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RobM

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Everything posted by RobM

  1. Yes - that's the one option - to have the grid feed inverter feed PV energy to the second inverter. Yip I think you're right - if I am running a cable and can use cheaper cable like suffix, less loss - array voltage around 350V
  2. I have a PV array on one building connected to a grid tie inverter. I have added a Sunsynk 5 kW with battery in another building to provide power during grid outages. Its is not possible to have the Sunsynk in the same building where the PV array is, there is no space to mount it with the battery. So the question is how to get PV power to the Sunsynk? its either a long run of DC cable (25m) or some setup where the grid tie inverter feeds the generator input of the Sunsynk. Solar DC cable expensive. Is there an issue with using normal AC cable of the right gauge if it's in conduit? Any ideas welcome. Rob
  3. I notice that Segen Solar have put out a notice saying that the newer Pylontech batteries do not currently work with the Kodak inverters (Axpert) and need to be treated as dumb batteries. Kodak User settings.pdf
  4. Hi All, I have an Axpert King 5 kW with a very tired set of agm batteries. I want to get a lithium battery that will communicate with the inverter. The manual and settings refer to pylontech. Does anybody have experience with what batteries are compatible (i.e. communicate properly) with the King. Main firmware version: 71.90 My options are Hubble AM2, Greenrich UP5000, Kodak BL5, Pylontech US3000, Pylontech UP5000 Any advice would be most welcome. Thanks - Rob
  5. I was told by a Sunsynk technical advisor to permanently bond the inverter output to earth. He maintained that this was safer than a bonding relay as the relay could fail. A number of electricians I know who install inverters follow this practice.
  6. I really believe this is the next step with domestic power management. Weather based power generation like wind and sun on a utility scale already has very stable and accurate predictor models. I'll follow with interest.
  7. A client has asked me about using a lithium battery with that inverter. Some smaller inverters have issues with lithium batteries because they can't set their low cutoff voltage properly and when discharging the battery is at risk of BMS cutting off - needing a reboot. What's your experience?
  8. It seems one needs to be ultra careful about connecting any inverter with grid feed potential with the HXE310-P meter. If it trips there seems to be no way of resetting it short of getting City Power to reset. How did you get the problem solved?
  9. You may find this info helpful: Luxpower Support Email: [email protected] JHB Tech manager Jonathan: +27 74 098 0707 JHB Support Manager Owen: +27 84 975 5067 Cape Town Support Manager Andy: +27 82 555 5077
  10. default customer code is inf01 worked for me
  11. HI - Any recommendations on a supplier that I can get a few odds and ends for solar installation. Walk in. No time for mail order. Thanks.
  12. @AndrewRyan, divergent question: The Luxpower SNA does also seem to feed into the grid side. I cant find any detailed information about the difference between how it works and the LXP. There is a big difference in price. I am guessing the SNA does grid blending at a DC level like the Apert King where the LXP does proper blending at an AC level. What are the significant differences? Rob
  13. Just a random note. Growatt tech support is hopeless. They may make some good products but to get anyone to understand anything that you cant get out of the manual is scary.
  14. @DJI I would. Either the supplier must offer a fix or take it back. Which model do you have? If you are going to use an Axpert type inverter go for Kodak as they have proper backup and 3 year warranty.
  15. I did use watchpower - off the top my head I'm not sure if it was before or after this 27.6V thing started. I did reset everything to defaults using the watchpower function but this made no difference.
  16. Thanks @zsde, I'll take another look although I am pretty sure its all voltages. The inverter in question is the SPF 3000TL HVM which is a somewhat lesser beast than the 5000ES which I assume you have. This is used as a backup system so no PV, just grid power. It spends most of its time in grid bypass mode (slowly wasting away battery capacity). I am not aware of a firmware upgrade and the Growatt people confirm it has the latest firmware. I found the Hubble support line very helpful. I logged a query through their web site and someone called me and answered my questions directly. The local Growatt support guy seems to be little more than a postbox with scant product knowledge. The Growatt "international engineer", Amos is responsive but frequently gets the wrong end of the stick and also has to refer queries to "Research". I am now thinking Kodak is your best bet for Axpert type inverters. They are distributed by Segen Solar who carry spares locally, have knowledgeable tech support locally and seem to be a well run outfit.
  17. Hmm, yes this seems to be a more intelligent beast, different model to TL-HVM.
  18. Where did you get it? Online through web site?
  19. Would solar assist tell the inverter how to charge and overcome the deep discharge problem?
  20. I agree. The Luxpower is free of the Voltronic legacy and seems a much better design.
  21. Hi @zsde - yes I have indeed used recommended settings and the Growatt "International engineer" has confirmed firmware is latest. (sigh). I am now using USE2 for battery type as recommended by Growatt guy. This looks like a design issue which is particularly dysfunctional when using lithium batteries with no comms.
  22. With a battery with comms at least it only goes down to 95%. As much as this wastes solar power and cycles the battery unnecessarily at least it's still fairly viable. With dumb lithium batteries its a much bigger mess because the battery discharges deeply even when there is power available.
  23. I'll get straight to the point. If you are thinking of using a Growatt SPF series inverter with stand alone Lithium batteries, DONT! Growatt, for reasons known only to themselves have a charging algorithm that abandons the battery after charge, leaving it to supply a load (solar) or just invisibly feed its internal circuits (about 1A), slowly discharging to some mysteriously defined threshold where the charger kicks in again and tops up. This is purported to be 95% SOC or 2V drop below -?? float apparently. The 95% SOC (State Of Charge) threshold seems to be linked to a Lithium battery with comms to the inverter. Otherwise it's the 2V drop. Now.. enter a lithium battery with no comms. These are all the rage now and selling like hotcakes. The Hubble S120 being a good example - internal BMS with external balancing unit when connected in series. Lithium batteries have a very flat discharge curve so a small drop in voltage represents a big drop in SOC. This is quite different to lead acid batteries which have a relatively bigger drop in voltage with drop in SOC. Enter the Growatt dreaded algorithm: Without comms to the battery the inverter seems to estimate SOC by means of voltage drop. The magical 2V drop translates to a big drop in SOC for a lithium battery. The upshot of this is the "clever" Growatt algorithm essentially lets the battery discharge to around 30% or less before re-engaging the charger. That said I have yet to see this in action. Perhaps I have been too impatient. Its more like a 2V-ish drop. What this means in this case is that the poor Lithium batteries, in grid bypass mode are left invisibly feed the inverter at about 1V for three days or more before they are topped up. The result: constant relatively deep cycling of the the batteries for no good reason. A similar scenario would play out with solar as the charging source. Growatt claim that the logic behind this algorithm is to save the "charging relay" from wearing out. Seriously??? IFFF the battery were left completely to its own devices to rest with no load at all after charging this might make sense but to subject a battery to perpetual cycles (deep in the case of LFP) for no good reason makes no sense to me. The friendly Growatt "international engineer" has spent three weeks of confused exchanges trying to convince me this is normal and nothing to worry about. Nothing to worry about is also the Invest Solar guy's response. So there is my observation. I wonder how many others have unwittingly hit on what they thought was a cost effective long(ish) life setup. Wow - can't anybody make a decent reasonably priced inverter?
  24. I have recently set up a Growatt SPF-3000TL HVM and have picked up the same issue on Utility power. It charges and stays on float then after a while the charger disconnects from the battery, leaving to discharge until it drops below 26V, apparently. This can amount to discharge of around 30% before it wakes up and tops up. I have contacted the local (SA) Growatt technical support person who is checking it out with their Research dept...
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