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My Newbie Install.

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So, my install is nearly done, basically just some tidying up, and finalising parameters on the inverters.


Before starting on this "little" exercise, I knew absolutely zero about this sort of thing, and mostly getting info through Google and Youtube, I got to the point where I was comfortable to proceed.


My primary goal with this install was to lower my reliance on Eskom, get relief from the increasingly worse load shedding, and basically try do my bit for a greener future.


The main components of my system are:

 - two RCT Axpert MKS 5kva inverters. I did a lot of looking at different inverters and these seemed to be best value for money overall.

 - twelve Vision HF 12v 120ah batteries. Probably not the best choice, but for the time being, they seem to be working fine. I guess time will tell.

 - twelve Rensola 250W PV panels.

 - Retrofitted 18 evacuated tube system for my 200L Kwikot geyser.


A little while ago did some renovations on the house which included converting the existing garage into a TV/entertainment room, and building a new garage directly in front of it. The one downside to this is that the main DB board was no longer located in the garage, but in the one room where we spend most of our time at home.


Since I wanted to do this install (mostly) by myself, I didn't want the expense or inconvenience of making changes and pulling extra cabling to and from the DB board.


Luckily for me, there is a box where Eskom power comes into the property with a main breaker. This proved to be in an ideal spot to break away to the inverters.



I mounted the inverters on the wall in the garage, bought 2 surface mounted DB boards, and a whole lot of cabling and lugs.

The first DB board sits between and above the inverters and is where I have placed the breakers leading to and from the inverters. Main reason for these are so I can isolate the inverters individually or together from either the grid or the house or both as required.




The second DB board was stripped out, a nice piece of wood installed into it and converted into the bussbars to combine the  batteries to connect to the inverters.



I had an old steel cabinet in the garage near the inverters where I housed the batteries. Worried about off-gassing etc of the batteries, I removed a door.

The cabinet was not ideal as the shelves were not up to the task of holding up 120+ kg of batteries per shelf so I had to add some wood struts.



I ran like this, using the inverters as a battery backup for the house in case of load shedding for about 5 weeks.


About 3 weeks ago we had the evacuated tubes fitted to the geyser, and results were good. I set the geyserwise controller to turn on twice a day for 20 minutes each time just to top up the temps to 55C if required.



Since then, Citypower installed new meters, which seemed okay at first, and pretty cool as they come with their own little monitors which could be used to track power usage. I already had an Effergy monitor, so this was not really needed, just cool nonetheless as I didn't need to upload Effergy data to my PC to get daily usage.


This week was an exciting one as we had the PV panels installed.

The installers only arrived at 12pm which was not ideal as they didn't have time to complete everything, but they did enough to get the panels connected to the inverter.




Wife was very impressed the next morning when she woke up to the power monitors showing zero consumption from Eskom.




Right now I'm still deciding on output and charging priorities for the inverters, but I think I'll run off panels during the day, and grid at night, and the batteries will be my reserve for when there is no solar or Eskom.


Anyway, this is what I have so far, and any comments or suggestions are welcome.


I'll upload pics this weekend (hopefully)

Edited by viceroy
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Pics have been uploaded :)


Nope, no special software required to run the axperts in parallel. They already had the parallel boards installed so it was simply a case of plugging in the communication and power sharing cables and that was it.

The pics are showing only one of the inverters running though.

I did make a VERY stupid mistake of mislabelling the AC cables and blowing the inverter which has been sent in for repairs. Still turned on, but throwing an error about a soft bus start error.

I should be connecting the replacement in this weekend.

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Actually, both inverters have a parallel kit each. Yep, the 5kva (4kW) MKS

Anyway, you can connect the PV as you like, either all on one inverter or split between each inverter, so long as each inverter only gets a Max on 3kw of PV.

There is a setting on the inverter where you set this up

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Great job there.

What area you located in?

Which way is the panels facing?

How many units you generating per day?


I would like to recomend you look at putting the electrical cabling inside plastic conduit or trunking.

Do you have fuses installed on your 48V DC coming from the battries?

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I'm in JHB, Fourways.

The house sits about 45% from north, the panels facing NW and the Evacuated tubes facing facing NE.

I'm thinking about rotating the 3 panels on the flat roof to face in the same direction as the Evacutated tubes to take advantage of the morning sun.

I'm not sure exactly what's being generated. The inverters by themselves don't store a log, and I'm still fiddling with the supplied software, but it's not the most useful and only displays PV voltage when the inverters run in parallel.

However, since the panels went live, our daily consumption has dropped from 20kw/hr/day to 9kw/hr/day, so guessing 11kw/hr/day from the panels as a rough guess.


I have trunking ready and waiting to be installed. Just waiting on a proper battery cabinet and cable layout to be finalised before I install.

Yep, got a 100A/60VDC amp fuse for each inverter.

I was thinking of putting a terminal fuse on each battery, but not sure if that's overkill?

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Made a small change to the system this weekend.

Turned the 3 panels on the flat roof 90 degrees to take advantage of the morning sun.

Made a huge difference.

Previously at around 8am, I was seeing between 250 and 300W from PV.

This morning, that figure was around 880W.

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I had a company install the panels onto the roof, and they assisted with fuses and breakers for the batteries and will be supplying the electrical compliance certificate, but everything else was DIY.


I'll do a complete photo update of the install when its 100%


And will also add my thoughts about what I think I should have done differently.

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The company was Gauteng Water Heating.

The first part of the install went really well, but towards the end, their quality of service dropped dramatically, so much so that I still haven't paid then the final instalment.

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  • 2 weeks later...

Hi Viceroy


I am also planning a solar system and what you've done is exactly what I had in mind. Only, I want install a PV array of 6 kw, 3 kw per inverter. How is you inverter's MPPT performing, I mean how many KWh do harvest during this time of the year? One thing I noticed about the Axpert is that the maximum voltage of a PV string is only 115 V compared to 450 - 500 V for other hybrids. Does it mean more strings in parallel and how will it affect you cable thickness between PV array and inverter? I plan to put my inverter quite a distance from my panels and is concerned about the cable cost. 

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  • 1 month later...

Hi Viceroy,

I have the same inverter as you and I am planning to install pv panels. I was wondering what settings you used to keep the batteries only as a back up? I. E. Only use solar during the day an switch to grid at night. I would also like to know if you kept your battery cut off at 49v? Thanks John.

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  • 6 months later...

After the old batteries went belly up in December, we've been running totally on grid while we waited on insurance and for the batteries to arrive.

This has actually given us a good new base to work from.

Before we converted the geyser to solar and installed the gas stove, we'd average about 22kWh/day.

We're now sitting on about 10kWh/day, but I do turn off the fridges after 10pm and turn them back on again at 5am

I'd still like to lower this, and I think I need to get more serious with the family on usage.


Today the Omni Power 260ah batteries arrived and are being connected up in their new home.



These batteries are monsters compared to the previous 120ah batteries.

Total battery capacity is 24,960Wh whereas before I had 17,280Wh


I'm going to be changing things up a little this time round.

The inverters have been moved to a new wall in the garage, one that does not get warm because of the sun.

I'll be installing a Victron BMV-700 to monitor the batteries, and I'll be integrating this with JDP's software.


I'll hopefully finish moving everything over and installing this weekend.

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I'll be installing a Victron BMV-700 to monitor the batteries, and I'll be integrating this with JDP's software.


Do yourself a favour and get a BMV-702 if you can to measure midpoint voltages.


P.S. That battery stand of yours does not look like it will take the full weight of your batteries. 4x260Ah batteries weigh nearly 300kg.


Edit: I see they weigh 60 kg so nearly 250 kg.

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Do yourself a favour and get a BMV-702 if you can to measure midpoint voltages.


P.S. That battery stand of yours does not look like it will take the full weight of your batteries. 4x260Ah batteries weigh nearly 300kg.


Edit: I see they weigh 60 kg so nearly 250 kg.

I'll use the 700 for now, and possibly upgrade to the 702 when funds allow.


I said exactly that to the guy who assembled it and started putting batteries on it.

I will raise it again when I speak to his boss later today at the final inspection.

If it really comes to it I'll add reinforcing at the centre point of the shelf.

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..., and I think I need to get more serious with the family on usage.



Same here. SWAMBO and her siblings, my kids would have listened, was the most difficult part of the entire solar setup, to get working.  :D

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So I made some progress today.

Inverters have been put up, and connected to the batteries and Pv.

I've also wired up the BMV700 and thats working too.



The battery shelf still needs to be reinforced/ replaced with a stronger one.

Please ignore the geyser. It's never been turned on, and we have no intention of turning it on any time soon, so heat (WRT the geyser) and water leaks are not a concern.

Once I've pulled across the AC feeds, and tested the basic system, I'll put in place conduits to make it pretty.


In the meantime however, the garage is a hot place to be, I havent taken a temp reading yet (misplaced my IR thermometer) but I reckon its around 35C.

As such I've lowered the float and charge voltages to 53.0V and 55.4V respectively on the inverters.

Maximum charging current is 50A. On the side of the battery is states 52A initial charging current.

Are these values correct for the temps and the batteries?

I'm going to be pricing an extractor fan which will be mounted in the wall to the right of the batteries to expel hot air to the outside.

I also want to play around the JDP's software as well as it seems to do a lot of what I want in terms showing SOC, monitoring, and using SOC to change settings on the inverters.

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