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Basic load shedding solution


Naboo
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Greetings

I keep cycling from a basic load-shedding beating solution, to a basic hybrid solution, to hybrid with solar, to grid-tied, to stuff-i-can't-afford and then back to basics :) So, now that I'm back at the basics, please check my reasoning:

- I honestly don't need to run much, just beat loadshedding (TV, lights, wi-fi, phone charger, fridge)

- If I buy a hybrid inverter, I would need to hook it up to a DB-board or get someone to do it for me. Hybrid only makes sense for me, if I run the essentials from this hybrid inverter, and then I keep thinking solar - doesn't make sense for to have just a hybrid with batteries that are loaded through Eskom. Adding solar to the solution makes it at least R20k - excl installation (if I do it someone is getting fried, no doubt)

- My house previously had a generator, so there is a switch-over switch I could use. It would be manual, but it's there. Since I only need those basics, I could manually switch over to an inverter with batteries after switching off the stuff I won't need at the DB board. Since I don't need to run much, I could probably away with a 1kw or 2kw inverter. 

- Since I will run some electronics off the thing, I would need a pure sine inverter (my understanding is the modulated sine would work, but could either damage some electronics, or the electronics could refuse to work with the modified sine inverter.

So - for under R10k, I should be able to get a 1 or 2 kw power inverter (pure sine) with two gel batteries (100ah each), that I'll hook up to the "switchover" and manually switch over when load-shedding kicks in ... it's similar to a generator but without noise (and yes, it runs down in a couple of hours and I can't add more fuel).

Is there anything serious where I'm missing the point completely, or am I more or less on the right track?

Thanks in advance for any feedback.

 

 

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29 minutes ago, Naboo said:

- If I buy a hybrid inverter, I would need to hook it up to a DB-board or get someone to do it for me. Hybrid only makes sense for me, if I run the essentials from this hybrid inverter, and then I keep thinking solar - doesn't make sense for to have just a hybrid with batteries that are loaded through Eskom. Adding solar to the solution makes it at least R20k - excl installation (if I do it someone is getting fried, no doubt)

Not necessarily. Victron inverters make perfectly good UPSes, even if they are hybrid-capable. Plus, you can then mount the inverter in a trolley of some kind, but relocate it later when you do want to go solar (and buy the rest of the stuff, the solar chargers, PV modules, etc).

32 minutes ago, Naboo said:

- My house previously had a generator, so there is a switch-over switch I could use. It would be manual, but it's there. Since I only need those basics, I could manually switch over to an inverter with batteries after switching off the stuff I won't need at the DB board. Since I don't need to run much, I could probably away with a 1kw or 2kw inverter. 

Then why don't you consider a smaller Multiplus. I have a contact who built himself a camping rig with a 1.2kw inverter and two lead acid batteries (24V setup), and he plugs it into his house in exactly the manner you're thinking of.

35 minutes ago, Naboo said:

- Since I will run some electronics off the thing, I would need a pure sine inverter (my understanding is the modulated sine would work, but could either damage some electronics, or the electronics could refuse to work with the modified sine inverter.

I've never quite understood this argument. Most electronics have a switch mode power supply. The very first thing an SMPS does is to turn the 230VAC into 325VDC, then it uses a high frequency buck converter to drop the voltage down to something lower. The rectifier bridge that makes up the first stage in an SMPS is not going to care one bit that you're feeding it a square wave. The things that care about a good sine wave are small induction motors and microwave ovens.

My main issue with the MSW inverters (modified sine wave) is not the waveform, but just that they are generally so cheaply made that they don't last. You also cannot wire that into a house, because you cannot TN bond them, or at least, they are not TN bonded on their own and it is never clear if you can do it. If you use it, then you need an alternate distribution network... extension cords 🙂

41 minutes ago, Naboo said:

So - for under R10k, I should be able to get a 1 or 2 kw power inverter (pure sine) with two gel batteries (100ah each), that I'll hook up to the "switchover" and manually switch over when load-shedding kicks in ... it's similar to a generator but without noise (and yes, it runs down in a couple of hours and I can't add more fuel).

Hardware stores sell a small trolley with space for two batteries inside, and a Mecer inverter on top. It is meant for exactly your use case (but with extension cords, not wired into the DB). It works out about 8k before batteries, and closer to 12k after adding batteries.

43 minutes ago, Naboo said:

Is there anything serious where I'm missing the point completely, or am I more or less on the right track?

My only concern is tying it into the house wiring. SANS requires that it be TN bonded (that means neutral and earth must be tied together), and most cheaper inverters leave it floating and are not meant to be installed in such a setting.

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Before I went to a solar hybrid system, I had a UPS and did what you describe - just kept a few essentials going during load shedding. It does make a difference.

Now, this depends on the layout of the house, but I found that using two extension leads I was able to back up a fridge, two standard lamps and our entertainment systems. This left one outlet open on the UPS and I had a short lead from that to a double sided socket (OK... a very short extension lead) for charging phones and such. 

What made it all work is a property that all these systems have these days, that they cut over automatically. So the input side of the inverter was just plugged into a wall socket and the box was parked in a corner with the extension leads going around the edges of the sitting room so there was little danger of tripping over them.

But eventually I decided that it wasn't that hard to look into the crystal ball and see that electricity supply was going to be a problem for 2 years at least. And not just load shedding but, in Johannesburg anyway, all the other outages due to aged and overloaded infrastructure. And the price would continue to go up and that made the economic proposition better or at least less bad. Plus I had twice had to restock the deep freeze after long outages (OK, in the short term the insurance pays, but the insurer giveth and the insurer taketh away or else the insurer would not be in business). So I cut to the chase.

Solar isn't cheap, but you have to take a long term view of the costs and factor in the soft value as well - keeping the fridges going, keeping the security system on, being able to help out friends and family who are without electricity.

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Hi

I needed something affordable for my 24V CPAP machine (for sleep apnea) and keep the 12V Fibre box and Wifi Router going.
Looked at various options , would have loved an all-in-one solution like a Tesla powerwall but too much $$$.

For a short term solution I picked up a Flexopower  LITHIUM444 powerbank  , a sonoff smart plug to control the charging cycle and a very long lead to reach my bedroom from the study where it is located.

Ghetto I know but it works.

 

LITHIUM444 POWER PACK by FLEXOPOWER

Edited by Garth Arendse
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14 minutes ago, Garth Arendse said:

Hi

I needed something affordable for my 24V CPAP machine (for sleep apnea) and keep the 12V Fibre box and Wifi Router going.
Looked at various options , would have loved an all-in-one solution like a Tesla powerwall but too much $$$.

For a short term solution I picked up a Flexopower  LITHIUM444 powerbank  , a sonoff smart plug to control the charging cycle and a very long lead to reach my bedroom from the study where it is located.

As I understand it the Flexopower unit is overkill for this application (with it's built in inverter)

Your ONT and Wi-Fi  run on 12V.

And your 24V CPAP maachine runs on 24V (I presume) 

Both these requirements can  be provided by a mini UPS

Edited by Richard Mackay
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47 minutes ago, Richard Mackay said:

Both these requirements can  be provided by a mini UPS

True it was overkill but I was rather desperate for a good nights sleep after a bout of 2am to 4:30am loadshedding in our area in a week of Jan.
Takealot had same day stock and either the Ratel 430P was sold out/long lead times and my CPAP supplier quoted rather crazy pricing for a far less flexible/capable (24V DC only) solution.

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13 hours ago, Garth Arendse said:

Flexopower  LITHIUM444 powerbank

In the mean time this has sold out just about everywhere it was for sale. The reviews I've seen are very positive too.

13 hours ago, Richard Mackay said:

As I understand it the Flexopower unit is overkill for this application (with it's built in inverter)

For someone who is technically inclined, who can deal with the DC/DC converters, understands polarity, the required fusing and can source the right plugs to plug things in, I agree. But for the average person who knows next to nothing about such things I actually think a DC solution could be dangerous. An AC solution that works with the existing cabling is a far better option for such people.

Perhaps what is needed -- and you will probably agree -- is just a DC standard. And I am talking appliance level, not mini-grid. The 5V USB standard is already a huge step in that direction. I already have a VOIP phone that has a 5V USB supply, but so far I have not seen a Fibre/ADSL/LTE router or even an ethernet switch that runs from 5V USB. Of the DC appliances I have, the requirements differ, and could be anything from 6V to (a rather non-standard) 21V, and each one has a different style socket.

I would expect that such a standard would probably use 24V.

Edit: Also, try and make a warranty claim where you blew the thing up with a power supply that didn't ship with it... 🙂

 

Edited by plonkster
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3 minutes ago, plonkster said:

Perhaps what is needed -- and you will probably agree -- is just a DC standard. And I am talking appliance level, not mini-grid. The 5V USB standard is already a huge step in that direction. I already have a VOIP phone that has a 5V USB supply, but so far I have not seen a Fibre/ADSL/LTE router or even an ethernet switch that runs from 5V USB. Of the DC appliances I have, the requirements differ, and could be anything from 6V to (a rather non-standard) 21V, and each one has a different style socket.

There is consensus (from what I have heard on a  webinar) on the DC voltages going forward. They are: 5V, 12V, 24V & 48V

I think this is likely since if you see weird and wonderful voltages then it's typically old equipment.

As far as the plugs for these voltages are concerned we have a way to go. For 5V the vendors use USB (often micro USB)

The rest use variants of the 5.5 x 2.1 mm barrel plug but no differentiation for voltage.. 

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3 minutes ago, Richard Mackay said:

variants of the 5.5 x 2.1 mm barrel plug

And therein some of the issues, because the size and polarity is not standard in any way. Some work has already been done in this area, eg universal laptop chargers that come with an array of reversible plugs corresponding to the most common makes, and a range of voltages to select from. EG this one from takealot.

In my view the laptop problem is a simple one compared to the one we're talking about here. At least with laptops you have a limited set of manufacturers (HP, Acer, Lenovo, Dell being the most common ones), and within each manufacturer there'd be maybe 2 or 3 types of plugs. This problem becomes significantly more complex when you need to cover any piece of networking equipment made by TP-Link, Ubiquity, Billion, and what have you...

Another way to deal with it, is to pick certain common combinations. Eg, it's quite common that the internet router would be some kind of routerboard from mikrotik these days, and the Optical termination box for fibre is also pretty standard (Where I live, Openserve uses one from Nokia, Frogfoot uses some Chinese made one... pretty standard).

Or... or a little extra... just ship a small 250W inverter in the box. Problem solved 🙂

 

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5 hours ago, plonkster said:

And therein some of the issues, because the size and polarity is not standard in any way. Some work has already been done in this area, eg universal laptop chargers that come with an array of reversible plugs corresponding to the most common makes, and a range of voltages to select from. EG this one from takealot.

In my view the laptop problem is a simple one compared to the one we're talking about here. At least with laptops you have a limited set of manufacturers (HP, Acer, Lenovo, Dell being the most common ones), and within each manufacturer there'd be maybe 2 or 3 types of plugs.

Laptops often have propriety power supplies. They have handshaking between the laptop and the PSU so I find laptops quite difficult to supply power to from an external DC supply. My experience is with Dell but I'm sure they are not unique. 

As a result I have steered away from powering laptops from a DC supply and advocate that users keep a spare battery pack to provide extended backup time.

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2 hours ago, Richard Mackay said:

Laptops often have propriety power supplies. They have handshaking between the laptop and the PSU so I find laptops quite difficult to supply power to from an external DC supply. My experience is with Dell but I'm sure they are not unique. 

As a result I have steered away from powering laptops from a DC supply and advocate that users keep a spare battery pack to provide extended backup time.

Hopefully usb-c and laws like this from the EU (https://www.androidheadlines.com/2020/01/usb-c-charging-could-become-european-standard-with-drafted-eu-law.html) will finally be the end of this in coming years. There is no real good excuse for these proprietary supplies any more.

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Well, speak of the devil. One part of the new-house endeavour is the flat in the back that is supposed to become an AirBnB. So I bought some stuff on Takealot's "fire sale" and one of them was a new Samsung TV... which comes with a "drumroll"... 19V PSU brick 🙂

5 hours ago, Richard Mackay said:

My experience is with Dell but I'm sure they are not unique. 

Yes, I've run into this issue with Dell. If that center wire in the supply gets damaged, the laptop stops running full speed and won't charge. Then you have to buy a whole new brick.

I've seen the same issue with a Lenovo and an aftermarket battery. Thankfully there waas patched bios firmware to get around that.

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11 hours ago, mmacleod said:

Hopefully usb-c and laws like this from the EU (https://www.androidheadlines.com/2020/01/usb-c-charging-could-become-european-standard-with-drafted-eu-law.html) will finally be the end of this in coming years. There is no real good excuse for these proprietary supplies any more.

The regulators do have some clout so it's good to see this development in mobile phones. (Only Apple has a problem with this!)

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14 hours ago, Richard Mackay said:

I agree but I don't see the PC industry complying just yet.

Remember USB is a 5V system. It's not like PoE with a 24V or a 48V standard.

Laptops use much more power than mobile phones etc. so their PSU's deliver 18 to 20V which would  be a tough call for a USB supply! 

The newer USB standards (USB-C in particular) are actually multivoltage 5/9/15/20 - the last of which should suit most monitor and laptop supplies fine.
The specs for this (USB-PD) have been in place since 2012 already, recent macbooks already take a USB-C charger cable, theres really nothing stopping other manufacturers from doing so, well other than that they like the proprietary lock in, which is why a nudge from the EU is what will be required to finally get there.

Screenshot_20200229_120737.png.8366c5cc516c093c7c9a939604346d04.png

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A dell laptop with usb-c as well https://www.dell.com/en-us/shop/dell-laptops/xps-13/spd/xps-13-9370-laptop

Its been a long time in the making, and as usual it starts with the high end stuff that has to support it first, but more and more things will start to use it, and at some point with some luck we will reach a stage where consumers will avoid or be annoyed by any devices that do not simply take a standard cable.

Edited by mmacleod
Pushed enter halfway through writing post
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And if you already have PoE in place (like I do), all you need is something like this https://www.coolgear.com/product/36w-usb-type-c-poe-splitter-powering-pd-devices and you can power your usb-c laptop while also providing it wired networking.

So between USB-C (5v/9v/15v/20v) and PoE (48v) we already have two complementary standards that can cover most needs, the world just hasn't quite realised this yet or caught up to it.

Which is why I think for new houses that are going to have solar/batteries and so on (which runs best at 48v anyway) - planning PoE cabling in from the start is sensible, and lighting is a potentially good place to do that.

 

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