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A new installation


Richwost
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Hi Guys

This is such an interesting forum and I must congratulate you Energy for setting it up and for the value that it adds to so many of us who read it.  The responses from the likes of Plonkster, TTT and others are extremely interesting and valuable to us lesser mortals.

I have decided on the following 48V installation for my new home on a very small game farm.  I do not want to go off-grid.  I have 50kVA Eskom power, but I believe that we are going to have more and more power failures in the future as the lack of system maintenance kicks in.  What I want is something that offers "some" protection.  We are very happy to exercise substantial lifestyle modifications to live within the boundaries created by our proposed system in the event of Eskom failures.  

The guts of the system is as follows:

5kW Microcare Bi-Directional inverter

8 x 327 Sunpower Mono panels

8 x Trojan L16RE-B 6V 370Ah batteries

1 x 60w Microcare MPPT

2 x Microcare battery monitors (one outside, one inside)

We will have a 3 x Sunpower panel Geyserwise system for our bathroom geyser.  We have a gas oven and a wood oven (in addition to an electric oven) and a wood fireplace for heat.

The panels will be roof mounted at 30° due North, but we will keep them a good 100mm off the roof for some degree of ventilation.  We do not have a good option to mount them elsewhere because of the shading issue.

I would like those with experience to tell me firstly if they think our system is in "balance" and secondly, comment on our choice of manufacturer for the components.  I know that many of you will recommend Victron in the place of Microcare.  I would be interested to know why.

(I hope I am not overstepping the boundary Energy??)

We have not actually purchased any of the components yet, but we are keen to get going and so your comments will be of great interest to us.  In the event of power failures we will not want the system to take us along as if we were on Eskom power.  We will exercise our own form of power shedding.

We are going to do the installation ourselves.  My pal is a fully qualified (old school (but not old man!!)) electrician and although he has no experience whatsoever in this field, he and I are going to do the job.  We WILL be needing help and advice!!

So... how does our system look to you guys with the knowledge and the experience?  

I really look forward to hearing from you.

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Hi Richwost,

Glad you posted. The more opinions, the better the end result.

My only concern is Microcare support and after sales service.

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Hi Richwost,

Highly recommend victron, its in a different class.

Their specs don't lie, they have higher efficiency, lower self consumption, very reliable and accurate.   I can give you several other reasons but not without risking a possible lawsuit ;) 

Cheers

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Hi Richwost

Welcome to the forum.

I like you choice in batteries. See whether you can get the Trojan Hydrolink auto fill watering system.

What has drawn you to the Microcare suite of hardware?

Have you considered an Axpert? Axpert's are like girls from Boksburg (basically they do what you want of them). They not particularly flashy or hip but in my opinion solid inverters. They are a bit quirky and have some idiosyncrasies but deliver the goods. Having had one now for 9 months I can truly say that I would buy one again if I was to start all over again.

I must admit that I am totally offgrid and therefore have no need of grid-tie capability offered by more flash inverters..

Here in the Karoo you end up paying Eskom about R1800 before you have used a unit and so on a game farm I would encourage you to see whether you could be independent of Eskom  as your return on investment would be so much quicker if you could disconnect from them. It is not always possible if you have power hungry equipment on the farm.

 

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2 hours ago, viper_za said:

No No... The Plonkster man seems to like them more an more and even you sometimes :lol:

I do not want to talk about it. :rolleyes:

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Truth be told, my inverter has now been on for for +-4 years, 24/7 - so until it breaks ... the Volti's have NO chance. :P

Not once have I had to adjust it, not once has it not done the job I gave it, not once have I had to worry about firmware, it just sits there and works. :D

And the proprietary software, it worked from day one - and now I am improving on that. 

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Ok so now I can say I have seen brand fanboys on a solar forum as well :lol:

As I am a photographer I see Nikon vs Canon all the time. JPEG vs RAW

As a Solutions Architect I see the Microsoft vs Linux all the time

as a developer I see Open source vs Closed source

As a driver I see BMW vs Mercedes Benz

And now we have Victron vs Axpert.

Hahahahah

 

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Late to the conversation, I've been doing some "real work" (tm) :-)

After I've seen the WRND on the inside, I feel like I've been too hard on the Microcare. Look, absolutely no contest between the MC and the Victron, they are from different galaxies in terms of quality, but the Victron is twice the price of the MC. Of course none of that matters if your MC blows up after two years, but Microcare will fix it for you, sometimes for free.

The microcare unit is much simpler on the inside, at least the 40A one I repaired. It uses an opto-coupler for isolation, the buck converter is async (schottky diode for the free-wheel part, instead of a second MOSFET). This means it generates slightly more heat (because Schottky drop is higher than MOSFET), but to be honest, I appreciate the simplicity in this unit.

When mine blew up, it was actually fairly easy to figure it out and to repair it. The construction isn't on the same level, there was definitely some fudging going on with the gate driving in my unit. But it is entirely likely that the new units are MUCH better. I would be very surprised if they aren't.

So they are a bit of an unknown quantity, but somehow I feel better about them again.

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Hi Guys

What an incredible response.  I have thoroughly enjoyed watching them come through on my phone, but I am now at my desk and I thank you all very much indeed for your enthusiastic responses.

The panels got no reaction - so I am pretty happy about that.  Sunpower it is.

The Trojan batteries got very little reaction and what there was, was positive.  Thank you for suggesting the  Trojan Hydrolink auto fill watering system Chris.  I have never heard of it, but it sounds like a "must have".  I will most definitely look into it.  So - Trojan it is.

The matter of the inverter seems highly emotive!!  How did I get to Microcare in the first place? (You asked me that Chris)  It came from the first person that I ever spoke to on this subject about a year ago and I have subsequently met the Microcare hierarchy and I just feel comfortable with them.  But I am not committed to them yet and I have had the name Victron on my mind too for a long time.  No doubt it is better built and better everything, but isn't it a bit like comparing a Toyota Landcruiser bakkie with a Range Rover?  The Toyota would get you from here to Cairo - although not very elegantly.  The Range Rover would put a huge smile on your face until 200kms outside Blantyre when your onboard computer instructed you to switch off and seek a dealer "immediately"  - this while passing through a restless breeding herd of elephant with calves at foot.  

Or is that not a good analogy?  The Microcare brand is simple (or so I'm told) and they are close by.  It is a very difficult choice - both BLUE by the way - but very different in terms of their appeal.  I don't know anybody at Victron and maybe I should make contact and have a chat before committing.  

Those preferring Victron to Microcare is running at about 6 - 0 at this stage (including some of my friends), although Plonkster, you have put just a little doubt into everybody's mind I think!!  Where are the Microcare supporters?  Come on guys - don't be bullied into submission by the Victron Blue?

Axpert?  Hmmm... hasn't that got a very "Chinesey" feel about it?  If so - that is where I draw the line...

I will go ahead and get the batteries and the panels soon, but I will delay a while on the inverter while I investigate Victron.  Can anybody tell be where I can get the Trojan Hydrolink auto fill watering system?

Why did you leave Boksburg Chris?

Best regards to you all...

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Hi Richwost 

I am a cheapskate and for R10k you get a MPPT and a true-sine wave inverter. 

Microcare the equivalent kit is going to cost R20 000  for the inverter + R6000 for the MPPT.

Victron  is going to set you back R45 000 for the inverter + R12000 for the MPPT.

I am sure there are cheaper prices but you get the idea. 

My total install cost was 80k. If I bought Victron I would not have had panels and batteries.

In you analogy above you will find that the Range Rover (Victron) will get you to Cairo and the Land Cruiser may be the one that breaks down at Blantyre. Victron is expensive but very good. Whilst you are enjoying a celebratory glass of champagne with in view of the pyramids at Giza you will notice dozens of chaps there all driving FAWs who have made the same trip and the aircons did not even fail much to the amazement of everybody.

On a more serious note I opened my inverter up over the weekend to reverse the airflow. One of the idiosyncrasies of the Axpert is that the cooling fans blow down instead of up with the natural convection of warm air. The reversing of the fans now means that the inverter runs 14oC cooler. I was impressed with the components  well wound inductors good soldering etc. Everything electronic is made in China nowadays even though they may be designed elsewhere. If they are assembled elsewhere they use Chinese components.

Just after WWII Japan started its manufacturing revolution. and through the 1950s and 1960s Japanese products were synonymous with mass produced poorly manufactured products. By the 1970s  "Made in Japan" was the hallmark of well manufactured products. China's manufacturing industries are maturing much like Japan's did 4 decades ago.

What are my hassles with the Axpert? I quote from a previous post when posed the same question by TTT

Things that I don't like about the Axpert

  1. The software is useless.
  2. The SOC is useless. They could Coulomb count and come up with a better SOC. They have all the information and yet don't use it. Hence the fact that most folk add a battery monitor of some sort.
  3. The 115 VDC through to 145VDC limit on the MPPT. I am not sure how it behaves between 115 VDC and 145 VDC. The tend is higher and higher voltages on the input side of inverters and I am hoping they (MPP Solar) follow suit.(They have done this with the Affini a GTI out of the same stable).
  4. 10mm2 terminal for the PV (fine if you could run your PV input at 300-400V DC).
  5. The airflow is all wrong. Fans blow down against natural airflow of warm air.
  6. Parts of the manual are ambiguous. 
  7. The maximum low battery cut-off is 48V on a 4kW version. This is too low and has been solved by Coulomb but it should not be the customers job to make things work properly.
  8. I would like more control of the charging algorithm. Yes have a default but at least let the customer have some control. If he stuffs things up you can always have a "I told you so clause".
  9. I am sure the Trojan users would like higher charge voltages. (This has been addressed with the new SE series but they are probably not available in SA yet).

A nice to have would be a 2nd AC output that can be only PV/grid powered so geyser for instance could not drain your batteries.

Last on my wishlist would be the ability to boost the capacity of grid like Victron and Imeon. I seriously considered the Imeon because of this capability but being a cheapskate the Axpert's price won me over. Three Axpert's in parallel would still come in cheaper than an Imeon.

Richwost I have been a farm boy all my life and my experience of Boksburg girls is limited to meeting up with some as a very impressionable 17 year old at varsity. I have not been the same since!

 

 

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4 hours ago, Richwost said:

you have put just a little doubt into everybody's mind I think!!

My comments pertain specifically to the charge controllers. I had a charge controller which gave software problems, I shipped it to Microcare, but I didn't add any documentation in the box (that was a mistake). I did email them the tracking number, thinking that when it arrives the first thing they'd do is check the issue tracker (they use a web-based product for such support). I phoned a few days later, they said they tested it and there is nothing wrong with it. I then explained that you have to run it for a while, sometimes several hours, before the bug shows up. They replaced the PIC and shipped it back. When I unpacked it, I thought it smelled a little funny. Reinstalled it, it turned on, but it started acting strangely and then I realised it's definitely getting more of that burning smell.

Something had happened to it, and it probably started on their test bench, and the isolated DC-DC converter they use to drive the MOSFET on the high side was damaged. Transformer was properly melted.

I bought one of these Murata DC-DC converters from RS and installed it. R70 to fix it. And lots of fun learning how it works.

I spoke to others and it seems this was an isolated event. The only thing is... I was debating with myself whether I shouldn't use the opportunity to buy the Victron BEFORE I shipped it off for repairs. I had this dream that at some point I'm going to try a hub-1 setup, and for that I needed the big daddy, the 150/70. Then I decided to be responsible and rather repair my unit. When it came back broken... that was just the last straw :-)

The metal case of the MC is showing a bit of corrosion as well. I think it is a good unit if you're planning to upgrade in the next 5 years. That's roughly how long I think they should last.

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If i were to start all over again i would do away with the PV panel - Charge Regulator - Battery - Inverter setup and rather go with 2 inverters (one Battery inverter and one Grid Tie Inverter) or with a true Hybrid inverter.

The main reasons would be for better efficiency and battery management.

Also not convinced about using solar PV to heat water, unless of course you dump only your excess PV capacity into the geyser. (not that easy as you would need a control circuit for that)

Solar PV is only about 20 % efficient compared to Solar Thermal at about 70 % . 

Would love to hear the other member thoughts on this.

Any SMA sunny boy / sunny island fans out there?  (I spoke to a chap at the COC that told me that SMA is the most popular inverter for Embedded Generation applications) 

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I am most intrigued by your post Carl.  

While I fully admit to being a beginner in this field, I cannot grasp what you are saying.  Strangely, I am quite independantly looking at a double inverter system myself and I am going to post something soon under the title of "Double Trouble".  I don't want to go into that now, but how would you do away with the PV - inverter - charge regulator -  battery - inverter setup, while still having a solar system and a grid tied inverter?

There are so many people out there who are disappointed with the result of their investment into solar, and I don't want to become yet another one.  This forum is incredible and there is a lot of knowledge sharing and learning going on.  But your post had me beat.  What exactly would you do if you could start all over again?  I would be very interested to know - and I am sure that many others would too.

I am wanting to use solar PV to generate hot water, but I accept your point on efficiencies.  I have another reason for doing it which involves aesthetics to some extent and also some other logic.  I will go into it under Double Trouble.

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9 hours ago, Richwost said:

What exactly would you do if you could start all over again?  I would be very interested to know - and I am sure that many others would too.

At the time I did my installation, I did not have the option, but if I would redo everything now the only thing I would change is to install the infini 5KW Plus model instead of the infini 3KW Plus model and with that a bigger battery bank. The reason for choosing the 5KW Plus is only because the infini 3KW Plus is only able to charge up to 25A and that limits you to a 250Ah battery bank. The infini 5KW Plus model can charge up to 100A and therefor you can successfully add a battery bank of up to 1000Ah.

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10 hours ago, Richwost said:

What exactly would you do if you could start all over again?  I would be very interested to know - and I am sure that many others would too.

I would pretty much install what I currently have. Being off grid GTIs hold no advantage for me. I would have liked to go for a 500Ah battery bank and I knew I was going to do my solar installation in stages. My current battery bank will move over to staff cottages and I will get double my current size. It is all about compromises unless you have a blank cheque.

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I always knew that one day I wanted to be completely off-grid. The (in hindsight, very optimistic) plan was to cut 10% a year through various means, so that by year 5 I'd have cut consumption by 40% (10% year on year). In theory, it becomes easier over time because you're taking 10% of a diminishing amount. This would then counteract increases which, at the time, I expected would be around the 12% mark each year.

Though I did cut the bill in half right before I went on this crazy crusade, I wanted to cut it in half again. I'm a bit behind on that plan though... :-)

In theory, once I get to that stage (which would be around 10kwh a day from the grid) I would save so much on electricity that further expansions would follow more rapidly, and I should be completely off the grid by year 8 or so.

Of course, I thought I was going to get a second Victron inverter to parallel with this one. In the mean time, their inverters have improved so much that that would probably be a poor idea. I mean, it would still work... but the model I have cannot do sub-second switching and when you parallel it with a new one, the old one has to be the master... so some spanners have been thrown in some workses... :-)

If I had to redo it today, I'd go with the 3kva inverter instead. I think I'd leave the rest as is.

If I could redo it and MONEY WAS NO OBJECT... then I would absolutely also go with a grid-tied setup for the solar side, in other words, what Victron calls a hub-2 setup.

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As Plonkster said - If money was no object... For those of us that live in the real world, I am probably (from what I have seen so far on the various discussions) on the lower end of real available money (spent 4 of last 5 years with ZERO income). I am not broke, but buying even a single solar panel, kills the family budget for 3-4 months...

Your system not only has to be balanced as to your expectations, but also to affordability and long term benefits. I personally am still learning about things I could/should have done on my installation, but I did it on the "China" side of cheap to start, and it was without knowing a damn thing about exactly what I was getting into...

I should write a "Dummies Guide" with the lessons learned, and even now I know there are major problems with my own, self installed, installation - And I qualified as an electrician! Solar is a different ballgame, so take every bit of advice, even contradictory, and use it to build up your own experience. Guarantee that in two/three months after your installation you will be more knowledgeable than many solar salespeople out there, and will know exactly how to put your system together perfectly (budget allowing).

So, start off somewhere, decide whether you are almost dedicated to going "Solar" like many of us, or whether you want to leave it to do it's stuff. If you can't take the time to maintain your batteries, setting, etc, then go with a brilliant installer and leave their settings alone (feel free to discuss those settings with us first) - ie: let the MPPT control everything and replace the batteries every 2+ years (cos that what even a good installation can do without attention). Or choose the high end stuff, and keep your eyes on it.

As part of my Dummies Guide (See, I should write a book):

  • Priority 1 - NEVER skimp on the Invertor/Charger, it has to cope with your max load, and anything else you want to throw at it. It is pointless getting even a on-grid system that can't cope when everything is on (You would be better off staying with Municipal/Eskom Power)
  • Priority 2 - Batteries - There are a million choices, so at this point I am just going to advise to not go for standard Lead Acid (like a car), no matter how tempting the price. Batteries really define your budget, get the best value for money you can here. It is easy to add/change panels, but a battery commitment is for at least 3 years, preferably 10 years. After the first few months you CANT just add to you battery bank, it will have to be completely replaced, from scratch! (I have already learned that lesson hard and in my pocket)
  • Priority 3 - Panels - This may seem silly putting the actual energy part near the end, but with a bit of logic, it is far simpler to add PV panels to your system than it is to add batteries. Panels & the way you connect them, have to be within range of what the invertor wants/needs/can use... I recently just saw both extremes from friends who thought they would follow my "free power" path, and stuff was connected horribly (One Axpert 5kVA with a string of 6 panels in Series - Voltage completely exceeding specs, so the Invertor just shut it down, Another with the entire reverse, everything in parallel, so never enough voltage to do anything) - PS: For most people doing their own installations is not only DANGEROUS, but also illegal... I have stories, and this isn't even my job!

Apologies for the essay Richwost, just hope you keep passing on the info this way so that guys even more experienced than me can comment.

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Priority 4 - charge controller
Buy right that you can expand. Today you need X, tomorrow you want XXX - but don't waste the monies if the expansion is only going to happen in 5 years.
Then you buy a good brand name that that you can add another identical make and model MPPT controller, to charge the same bank from 2nd set of panels.
Note: Small systems with <1000w array, it is borderline to see a ROI benefit between MPPT vs PWM. Borderline. Above >1000w array, MPPT is a very good idea.

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My system work like a charm. My bill went from R2500 to R250 per month. So I am very happy. But and here is the but. If you can then go Grid Tied and use Eskom as your batteries. This will let you save your bank and you will only use it when there is loadshedding. I am now waiting to see if Rectron can order me 2 X 5kw+ Infinisolar GTIs. I only use around 4 kw so I only need 1 to run everything, but I know somebody will forget and put on a stove with a tumble dryer and overload the system. So I am specking the load for the people who don't know or forget. Thats why I have 2 x Axpert also, just for that reason.

 

BTW I installed my own system. I had 3 sparkies here ant they all looked at me if I was talking Greek. So I decided to read-up and do it my self.

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