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plonkster last won the day on July 13

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  1. When used with this inverter, the can cable is not used. For interest sake, this is what is sent on the CAN cable: Voltage, Current, and State of Charge information (the things a BMV would also do) Temperature information Charge voltage and current limits (more about that later) Warnings and Alarm conditions, eg voltage too high, charge current too high, temperature too high, cell imbalance detected Importantly though, even if you don't do use this information, the battery still has its own protection built in, so if there is a serious cell imbalance, a high voltage condition, or any such thing, the battery will protect itself. This information is there for more intelligent setups, so such conditions can be avoided or warned against before the battery trips/disconnects. For example the charge voltage and current feature: In a hybrid system, a hot battery can request of the inverter to discharge at a lower current and take the rest from the grid. Similarly, it can ask to be charged slower and rather feed the rest into the grid. Really clever batteries will lower the charge voltage if there is an imbalance, to accommodate the high cell. But very little of these features are useful outside of hybrid systems (in other words, with off-grid systems), and since that is what the Axpert is, you lose very little. I don't know if ICC can read the warning and alarm conditions, but it would be useful if it could.
  2. There is some confusion here... The Multiplus/Multigrid can't work without batteries. And you need a separate MPPT, it is not bundled with the inverter. But you can also use a PV-inverter instead of an MPPT (something like Fronius or SMA), this is essentially an inverter that turns PV directly into AC power and feeds it into the grid, no batteries. The Multi can work with such an inverter and charge the batteries from the AC side. But this is really not advisable for your situation, because the PV-inverter goes down when the grid goes down, and it costs much more than an MPPT. Watch the ESS webinar here for an overview (that's Matthijs Vader btw, the MD). Around 4:45 is the system you want, PV coupled to the DC bus. At 6:50 he explains how to run without the energy meter, you will likely do that as well, at least in the beginning. At 24:00 he explains why you want an MPPT over a PV inverter. The "color control" is the older control computer with an LCD screen, called the CCGX for short. The Venus-GX is a newer and cheaper option without the LCD (just so you know). The software also runs on the Raspberry Pi. You will likely not start with an ESS system, but I still think it is best to have an idea of the possibilities.
  3. Let me get technical (because I love it), and bolster my story with some math! If you draw a chart with time on the horizontal axis (let's say in hours) and current on the vertical axis (in ampere), then if you consider the area UNDER the line, it would be current multiplied by time, or amp-hours. If you've had calculus training at some point in your career, then you know the procedure for calculating the area under the line is known as integration, and if you've done any applied mathematics and/or numerical analysis type courses, then you know there are ways to approach the area using various techniques, the simplest which is newtonian integration. Newtonian integration essentially draws little narrow trapeziums below the curvy line and work out the area of each trapezium, and add them all. There are even simpler methods where you draw a narrow little rectangle so that the middle of the rectangle is on the top line (or consider converting a line chart to a bar chart so that there are millions of little rectangular bars for each data point). Again, the area of a rectangle is simply width times height, or in this case, current multiplied by delta-T. This is basically exactly what the BMV and the Multi does. The reason the Multi could not do it when you had DC chargers, was that it didn't know about "external" current. So the obvious answer is to make it aware of it. And it really is that simple. Every couple of seconds, you take the combined current from all the MPPTs and tell the Multi that "by the way, there's also this 52.3A coming from somewhere else", and then the Multi adds it in when doing its little integration dance. The result is an SoC determination that isn't 100% accurate... but guess what, lead acids aren't that consistent anyway, lithiums don't really get hurt if you're off by a bit, and it's a thousand times better than using the voltage to estimate it (at least for lead acid).
  4. There is rather a lot to explain and I don't want to overcomplicate things at this point. But let me put it simply. IF you have a Venus-GX, and all your solar chargers are Victrons, then you don't need the BMV. The Multi already has the ability to track the state of charge, and the Venus-GX tells the Multi about what the solar chargers are doing, so the Multi keeps a good state of charge even without a BMV. This also makes switching to and from the grid easy or even run grid-parallel. But if you decide not to go with a Venus-GX, then I would suggest getting the BMV instead. There is a way to configure the Multi so it takes a signal from the BMV to switch to and from the grid. This is a hard-on/hard-off configuration, it does not mix power from different sources. Also, when you later buy your new LFP battery, the BMS of that battery will tell you about the SOC and you won't need the BMV anymore. If it was me, I'd get the Venus-GX and leave the BMV, unless I had money to burn. It may sound odd... but it isn't, if the chargers are all victron and there are no DC loads, and you have a Venus-GX or CCGX, you don't need the BMV. The day my wife bragged to her colleagues in the office was the day I knew she bought in. The power went out, and she announced that she's going home because there's power there... Something else to be said about this: It's not going to help that you have power, but your internet connection goes down because some part of it runs from the grid or has only limited backup. Make sure you have more than one internet connection if it is really important to you.
  5. The Multiplus-II has a steel case, where the others have aluminium cases. The Multiplus-II is also not significantly cheaper (in fact it is bout 20 Euros more expensive), but it does pack a bit more features. It has slightly lower no-load consumption and it has the anti-islanding features of the Multigrid. But it also costs the same as the Multigrid. The only other feature it has is a detachable current sensor, so in an ESS setup it saves you some money on adding a separate energy meter. The Multiplus has a higher-rated transfer switch though (be sure to get the 35-50). Also see here. Personally I'd get the Multiplus, or possibly the Multigrid if it is not too much more expensive. Difference? The Multigrid is certified for NRS097-2-1, in other words, it can be tied to the grid in South Africa. The Multiplus only complies with NRS097-2-1 if you add another anti-Islanding switch. The easysolar is nice and all, but doesn't in my mind represent much of a saving over individual components, and it sort of commits you to an all-at-once decision. I personally prefer multiple smaller MPPTs rather than one large 150/70. Also, if you go 24V (nothing wrong with that), it limits your battery choices later when you want to go LFP. In terms of the best value options available now: You'd be limited to the FreedomWon Lite-mini battery, as that is one of the few 24V batteries made locally.
  6. plonkster


    Nope. There was a big old switch that turned it on when the grid was connected. I mean it differs from the 5kva in that it doesn't run the same pipeline "in reverse" to do the charging, instead it had a separate charging pipeline. Of course not. At the very least it must be big enough. But in theory you need very little modification to get there if you already use a separate charger. That might be how they do it. In fact, I think you may be right, I will say why below. You could do a Buck-Boost converter between the low-voltage DC bus (aka the battery) and the high-voltage DC bus, and then bring your AC input directly onto the high-voltage DC bus using only a rectifier... but what do you do then with low voltage input conditions? You'd need an extra buck/boost between the rectifier and the DC-bus to ensure you have a constant +-340V on there. But I seem to recall they do this anyway: The boost stage has a fixed ratio, so they already have another DC/DC stage in there to get a stable high-voltage DC level. There is a 3% difference in efficiency between line mode and inverter mode (93% for line mode, 90% for inverter mode). If it was fully double-conversion, line mode must be less efficient than inverter mode. That's why I think you're probably right.
  7. Exactly. It doesn't communicate with the inverter. ICC can read voltage and SoC levels from it using the other cable though, which is where all the magic happens. Even on Victron systems there is no CAN-connection between the battery and the inverter. The battery talks to the control computer (Venus-GX, CCGX) and that then relays the messages to all other units that needs it (the inverter and the solar chargers).
  8. Missed this one. Absolutely. I used to run my fridge and freezer from a 200Ah 24V bank, did so for more than two years. A+ fridges should have a start peak of no more than maybe 800W (my A++ Bosch does around 450W), and they rarely require much more than about 1kwh or so to remain cold. My 200Ah bank was sufficient to ride through 4 hour outages easily. About the UPS: How about spending that money on a small generator instead, if you want to buy a bit more time? People sell those things cheaply in the second hand market, just make sure it works before you hand over any cash :-) If you end up with a three-day outage (as some of our friends in Pretoria East right now, apparently a substation was damaged during "protests"), that's then also your future insurance counter-weighed against the small bank. Second-hand generators also have good resale value (eg, they sell for close to what you paid... second hand ;-) ).
  9. Price difference between the 24V and 48V models are negligible. If you search this forum some years back you may find some musings and reasons: Back then 24V meant less batteries, ie you could start even smaller. Now that many LFP batteries come only in 48V configurations, future proofing requires that you go with 48V. Get the Multi! The phoenix is just an inverter, it's not even hybrid, it can't run ESS (the hybrid storage system) later. In addition, the 48V 3KVA Multiplus is by far the most popular unit and because of that it benefits from volume, ie it is well priced. VRM is free. The official control units are pricey (over 4k for a Venus-GX, around 8k for a CCGX), but they are fully loaded with all sorts of connections, they are absolutely worth it for someone who uses all those connections (especially the venus-GX, a USB canbus interface is not cheap and you'd be hard-pressed to roll your own, even half as neat, at the same price, also compare competition eg solarlog to get an idea). But you can do it with a raspberry pi and various cables. I've previously estimated the cost of doing it this way (doing it properly with a din enclosure) around 2.5k. Just one note: Pi 3B support is lagging a bit behind, it's on my todo list :-)
  10. Time to read the other post and reply a bit more sensibly. A decent lead acid bank now costs about the same as a pylontech rack, or only very slightly more. For example, let's say you buy something like Trojan's 85Ah deep cycle 12V batteries, at around 2k each (I expect them to be a little more than that), then a 48V bank sets you back around 8k-10k, and at 50% depth of discharge stores around 2kwh. A single pylontech stores the same, last three times longer, costs 15k, and allows you to extend the bank later. Something to keep in mind though, wish small banks, is they usually allow limited continuous power. For example, that Pylontech rack will want a limit of 35A, which limits you to about 1.6kva in any case. The lead acid bank will want C/5 at most, or 85/5 = 17A, and with lower voltage efficiency you'd be limited to maybe 800W. I have a direct interest in you buying that blue box, so you are welcome to ignore me if you want :-) I don't think it goes for 27k. My pricelist says 1200 euro, which is less than 20k ex vat. In my experience (they are built in India, the price in Europe is usually more than here), it should go for less than that. The truth is that all the other makes are around that price, if you look at Goodwe for example, or even the infinisolar which though slightly cheaper is at least of the same order. Those are also hybrids and closer to being natural competitors. The reason for it being so cheap has been debated ad nauseam. My theory is that they make up in bulk for what they lose out in profit, and that their large footprint in the UPS market means that the tiny solar market they sell to is money for mahala. The other makers are dedicated solar manufacturers and usually expect to make profit on each unit. The axpert switches back to grid if the load is too high or the battery too low. It is hard-on/hard-off. Either the whole load is from the grid, or the whole load is from the battery. If it's in inverter mode and a large load starts, it moves to the grid entirely. The hybrid inverters only takes the DIFFERENCE from the grid, so if a 2kw load starts it would take 1kw from the batteries and 1kw from the grid for example (depending on how you set it up). Edited to add: Just for the sake of full disclosure, remember that you need extra equipment to use the nice features of the Multiplus. You usually need to invest in the communications dongle (The mk3-usb, about another 1k extra), possibly one of the control computers (Venus-GX, CCGX, or make your own with a Raspberry Pi), and then all the other cool stuff becomes available. You don't have to buy all of that stuff on day one, and even just the mk3-usb and the assistant stack (which is like small apps that runs on the inverter and gives you extra features) already makes it worth it. The point is: You get the best of both worlds, as TTT said, it's install and forget BUT it is also very tinker friendly.
  11. Confession, I didn't read the long posts up to here. But I did want to weigh in: My situation in 2013 was similar. I could not afford the financial loss that went with the power failures. I had less than 30k to work with at the time. And back then none of the Taiwanese inverters were available anyway, pretty much the only inverter that ticked all the boxes (allow some self-consumption) was the Victron Multiplus. So I bought the best one my money could stretch to, a 1600VA 24V model (they were a cool 12k back then), added two pretty crappy batteries to it and 300W worth of PV. Then I bought some steel, got out the old welding machine and welded up some frames, and did the install myself. And that was version 1. The funny thing: I still have that 1600VA inverter. It handles all the stuff you listed (top-loader washing machine, fridge, freezer, televisions, computers, lights), but none of the high-end users (hair dryers, geyser, stove, etc). It turns out that the inverter I bought is a hybrid though (can run grid-interactive, ie mix solar, pv and grid power), and this is where I went with it eventually. As TTT suggests, I use it to run everything below 1.2kw during the day. Any load larger than that simply draws from the grid. So I get my savings, up to 10kwh a day, and everything works except the large stuff. I will however move to a 3kva at some point, and the only reason I want to do that is 1) so you can heat something in the microwave and make some coffee in the morning, and 2) so the wife's hair dryer works. Happy wife, happy life. So my opinion, when you have the advantage and/or curse of having to start small: You might be better off with a small Multiplus Compact than a large 5kva Axpert. Yes, they cost more.
  12. The can cable might be meant for other inverters. With a Victron setup you snap it directly into the back of the CCGX in the relevant RJ45 canbus connection and it just works. That might be why you have the cable.
  13. Shot in the dark... but try removing that cable. Unless I missed something (which is very likely... I don't deal with this inverter nor want to), the RJ45 plug on the inverter is not a canbus connection, it's a serial connection. So connecting it to the can port on the battery will 1) not work and 2) possibly mess up the serial comms and explain exactly why it is not working. Unless the axies has grown can capabilities, then you must please tell me.
  14. plonkster


    Spec sheet lists a 93% efficiency in line mode and 0ms transfer time. That practically shouts double-conversion. So I went back to Voltronic's site and noticed that though they look similar, the "King" and the VMIII is not the same thing. The King model takes the usual 115V on the MPPT, the VMIII goes higher. I suspect the King model is probably a 5048 with a separate charger (which I believe the 3KVA model has always had anyway).
  15. plonkster


    Not personally, we have conversed via email once or twice. Their prices are better than sustainable and they have a good variety of products. Website seems well-maintained. I ordered a vedirect cable from them once, which hardly constitutes a big order, but they don't come across as a GWStore-type place, they seem quite trustworthy.