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Coulomb

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  1. Thanks
    Coulomb got a reaction from Kilowatt Power in Axpert 3Kva MKS with more than 600W solar panels   
    Yes, they'll all limit the SCC power to a safe value under ideal (slowly changing) conditions. But in the real world with clouds and loads switching on and off, the PV vharge current control system, designed for 625 W (25 A @ 25 V) will overshoot and undershoot quite badly with a 100% oversizing of the PV input. It might be your battery (quite possibly more expensive than the inverter) that blows up eventually.
  2. Like
    Coulomb got a reaction from Calvin in Why do Axperts run hot in Hybrid (SUB) mode, but cool in SBU?   
    My understanding is that the models that have SBU output source priority, when blending AC-in with battery/PV power, simply place the inverter output in parallel with the AC-in (so AC-in is connected to AC-out), and they carefully push power from the inverter into this "AC bus". If the inverter is rated at 3 kW, then the inverter could happily supply 4 kW to a load, with 1 kW if that coming from AC-in, and the inverter running at 3 kW. Of course, the firmware has to synchronise the inverter with AC-in first (they do that all the time anyway), and adjust its output voltage so that the VARs flow is correct (usually voltage determines reactive power, and phase determines real power).
    Of course, that means that the inverter could (and will be, for a short time) pushing power back into the AC mains. They obviously don't have the regulatory approvals to do that with all the rigmarole that is required, but they seem to get away with it because it's only a brief burst of power until the control circuit adjusts to the altered load. That's another reason I prefer to stick to the 145 V max SCC models; none of them attempts to do this.
  3. Thanks
    Coulomb got a reaction from Kilowatt Power in Axpert MKS 3K-24 (PF1) 600W MPPT with 810Wp Panels   
    I've relaxed my recommendation maximum oversizing a bit, I suspect that 25% is generally ok. Your proposal is 29%, which I think is still too much. Can you find a pair, say 360+410 or 375+410, where the Vmp are within 5% of each other?
  4. Like
    Coulomb got a reaction from JaseZA in Axpert MKS II SUB (Solar-Utility-Battery) mode   
    If you are asking are the MAXs more or less the same as the Kings but with more power output, then no, the Kings have some extra functionality (basically, they have an AC-DC converter that allows for zero time transfer). Also, the Kings are 145 V max SCC.
    As far as I know, the MAXs are more like high power versions of the Axpert MKS II, except also with removable display. So that makes them like higher power Axpert MKS III (PIP-5048MGX) (I hope I got those right).
    If you like: take an Axpert MKS II, add a removable display, now you have an Axpert MKS III (PIP-5048MGX).
    Take an Axpert MKS III / PIP-5048MGX and increase its power to 7.2 or 8.0 kW, and you have an Axpert MAX.
    Take an Axpert MKS III and take away the ability to parallel, make the fans weirder, and cut a few corners, now you have an Axpert VM III.
    Take an Axpert MKS II and take away the ability to parallel and cut a few corners, and you have an Axpert VM II.
    Take an Axpert MKS II and replace the SCC with a 145 V max version, remove the SUB option, and you have an Axpert MKS (64 V or 58.4 V version).
    Take a 64 V Axpert MKS and add an AC-DC converter, put back the SUB option, and you have an Axpert King.
  5. Like
    Coulomb got a reaction from Schnavel in Axpert MKS II SUB (Solar-Utility-Battery) mode   
    If you are asking are the MAXs more or less the same as the Kings but with more power output, then no, the Kings have some extra functionality (basically, they have an AC-DC converter that allows for zero time transfer). Also, the Kings are 145 V max SCC.
    As far as I know, the MAXs are more like high power versions of the Axpert MKS II, except also with removable display. So that makes them like higher power Axpert MKS III (PIP-5048MGX) (I hope I got those right).
    If you like: take an Axpert MKS II, add a removable display, now you have an Axpert MKS III (PIP-5048MGX).
    Take an Axpert MKS III / PIP-5048MGX and increase its power to 7.2 or 8.0 kW, and you have an Axpert MAX.
    Take an Axpert MKS III and take away the ability to parallel, make the fans weirder, and cut a few corners, now you have an Axpert VM III.
    Take an Axpert MKS II and take away the ability to parallel and cut a few corners, and you have an Axpert VM II.
    Take an Axpert MKS II and replace the SCC with a 145 V max version, remove the SUB option, and you have an Axpert MKS (64 V or 58.4 V version).
    Take a 64 V Axpert MKS and add an AC-DC converter, put back the SUB option, and you have an Axpert King.
  6. Like
    Coulomb got a reaction from Kilowatt Power in Max pv watts for Axpert inverter   
    Thank you for being precise about the model; it's so refreshing.
    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.
    I wish Voltronic were more helpful with this sort of thing.
  7. Thanks
    Coulomb got a reaction from woodenmonster in RCT-AXPERT 3K Burned circuit board   
    Tricky. Especially since your model doesn't seem to have component designators on the bottom of the board (e.g. Q100 for transistor number 100). I can't find any part under my 5 kVA spare board that looks anything like your top photo. So it will be a challenge to find out what the burned component is supposed to be.
    With the capacitor on the top of the board, it looks like it might be similar to several 1 nF capacitors that the spare board has. Check for similar sized components nearby; if they have 103X on them (where X is unknown, I can't quite see, it's probably just a tolerance letter), it's likely a high voltage ceramic capacitor with the same value and specifications as others nearby. It might be an EMI capacitor, connecting something lethal to ground, in which case it has to be a Y rated safety capacitor. Note carefully any markings on its siblings.
    Of course, that may not be all that is actually blown.
  8. Like
    Coulomb got a reaction from Trev501 in Another Newbie :-)   
    The VM models have weird fan control. It looks to me that only one fan may be PWM controlled; the other may be on/off. This seems to be one of the cost cutting areas for the "V" (Value?) models. It doesn't seem to me to be a good place to cut costs. Others have mentioned that the VM models are noisy.
    You won't need the cable between the inverter-charger and the battery. But when you add the second battery module, you'll still have to use the short RJ-45 (or is it RJ-11?) cable(s) between modules; that's how the BMS on each module talks to the others.
  9. Thanks
    Coulomb reacted to Calvin in Axpert King 5Kw (4000w PV) - Firm 71.90 (stock)   
    Maybe just a typo, but everything suggests that it is in fact a 16 x 3.2 cell battery.  The 51.2 nominal voltage is 3.2 x 16, also 54V charging is far too high for a 15 cell battery.
  10. Like
    Coulomb got a reaction from Trev501 in Another Newbie :-)   
    The inverter model doesn't matter as far as the battery settings are concerned (assuming battery type is USE). There are several sets floating around; these are the ones I recommend:

    Correct.
    There is a largish capacitor across the AC input, and this (or something else) causes significant imaginary power to be drawn by the inverter. This does no harm, and you only get charged for real power (which is a small fraction of that), so just ignore it. Voltage times current gives you apparent power, which in this case is close to the imaginary power. The capacitance will actually slightly correct your house's power factor (which is almost always inductive).
    Chris' settings file was written a long time ago, before batteryless operation was possible.
  11. Like
    Coulomb got a reaction from aquarat in Is my Axpert King destroying my Pylontech battery?   
    54.2 means 54.2/15 = 3.613 VPC average. This isn't great for the cells, but not bad either. The small charges and discharges are inevitable, and would not be hurting, in my opinion.
    However, it would be better for the cells to stay around 3.5 VPC once fully charged, or around 52.5 V total. It would be great if one of you Pylontech guys figured out the commands to send to the Pylontech BMS (via the console port, an RS-232 port different to the main RS-485 data port) to change the float voltage to that 52.5 V. I think that then the inverter-cable-to-BMS system would work well, with good cell longevity, and few if any panic disconnects from the BMS due to the Axpert overshoots.
  12. Like
    Coulomb got a reaction from epromise in Patching Axpert Max 3.6 with 7.2 Firmware   
    Yes.
    I hope not.
    Let's just say that I'm handy with reverse engineering.
    There used to be, and it was very convenient. Alas, the arrival of the clone makers made it much harder to get firmware updates. But sometimes you just need them, and if so, you have to ask your supplier. End users need not contact Voltronic Power directly.
    You have to ask whoever sold you the inverter-charger. They in turn contact Voltronic Power if they deem it important enough. It can be a slow process.
    Greetings to Austria, from Australia 🙂
  13. Like
    Coulomb got a reaction from wolfandy in Mercer 5KVA   
    That's usually called SOL (SOLar first output source priority).
    I've not heard of an Axpert (most Mecers are Axperts) that only has one Output Source Priority setting option.
    What model do you have? There are many 5 kVA models.
    What are you using for changing settings? Front panel buttons, Watchpower, ICC, or some other monitoring software?
  14. Thanks
    Coulomb reacted to wolfandy in Axpert 5KVA - Pylontech Batteries - settings   
    Hi @Clivevan
    First off, congrats on your new Pylons 🙂
    Did you also purchase the Pylons comms cable for ICC? So that you can connect ICC to your Pylons and read the BMS data? It is not the cable that comes with the Pylons, but something that you need to buy from ICC. If not, then I would highly recommend it - because then you can get around having to use voltage readings and can do the change based on SOC as per the Pylon BMS (significantly more accurate)
    Briefly drawing from your batteries is normal. This is due to the fact that when your load increases, your MPPT simply cannot adjust output accordingly that quickly - and hence your inverter will draw from the batteries to make up the shortfall. To my understanding, this will not hurt your batteries. I am having a cloudy day, so my charts are all over the place - but you will see that I also briefly draw from the batteries regularly

    I agree that something is weird in your system. I would suggest making the following changes:
    Bulk: 52.5V
    Float: 51.8V
    Could you please post a screenshot of your Graphs -> Battery Trends charts? That will help better understand what is happening with your batteries
    And maybe also the Settings -> Batteries tab please
  15. Like
    Coulomb got a reaction from wolfandy in Advice Needed on Axpert Hybrid Solar Inverter setup.   
    I agree with @wolfandy here. I realised I blundered on an earlier post; I've added this:
    If you aren't allowed to wire the modules in series, it will be because of the built-in BMS. If you could somehow disable the BMS from disconnecting (and if you could provide some other way of saving the battery if the inverter tries to excessively discharge or charge it), then you could wire them in series.
    Axperts (like your new ECO Hybrid, which isn't a Hybrid as we usually define the term these days) are perfectly capable of charging LFP batteries, especially when the LFP flavour of patched firmware is used. I use a pair of similar inverters myself, with a home-made LFP battery (which has a home-made BMS).
    Your inverter hails from 2015, before the emergence of clones, and appears to be quite genuine.
  16. Thanks
    Coulomb reacted to wolfandy in Advice Needed on Axpert Hybrid Solar Inverter setup.   
    You need to answer the underlying question if the 2 Blue Nova can be stringed together to provide 48V or not. If yes, then your inverter should be able to charge them (with the correct voltage settings). And you'd obviously still need to take Coulomb's warning into mind regarding your max draw (which is no problem for as long as you stay disciplined. I also started off with 1x Pylon, which meant I could not draw more than 1800W continuously)
    I have absolutely no experience with Blue Nova - so I'd suggest you give them a ring directly and see what they say about using your batteries for a 48V system
    Oh - and if yes, then you should make sure that you upgrade your inverter to Coulomb's latest patched firmware 73.00e (LFP version)
  17. Like
    Coulomb got a reaction from Marius De Kock in Youda's off-grid LAB   
    (Raises hand)
    To both: remembering 10base2 and getting old 🧑‍🦽 😮
    Edit:
    And 300Ω ribbon and splitters for analogue TV, and the valve tuners that they connected to, usually with a 6BL8 valve (and one other).
  18. Like
    Coulomb got a reaction from hoohloc in Parallel connected inverters communication to battery bank   
    IF that's the case (i.e. there is no connection between the batteries of the two inverters) then that's not right.
    There should be a spare positive and a spare negative terminal on each battery pair. Connect the spare positive to the other spare positive with another set of cables; same with the negative obviously. If you're not confident, try and get someone to do this for you. Maybe even your present installer will do it, even if "just to humour the customer".
    It's not ideal, but it should work and prevent problems in the future. I believe that the master will look for battery voltage differences with the slave, and stop with a fault code if it detects a problem. Also, without the battery pairs being paralleled, the charging algorithm will be confused, and one of the battery pairs will likely not get fully charged, or at minimum, at times there will be spare PV capacity that goes wasted.
  19. Like
    Coulomb got a reaction from DrLoLCat in Wiring a VMIII/King to the Grid input of a VMIII for extra solar energy   
    Oh. So the BlueSolar will talk to the BMS of the battery as well as the VM III inverter? I suspect you can only run one with the BMS.
    I would connect the BMS to the charger with the highest power, and set the other one to fixed voltages a little lower than what the BMS is going to ask for. For example, 53.0 and 51.6 V. So then the BMS gets to control the last stage of the charge. You may have to play around with the settings to get it right.
  20. Like
    Coulomb got a reaction from DrLoLCat in Wiring a VMIII/King to the Grid input of a VMIII for extra solar energy   
    I don't see what you achieve by this. You are still limited to 5 kW output, but you've paid for 10 kW.
    Why not just get an external MPPT to charge the 48 V battery directly? With 5 x US3000, you would not be worrying too much about charging with too much current (they can take 185 A between them). Most of the time, the loads will be using at least 10 A as well. So with 80 A from your VM III, you could afford at least 100 A of external charger (at least, from a charge current perspective, maybe not a hip pocked currency perspective).
    You can probably get quite a large external MPPT for less money than a second VM III.
    I'm also not a fan of feeding inverter outputs to other inverter inputs; they are expecting sine wave inputs, and the outputs from inverters may have high frequency noise that doesn't bother appliances, but might upset the downstream inverter.
  21. Like
    Coulomb got a reaction from wolfandy in Mercer 5Kw 24 V shutting down   
    The Victron can't know your actual battery capacity; it's probably programmed to assume an actual 100 Ah battery.
    How old are the battery modules?
    If you don't have patched firmware to fix the premature float bug, your battery may not be getting a full charge. That has two effects. Firstly, since the "tank never gets full", you'll have reduced run-time. But sadly, it also gradually ruins the battery, as lead acid really wants charging to full every cycle for reasonable life. Unfortunately, the default low battery voltage cutoff value (21.0 V) is way too low for the typical South African situation of regular load shedding.
    You should check your battery voltage, both when charging and when discharging. Make sure the battery gets to about 56 V for about an hour each day; the net battery charge current should taper gradually for that hour down to a few amps.
    On the discharge side, check that the battery voltage drops roughly linearly, with no sudden jumps (except at the start where it stops charging and starts discharging). So you should see a gradual decrease in battery voltage from about 25.6 V or so to the cutoff voltage, which should be about 24.0 V. If you are regularly draining the battery to about 21 V, that's going to kill a lead acid battery in about 2 months. Frustratingly, you have to leave about 50% of the available energy in the battery, to achieve normal life (2 years or more, maybe 10 years if the battery is good quality, and is always charged properly). You should also check that the two 12 V modules have about the same voltage (within about 0.1 V) at all times. If not, use a car battery charger to charge the one with the lower voltage, until the voltage at rest after about half an hour is close to the other one. Long term, a battery balancer seems to be a good idea.
    If it gets a proper charge and discharges smoothly from ~25.6 to cutoff, then sadly the capacity is drastically curtailed. It looks like a 3-6 Ah battery at this point, depending on where your cutoff voltage is set.
    100 Ah @ 24 V nominal is very light for a 5 kW system, even if you don't use anything like full power very often. Self consumption will be quite high for a 5 kW inverter, I'm guessing about 50 W, or some 2 A continuous drain.
  22. Thanks
    Coulomb reacted to Solar Assistant in Mecer King - Host of Problems   
    Hi @coulomb, just to be clear: we don't recommend specific charge/cutoff voltage settings, we only recommend setting battery type "User" with values filled into the charge/cutoff voltage settings as desired by the user/installer.  I agree your recommendations are better than what is configured in the screenshot I posted.
  23. Thanks
    Coulomb reacted to Paul van der straat in Axpert MKS 5KVA Inverter - 48V   
    Hi, i have the factory specifications on the TX6 or part number 41-070185-00g, you can remove it and then have it rewound according to specification. Email me if you need it I'll send it to you. [email protected]
  24. Like
    Coulomb got a reaction from Calvin in Mecer King - Host of Problems   
    Good point. I'd have to re-enable the editing of those settings, another small patch. No big deal. I'd also have to patch commands that modify settings (e.g. PSDV to set the low DC cutoff voltage) to work even if the battery type isn't USER. Only a handful of minor patches, though they do tend to add up. So something like this will likely have to wait until I have a King in hand. I'm nearly ready to order one anyway. 
    The change would be for all BMS direct connection protocols, not just LiB or PylonTech. If you didn't want this change for whatever reason, just set the limits very high or low so that they have no real effect.
  25. Thanks
    Coulomb reacted to MrOccO in Pylontech US3000c   
    Hi Guys, just an update. I have managed to get it working. @YellowTapemeasureThe unit does have a console port but now they use a RJ45 connection. My frustration is dropping 20k per battery and the vendor does not want to know you in terms of support. Frustrating. Anyway the pinout is as follows for anyone else looking for it:
    RJ45 CONNECTOR:-------------- > DB9 RS232
    PIN 1 -------------- > NOT CONNECTED
    PIN 2-------------- > NOT CONNECTED
    PIN 3-------------- > PIN 2
    PIN 4-------------- > NOT CONNECTED
    PIN 5-------------- > NOT CONNECTED
    PIN 6-------------- > PIN 3
    PIN 7-------------- > NOT CONNECTED
    PIN 8-------------- > PIN 5
    Yani from Multisib had to make an update on his brilliant program and now Multisib communicates with Pylontech and Invertor flawlessly. 
    Thanks @DeeJayand @YellowTapemeasurefor your valuable feedback.
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