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  1. When the BMS provides a charge voltage, the Multi assumes the BMS has already done any temperature compensation and will not add anything extra to it. In other words, for most people with managed batteries (ie with CAN-bus connection), no need to bother with temperature. The battery already handles that. Mmmh found the post... https://community.victronenergy.com/questions/61583/vebus-smart-bluetooth-temperature-overrides-venus.html
  2. Pylontech is 15-series LFP and cannot go above 54V (the BMS switches off). Lead-acid can float at 54V but it would take a week to recharge it at this low a voltage. It needs 58V to absorb properly. If you had a 16-series LFP battery, that would change things a bit. It would still not be advisable (mostly because of the danger of a bad lead-acid bank in parallel with a healthy LFP string!), but it would at least work in an emergency
  3. Indeed, that is much clearer. It seems there is indeed an inverter limit AND a feed-in limit. 3.5kW feed-in limit, and 13kW inverter capacity. Are you talking about the new feature in Venus 2.60 where you can limit the amount the whole system feeds in? That was actually written for the German market (they have a 70% rule, you may oversize the array, but must limit your grid feed-in to 70% of the total), but can easily be used for the same thing in Cape Town. The trouble with this whole thing (at the moment) is that the speed at which the system pulls back is nowhere near what the rules asks for. The rules wants you to pull back 90% of the way within 2 seconds. But it is a software limit and it ticks the boxes, so.. maybe? I disagree. I read somewhere (I cannot remember where) how they determined this figure, and 25% is actually leaning on the generous side given the shape of our grid infrastructure. In places like Germany there are already protocols and standards for instructing grid-coupled PV-inverters to change their power factor. The grid can use the connected embedded generators to correct power factor... this is literally the level of control that will come, and we are a long long way off. The German grid code also has a ramp rate (at which power is increased/decreased when it feeds into the grid), and that ramp is in both directions (in and out). We have none of that in SA. Until we do, we'll have to live with certain constraints.
  4. They are. NRS097 describes the exact operating conditions outside of which they must disconnect. Any even that trips one of them could trip all of them simultaneously.
  5. I've been told that the limit is not about how much you feed in, but how much the grid has to "pick up" if your embedded generator trips. So if you have a 5kW generator and you also have 5kW of loads on your property (so an ideal situation with 100% self-consumption and nothing is fed into the grid), and your PV-inverter switches off for whatever reason (trips), then the grid has to pick up 5kW, which is more than 25% of your connection size, and something they don't want. In practice however, we've seen them sign off 5kW systems with large battery banks (hybrids, so the ability to carry loads from the batteries adds to the picku-up) as long as the PV component is below 3.5kW. At the time, I said to the poster: Let sleeping dogs lie. Soooo.... my gut feeling is they won't allow this. Logically they shouldn't, if it really is about the pick-up.
  6. I'm telling you... it was because I was still consuming the first cup of covfefe!
  7. No idea, ask on Victron community?
  8. yeah... a light year is distance, not time... I think the official term is to "necro" the post. Then again, I've always wanted to do a Spongebob insert weird voice "X years later" thing
  9. Until recently, the 150/35 was the smallest MPPT that could be used in a 48V system. There were smaller MPPTs lower down (100/15, 100/50, etc) but they could only be used up to 24V. The 100/20-48 changed that, it can be used in a 48V system. But you'd probably need two of them in your case The Smart MPPTs have bluetooth, of course, but internally they have a slightly different architecture too, a different system-on-chip (aka cpu) setup. To the average user that probably doesn't matter at all. But there is also this thing called a current clamp, the newer MPPTs have a hardware clamp, which means that when the maximum current is reached it is held down in hardware. The older MPPTs handled this in software. If there was an overcurrent event (which could happen when you have cloud edge effect or the light level shifted very quickly), these older MPPTs stop charging and ramp up from zero. If you intend on oversizing the array, the newer ones are more suited for that. The 150/45 is therefore in a different class to the 150/35, but it is of course also reflected in the price
  10. What they are talking about is not sulphation, but rather stratification (heavier parts of the electrolyte sinks to the bottom), and this does not happen in AGM batteries. So the advice is in fact misleading and will likely shorten the battery life rather than extend it. Edit: Also, you don't have to discharge a battery to counter-act stratification (in a flooded battery). You merely have to raise the charge voltage to a gassing voltage so that it bubbles a bit and the acid mixes.
  11. That model's been on the market for close on three years now... It's the smallest model in the "new" hardware platform and on a technical level a more advanced product than the entry-level 150/35 (although, now there is a 100/20-48 which is the new entry-level model). I have one in my home system... no complaints. It's like a Toyota Camry, boring but just works.
  12. Haha, did I proof-read my post? Yes. Did I notice the mistake? Yes. Did I expect someone else to notice it? Yes. Did I fix it... no, of course not, I was only half-way through the coffee recharge
  13. Depends on battery voltage. If (just before the load turns on) the battery is already at the maximum voltage it should be (for the charging phase, whether that be absorption of float), then the MPPT may be running stable, but it is not running flat-out. It is running current/voltage limited. When a load then turns on, the battery voltage drops slightly, and the MPPT now has to switch from limited mode to tracking the maximum power point. Only, it doesn't know where the MPP is, it has to go looking for it. While it looks for it, the power will go up and down. Different MPPTs do this in different ways. Some simply restart from zero (so Axpert owners typically complain about losing PV for a few seconds), and others scam from wherever they are in three sweeps (so Victron people want to know why every now and then it makes these three quick dips...)
  14. Aaah ok. I scrolled right to the top, didn't see one, and made assumptions Yes, you can run ESS on a backup inverter... you still need to disable storage mode though. Otherwise the inverter will still drop the charge voltage after 24 hours... and will then Keep the batteries "charged" at this lower voltage. In other words, it would not really be any different to what you have now.
  15. No GX device in this system. Storage mode activates if you've been at float more than 24 hours (if I recall). It's a non-gassing voltage (it extends battery life) but it doesn't completely counter-act self-discharge, so a periodic recharge cycle is done. To get out of storage mode, however, the voltage needs to drop low enough, and I'm not quite sure what is low enough, but if it doesn't the charger does not go back to bulk. Simplest solution: Use VE.Configure and disable Storage mode. Storage mode is no good for regular power failures. Only use storage mode if the batteries really spend long periods at float, by which I mean more than a week at a time...
  16. It occurs to me that we're dismissing the OPs idea rather than doing what would probably be expected of a bunch of solar power enthusiasts, that is to promote it... Of course the pitfalls needs to be carefully considered. Truth be told, unless this is no more than 3 or 4 flats in your own backyard, I'd spend the money on a large Diesel generator and roll the cost pro-rata (on the overall electricity use) into the rates. Much more capacity for much less money.
  17. Well, there's your problem lady (quoting Eric O. from South Main Auto, love his Youtube channel). Probably blew the FETs on the H-bridge causing a dead short. Can usually be repaired by a competent shop. Or buy a better inverter.
  18. I've done that, a little differently though. There is a small business run by a friend next door, and we literally have an extension cord doing duty. I wired in a Sonoff POW in the head of the cable, configured it to allow 500W max for 30 seconds. This is a tad better than a 5A breaker, because a breaker only trips instantly at 5In (5 times the nominal rating), which means people can overload it by as much as 200% for several minutes. To assess how a communal setup would work, one should look at existing shared setups. Back in 2008, I had an Adendorff leaflet advertising a nice large generator, showed it to the boss... he showed it to the guy next door, and by the next day they had ordered two generators, to be delivered in one shipment. The generators arrived... and only then we realised they were three phase. We had enough power for three offices... So they sold one, walked over to the office one down and offered for them to buy in. And ran three offices from one generator... and that is when you realise it is not as simple as you thought. It works for the most part, but many days you had to walk over, ask them what they are doing because the generator is dropping RPMs and your laser printer cannot work...
  19. Your point 1 is actually a good one too. I can just see someone wire up his 5kVA gennie (because that's quite a common size at your hardware stores), and grabbing the nearest 10A cabtyre to wire up his connection...
  20. There are many many reasons a suicide plug is a very very bad idea. 1. The danger of turning on the main breaker before removing the "alternative supply", thereby energising the grid. This can get you in serious legal trouble, especially if someone dies because of that. 2. Part 2 to the above, turning on the breaker and forgetting the generator/inverter is still connected... and blowing it up. 3. Leaving either end disconnected while energising the other end can cause someone to be electrocuted. Again, legal trouble could be in your future. 4. You're feeding energy in on the wrong side of the RCD. While doing this, you have no earth leakage protection. 5. With many generators, the supply is floating. This means there is no protection against a single earth fault because your TN bond is disconnected with the main breaker. In general, the best thing is to never ever even suggest to anyone that this sort of thing is possible. I mean literally the only time I would even consider it is if I'm snowed in in some remote cabin and it's an emergency, I'm literally going to die unless I get the power on NOW... then maybe. Otherwise, just no.
  21. When using a Fronius PV-inverter in a Victron system, you will remove the Fronius meter, and reconfigure the Fronius to have no limit. You will then enable modbus-tcp for it, and then configure the GX-device to control the Fronius. The Victron system then acts as the limiter. The ET340 is then used by the Victron system. Just a note on the ET340. I far prefer the older EM24. The ET340 is really slow on its measurements (2 second refresh rate). If you have old style disk meters you may not care, just something to keep in mind.
  22. Aaah, so it's pre-emptive, not reactive. I bet it is expensive..
  23. Need a bit more detail. Do you, 1. Want to run a Victron inverter, with a GX device an an ET340... but then have the Fronius use its own energy meter? 2. Want to run a Fronius inverter, but use an ET340 with it? 3. Use the ET340 in a Fronius system that already has its own energy meter, for some sort of independent metering. The answers would be: 1. Using a Fronius inverter in a Victron system with its own energy meter is not supported. 2. You can't use an ET340 to control the limiter in a Fronius (aas far as I know anyway). 3. Of course you can do that, the two systems would just be independent of each other. I also have to note, at this point, that the ET340 is not a Victron product, although they do stock and resell it. It's a Carlo Gavazzi product.
  24. Correct. On the negative side of the battery, as close as possible, on the battery side of the fuse (otherwise the voltage drop across the fuse affects the voltage reading). The BMV has its own small red wire that feeds it power, and this is separately fused. This is the only protection the shunt and its electronics need. Also, when using a steel case, you should ideally have the fuses as close as possible to the battery (the point of two fuses is to protect against multiple earth faults, eg should the battery cable short out against the steel case). Normally this means putting a fuse as close as possible to the positive pole of the battery. So shunt as close as possible to the negative, fuse as close as possible to the positive. If not possible to put a fuse inside, then make sure a short to the metal case is physically unlikely.
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