jharber

Thanks, that’s clarifying. So that pass-through cap is exactly why one would use an automatic changover/bypass, no? So that the inverter doesn’t have to pass through grid power? None of the plugs are on the essential side, just the geyser and stove. So it seems we have little choice but to freeze.

Hi there. I am asking more for my education than anything, as I am moving on from this house for (mostly) other reasons. In the last few very cold weeks, putting more than a couple of heaters on has been tripping the 5kw inverter, despite being on grid power. The landlord and installer confirmed that the grid power is wired directly through the inverter, and insist that it’s totally standard to install this way. Effectively we are capped at 5kw at all times, by design. Now I don’t know about standard, but it’s definitely not universal—I have been involved on the client side in the installation of several systems, all of which have some sort of automatic or manual changeover. And it seems bizarre, since an automatic changeover switch is all of R500. Is this arrangement in fact standard and indeed preferred, as the installer says? He also said something about the grid load being capped at 38A before the inverter, and at 15A by <something hard to follow> so it’s not much difference. This doesn’t sound right to me. It’s an odd arrangement with a lousy old DB and a new one, and I think the stove, AC, and inverter are on the old one and everything else the new. Have I got the wrong end of the stick here?

Hi all Today I noticed that the LED strip lights in my kitchen run off a little 12v wall wart with a standard DC connector. That gave me the idea of hooking up a little DC UPS to them. However, all the DC UPSs I have and everything I can find online is meant to be always-on, for wifi and such. I want something that behaves like one of those load shedding bulbs—that always responds to the same on/off switch, regardless of whether it's running off mains or battery. Does something like that exist? Anyone running something like it? Thanks

This is brilliant information. Thank you! Am I right that this, at 100A, would also be compatible through eWelink: https://www.robofactory.co.za/smart-switches/371-100a-1p-smart-circuit-breaker-with-monitoring-ewelink.html

I need to do something that really isn't all that technically complicated, but a little opaque to someone outside the biz. I have 41 flats (owners and tenants). I need a device on each unit, at either the meter or on individual DBs, that will feed usage data. I then need to be able to apply simple logic to those feeds (if we're on battery power; is current draw greater than x; has total draw exceeded y since going on battery) and then be able to a) send an alert. preferably text but other options possible b) cut off an individual flat if need be We have already integrated sonoff smart switches to shut off geysers etc. automatically when we're on battery power. So I know it's possible to have a system that takes inputs, applies logic, and sends outputs. Bonus points if: a) it allows remote meter reading b) it costs <R2.5k monthly e.g. for the management platform. We can pay upfront for the hardware and setup. c) it has an interface that will allow us to adjust parameters and logic Please don't say "don't do a central system". We've cracked the finances, it's a good plan and doesn't depend entirely on solving this problem. But this would smooth the way significantly. Thanks

Hi. We need real-time total load monitoring for 41 individual flats. Preferably it would be possible to set alerts on individual loads, both draw and total usage when we're on battery. Are there Sonoff products that will make this possible? We will already be using Sonoff switches on DB boards so hoping for an easily-integrated system. Thanks Jesse

Thanks for the quick replies, everyone. @87 Dream I'll be dropping you a message. Noted everyone's response re: the legality of two buildings doing this together, that's very important to know—so thank you. I should say that in general we're not inventing anything new here, either technically or institutionally. There are companies that do collective solar, we've approached a few for quotes, and we're going to go with one of them—I'm just trying to educate myself as a prospective client. @Bobster it sounds like that building owner screwed up pretty badly. We, like a lot of buildings, pay a single municipal electrical account and flats get billed by the body corporate based on individual usage—changing the origin of the power going into individual meters needn't *in principle* change anything about how that works, although we all know that things can go wrong in practice. So don't worry—tenant bobster with his tropical fish will pay his fair share!

Hello all I'm working with my body corporate on a whole-block grid-tied PV system with battery backup. The idea is that the economies of scale of 41 flats will change the economics for us, and even more if we can team up with the neighbouring building of 68 flats. Has anyone else been involved in something like this? We're looking for a power-purchase agreement setup from a specialist company. I'd be interested in hearing about other people's investigations/experiences/prices/etc. I'd also be interested in any links to panel and battery calculators (or just excel models) that can cope with the numbers involved (12000-25000KWh depending on the month) since they all seem to cap out at amounts for single-dwelling mega-users. Thanks! J