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I currently have 10 300w solar panels connected to a 5kva Apert (Mercer) invertor.

1) What is the max 300w solar panels can I connect to a  5kva Apert invertor ?

2) Should the max be 12 panels, what advantage might I experience by doing that ?

a) batteries will be fully loaded quicker ?

(b) I will use lesser Eskom power ?

3) Will the cost of the additional 2 panels out weight the saving on my Eskom account, over a 5 year period ? 

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I would like to know if it is safe to pair AGM and Gel batteries. I recently built a string of 4 AGM batteries in series. A deal has come my way of 4 gel batteries I intend connect in another series string and connect in parallel with the AGMs if it is safe to do so. 
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I am posting this to help with system sizing for people considering going off grid. This is one years monthly production figures. The system size is as follows:


3000W solar array, two separate arrays of 6x300W and 4x300W panels, through separate MPPTs. Fixed angle installation, 1800W at 30deg north, and 1200W essentially flat (roofs dictate the angles)

Diesel generator for backup.

Wind generator (I can't measure this but I guess it makes 1or 2 kwH per month depending on wind)

Solar geysers (no electrical backup)


Household of 4, normal fridge, freezer, washing machine, computers etc etc. Water pumping from borehole, pool pump (2hrs in winter, 6hrs in summer).

Gas stove for cooking, wood fires for heating.


8x150Ah Trojans, currently 2.5 years old.

I have been measuring the montly production for a year now since I upgraded the system to 3000W. Note that the graph is more of consumption rather that production as the batteries float on most sunny days, so there is excess production mostly. If the weather is overcast I run the generator, rather than stress the batteries, especially in winter I run the generator for an hour or so in the morning to power toaster, microwave etc before the sun is up.

The seasonal effect is obvious on the graph, the pool pump is used more in summer which accounts for some of the extra power consumption, I'm not sure what all of the other extra consumption might be, I think we are getting less frugal with power use as time goes by and we are used to the system, so we vary from about 300kWh per month in winter, to almost 450kWh in summer. Solar efficiency varies from around 3 in winter to 4.5 in summer (kW produced/kW installed per day).

Diesel use peaks in May & June as would be expected, you often get overcast days in May.

So here's the figures, I hope someone will find this useful.


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I'm new to the forum and to solar so would appreciate help please.

I've bought 7.5ha undeveloped land in Cape Farms inland from Melkbosstrand 5km from Atlantis. Going to install a container and barn in the next month to start the development.

So, I get Eskom to come give me a quote and they say the whole process takes 180 working days, not sure if they can do prepaid in my area, bla, bla... I take it as a clear sign that I need to go solar right now.


My take is that I need to start with a system that caters for the 12m container (which will be in the 280m2 barn) and barn. Then, when we build cottages on the land down the line, each will have its own system. Does that make sense or not?

So Guys, if I need say 600kw pm (does that sound right?) for the barn, what is the best solar system for that please?

I would really appreciate some good, wise advice and help.
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Hi Guys, 


I am new to this forum, mainly registered since reading a bit and want do download the axpert manual,but need atleast 5posts. So let me introduce myself. 

I am a qualified Millwright,working on Dragline control systems for a big company, been in the industry for 5 years and programming PLCs the past 2 years. Learning a lot about power factor etc. 

I recently decided to buy a small system due to load shedding we will soon start to experience. Recieved it this week and will start to install on sunday. 

It consists of:

Axpert 5000mks

2x 260w JA solar panels

4 x 105ah 12v batteries


also requested a quote on another 4 batteries and 2 panels to expand a bit


Any installation tips,calculations etc you guys can assist me with? Whats it good for and what not. At first I wanted to use it on all plugs and lights with the utility bypass function. But after reading a bit it seems it wastes more power when bypassing


current daily usage of about 40kw per day. Between 5-7 people in the household. Big swimming pool. And electric geyser. 
  • 56 replies

Hi Guys,

My name is Andries and live in oudtshoorn (Grootvoël Paradys)

so I registered last week to this forum and was browsing a bit and so,cannot believe I find this forum earlier.

My Current installation is Powerstar IR 3000 (24V) inverter,60A MPPT Controller,6x 200AH AGM Batteries,victron battery balancer and approx 1.2kw pannels,I was browsing and reading allot about the axpert type inverters and realise most of the guys using 5kva. I received my inverter yesterday and going to install it this upcoming weekend,picking up tomorrow new fuses,breakers,boxes and some new battery cables,is there anyone that have experience with the 3kva and anything that I need to know about?

Kind Regards
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I would really like some suggestions before forking out a lot of money. 

My thoughts are for:

24 off 265w panel array mounted on a car port (to be constructed to suit - space no concern).

A 6kW 48v inverter. Is a combination inverter charger preferred? Must be hybrid to balance loads in the background.

4 off 200ah batteries to supply 48v

I need recommendations for:

Are there ideas or designs available to tilt the panels to suit the season. I read about different angles for winter, summer etc. No big trees around.

What makes do you recommend.

Is there a way of making a house distribution board more intelligent to control or manage different loads at  different times as solar energy is generated? By interlocking circuit breakers to switch on or off sequentially. 

Which companies are recommended - I am not looking at one man shows here. People die and retire.

I am looking for at least a 10 year backup service as I am getting older - already retired :-)

my non technical wife must be able to manage it when I am not around.

My house is in Witbank.

  • 53 replies


I recently installed an SMA sunny Tripower 25Kw 3 phase GT inverter with SMA energy meter and SMA sunny home manager there are 15Kw of panels attached- however the readings below were taken during my experiments with only 5Kw of panels attached. I configured the export limitation settings on the home manager and the inverter per the SMA 'official" youtube webinars for '0W' of export.

I have strange readings on my 'el cheapo' amp clamp meter.

The above readings for utility make no sense when the GT inverter is operating. I conclude the slight differences in readings between load and utility amps with the GT switched off relate to the lack of accuracy on the cheap clamp meter and slight timing differences as I take the readings and the laod changes in that time.

My problem is this - the SMA portal graphs will show zero import/ export during the day, however the utility smart meter is showing that power is being consumed (or perhaps exported since it is the type of meter that charges customer whichever way the power flows).


I can see the inverter divides the power generated equally accross the phases - I understand this relates to power regulations when one is exporting to grid, however I dont understand why this is needed when there is zero export?

Has anybody got experience with SMA tripower and export limit setups? what should the behaiour be?

Can anybody explain the wierd current measurments - what is that caused by?



  • 2 replies

Hi All.

Hope great. We have a good supply of German Made Recom Solar Panels in Stock. We are providing them per Pallet of 25 Modules at R49,875 Inc Vat.

Amazing German panels. with all the warranties etc and certifications. TUV.

Please do find the attached Specification sheet. We have a fair amount in Stock. We have sourced this when the Exchange Rate was strong.

Unfortunately next year the Rand is not looking great. Thanks Guys First some first serve. Please do find the attached Specification sheet.,

Delivery can be arranged to your premises.

I hope this is helpful.



  • 1 reply


Trying to learn and understand the basics with a view to self-installing a completely off-grid system. The plan is to get rid off Eskom completely. Just received a R97 000 bill , cant be correct but Im tired of dealing with these idiots. And the power has been on and off all week so really want to show them the middle finger and be self sufficient.

Have done my initial sums and figure a 2,5 to 3kw inverter should suffice for now. I can move this to another building if i upgrade later so not too worried about future proofing. Would rather ensure I can add panels and batteries.

I have a question regarding 2 Axpert inverters. The first is the Axpert KS 3K-24 and the second the Axpert MKS 3KP-24. On the second one I see in the specs the MPPT Range @ Operating Voltage is 30 VDC~80 VDC and if I understand correctly it will not work unless the panels are supplying in that range? If so I would need to connect panels to ensure at least 30VDC. Now the first example I linked to there is no mention of voltage range. Is this because it does not have a MPPT charge controller? Would I have to buy a separate charge controller if I went with the KS but not if I went with the MKS+?

The KS3K 24V is a good price on Takealot at R5999 

One last question for now: Was looking at the SAMIL Solar Solar River range ans I see the voltage range is 165-500V. That is a bit difference to the Axperts and I would need a lot more panels in series to reach the minimum. 


Thanks in advance.





  • 55 replies


I would like to put my standard pool pump onto my 2x 5kva Axperts in parallel. The documentation states that the Axpert can operate appliances with motors but i don't see any detailed specifications.

The pump will run during the day so on most days should run directly from solar panels. 

Has anyone done this yet? if not do you foresee any problem?
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de-salination energy cost per liter fresh water
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calling all pipe/water/tank gurus ;-)
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Imeon 9.12 3-phase installation
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So CoCT sent me an angry letter and they are threatening fines and such, so I drastically have to reduce my consumption somehow. 150 liters/person/day is easy enough and we've done that since November last year, and with some effort (mainly carrying lots of buckets between baths and toilets) we can get it down to 100 liters/person/day. But the main trouble is that the washing machine uses a good third of our "allocation". With our present setup, we can get down to 80 liters/person/day if we live like hobos (well not quite, but it's getting quite hard), and rainwater tanks... forget it, there isn't much rain to be had. So I've turned my attention to my well point.

The well point isn't very deep. Maybe 3 meters. But there's at least a kiloliter down there that I normally use to water the garden (which we've also stopped doing). Of course I can use this water directly to flush toilets, but again: roughly 6 liters per fill, and we don't flush the toilet 20 times a day. More like 5.

Which brings me to my question. What kind of dangers are involved in using the well water for the washing of clothes? What would it take to filter it just enough to make it safe? My gut feeling says that I want to at least get any sediment out of it (so as to not discolour anything), and that anything that can be an irritant (heavy metals perhaps?) should probably go too. Ecoli? Would probably depend on the exact count. And then there's the TDS (total dissolved solids) which apparently you want to be below 1000 ppm. Other than that, taste and smell won't matter.

So, my fellow amateur experts, what say you? Can this be done? What would be needed?

Edit: I've already sent some water to a lab to have it tested. It's a fairly expensive test, but apparently you can't do much until you've done the test. Still would like some opinions.
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The start of a axpert installation. 
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My battery bank is failing and I am contemplating what sort of batteries I should buy as replacements. We are limping along and the batteries last a couple of hours until we go to bed but do not last through the night.

I am going to discuss batteries in general and try and avoid specifics so that folk considering battery purchases are aided in their own decision.

I think the first decision is deciding whether you want to go vented or not. In our case the "power room" is a corner in our TV/study/workroom so unless I end up with an innovative battery box that vents outside I would not want vented batteries inside our home. Battery boxes are common in the US which is considerably colder than SA and batteries are kept indoors to prevent them freezing. There are lots of designs on the net and I thought I would put a piece of 32mm conduit through just below the window sill. This would not be easy as the walls are over just over 450mm thick. This would enable me to have Trojans the only vented batteries I would consider.

If I were to go with sealed batteries one could add Lithium batteries to the smorgasbord of options available to you.

The second but probably deciding factor is cost. Lithium and 2V cells (both VRLA and vented) cost a whole whack but should outlast the other options available. I would have to be sure that the Lithium batteries I looked at were compatible with my inverter. I don't think my funding would stretch to a Lithium bank but if I have to replace my inverter too it would make it an exercise in futility.

The third deciding factor (for me) would to have batteries with sufficient Ah rating so that I could have a single string of batteries. This would exclude doubling up on the current brand of batteries I already have along with the bulk of the VRLA batteries on the market.

So what are my options if money is no object:

Lithium that is compatible with my inverter

VRLA "sealed" 2V cells

Trojan batteries in a vented battery box.

My budget is probably going to reverse that order .


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To improve air quality, Britain and France will ban all new petrol and diesel cars and vans from 2040 amid fears that rising levels of nitrogen oxide pose a major risk to public health.
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I have Rectron 5KVA inverter

 8 X 100AH Lead Acid Batteries connected to produce 48Volts

6 X 310Watt Solar Panels connected 3 sets of 2 in parallel

Please Please Please will someone PLEASE tell me how to “setup” the Inverter. I please need to know the following cause I could do the installation using logic and common sense but I don’t have the knowledge or understanding to do the INVERTER set-up and fearful I may damage/cook/boil the batteries. I need to know:

·        Point Back Voltage (drop batteries and back to utility/Eskom)

·         Bulk Charging Voltage:

·         Floating Charge Voltage:

·         Low DC Cut-Off Voltage:

·         Max Charging Current: Solar

·         Max Charging Current: ESKOM/utility

·         Max Charging Current: Solar + ESKOM

PLEASE will some of you electrical wizards come to my rescue and “save the day”? Thanking you in advance.
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Can someone please explain how to calculate how much energy it takes for heating water? If I have a 2kW geyser element for instance, how long will I have to run it to heat water say 30 degrees warmer? I'm basically trying to work out how long I will have to run my generator to heat the geyser up to SWAMBO's temperature tolerance limits..
  • 51 replies

Good day guys, I have a 6kw solar array.

2 Axpert mks 5KVA running in parallel

6 strings of 4 panels (Renesola Virtus II 250W)

String output under load 110V 5A

3kw east & 3kw west On a normal roof tilt.

I would like to know what your maximum PV output is this time of year.

Between 11:00-13:00 I get about 3000W. it seems to be a bit low, I know i am pushing the MPPT to its maximum voltage.

Any recommendations ?


  • 27 replies

Hi. We installed an Axpert 5kVA inverter (offgrid setup). After adding a BMV702 realized the axpert uses 65W with absolutely no load attached other than itself. This seems excessive, or is it correct? Any thoughts or similar experience
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many people think water in a rain water tank is just for garden usage, toilet flushing etc. and in order for the water in them to be 'useable' the tanks must be flushde or scrubbed every now and then.
we have been using water [FOR DRINKING!] from a 5000l tank which is fed by a slate roof for more than 5 years WITHOUT the tank being cleaned - and still the water is clear, does not taste of anything and we [me and wife and employees] are still healthy and alive [as i type...]
note: no special filters, only a piece of rolled-up chicken wire at the inlet and NO first flush.
two methods [preferably used together although we usually forget about the second one for months on end...];
a 21v pv mounted on top of the tank supplies a current to a small copper [99% pure] anode and a small silver [99% pure] cathode [can be reversed also] inside the water which releases positive ions. these ions bind with negatively charged ions inside bacteria and algae [slime] eventually leading to cell death.
get ordinary household bleach which contains about 3.5% sodium hypo-chloride and pour 250ml [cup full] per 5000l water once or twice a month - if there is a slight chloride taste or odour, don't worry, it will vanish in two or three days.
in Christ

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I have an old 300 l flat plate collector solar geyser which will eventually expire (I can see it coming). When I replace it I am thinking of getting 2 150 l EV geysers an putting them in series so that if I need to use Genny power to heat water in winter, I can select whether to hear 150 l which will be quicker , or 300l which will be slower. Are there any pit falls in doing this?
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Hi, I'm in the final process of setting up my infinisolar 3kw+ and would really like to know what settings others are using or recommend.
Here is my kit:
250w Panels x 12
Trojan t105's x 8 (48v)
Infinisolar 3Kw+
This afternoon I hooked up the infini to the battery bank, solar panels are on the roof but not mounted or connected yet so I'm looking to connect in UPS/Backup mode for now
At this stage I'm curious to know what more experienced members would recommend for parameter settings, I've attached a screenshot of what I have and I'm a little confused on a few of them quite frankly. The unit keeps on running the fans every few minutes even though I'm at full float voltage... (there is no load connected at this stage, 1 step at a time)
Ac and battery bank connected...
300w power draw even though there is no load applied and batteries are fully charged, is that normal? I can't see what it needs that much power for when theoretically in standby, I'd see this adding up quite considerably over a period of time.
The fans also keep on switching on every few minutes, I find this curious as there is no load and the batteries are fully charged
I'm really confused what mode to put it in for backup, is it right according to attachment?
Battery specs trojan T105, 6V 225ah
Absorption charge 7.4 x 8 = 59.2 (can't go higher than 58 it seems)
Float Charge 6.6 x 8 = 52.8
Equalize charge 7.75 - Can one equalize with the infinisolar?

I'd really appreciate any input...  thank you!
  • 162 replies