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Everything posted by Nonlinear

  1. I have a set of Mecer Axperts in parallel and am slowly migrating to the blue side. I still retain a keen interest in the Axperts because I maintain they are acceptable for most people who run them within their capabilities. Also, having lived with them for a number of years I have experienced the highs and the lows of owning Axperts.
  2. I am quite aware of that, I was hoping to use that as a gentle introduction to the topic.
  3. It was a struggle (to put it mildly). For bonus points I can confirm I used the regulation SANS cable too which was even harder to do. Correct. The problem though is small differences can have a large impact when resistance is already low. So, for example, with a very large (say 16mm2) cable the resistance on each could be very low, about 0.02Ohm. Now a small difference due to terminations could make the one cable 0.025 and the other 0.015. Now you can see that the resistance differential is potentially a problem. If you use smaller cable (say 6mm2, which would still be legal) then the nominal resistance would be about 0.1Ohm, now a small change in due to terminations would only change that from 0.105 and 0.095. So now a small resistance change is not a problem. On my two inverters I have noticed that despite my best effort at getting the cable lengths exactly the same, and terminating exactly the same way, the one inverter always runs with more load. There may be other reasons for this that I am unaware of. Indeed it is.
  4. Having read through this with some interest I would say that your best bet may actually be Victron Quattro units 6x10kW. Coupled with each would be 250/100 MPPTs and each with about 40kWh of storage. The reason for going even larger than the 8kW would be the fact that air-conditioners are particularly unpleasant loads at start-up. Additionally the Quattro gives you the option of connecting generating power as a secondary AC input and they have the option of running PV on both the AC and DC side which allows you to connect some of the panels (via a Fronius) on the AC side thus sparing you the need to couple all PV on the DC side. The Victron website has a few reference projects using Quattro units at roughly this scale. Disclaimer: I do not work for Victron and don't run them in my setup.
  5. I'm not sure if it is of any benefit here: For a few years I ran two PF0.8 5kVA inverters in parallel until a lightning strike right outside toasted their communications boards. They were replaced by new Mecer units that are PF1.0 5kVA. I can confirm that the newer units are significantly louder than the older units. As Coulomb puts it, objectionably loud. I can also confirm they are always loud even though the temperature is never high and solar production is always well within the nameplate capability of the units. The WAF on these units dropped from 10 to 1 as a result of the noise.
  6. Interesting topic. I have something similar. Two parallel inverters. Breaker on the supply side of each and breaker on the output side of each. Breakers on the supply side are 40A each and on the output side are 50A each. Single pole (common neutral) on the supply and double pole on the output. I currently have one isolated and removed (long story) and the other is operating seemingly well. I tried to match wire lengths on the input and on the output. My mistake: I think I oversized the wires on the output because I had a future upgrade in mind. My wire size is 16mm2. I'm fairly convinced that even though I attempted to match the wires as best as I could I think with wires that size small differences can make a big difference. Opinions? I can say that in most other respects the system seems to work well and has worked well for quite a long time (barring a lightning strike).
  7. Hi, thanks for the quick response, sent you a WA.
  8. Ouch. OK, that is on the other side of the country. Let me see what other options I have. Does it have a parallel comms kit?
  9. Thanks @P1000 I'm happy to report the FTDI converter works. Results of dmesg [160585.535658] usb 1-1.4: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [160585.535666] usb 1-1.4: Product: US232R [160585.535672] usb 1-1.4: Manufacturer: FTDI [160585.535679] usb 1-1.4: SerialNumber: FT4WLQTJ [160585.571538] usbcore: registered new interface driver ftdi_sio [160585.571583] usbserial: USB Serial support registered for FTDI USB Serial Device [160585.571745] ftdi_sio 1-1.4:1.0: FTDI USB Serial Device converter detected [160585.571823] usb 1-1.4: Detected FT232RL [160585.574534] usb 1-1.4: FTDI USB Serial Device converter now attached to ttyUSB1 No reboot required. Next I'll try to make up a little breadboard with the chip you suggest above and play around to see if I can get it to work.
  10. I saw the FTDI stuff on RS (because I buy there anyway for business reasons) but I was not sure if it would work. I am almost at the point where I would say cost is a minor/secondary issue simply due to the immense inconvenience/time/money involved when a surge damages the communications on some of your kit. It has taken months of haggling with the bank and quite a large amount of my own money to get my solar system back online. I'll have another look at the FTDI and I will also read up on the ADuM (is that Analog Devices or just a coincidence?). Thanks for taking the time to post.
  11. Hi Everyone, Can anyone provide me with suggestions for reputable RS232/USB converters. Preferably I would like recommendations for converters using the PL2303 chipset (because I know it is well supported under both Linux and Windows). I would also like to hear members opinions on isolation or opto-isolation on these converters to ensure that surges and other nasty effects are not sent through to the expensive equipment connected on the RS232 side. As you can probably guess I lost some equipment due to a surge transmitted on the converter to batteries and inverters which fried the comms on these devices. As a bonus, it would very much be appreciated if these were obtainable in South Africa.
  12. Hi Fredi, I had exactly the same RCT Axpert. Upgrading to the firmware maintained by @Coulomb (and Weber and others) at this location https://forums.aeva.asn.au/viewtopic.php?p=53691#p53691 (actually that link is to the first post which is a must read to give you guidelines on the entire process). It made a huge difference to my system performance.
  13. I'm confused. I thought you were selling two of them. Was about to PM you but then I saw this.
  14. I was dumb enough to make that mistake (just as the "split"/"solar wars" happened). I explained my situation to Manie and he was gracious enough to come to an agreement with me. So kudos to him for that alone. I admit that ICC is not perfect and has had (and still has) it's issues, but usually Manie does try to fix whatever bugs may crop up. From that perspective alone it is worth it. Like other posters above have said, I could probably write this myself, but why bother spending hundreds of hours (that I can rather spend on billable work) when something is available out there. My only bugbear now: the software is tied to hardware, these Pi boards are great, but nothing lasts forever and especially not on the Highveld during summer, no matter what protection you think you have in place. Finally, my last 2c: I really enjoy these kinds of discussion, open/fair exchanges of views are good for everyone and broaden my horizons.
  15. Hi Forum Members. I'm also in the market for the PylonTech batteries, specifically the US3000B version. I have managed to give my lead-acid batteries a second life thanks to some good advice on the forum but now I think it is time to start planning ahead. Any advice from members would be appreciated especially with respect to combining these batteries with an Axpert parallel setup (I suspect @Chris Hobson may be running something like this). If you are able and willing to supply feel free to PM me or respond here. I'm hoping @SilverNodashi and others are still following this thread, it's a little old but not too old I hope.
  16. Thank you. I think I'll give it a go.
  17. Very, very interesting. Thank you @Solaris. I think I'm going to try that. I will also be googling those Devel systems. Weight is not a significant concern for me but I'm a little space constrained. Do you have any experience with these inverters and Lithium batteries?
  18. Thanks @Coulomb. To be honest I've been pondering switching to the 73.00e from my current 72.70c now that my batteries are getting older and especially I have actually seen the kettle cause exactly this kind of trouble where the system switches even though the real DOD is not as poor as the Axpert thinks. I'm a little nervous though, the 72.70c firmware has served my two Axperts (in parallel) really well. Is it worth it?
  19. Thanks @Solaris. I do have the balance wires, which I'm hoping helps a little. I wired them as suggested in the BMV manual. I'm using a BMV702 and it has started to alarm on the voltage difference alarm, but luckily not often. Still, I'm a little worried but not too surprised, especially since my Axperts are not known to be very kind to batteries in general. I'm hoping to get a few more months out of them and then probably switching to the PylonTechs. If only there was an inverter that is reputable, well-designed and that can be paralleled to provide the power that my Axperts give.
  20. Hi All, I was hoping someone would have some advice on the best way to rotate lead acid batteries. I have a lead acid battery bank consisting of 8 x 12VDC (nominal) connected in a 2x4 bank. They have been in service for more than a year now and after measuring individual cells recently I noticed they are not as even as they should be. I am thinking of taking the first and last cells in a bank and making them third and second respectively and making the original third cell the first and the original second cell the last. Any opinions? Am I over-thinking this?
  21. @Coulomb I was wondering if your 73.00e firmware will also help with respect to DOD on older batteries specifically with the "KettleComp". It should prevent unnecessary switching when DOD is not as deep as the Axpert thinks. I think though that the 73.00e is not applicable to these smaller inverters.
  22. My understanding is that centurionsolar and ICC have parted ways. You may instead want to go to the source and contact @Manie or [email protected]
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