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Max pv watts for Axpert inverter


alistair

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So i got my Inverter today :)

This is my plan for wiring it up.

 

AC Input to come from nearby plug point.

DC Input to come from Solar panels - DC Circuit breaker (25A) to be installed during the week.

AC Output to run to Multiplug and then to required locations.

Batteries in to Inverter with DC Circuit breaker (66A) to be installed during the weak.

Does everything seem okay?

 

Inverter model? It is not a good idea to connect the batteries to the inverter without a fuse or breaker in line.

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Its a 3Kva using 4X102Ah batteries in 24V configuration.

 

I will also look at ACDC on Sundaty morning to see if they have any that i could install when doing everything on Sunday, otherwise it will have to wait until the electrician comes during the week.

 

My current off grid setup has no breakers at all, but want to do this as correctly as possible.

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Its a 3Kva using 4X102Ah batteries in 24V configuration.

 

I will also look at ACDC on Sundaty morning to see if they have any that i could install when doing everything on Sunday, otherwise it will have to wait until the electrician comes during the week.

 

My current off grid setup has no breakers at all, but want to do this as correctly as possible.

 

The 3KVA 24V Axpert will draw up to approximately 100A, not 66A. You'll have to get a >100A breaker/fuse.

 

The fuse/breaker in the battery line is not so much for "correctness", but rather for if something inside or close to the inverter goes wrong - in that case you will probably melt the battery cables and severely damage all the batteries.

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Late to the conversation :-) On a very generic level, you get two kinds of MPPT controllers. Some can deal with oversize arrays and some can't. Most that I've seen can, they simply don't optimise past their maximum. So when there is more than the maximum available, the charge controller simply "clips" the excess power, so if you plot it on a chart you'll get flat tops instead of rounded tops. So the question is whether the MPPT controller in your Axpert is such a controller or not.

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My 5kVA is so quiet under normal load I did not realise its fan was on until I turned my PC off. Sometimes I end up sleeping in the same room as the inverter as the room has a fireplace and is warm in winter. Under heavy load there is the hum of fans working hard but it is not excessive. Earlier Axperts were noisy. 

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Hi Seth Well done it is a lekker feeling  :). There appears no battery fuse and/or disconnect and ditto for your PV line.

That is correct. Going to have an electrician come in this week to install fuses and breakers. A bit above my grade for installing and finishing it off well. So will get it done properly.

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  • 2 weeks later...

Another quick question: How noisy is the inverter? Would it be noticeable if its in the next room in the middle of the night?

It can be a bit noisy (to some people?) if the batteries were drained quite a lot and it has to recharge them quite quick. And under load it could also be a bit noisy. About the same as a gaming PC with some 8cm fans running on a full blast.

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So i have found fuses from ACDC that are big enough to install for batteries and panels. But i would also like a cut off switch as dont like the idea of pulling out the fuse alone. This seems to be a problem that i cannot find any help with. I found a 100 Amp Isolator that is reasonably priced, but unsure if it will work correctly with DC current.

What do people use? in all the pics ive seen between batteries and inverter there is a switch which i assume is an isolator?

Please help?

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So i have found fuses from ACDC that are big enough to install for batteries and panels. But i would also like a cut off switch as dont like the idea of pulling out the fuse alone. This seems to be a problem that i cannot find any help with. I found a 100 Amp Isolator that is reasonably priced, but unsure if it will work correctly with DC current.

What do people use? in all the pics ive seen between batteries and inverter there is a switch which i assume is an isolator?

Please help?

You can't use AC Isolators for DC, they are not designed to handle the arc created when open circuiting.

My battery fuse is bolted onto the battery terminal and the cable bolted on the other end. To replace, first switch off the inverter then no sparking occurs.

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DC breakers is a damn pain in the proverbial. Can't find them, and if you do they are very expensive. From what I remember from way back in school... you can use an AC breaker rated at ten times the current. I saw a couple really nice ones at a local demolition/second hand building material place. All the old switch gear in buildings come out and it's on a shelf... some are so heavy that you need two hands to move the switch.

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You can't use AC Isolators for DC, they are not designed to handle the arc created when open circuiting.

My battery fuse is bolted onto the battery terminal and the cable bolted on the other end. To replace, first switch off the inverter then no sparking occurs.

So would you suggest just using fuses between batteries and inverter? And if i need to shut down, just turn off inverter and then remove fuse. No switches?

Are there any fuses on a site like ACDC that are DC rated for 100 Amps? Can you send a code or site that has these?

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So would you suggest just using fuses between batteries and inverter? And if i need to shut down, just turn off inverter and then remove fuse. No switches?

Are there any fuses on a site like ACDC that are DC rated for 100 Amps? Can you send a code or site that has these?

 

Fuses are perfect. When a fuse goes open circuit and needs replacing, there are in any case no current flowing and when you open the fuse holder it will no arc. 

 

Regarding the battery fuse: Switch off the inverter and use the bulb trick to slowly charge the capacitors in the inverter before closing the fuse holder after fuse replacement - that will prevent the arc when you close the fuse holder.

 

Regarding the PV fuse: Switch off the inverter and just close the fuse holder after fuse replacement - the current is much lower on the PV line and will not cause such a big arc. Alternatively wait until sunset and then replace the fuse.

 

Battery fuse holder: CMS2258.1

Battery fuse: 2258.100

PV fuse holder: 211PV

PV fuse, depending on string current:

10A: 30F10PV

12A: 30F12PV

 

The fuse should have a rating of 25% more than the continues current through it, to avoid nuisance blowing.

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I was given a Gewiss c50 GW92012 breaker, by an electrician, also rated for DC, to disconnect my controller from the panels. They are about R150 each I think.

 

Then last week I moved over to Anderson connectors to disconnect my panels completely from the controller, after the lightning we had.

Between controller and batts, I also use Anderson connectors, as it just makes it easier to move things around.

But between inverter and batts, I only have fuses ... for to disconnect things there any easier here, tends to switch off a lot of things. :-)

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I was given a Gewiss c50 GW92012 breaker, by an electrician, also rated for DC, to disconnect my controller from the panels. They are about R150 each I think.

 

Then last week I moved over to Anderson connectors to disconnect my panels completely from the controller, after the lightning we had.

Between controller and batts, I also use Anderson connectors, as it just makes it easier to move things around.

But between inverter and batts, I only have fuses ... for to disconnect things there any easier here, tends to switch off a lot of things. :-)

I was also thinking about something like this type of connector to make sure if there was a bad lightning storm, i could completely isolate the panels from the rest of the system. Anywhere around Jhb have them?

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Sethm, here is the importer, for Anderson: Tarryn Janion Email here at: [email protected]

 

Or look at the generic one here: http://www.4x4direct.co.za/electrical-power-plugs-and-sockets-c-45_48/50a-heavy-duty-connector-block-red-p-1161.htm 

Ps. Note: Anderson inner connectors do not fit on the generic one ... I tried. 

 

Just need the right crimper, do not use a vice. :-) Does not work. 

Crimper can be bought at http://www.hellermanntyton.co.za/tools.html the Medium Duty (yellow one) in the pics. Good investment if you make your own cables.

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  • 3 years later...

I have a 24 v axpert 3KVa inverter. Not the plus model.

In terms of the MPPT charge controller it says 600W max 75voc @ 25 Amps.

What does this mean what panels do I need to buy to make max use of the above specs.

Any help is appreciated 

Mike from Durban, S.A.

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16 hours ago, Mike Nofal said:

I have a 24 v axpert 3KVa inverter. Not the plus model.

Thank you for being precise about the model; it's so refreshing.

16 hours ago, Mike Nofal said:

In terms of the MPPT charge controller it says 600W max 75voc [and] 25 Amps.

What does this mean what panels do I need to buy to make max use of the above specs.

The 25 V is on the battery side. This is an older model, where the 600 W figure is the nominal battery voltage (24 V, later models use 25 V) times the maximum charge current. So all you know is that you can connect at least 600 W of panels, because that's the only way you'll ever get 25 A into a 24 V battery (600 W output requires at least 600 W input).

So all we can do is use general guides. @plonkster  has suggested 20% maximum over-sizing. I'm now advocating a maximum over-sizing of 12.5%, merely because the latest models that do have a realistic maximum PV panel power specification, it's 112.5% of the maximum solar charge power, using a nominal, rounded battery voltage like 50 V or 25 V.

In your case, I would put the limit at 112.5% of 25 V x 25 A, or 1.125 x 625 = 703 W. If we go with Plonkster's 20%, it would be 1.2 x 625 = 750 W. These models really do have tiny solar charge controllers built on. If you need more solar power, you'll have to provide a separate MPPT charge controller and connect its output directly to the battery.

16 hours ago, Mike Nofal said:

Any help is appreciated 

I wish Voltronic were more helpful with this sort of thing.

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  • 3 weeks later...

Hi guys newbie here.

Im doing a install of an inverter/batteries/panels at home. I have an axpert 5kva inverter, now I need to spec the solar panels. 

Currently looking at the Canadian solar 400w panels (thinking to make it into a car port like makro) but I'm not sure how many panels and setup (parallel vs series). 

Inverter specs:

Maximum PV Array Power: 4000w

MPPT Range @ Operating Voltage: 60VDC ~115VDC

Maximum PV Array Open Circuit Voltage: 145 VDC

Maximum Solar Charge Current: 80A

Maximum AC Charge Current: 60A

Maximum Charge Current: 140A

Do I look at the NMOT or STC specs for the panels. Do I need 9? Or 12?

https://cdn.shopify.com/s/files/1/1776/7837/files/CS3W-P390-405_HiKu_Poly_MBB_IECUL1000_1500_F9-S_BS-White__v5.563.pdf?915621011663269934

 

Any help would be really be appreciated - explain slowly I'm still learning. 

Thanks in advance. 

 

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  • 3 years later...
On 2015/08/11 at 8:24 AM, superdiy said:

 

Chris, you are spot-on. The most important thing here is to never exceed the inverter PV input voltage. If the inverter specs says that it accepts 600W from PV, that simply means that the inverter can utilize up to 600W from PV, even if you have 3000W worth of panels connected, the inverter will only use up to 600W of the available 3000W. Current and power is not an issue - just do not exceed the max PV input voltage.

Hi there, I have bought a 3KVA MKS Plus, how many panels can I connect to it?

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