Hannes7212

Hi, I think the re-discharge value is for the scenario where the inverter turned off because it reached the critical low battery setting (the inverter turns off but if it has solar it will still charge the battery). When the battery gets to the re discharge level the inverter will automatically turn on again. I think this setting is only on some of the Axperts (King for example) and not on the base off grid Axpert (wish it was...). Hope that helps (and I am not 100% sure about this but got it from a solid source when looking for a setting like this on an Axpert 5k MKS)

If I remember correctly FW has been using Sinopoly cells in their batteries but I have not seen that with my own eyes. Someone close to the industry (of assembling batteries locally) told me that some years back. Interesting pricing on these and FW has a good track record for reliability. As installers we can wind up in deep trouble if you support the wrong product. We have over 800 Lithium batteries in the field and it is a big decision to put your name behind a product. Others in the industry who have been using FW for long swears by them even if the price looses them some work from time to time.

Hi Dave, are you running the SolarMD V2 logger with your system? The default setting if you are running the Axpert Ai software is to switch the Axpert to grid power at 20% and back to solar power at 30%

Hi "Bulldog", I would really like to chat to you about your setup. I am in the process of designing a 90kVA Victron backup and have also tried to get away with the Ziehl route for compliance (I am using 6 x Quattro 15kVA) but was told it will not fly by CoCT. I came up with another design that will be approved but I think I can do better, but not sure they will approve it. It sounds like you will know. I will really appreciate it if you can drop me your detail to [email protected]. Thanks

Hi and thank you again. I found that webinar very good - watched and rewinded a bit before I did my first ESS installation. So I think you have answered me. Running ESS will effectively do what I want I think - there will be no switch between pure grid and battery (like an Axpert, dare I say it) when the battery goes too low, it will just draw more from the grid. I got my new Mulitplus II on Monday and will hook it up here at home to do some tests with.

Hi, I have been playing with power assist / grid feedback from DC coupled system etc but had to urgently install my test equipment for a client with a problem. Waiting on the MPII to arrive to continue testing but very curious so hoping to get a quick answer from the experienced guys talking here: System in question: - Three 12kVA Quattros (enough to handle all loads in the residence) - 20kW DC coupled PV (Victron MPPTs of course) - Generator (45kVA three phase) - Grid power available - 75kWh Lithium bank Question: Question: Can I set the system up in such a way that it effectively never "switch" between grid power and inverter power like it would when used as a backup system only? In other words it must always use energy in the this order of priority: PV, battery, grid, generator and stay in inverter mode under all conditions. I played around with this a little but before concluding my tests had to give up the equipment as I mentioned, so not 100% sure I tested all scenarios. It looked like it was all possible though using ESS. It would seamlessly blend in power from the grid when the battery got too low at night and turning the AC input on and off did not rattle it at all. Any comments will be much appreciated.

Hi all, a new client of mine with a nice 2 x 10kVA Quattro plus Kaco grid tie inverter setup asked us to supply and install 6 x 7.4kWh SolarMD batteries to replace his lead bank. We did this - all good. Got the batteries to talk to the inverters via the CCGX. Using ESS assistant. But now there is fine tuning to be done and I am not the Victron expert yet. I did confess this before taking the job and agreed with the client we will call in some expert to help with the final setup. However this proves to be a bit of a challenge (finding the expert!). Can anyone recommend someone who will come and help us on a consultancy basis? I am also lining up a few other Victron projects now and need to know that the support is there while I get myself and team certified over time on the products. Many thanks

I am also attaching the document I refer to in the email proving the "non grid tied nature" of the Axperts. It is called a LynX 5k in the report as this was done for the inverters SolarMD imports directly from Voltronic, rebranded as Lynx. It is the Axpert MKS inverters. Addendum to Declaration of Compliance of SMD LynX 5K Inverter to NRS097_ 22 Oct '18 (Final).pdf

Hi, yes I am sure it is ok to share the discussion: The first reply on the application: Good day Please use ref no: 30327856 in all correspondence to this office. On a 60Amp single phase connection the total capacity of embedded generation allowed is 3,5kVA. 5kVA as filled in on your application is not allowed. This application as it is now cannot be approved My reply: Hi Leon, I do not understand your reference to the breaker size vs generator size as that is only applicable to a grid tied system. This client has a UPS installation with PV generation to charge the batteries. I trust that clarifies it a little better. Regards, Hannes Leon's reply (CoCT): Good day Unfortunately no All system connected to the internal wiring of a premises via a changeover switch falls under the 25% limitation, off grid and on grid My Reply: Hi Leon, Thank you for taking the time to answer. Help me understand please: If the device that you call the "generator" has no way whatsoever of generating power on it's AC input side (the side connected to the City's grid via a breaker), would the City still impose the 25% generation limit? To be more clear, what I am asking is exactly the same as asking if I can connect a load like a tumble dryer to my residential DB board that exceeds 25% of the amp rating of my main breaker. Please do not think I am trying to be sarcastic or clever, I am merely trying to illustrate that we are not in any way talking about a generator here as far as the grid is concerned when we are talking about the AC inverter component of an off grid system. The PV that does the generation is not connected to the AC supply from the City, it charges the battery bank only. As I said before, I do understand this argument is not true for a grid tied inverter (battery inverters as well) such as the SMA Sunny Island range of inverters. What I am talking about is only for devices where we can prove that it cannot feed back power to the City's grid. We understand why this is important and went to great lengths and expense to prove this for the inverters we use for "off grid" installations on the City's network. Again I say thank you for taking the time to respond so we can get to the technical root of the concern so that we can address it from the installers side. Regards, Hannes Leon's reply: Good day On application ref no : 30327856. No single line was provided with the application. Please provide the single line so that I can see what you are trying to explain. My reply: Hi Leon, I appologize if the client did not send all the documentation we provided in. I have attached it. Regards, Hannes Leon's reply: When you design a residential development a ADMD of normally 5.31kVA (medium size house) or 4.04kVA (small house or flat) are being used to design the electrical network. The power that the SSEG system generates may not be higher than the ADMD of a domestic house that is connected via a change over switch as the supply of the UPS DB board is shared between our grid and the SSEG system. If our grid has to pick up a load of the UPS DB board that exceeds the ADMD of the design standards upon change over of the change over switch it can destabilize our LV network. For the above reason City of Cape Town has decided that the 25% limit will be placed on the above off grid SSEG applications. Please note that the system as in the single line as provided is a Passive standby UPS utilised as off-grid hybrid SSEG. For stand alone off grid system that is not connected in anyway to the internal wiring of the domestic premises or the grid the 25% does not apply. Hannes again: This was the end of the email conversation. At this point I phoned Ryno van der Riet (Leon's senior I believe) and he basically confirmed all of above. In the mean time we are sitting on quite a few other applications that were approved (often larger systems on single phase) by other areas in Cape Town, I did not want to start this discussion yet out of fear of making life difficult for the clients that were approved or other officials in CoCT's employ.

Good summary and I think I agree with it.

No it is true that if it goes to bypass mode it will draw from the grid. And it can be set to charge from the grid as well. The change over is actually on the output line to bypass the system.

How do I do that? LOL sorry

No I filled in the proper "DECLARATION FOR OFF-GRID SMALL SCALE EMBEDDED GENERATION" form

Hi, the post heading reads "is your system legal..." so I thought I would share some of the interesting discussion I had with CoCT officials today. I am trying to find out if I am the only one who has been given this line of reasoning as I would expect quite the outcry if it "got out" so to speak: Context: Small system using an Axpert inverter (5kVA), 4kW of panels and a smallish battery bank. It is connected correctly, COC, change over etc... The application to CoCT was rejected for the following reason: The maximum size of the "generator" on a 63A single phase connection is 3.5kVA. Ok, that is true for a grid tied system, but this is not a grid tied system. We have proven lab results showing it is not and it cannot feed back. I send all this documentation in, along with the argument that the size of the PV array is not relevant either as the PV power cannot ever make it back to he grid - it charges the batteries. This argument gets accepted and I start to feel happy again. BUT THEN, I read further. They are now saying that the size of the inverter from a load perspective is too big for the grid connection to the property, it has to abide by the 25% rule. I then phone to clarify because surely this cannot be right, right? I end up speaking to what I am told is the guy who makes the final call on this and he confirms that the size of the inverter (off grid or not) cannot be bigger than 25% of the grid connection. So for a 63A single phase connection you are limited to a 3.5kVA inverter. This is why: If the inverter goes into "bypass" mode due to low battery / solar conditions the sudden demand on the network is what they are concerned about. I would find it amusing but coming from this guy it is not. We could not even get to logical questions like What is the main breaker for then? What if my two 3kW geysers kick in at the same time? That is much worse than the little inverter switching to grid power. The fact that he referred me to the grid tied generation limitations (which I am very familiar with) in this conversation about an off grid inverter is very concerning and demonstrates a severe lack of understanding of the technology they are trying to regulate. So my question to this group is: Have you heard of this and do you have any suggestions on how and who to take this up with in the CoCT structure? If they are really going to apply nonsensical rules like this one cannot blame the crowd who suggests there is something sinister behind all the regulation like trying to stem the spread of PV in the City. I have never been in that camp for the record. Greetings

Hi Yoda, Thank you for taking the time to respond. That self consumption is quite high yes - I have observed this as well. We are planning on integrating it with the Lithium battery's data logger to do the online reporting so I will sidestep the WebPro card! Thanks again and regards, Hannes

Hi all, I have a client that needs a hybrid system. We do not do these often, have only done a few small ones but his is a little bigger and we need in the region of 30kW PV, 5kW per phase (3phase) backup with 20kWh Lithium storage. My preference is SMA, but as is usually the case it gets too expensive when building up a three phase hybrid system. So here I am considering Infini again, but I do not know them. I have lots of hours with the little Axperts and they work well for what you pay for but I would appreciate opinions on the reliability of the 10kW Infinis. Much appreciated!

Yes I can vouch for them. I have installed about 50 or so of their batteries and have not considered another brand as they just work as they should.

Hi, on getting a parallel setup going.. After everything is connected correctly, ensure the inverters are switched off at their switches. Now apply PV power to them so they can wake up (they will start charging as well). Now go one by one and set the parallel setting to PAL (assuming single phase). Once done for all inverters, start switching them on one by one. Wait for the AC out to come online on the first one before switching on the second one etc... Note, the PAL setting can ONLY be set when the inveter is "awake" and switched off. That state is only possible with PV power connected in an off grid setup. If your PV is not yet available, you can get to this state when you apply battery power but you have to get into the menu quick as it will turn off again if there is no PV detected. Hope that helps. O, and if you did all this and you still have issues I have seen that it was required to turn them all off (disconnect battery) and power back on again. I only had that scenario twice in many many installations and can't say why it happened.

Hi there, I have about 20 or so Lithium based systems in the field (most of them on Axperts) and the batteries I use have CALB cells. If you have one battery (3.6kWh) on a single Axpert I find that if you set the cut-over to grid at 48V you stand the risk of the BMS turning the battery off at about 46V to protect the cells (I do think that is quite a conservative cut off value). This only happens if the load on the battery was very low so it drained it slowly to 48V, really getting the most out of it. If a spike caused it to switch at say, 20% SOC, then no problem. But if discharged very slowly without spikes to 48V that battery is basically flat. So, until we can let the Axpert act on SOC and not voltage (there is some development locally on that front), I am forced to leave that cut-over voltage at 50V for small banks and 49V for larger banks (10kWh and up). And for what it is worth we float those CALB cells at 53.8V and then they charge up nicely to about 90 - 97%. I dont like pushing them to 100% every day. Hope that helps. Cheers

Hi Plonkster, happy to give you details one on one but would rather not comment publicly. Suffice to say the "old" bms could never get the balancing of the cells right which is why it always switched off pre-maturely. The good news is that the cells still test very good (as in as new) 18 months later. And I did put that battery through a beating so that is very good to see.

Well said and totally agree which is why I bother to read, and when I can, contribute. Very sad to see how people can get all snotty with each other if you don't mind the term on many (particularly international) forums. Proud to that is not the case on this one.

My apologies gents. I have not measured the latest Axperts and when I calculated this before I now realise I could have been counting one or two other items on the DC side as well. SO, like a true "I am never hardly ever wrong" type of person my wife claims I am I set off to prove you all wrong and I can report the following: But now I must confess that that is two Axperts in parallel drawing a combined 1.593 amps at 51V from my very lonely single Lithium battery (as the other one has been sent in to be repackaged with a real BMS). So 40W per inverter it is! Some guys in this forum are just never wrong. I hate that.

Hi, I will not recommend pairing one of these with an Axpert for the following reasons: - Axpert self consumption from battery is approx 70W (yes even in Bypass mode). That is a full kWh during a winter night. So if you set your inverter to switch to Eskom lets say at 50V and you had a slow discharge to that point (no big peaks pushing you to to bypass mode prematurely) your Pylon will have less than 20% charge left going into the evening and will discharge fully due to the Axpert self consumption and the battery will shut down, shutting the system down. - Axpert 5kW (the new ones is 5kW) can draw 100A constant current which will probably damage the battery if there is only one. The spec says it can only push that for 15 sec. From my experience the smallest you can go with Lithium on the Axpert is 3.6kWh so running two Pylons should be fine. On that calculation of yours. Theoretically and ignoring losses etc a 2.2kWh battery can deliver 2.2kW for one hour or 5kW for 2.2/5 = 0.44 hrs or 26 minutes. d

Yes I have two inverters that were imported from China in Jan / Feb this year which is the new hardware (from the outside at least). They have the updated 80A MPPTs, but still 4kW on the inverter side. With this 72.40 software they run at 5kW (I can make 100% sure of that today). I cannot remember what version the shipped with.

I agree (about being wary of software upgrade resulting in 25% more inverter...). Those two I run at home only and they don't often see high demand but I will keep and eye on them.