Jump to content

Mecer 5kW-48V MKS II


Antony

Recommended Posts

7 hours ago, Coulomb said:

It won't produce more than the inverter can handle, except perhaps for brief transients if the control system becomes unstable.

It seems that the Goodwe will draw a maximum of 5400 W (its "DC power" rating), and it's recommended that no more than 130% of that figure is connected, i.e. you would be safe with 130% x 5400 = 7,020 W.

Hi Coulomb

 

I'm trying to find your reference to the 5400 W DC power rating from the datasheet I have, please help.

https://cdn.shopify.com/s/files/1/1776/7837/files/Hybrid_ES_Datasheet.pdf?16121032442884909209

https://cdn.shopify.com/s/files/1/1776/7837/files/ES_SERIES_USER_MANUAL.pdf?16121032442884909209

Link to comment
Share on other sites

On 2018/09/21 at 6:33 AM, Antony said:

Any issues with this inverter I should be careful of?

I see its being "marketed" as off-grid.

Also anyone know the Centurion Solar inverter control module "for maximising the potential of the Pylon batteries."

 

 

Hi,
"A grid-tied electrical system, also called tied to grid or grid tie system, is a semi-autonomous electrical generation or grid energy storage system which links to the mains to feed excess capacity back to the local mains electrical grid."
 
Why is the Axpert seen as a grid tied inverter?
The way i understand it is that the Axpert is an off grid inverter. (Might be wrong - Please help me to understand this if i am wrong?)
 
At no time is the inverter output connected directly with the Grid. (Except maybe in a severe fault condition and the safety relay did not operate and stands in the closed position? This can also happen with any other machine in fault condition)
There is a double pole input safety Relay feeding the Grid supply
There is  a load output relay connecting the load either to the Grid when the Safety Relay closes and inverter is switched off or to the inverter output when inverter is switched on and Safety relay is open.
There is an inverter output /charging input relay connecting the Inverter output to the load in the first case (Safety relay opened in this case) or to use the Grid to charge the batteries (Safety relay closed in this case)
The controller either connects the Grid directly to the output load and at the same time giving Grid supply for charging the batteries.
Or in the next case the controller disconnects from the grid with the Safety relay and then only connecting the inverter feeding directly to the output load . At no time are these two directly connected (Inverter when feeding output and Grid supply). That is why there is a transfer time of 10ms to 20ms. Similar to a off line UPS system. On a grid tied system there are usually no period when the output switches off momentarily (Dark chop-over) as transfer from grid to inverter or inverter to grid takes place with connection of both inverter and Grid together for the period of time while transferring load. (Life chop-over due to synchronization that makes it safe) 
 
We can see that the Grid might feed into the rectifier/charger to charge the batteries or that that the solar can charge the batteries with DC to DC Buck/Boost converter but this is controlled to put out a DC current to charge the battery or to feed the DC bus. However at no time can the controller switch on the inverter when the Grid safety relay is closed.
 
In a Grid tied system the input and output of a grid tied inverter needs to be syncronised with the Eskom grid to enable any feedback into the Eskom grid.
If synchronization has not been achieved and the output connects with the Grid an out of phase condition will occur that will probably cause severe damage.
As far as I understand the Axpert never syncronise with the grid for the intention to feed back to the grid. (Reason for Dark Chop over)
 
image.png.4155890fae41acbb8149d3894d8c1ce0.png
 
Would like some feedback to understand better?
Regards
Pieta
Link to comment
Share on other sites

1 hour ago, Pieta said:
Why is the Axpert seen as a grid tied inverter?
The way i understand it is that the Axpert is an off grid inverter. (Might be wrong - Please help me to understand this if i am wrong?) 

It's a matter of definitions. As long as you don't mix and match definitions halfway through an argument (in debate circles known as equivocating) you can usually make sense of it. CoCT considers it gried tied if it is in any way tied to the grid.

1 hour ago, Pieta said:

At no time is the inverter output connected directly with the Grid.

When charging the part of the inverter that's normally the output gets tied to the grid and then it runs in reverse to charge. But this inverter has other problems too. The changeover relay isn't sufficiently interlocking and doesn't open wide enough (4mm required apparently). It also fails SANS 10142-1 rules apparently.

Link to comment
Share on other sites

6 hours ago, Antony said:

Yikes! I just used data from the first manual I found: https://anro-developments.co.uk/wp-content/uploads/2015/06/Goodwe-ES-Manual.pdf . It says that each MPPT can charge at 15 A (that has to be PV side although Axperts always talk battery side). Your manuals say 11 A. There are three figures from the three sources for the maximum DC power: 5000 W, 4600 W, and 5400 W. And 11/15 × 5400 = 3960, so even if the current is taken into consideration, they still differ. I have no idea why these figures change so wildly. 

The URL for the user manual I used has June 2015 in the date. I can't find dates for the others in the URLs or in the files.

Your User manual has "340-00004-02" on the front page; mine has "350-00082-01", suggesting that mine might be more recent.

The version on the Goodwe site has "340-00004-03 Version: 1.0". It states 6500 W maximum DC input power, and 11 A per MPPT.

Perhaps they upgraded the MPPTs at some point and most of the on-line manuals are not yet up to date. Frustrating.

[ Edit: One piece of consistency: 130% × 5000 W = 6500 W. ]

Edited by Coulomb
Link to comment
Share on other sites

4 hours ago, Coulomb said:

Yikes! I just used data from the first manual I found: https://anro-developments.co.uk/wp-content/uploads/2015/06/Goodwe-ES-Manual.pdf . It says that each MPPT can charge at 15 A (that has to be PV side although Axperts always talk battery side). Your manuals say 11 A. There are three figures from the three sources for the maximum DC power: 5000 W, 4600 W, and 5400 W. And 11/15 × 5400 = 3960, so even if the current is taken into consideration, they still differ. I have no idea why these figures change so wildly. 

The URL for the user manual I used has June 2015 in the date. I can't find dates for the others in the URLs or in the files.

Your User manual has "340-00004-02" on the front page; mine has "350-00082-01", suggesting that mine might be more recent.

The version on the Goodwe site has "340-00004-03 Version: 1.0". It states 6500 W maximum DC input power, and 11 A per MPPT.

Perhaps they upgraded the MPPTs at some point and most of the on-line manuals are not yet up to date. Frustrating.

[ Edit: One piece of consistency: 130% × 5000 W = 6500 W. ]

This is all too confusing... as I see it I may buy too many panels and the Goodwe I may get is an older version...  I basically need to get the inverter 1st to determine actual PV input...

I suppose I can always buy less panels and add 2 or more later.

Link to comment
Share on other sites

5 hours ago, Coulomb said:

Perhaps they upgraded the MPPTs at some point and most of the on-line manuals are not yet up to date. Frustrating.

[ Edit: One piece of consistency: 130% × 5000 W = 6500 W. ]

I have sent Goodwe an email to clarify which version is the correct one.

Link to comment
Share on other sites

18 hours ago, plonkster said:

It's a matter of definitions. As long as you don't mix and match definitions halfway through an argument (in debate circles known as equivocating) you can usually make sense of it. CoCT considers it gried tied if it is in any way tied to the grid.

When charging the part of the inverter that's normally the output gets tied to the grid and then it runs in reverse to charge. But this inverter has other problems too. The changeover relay isn't sufficiently interlocking and doesn't open wide enough (4mm required apparently). It also fails SANS 10142-1 rules apparently.

Thanks Plonkster for the reply!

I believe that most of the standby ups systems with bypasses today then also do not comply as the bypasses of these systems works very similar to this layout.

The 4mm air gap might be a valid point...

 

Link to comment
Share on other sites

3 minutes ago, Pieta said:

I believe that most of the standby ups systems with bypasses today then also do not comply as the bypasses of these systems works very similar to this layout.

Yup. But it only falls prey to SANS 10142 once it becomes connected to the distribution board. The small under-the-table models have it easy: They must not electrocute you and not burst into flame... that's about all :-)

Link to comment
Share on other sites

  • 7 months later...

Good day, I need to know if there are any limit on the wattage of a mecer2 5kw in bypass mode, or is it only on the inverter output side (dc bus). For example if the load is 7500w and the inverter is in bypass mode. Will it be fine?

Thank you

 

Link to comment
Share on other sites

The specifications seem to say no, 5 kW max. The relays are rated for 40A, so 8.8 kW @ 220V, so they are OK. The input breaker is rated at 40 A, suggesting that it's protecting circuits capable of 40 A. Remember that this current is flowing through PCB tracks (thick ones, double sided, with plenty vias, but still). I would think twice about having electric stoves or similar running through the inverter. 

Link to comment
Share on other sites

I have an Axpert clone and initially had the stove wired through the inverter, with the stove and a kettle on, in bypass mode, it was easily exceeding the 5kw with the alarm beeping away. It is now wired just to my lights and plugs and its far more happy, although I won't be able to use heaters and kettles at the same time anymore

Link to comment
Share on other sites

  • 1 year later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...