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Noob looking for advice


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Hi guys

Been reading the forum for a few days and really impressed with the knowledge of some of the members here(far more knowledge and practicality than most electricians/salesmen I know)

I currently have a mecer 3kva axpert and 2 x 200ah Gel batteries.

I am using a changeover switch and have to switch it on(to inverter) during loadshedding. 

3kva is far too small to leave it on inverter mode the whole time and hence the upgrade.

 

I ordered an Axpert 5Kva MKS II which should arrive by friday. I will then get my electrician to add a few more breakers to the inverter DB.

I know that I will require 2 more batteries and I plan on getting another 2 x 200ah Gel.

 

My questions

1. If I get another 5kva will this then equate to 10kva supply?

2. Will 4 batteries still work with 2 inverters connected in parallel?

3. Does the inverter have to be the same make(ie MKS II) or can I use any axpert 5Kva inverter - The only advantage I can see to this is the cheaper price. Are there any disadvantages?

4. In a few weeks I plan on getting solar panels , how many of what power would I need for 2 x 5kva connected in parallel to achieve maximum efficiency?

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10 minutes ago, Richard Mackay said:

How has your 3kVA inverter being doing with the 2 x 200Ah batteries?

How long do they run and what are you powering?

Hi Richard

I powered a couple of led lights , fish tank(+-50 watts) / inverter aircon(+-400w) and my pc etc. Usage was between 20 to 60%. Only been using it during load shedding. A few times we ran it for more than 2 hours. Once it ran for +-7 hours with no issues. 

I would now need to power another aircon(non-inverter type) / hairdryer / possible microwave / kettle (ofcourse not all on at the same time)

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5 hours ago, ShaunKZN said:

1. If I get another 5kva will this then equate to 10kva supply?

2. Will 4 batteries still work with 2 inverters connected in parallel?

3. Does the inverter have to be the same make(ie MKS II) or can I use any axpert 5Kva inverter - The only advantage I can see to this is the cheaper price. Are there any disadvantages?

4. In a few weeks I plan on getting solar panels , how many of what power would I need for 2 x 5kva connected in parallel to achieve maximum efficiency?

1. Yes, max supply per inverter 5kva;

2. It will, but could be a little light, I have no experience with Gel batteries, I do know that depending on the age of your current batteries, you can not just add on, except for lithiums where you can add on over a period of time;

3. Is better to have the same inverters, more important is that the firmware of the inverters are the same;

4. You could be limited to around 4000w input per inverter depending on the inverter specs, you need to be within the Amp and Voltage parameters also.

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7 minutes ago, Wilfred said:

1. Yes, max supply per inverter 5kva;

2. It will, but could be a little light, I have no experience with Gel batteries, I do know that depending on the age of your current batteries, you can not just add on, except for lithiums where you can add on over a period of time;

3. Is better to have the same inverters, more important is that the firmware of the inverters are the same;

4. You could be limited to around 4000w input per inverter depending on the inverter specs, you need to be within the Amp and Voltage parameters also.

Thanks for the clarifying that Wilfred.

 

Batteries are just 3 months old. 

Specs :

  • Maximum PV Array Power: 4500 W.
  • MPPT Range @ Operating Voltage: 120VDC ~430 VDC.
  • Maximum PV Array Open Circuit Voltage: 450 VDC.
  • Maximum Solar Charge Current: 80 A.
  • Maximum AC Charge Current: 80 A.
  • Maximum Charge Current: 80 A.
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2 hours ago, Quat Allah As Shams said:

 I have the Axpert MKII running with 14 x 335w Canadian Solar (7 Series 2 Parallel)

I plan on using 2 axpert MKII's. Can I set it to run from battery(and charge via solar) / or direct through solar / 

My only concern is that there should be enough juice left in the batteries when loadshedding strikes. What settings would be ideal to achieve this?

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4 hours ago, ShaunKZN said:

My only concern is that there should be enough juice left in the batteries when loadshedding strikes. What settings would be ideal to achieve this?

Mainly output source priority (setting 01) = SOL. This setting keeps the battery as full as possible, while using solar power as much as possible during the day. It switches to line mode (utility powers load) as soon as the sun sets.

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37 minutes ago, Coulomb said:

Mainly output source priority (setting 01) = SOL. This setting keeps the battery as full as possible, while using solar power as much as possible during the day. It switches to line mode (utility powers load) as soon as the sun sets.

Exactly what I need! Thanks Coulomb!

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Ok so the inverters are on the way , should have them by tuesday.  Next on the list is solar panels. Planning on panels within the 300w range (45V / 9amps)

Distance from panels to inverter(combiner box first) is roughly 20m. I'm looking(for now) at getting 8 panels. ie. 2 strings of 4 panels each(series)

My combiner box will house the PV cables -->fuses--->busbars-->PV breaker.

This is a parallel (2 * 5Kva) system so I understand that I would need to supply both inverters 

More questions :

1. What size cable should I use from panel to combiner box and what size from combiner box to inverter(+- 1.5m apart).

2. What size fuse should I use for these cables in the combiner box(plan on adding more panels later).

3. What size PV breaker would be sufficient?(also would I be able to output 4 cables from PV breaker to inverters or should it be 2 cables --> Busbar --> 2 cables to each inverter).

4. I have 4 x 200ah Gel batteries , what rated fuse should I have on the positive line in a system like this? If I plan on adding 4 more batteries will the rated fuse need to change?

5. Can my battery Busbar be in the same PV combiner box?

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