shifttymike

Ah, that’s fair on the 5kva/4kw point. Plus they don’t have MPPTs so that’s a separate (significant) cost which almost invalidates the cost argument. (It’s early, sorry) I’m still inclined to go this way because the parts to replace are smaller, if you lose an inverter or MPPT and the warranty thing doesn’t work, you’re in for at most R13k for a new component and you can limp along until then. I’ve been scared off a little by Sunsynk units failing and people having nothing until the repair is complete. For someone trying to get to a point where the grid is no longer involved, that’s not going to work.

I’ve been thinking about this a lot lately. For a 15kw system, I’m considering 3x Victron 5kw multiplus GX units in parallel. And that’s splashing out to have controller redundancy as well. Cost comes to around R39k which is cheaper than I think any 15kw single unit option and if one fails, you still have 10kw of capacity while you wait for repairs. Alternatively, you can just buy another unit outright. Also easy enough to just add another unit and go up to 20kw for relatively cheap (if your design accommodates it) I can’t seem to find a good reason not to do this. I’m aiming to get as far off grid as possible so redundancy is important for me and while it’s served me well for the season of life, I’m not getting another Axpert. ITO software, I believe they expose a ton of control so with a bit of HA hackery (or solar assistant), I’m comfortable that I’ll be able to manage things well enough.

@Jacques1982 did you perhaps manage to figure this out? The "Premium" variant isn't on RCT Zone website, but it seems like the only difference between that one and the standard VM2 (which I have) is the dedicated BMS comms port. I ask because I'm struggling to get any sort of information out of the serial port on mine. It's this model, it comes with a serial cable and I can confirm that it is responding to commands, but doesn't seem to be compatible with whatever protocol the other Voltronic inverters use. WatchPower and ViewPower have yet to discover it. When sending a newline character at 2400 baud, it responds with: (NAKss I've tried this: https://github.com/ned-kelly/docker-voltronic-homeassistant, but it doesn't understand the responses. Running with debug mode on, it shows the buffer contents which clearly shows some of the configuration (float/bulk charge voltages, AC voltage and freq.) so there's some overlap, but it's not compatible. I really don't want to have to reverse engineer this, there are enough other projects piling up 😅

Oh, and I will get a "sparky" to double check all of this. I'm fairly confident it's all safe and mostly to code, but will need someone who does this for a living to confirm.

I've confirmed my understanding, more or less. Despite the inverter not being a "whole house inverter", I've finally figured out through trial and error the following: There is zero earth leakage protection on the inverter. If there's an earth fault after the inverter while it's running in bypass, the house ELCB will trip and the inverter will start inverting and you'll get electrocuted by that instead of Eskom. Not ideal An ELCB after the inverter, regardless of whether the inverter is inverting or on bypass, does not work because the small inverters don't do E-N bonding. I tested up to 35mA and it just looked at me. This functionality can be added with a purpose-built box like this or possibly just a NC contactor with the coil powered by mains (there may be some regulatory stuff here about mixing mains and inverter power) As with the bigger inverters, adding E-N bonding will require you to run the inverter off an un-protected circuit as it will cause the mains ELCB to trip whenever the power returns, a problem reported in a few posts on this forum I've probably spent as much on cabling and breakers as I have on my inverter, but the idea is to future-proof it so that when I upgrade, I don't have to change much. I haven't implemented the E-N bonding and ELCB yet, but it's only powering the light circuits and non-earthed equipment (TV, laptop, router etc.) Here's my lighting db. There's a 2-pole isolator plus a CB per light circuit, the ones in the main db are not in use but may be re-purposed to power the inverter in future as they're not earthed. It works a treat. Having the lights in-line (no-changeover switch) makes a big difference.

This is the db. I won’t accept judgement because we don’t live there yet, I promise to at the very least clean it and redo the labels 😅 But it looks like there’s probably enough room to expand. Apparently things have been shuffled around since I was last there. So if I understand this correctly, I’ll have 2 EL breakers. One for the Eskom fed circuits and one after the inverter, right? Same earth connection to both. And a second neutral bus bar for the inverter into the various beakers.

Yip! 0 Ohms between mains neutral and inverter output. Exactly. This is what I meant by "in-line", I don't want to have a switch-over since the inverter handles switching between mains/solar/battery as required. It prioritises solar, then mains, then battery. The bypass switch makes sense, I will ask about this. 800W total. It's a bit of a pain because the panels need to be 12V (ocv of 17-21), so they're kinda hard to source. I did find a 300w panel on Bid-or-buy for R1700, but who knows what it actually is? 😬 When I do this, I understand I'll need a sub-db for the DC side. Due to the nature of solar panels and lights, I won't be using the lights when the sun is out so it will be mostly to keep the electricity cost of the system down and increase the battery runtime (and consequently lifetime) in the day. My office needs about 150w max and the home theatre is about the same.

It's not a UPS, it's a small inverter with a built-in MPPT charger. The manual for it has a diagram showing how to wire it into your db, although there's no earth in the diagram 🤔 I certainly wouldn't wire a UPS into my house's power because you're right, they're not designed for that. Will do. She's not crawling yet, but as soon as she's mobile, we'll be baby-proofing everything.

Found this thread (missed it in earlier searches): Was quite enlightening, although not exactly the same scenario (I'm intending to feed my inverter post-EL). I guess the answer here is that "it depends" on how my inverter handles the E-N bond, and it's probably going to be safest to run a sub-db with its own EL. Although if I have a common earth then am I not just creating a neutral loop again? 🤔 What might be helpful is to have an electrician test the inverter and confirm its behaviour. Then we can start making informed decisions.

I've contacted a local contractor, although despite being qualified to sign off on installations, I'm still not 100% confident that without knowledge of the inner-workings of the inverter, he'd be able to safely say that a given solution would work without testing it. I guess I should find someone who specifically does solar, this would be more in their wheelhouse. This just raises more questions, there's no EL on this inverter, just a regular plug outlet. Nowhere does it say you need to add earth-leakage 🤔 For sure, that's kind of my goal as well: to keep costs to a minimum while getting the maximum value. I have no debts aside from the house we just bought (that is to say that I have a lot of debt ) and installing a large system would bring that to a swift end. My main goal is to figure out why this can't all be done for relatively little money. That LiFePO4 battery packs quite a punch and I don't have to worry about going over 30% DoD. The inverter, at 680w, is more than enough for my 250w lighting budget (and then some). Why does it have to cost tens of thousands to stay out of the dark? Now for the questions: This inverter has no EL, just a resettable fuse and overload protection (both of which are for overcurrent). What happens if there's a short from live to earth and mains power is dead (load shedding)? The diagram in the manual says that you can wire it into the db, except there's no EL in that diagram, before or after the inverter. If it has to go after, then it implies that your entire load has to run in-line which is obviously not viable with an 850w inverter. So what is the wiring supposed to look like? Can you have EL both before and after? If you have a common neutral and earth but live goes directly into the circuit breaker, then I can't see how the EL would be functional with no reference to the current in the secondary live wire. Off the back of the last question, would it perhaps be an option to have a, say 10A breaker in the main db to feed the inverter, then a sub-db with EL and all the light circuits? Something like this: https://leroymerlin.co.za/db-board-populated-8-ways-surface-mounted-lesco-81422450. This would avoid creating the neutral loop as the secondary side is isolated, but I don't fully understand the repercussions of having a second EL. Without a schematic, it's difficult to know, but there must be some kind of convention. Surely I'm not the first to want to wire the essentials in-line? Also, at this stage I only have 1 kid and she's not even crawling yet, so she doesn't care much about the plugs being wired and it's probably for the best if they aren't My wife mainly just wants to be able to cook and see what she's doing, and for that we have a gas stove, so as long as the lights and the internet stay up, there's peace in the world. I plan to split the oven's power between the gas igniters and clock, and the oven elements/fans so that you don't have to get the matches out to use the stove when there's load shedding. I'd go with the Veti modular plugs so that I can have a standard plug and dedicated plug in the existing flush-mount box. One in the kitchen (stove), bedroom (misc), lounge (TV) and office (laptop/screen). The idea is that in a few years, we can upgrade to something bigger and carry more of the load. The house wiring I'd like to mostly do once, so 2.5mm cabling everywhere etc.

I like this, very resourceful! I'd actually never heard of Dace until now. We're planning on having functional, bright light in each room as well as "ambient" indirect lighting (think warm white, corner lamps, under-counter lighting). Might be worth doing a 12V solution for that, won't need an electrician. Until I decide I want to use the existing light switches then we're back to square 1 😂 My desire to do things "properly" does not agree with my budget...

That's a fair point. This is all planning for the house that we bought and are moving into in January, so it's hypothetical for now. I'm aware of the CoC issue, and for exactly that reason (having to add breakers, run new circuits etc.) we're going to need to get an electrician in anyway, so consider this thread an educational exercise, for my own curiosity: How do you wire an inverter in-line? What happens if you have a shared neutral and the power comes back? I read somewhere about someone having an issue with the power coming back and his mains EL tripping, it had something to do with the way the inverter handed the E-N bond and it taking too long to switch, but there wasn't much detail beyond that. If you go 100% LED only and have an average of 20w of light per room (which I think should be plenty), I count... 12 rooms including outbuilding, garage, bathrooms etc. That's 240w on a 850va (680w) inverter assuming every light is on. Given that we've just bought a house and money is tight, we won't be going full solar any time soon and I wouldn't want leads running through the house for years. I've theoretically got the capacity, and the most convenient way to light a house during load shedding is to just keep the existing lights functional, so I want to see if there are other hurdles I'm not aware of that might make this more of a challenge than I expected.

Bump TL;DR will connecting the incoming neutral to the inverter's output neutral create an issue when the power returns? (switching from inverter back to bypass) It's just not the kind of thing I want to test to find out, would rather be sure in theory before hooking it up.

Well, it has arrived. Surely someone knows better than me? I'd really appreciate some guidance, pretty please I did some measurements with a current clamp in the flat we're staying in and the lights circuit is drawing more than I'd expect... (about 1.4A). Need to narrow down where the big draw is because it's all LED and CCFL in a 2br apartment. ~320w seems like a lot. I'm hoping for more like 200w. Also, 12V panels are a pain to find. And the low OCV means high current for the same wattage. Not that I'm quite there yet, just doing the research for the next phase of this project. So far I'm very impressed with the inverter. PC and home theatre don't notice the switch-over at all, speakers don't pop, screen doesn't blink, it just keeps on going.

The manual includes this... diagram. Maybe it's just me but I find this quite difficult to follow. It seems that I need to have common earth/neutral and effectively only use live from the AC output on the inverter. This immediately raises the concern of connecting neutral on the input and output side of the inverter. If it's in bypass, then it's the same thing, but if it's running off solar, or running off battery and the power comes back, won't that cause an issue? Assuming I didn't misread the diagram and that my concerns are non-issues, I should be able to run the live output from the inverter into the lights bus-bar and be done, correct?

I did notice that, and the seller actually contacted me and said that he can't sell me that combo due to this. But from the battery datasheet: • Compatible with most UPS & Inverters using AGM/VRLA charge setting • Easy drop in replacement for old lead acid battery installs • Perfect replacement Lithium solution for upgrading your lead acid installation He contacted Hubble and they said that it should work, although he won't guarantee it. I'm willing to take my chances.

For background, this is my scenario: I want to run a... fair number of devices off a small 850VA inverter. The one hurdle I have is that I want my house lights to keep working when there's load shedding, and that requires fiddling with the light circuits. How does one go about wiring an inverter so that it's in-line with Eskom power? I'm a 12VDC and below kinda guy, so I don't fully understand the issues with earth/neutral bonding etc. How viable would it be to add an additional breaker, fed by the inverter, which feeds a bus bar into the light circuits? What happens to earth/neutral? Is it an issue to have 10 or 15A breakers on the other side of a 850VA source? (so the inverter will trip before the breakers ever do). I currently have 2x10A and 2x15A lighting breakers. I do understand that I'll need an electrician for this to do the work and issue the CoC, but would like to understand the process. Please help, I don't want to burn my house down 🙃

Yes yes, I know I must be about the 100th person in this scenario I studied electronic engineering, so I have some background as well as some ambitious expectations. They say someone who knows a little is much more dangerous than someone who knows nothing at all I have bought myself a 850VA/680W Homaya inverter (Schneider Electric) along with the infamous Hubble S-100 100ah 12V LiFePO4 battery. There were a couple of reasons I went for that particular inverter: Reputable brand name (SE) Pure sine wave 800W solar charger (12V panels only, a bit meh) 12V 20A output for DC equipment (adds an additional 240w to your power budget, batteries permitting) The use case is: Alarm: 12V, no idea of consumption Electric fence: 12V, no idea of consumption CCTV (future install): 220V, should be fairly light Internet (ONT + router + 2 wifi APs): 12V for ONT+router, 220V for APs (they need 24V minimum for PoE) My office (laptop, screen, amplifier): 200VA peak when laptop running off charger, closer to 80VA if not House lights: 220V, about 250W peak If I run to 60% DoD on the battery, that means about 350W continuous load over 2 and a bit hours of load shedding. I suspect this should be pretty doable. The house lights will only draw power when I'm not working, they won't all be on at once, and the fact that I can run a bunch of stuff directly off 12V is a huge win for efficiency. Nothing is particularly high power and I mainly want to not be inconvenienced when load shedding happens. Later, I want to add at least 2x 160W panels, probably 4 in total which will limit the drain on the battery and start saving me some electricity. When I win the Lotto, then I will start looking at a separate, bigger system to keep more stuff on and limit my Eskom bill. If I need to drop the consumption, I could throw some 7ah batteries at the alarm, CCTV and electric fence and leave them off this system. The fence is the only one I'm worried about as the power draw is probably quite significant once it actually starts shocking. The others are probably fine to stay on. Yes, I know I'm a little crazy but I'm going to push the limits of what I can get out of a small system like this. I think that not having a desktop PC and running a bunch of stuff directly off 12V means that this might just be crazy enough to work... That's me, in the context of this forum I'll be around asking silly questions.