some is mathematics... sorry man, I type faster than I think some days! :-)

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I was able to install the 12 panels onto the roof over weekend and am now looking at how to connect the inverter.

As I currently dont have batteries I'm trying to figure out whether there are specified settings / profile I should use?

Grid Tie seems an obvious choice, but that would mean feeding into the grid (I think).

I've temporarily connected it to the DB board but the WR warning keeps on showing on the screen.

 

The good news is that I figured out that it can indeed handle more than 3KW load. I've pushed it up to 4.8KW for 2 minutes, but that was at night with only grid power, so I think it is in a bypass mode.

Below a picture of my handywork.

IMG_6657.JPG.a0390db691e579f3cd32d6aec28b92d5.JPG

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@Analytical,

It all depends on the length and depth of the "overload". In my view, Infini's are more tolerable than Axpert. My Axpert user to trip frequently in the beginning, as rest of household wasn't used to serial power use yet.

Since moving to infini before winter, I must say I haven't had a "overload" trip occur. And I have the whole house with two geysers etc on it.

So re-heat that cup of something in the microwave for 30 secs, but I wouldn't cook rice for 10m while the geysers are on. The inv. will beep repeatedly, so just listen for it.

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Hello Analytical,

 

I'm new to the Forum.  This is my first reply to anyone.  I, too, am fairly new, but I have gathered a lot of information on YouTube from many different people.  What I have found is interesting to say the least.  To answer whether your unit will handle beyond 3kw...well, that's not something I would try, however I did view a video on YouTube where a guy in Africa put 3 times the rated power of his inverter through it because he set it to Utility only.  That said, I'm not sure that's a good idea, but apparently it's been working for him.  If that's true then my test unit, a little 2400W hybrid inverter should be okay.

My unit, like yours, was probably made by MPP SOLAR.  And yes, there have been a lot of differing views on it.  Personally I think some guys are maxing the units beyond what they were made to do.  My test unit is exactly that, but I only test to the limits and not over.

 

For instance you mentioned more amps than watts...Though it is necessary to run higher amperage at times, I would try to avoid higher amperage.  I set my PV array with higher amps in mind, at first, to help charge the batteries faster.  I reconfigured it into serial to keep amperage down for two reasons, to keep the heat from the amps at lower temperatures and to keep from excess amperage when the "cloud effect" occurs.  Still, higher voltages can also incur problems in the system, but it's less likely to burn anything down due to heat.  Here is a video of two loads running.  I have a video with three, but it went into over voltage and switched to grid use once about 55 amps were reached.  

What I will say is MPP SOLAR (Axpert or Infini) should not be used beyond their specifications and one should really read the manual carefully.  There are some not so easy to understand points where maybe a translator (Chinese to English) did not work well.  A guy who's had experience for four years recently posted/asked how to set up [1] to either SOL, SBU or UTI.  Two guys on there thought SOL meant just using SOL was the most efficient way to run the machine.  I guess it depends on what efficiency means to each user, but if they mean the "least amount of utility used", that would mean to use SBU (Priority is Solar, then the Battery and finally Utility).  So yes, even older users can be fooled by the wording or translation.

Here is a video that goes through a little bit of the Menu setup adjusting the [1] and [16] selections.  I hope it helps you see some of what you'd expect from those units....though I think your Infini is a bit more advanced than this one.  

It may be a Hybrid, but I think that France's Imeon is a bit more robust...as they have a really top end warranty.  This is where MPP SOLAR and all it's clones have some "maturing" to do, but for the price...it's still hard to beat especially if you're just learning.  Much cheaper to blow one of these units up than an Imeon, an SMA, a Kaco, etc.  SolaX, Goodwe and Growatt are also Hybrid, but are Chinese.  That said these are top quality Chinese brands at higher prices.  What I am finding, though, is that MPP SOLAR is now also making units for Growatt, Giant and Voltronic.  All of them exactly like that of Axpert, Infini and others.  The regional certifications probably change a bit of their circuitry to pass in different countries, but the unit and its' operation are the same.

Your unit might have parallel capabilities.  This might solve issues of going over while still using a set amount of PV.  If you have three units, you can actually build a three phase system and just connect it to a junction box where you can separate them into three phase and single phase "areas".  Three Inverters in parallel with a 4000W PV array will still give you more, per day, than your 15kW a day use.  I believe the unit you're talking about has some grid tie capabilities.  Mine doesn't give back to the Utility company, but I can supplement my system with it.  But at 4000W worth of PV that gives you 4000x.8x5.5=17600W = 17.6kW a day.  (0.8 is average because there's inefficiency and 5.5 is an average total "perfect" sunlight ~ not knowing how much actual sun you have).  Anyway, I aimed slightly higher for your system though you only need 15kW a day.

I've written a lot too now.  I hope it helps and, at least, answered some questions.  In the end, I personally think the MPP SOLAR's and their clones are fine if you don't try to kill them.  If you want the best...then SMA...period, but once in a while they will also fail.  Still, there are two guys I know with SMA's and MPP SOLAR (Infini).  They love their MPP SOLAR and they know their SMA's will work.  I know Outback is coming out with their Hybrid and many others are following suit.  That says "something" about hybrid units that MPP SOLAR have made popular.  It's making a sweep of the market structure for sure.  I think they've solved a lot of issues through software.  My test unit is only three months old and before I started videos, I did a lot of tweaking.  The battery was the hardest part, but I later found out that people were draining my water tower so the battery kept coming on (at night) and drained the battery along with the water.  Hahahaha....that problem has been resolved.

 

Anyway good luck.  Hope it helped either way.

 

Peace..

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Thanks to all who have responded so far.

I've been running the system for the last few days, but I havent decided how I would like to implement it permanently into the DB.

Some feedback on what I have learnt so far.

I've never realised how many clouds are in the sky during the day until I started watching my PV output. Today was the best so far and I have generated around 23KWh. There is a bit of a difference between what PVoutput logs and what Emoncms logs, but I assume that to be due to the more frequent logging on Emoncms. I keep on comparing my output to @pilotfish as I think he is quite close to me, just to make sure he is also suffering from clouds and it isnt my setup acting up :) I've joined the SA team on PVoutput as well.

Self consumption is good so far and I am able to use all PV power being generated.

image.png.eb1183a6be855f41affec95c0011566a.png

You can see the reduction in electricity usage in the middle of the day. The high consumer in the morning was the geyser, due to a cloudy and cold day yesterday (and kids bathing the previous night), and oven in the evening.

image.png.b2b708c6f2559b638c9ae40873e6201e.png

I've got a trial of ICC running, which I find very useful, as I like seeing data being logged and being able to check up on my house remotely. I'm currently running it on a HP N40L microserver, but it seems to be getting overloaded with all the things I'm running on it, so considering getting a Lenovo Tiny PC to run these types of services on, and also my CCTV, or start trying to figure out the Pi version of ICC.

The inverter can indeed run on loads above 3KW. I've also tested it whilst running from PV in day time, and it is combining PV and Grid. The overload indicator lights up, but no alarm sounds. This makes me think I can connect more circuits to it once I let it feed into the DB, as it seems to handle load above 3KW at least for a few minutes, so I dont have to be too worried about the microwave or kettle.

image.png.2f975ecc416df6368c990136ea23c9f1.png

There has been no issues with the prepaid meter yet. I assume it is because I dont have it in grid tie mode and not trying to push back into the grid, so that works really well at the moment.

I currently have the load side of the inverter going to a plug point, which I run my mining rigs off.

I need to consider getting my inverter setup more permanently. I'm looking at changeover switches and surge protection devices. If only one place could sell them all! I'm trying to keep my sub-DB circuit breakers and changeover the same brand (Hager), and possibly looking at their SPDs and PV fuse holder as well. Livecopper seems to be able sell most of these to me, but I havent confirmed all parts yet.

Once I've done that I'll also start thinking about the batteries. I'm trying to keep it cheap (backup power only, no real requirement for frequent cycling), but when you work it out the price difference between the cheaper option and the better quality isnt that big. Come on lithium, drop those prices, so I can rather spend my money only once.

I guess that is all for now.

Thanks for reading.

 

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@Analytical 

Hi, I have been using the Infini 3kw plus for roughly a year now. It will happily handle 6KW in hybrid mode without issue. You will need to keep in mind that should eskom go down, the inverter will trip on overload at those loads (though it will handle it for a short period). This has happened a few times to me and is a pain.

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I am experimenting and testing an off brand MPP SOLAR Hybrid Inverter.  It runs quite well so far and I have done some things to prevent issues that others have had.  It's been four months and so far it's worked without a hitch.  Being hybrid it will use the sun during the day directly and supplement battery when you need more, but at night it automatically goes into battery mode.  You can get them as a hybrid that can grid tie, but the return was minimal as there is a cap to the money you can make from the power companies where I live.  My hybrid only uses the grid as back up for charging in case there's little or no sun, but the grid here goes down quite often and my solar acts as the back up.  Here are two links to help understand how I maintain my batteries and how I've setup the unit.

 

 

 

 

 

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I am finally on the sixth month of this rebranded MPP SOLAR inverter and I have to say (knock on wood) so far so good.  In fact, I've been quite impressed by its' ability to take direct sunlight and immediately change it into AC Power.  In this video that's exactly what you'll see.  If it used the battery, at all, it was minimal.  I used a 360-370 watt power grinder on and off for about 15 to 20 minutes (most of which I just ran it for extended periods of time).  I was testing two things....the over voltage (if it came on every time....it didn't) and how much battery was used.  Surprisingly, with only 600W of panels in series and a lot of sun, the battery was already at float when I was finished using the grinder.  This little unit was my first start at "testing" and "studying" what best way t use solar.  Impressed so far...hopefully I don't jinks myself.  Anyway...here is the video.

 

 

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Hi Guys

Just want to give you my opinion on the Infini. I have a 3kW unit installed in my house now for 3 years and no issues.

Just to clarify the difference between Grid-Tie, Off-Grid and Hybrid.

Grid-Tie is when you supplement the grid either by feeding back into the grid or just to supply enough power to your appliances when using grid limiting device, no batteries invloved.

Off-Grid is when you make use of batteries to supply the load, the solar panels charge the batteries and the battery power is converted to the 220V, when batteries run low, it switch over automatically the your backup (Eskom or generator)

Hybrid is a combination of Grid-Tie and Off-Grid, so you can Grid-tie and run feed some major appliances with solar power with or without feeding back into the grid, if you have pre-paid, then sorry, you need to have an energy meter connected that will do the grid limiting. On the battery side of the inverter you can then have some essential loads that you can power for instance when Eskom is out. So some suppliers spec the Axpert Off-Grid inverters as HYBRID, but in fact they are only off-grid.

The 3kW Infini can give you 6kW output when connected to Grid, but only 3kW when grid is not available.

Thanx for all the input from different users and their opinions

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On 3/13/2018 at 9:26 AM, Kobus van der Watt said:

Off-Grid is when you make use of batteries to supply the load, the solar panels charge the batteries and the battery power is converted to the 220V, when batteries run low, it switch over automatically the your backup (Eskom or generator)

I prefer to use the term "Grid Assisted" where grid power is used as backup and "Off-Grid" where no grid is available or used.

The reason for differentiating is that design requirements can be very different for the 2 options - An "Off-Grid" system would normally have a battery bank offering a couple of days autonomy to minimize reliance on a generator, whereas a "grid assisted" systems can have a battery bank ranging from similar to that above down to a minimalist battery bank, using PV when available and grid when not, with battery just there to carry through the transition.

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6 hours ago, pilotfish said:

I prefer to use the term "Grid Assisted" where grid power is used as backup and "Off-Grid" where no grid is available or used.

The reason for differentiating is that design requirements can be very different for the 2 options - An "Off-Grid" system would normally have a battery bank offering a couple of days autonomy to minimize reliance on a generator, whereas a "grid assisted" systems can have a battery bank ranging from similar to that above down to a minimalist battery bank, using PV when available and grid when not, with battery just there to carry through the transition.

Awesome Post

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