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Crit my idea ... pull it to pieces, I can take it.


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38 minutes ago, plonkster said:

-- and set it to something nice and high, like 1

The rc.local file inder /data/ contains this:

sleep 10
dbus -y com.victronenergy.system /Debug/BatteryOperationalLimits/SolarVoltageOffset SetValue 1

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34 minutes ago, Fuenkli said:

Do the power diverters also work if the GTI is set to zero export?

Well.... yes they work, but probably not in the way you want them to. If you're going to run pool pumps and things, you'd probably have to turn off the zero export, or at least set the value that it aims for to something slightly negative.

Otherwise, the inverter will adjust back and forth and the power use will hover around zero, sometimes going slightly positive, sometimes slightly negative, and depending on the diverter setup it will possible switch on and off repeatedly every time it drifts across the line.

I believe these diverters are made by people in the UK who are allowed to export to the grid, but would rather run their hot water cylinders at the time, in other words, they actually need grid export to work.

On this forum we have surmised that in cases where you have nuisance tripping of prepaid meters because of those accidental bits of feedback, a diverter might be beneficial as it can divert all those little accidental feed-ins into a water tank. But that is quite different from running pool pumps :-)

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2 minutes ago, plonkster said:

Well.... yes they work, but probably not in the way you want them to

thanks Plonkster for the information. It looks like unfortunately the available diverters will not work well without turning off zero export. I am hesitant to allow the inverter to export (even a small amount) because my meter charges me for the units exported. 

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5 minutes ago, Fuenkli said:

... my meter charges me for the units exported. 

Same here ... so I watched it the one day, the cents I pay for pushing power back via the PAYG meter versus the cents I save for not paying when the load increases the next moment. 

The perfect place to be: Able to sell power back at a profit / or use the grid as a battery for evenings.

... but that ain't gonna happen, guys and gals, not until I'm Pressi of the Republic of the Western Cape ... after I built the wall, after having had turbines installed in the Huguenot tunnel.

 

DUCK!!! Stone coming!

I find it quite interesting the max inverter sizes that CoCT dictates, based on the main breaker size. Seems to me there is a method in their madness.

And then the you have the daytime use vs evening use. ;)

Sometimes I catch myself that I overthink the power usage. The ART lies in matching the panels to the loads ...yet in summer you have more, winter you want more ...

So my thinking is timers, put things on timers, starting times staggered during the day to optimally use all available power, carefully matching the panels to the loads, per the hour of the day.

Edited by Guest
Refined the 1st sentence.
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11 minutes ago, The Terrible Triplett said:

I find it quite interesting the max inverter sizes that CoCT dictates, based on the main breaker size. Seems to me there is a method in their madness.

I think they asked an engineer to come up with a safe value that will probably be okay without too much extra investigation, probably based on transformer sizes, other loads/consumers on the same transformer, ability of that transformer to take power back upstream (which it is not designed to), and things like that... or in short: There's probably a super technical reason for that number as much as it also helps a tiny bit with the local politics where we don't want the funders to install too much solar :-)

15 minutes ago, The Terrible Triplett said:

So my thinking is timers, put things on timers, starting times staggered during the day to optimally use all available power, carefully matching the panels to the loads, per the hour of the day.

Too much trouble. PV panels are cheap. If you have the roof space, just put up more panels and run them less efficiently in summer (or run air conditioners with the excess).

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31 minutes ago, plonkster said:

Too much trouble.

Why? We have had geyser / pool pump timers in place since before solar.

You plug the "off the shelf" timer into the plug / DB board, set it, plug the fridge / freezer ... whatever ... into the timer / circuit and be done.

We must not confuse the DIY fun with stock standard off the shelf timers out there already. :D

 

31 minutes ago, plonkster said:

There's probably a super technical reason for that number ...

And backed by stats apparently like the average power a house uses in a day to not have too much surplus.

We know of huge arrays with inverters in parallel ... overkill if you really sit down and analise it all with a very sharp pencil.

 

It is easy to say buy more panels, it is cheaper ... but is it really?
Once you have the panels + cabling + sundries + frame + labour (your time is more valuable at the office than on the roof), you could easily look at 5 digits stating with a 1 in front from a reputable installer with a CoC.

So you can do it cheaper DIY. How much cheaper - you save maybe the R3k daily labour charge. you are still looking at 5 digits with what corners cut?
Do you get a CoC for a DIY install?

Versus better time/power management at a fraction of the cost of adding more panels. 

With Eskom not having hiccups, the reality is setting in: Is it worth it?
And some would say "Hell yes!"
And I will askHave you had to replace that battery bank / inverter / panels, getting that a CoC / conforming to regulations?

Being frugal and wise in one's power usage is THE BEST tip anyone can give, for lowering your costs, not more panels. ;)

EDIT: Unless you can sell it back or use the grid as a battery.

Edited by Guest
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23 minutes ago, The Terrible Triplett said:

It is easy to say buy more panels, it is cheaper ... but is it really?

There's going to be a balance point somewhere I think. Timers for geysers and pool pumps makes perfect sense, no argument from me.

But I have an interesting case and I actually wonder what the best option is. I don't have enough panels to power both the geyser and the tumble dryer simultaneously for example, and as it turns out with the long haired bipeds, they get out of the shower and while the geyser is still running they start the washing machine. Now you could delay the geyser to a later time... but by then the washing has been transferred to the tumble drier. I can turn it off manually (which I do ever since the timer broke some years ago and I didn't bother replacing it yet again), but then I have to remember to turn it on again, preferably while the sun is still high in the sky.

So there are two options really: Add more panels so they can both run simultaneously, or add some intelligent control of a contactor for the geyser so it literally runs in the intervals between other appliances. Not a difficult thing to do and means the existing panels can cover the loads better without cycling the batteries. But added complexity...plus... I still have room for more PV, I can use it to run air conditioners. Our lowest consumption in the year is in October and November, and then again in March and April. In December-Feb it shoots up due to AC use. So I can justify more PV panels over time switching at the moment.

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7 minutes ago, plonkster said:

I don't have enough panels to power both the geyser and the tumble dryer simultaneously

Your scenario fits my timer idea spot on.
- Simple, geyser goes on at a pre-set time ASAP in the day. Just that one time. If needed, 2nd time is manually switched on, if needed.
- Tumble dryer at a 2nd pre-set time AFTER that, when the geyser cannot switch on.

Will save you a trunk full of money and push your array towards optimal use, with a teeny weeny little communication.

Then you sit back and watch it ... before you by more panels. You may find this quite entertaining to shift the power cycles in the house, with smiles all round.

And you live in Cape Town right ... seriously look at EV tubes.
In winter they work 10 times better than any array you may have. You could go off-grid with your geyser, as we did.
You could do the EV tubes for less than upgrading the array today.

And remember, Eskom is always there to back you up.

Trick to EV tubes:
1) Do not replace the geyser, it still works, so you save a lot on parts and labour.
2) Yes the EV tubes will make that geyser pop faster, but when it does, that is then an insurance claim. You are paying for that.
3) So it pops, take that insurance payout, add some to it, and buy a external real geyser with a 10 year warranty.
4) If you can, make it a 400l system ... 200l is fine, but the more water you heat with EV tubes, the better.

Re. the geyser, sit back and relax, winter and summer.

Note: A real solar geyser like i.e. a Duratherm keeps the temp much better than the cheap "solar" geysers they install - and insurance helped to pay some of it, legally.

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13 minutes ago, The Terrible Triplett said:

- Tumble dryer at a 2nd pre-set time AFTER that, when the geyser cannot switch on.

Tumble dryer is a electronic push-button thing though. Effort to modify it... and warranty void most likely.

My idea is simply this: The geyser is not a priority item until at least 3PM. So you can turn it off at will at any point prior to 3PM if there is something else that wants the power :-)

I have a prefeed system, so in summer I need only a little power to keep the tank warm. The solar geyser on the outside feeds it with hot water so it rarely needs to tun on to heat actual water for use. At least in summer...

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4 minutes ago, plonkster said:

Tumble dryer is a electronic push-button thing though.

Sell it, go old style, then a timer works perfectly = saves money. :D

As jokingly as I say that, that concept came from my 79 year old mother, when I pitched an idea to her, and she asked me a simple question.

 

12 minutes ago, plonkster said:

The geyser is not a priority item until at least 3PM

I'm getting a Geyserwise timer for a non-solar geyser for R400 + courier fees, as the people are doing that manually currently, and I want to help schedule that.

Like I said, one can add more panels but is it really cheaper, when other changes can happen that does not required additional spending? Especially if one has investments that can always do with a top-up instead of panels you cannot take with you if you immigrate. You have been contemplating that, no? ;-)


Derailment ahead: (to back my point on immigration)

Ps. With Nene being hung out to dry, makes me think of "He that is without sin among you, let him be the first to cast a stone ...". Respect for the man, he stood firm, did not bow, and lost his job and creds.

We have interesting times ahead for it is but the first layer of the onion being peeled. Waiting for a deal where Cyril is linked to, to surface. That is anything but inevitable. ;-) 

Only one whom I think who is lilly white is Gordhan.

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15 minutes ago, The Terrible Triplett said:

Sell it, go old style, then a timer works perfectly = saves money. :D

Old style tumble dryers are absolutely terrible. They have 4KW elements and rarely have a thermostat. The new condenser unit saves more money just by being modern than it loses because of the lack of timer capability.

15 minutes ago, The Terrible Triplett said:

You have been contemplating that, no?

After the most recent trip over the waters... by day 5 I was convinced I never want to move to Europe. By day 7 some of the charm had come back. Overall, Europe remains a backup plan, it is not THE plan.

Edit: Stupid stuff like trying to find sinus medication. Walk into a pharmacy... no shelves like in ours. Just counters. Take a number, wait your turn. And I cannot get pseudo-ephedrine without a prescription. That alone means I am going to have a very tough life just in terms of some health conditions... :-)

Edited by plonkster
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30 minutes ago, plonkster said:

Old style tumble dryers are absolutely terrible.

They are. But it is in the way it is used. We don't use a dryer, and if we do, it is for less than half a load or maybe 2-3 items so we want it hot and fast. 10-20 minutes and it is done. When we had babies / toddlers, total different ballgame, but even then, we made a few plans. My dearest is quite good with that. My mother never had a dryer ... and she used those old cotton baby "doeke". So it is all about perspective, convenience and needs, as we don't "need" dryers.

My parents fridge is old and rubber leaks still, but works. So I explain the newer fridges and their A+++ rating and price tag.
So Dad sits there and asks, so per kw, how much per day for the old fridge, that still works?
We worked out it will take years to recoup, even worse if he keeps the old fridge, that still works, pays Eskom each month, keeping the cash in a interest bearing investment, till he has to replace the fridge, and then there is Gumtree, as the fridge will outlast them.

Panels, I say we need 1kw more. So he asks, how much to do it? How much will one save per month and for how long? 
I WANT more panels. :-)

My point. There is something going for the simpler things - or it is my age, that I am now questioning these things more. ;)

 

35 minutes ago, plonkster said:

... move to Europe ...

Jip, it is not for the faint of heart. You need BIG cannunies, strong family bonds if family goes with.

For they say moving house is the third most traumatic thing after death and divorce (well, depends whose death) ... wonder where immigrating will rate?

I want to drive trucks in the USA, see the entire country over a few years, live in the truck as far as possible - they are seriously jacked, like top of the line caravans. But I think it is going to be way tougher than anything local, the different cultures, what works and what not, not forgetting medical costs there ... then again, to do same job in SA / Africa, o my word, you need cannonballs!

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3 hours ago, The Terrible Triplett said:

 

So my thinking is timers, put things on timers, starting times staggered during the day to optimally use all available power, carefully matching the panels to the loads, per the hour of the day.

Look at Sonoff switches. Their basic unit can do 10A and cost about 150 bucks. You can schedule them with your cellphone and have the advantage you can be downtown Cape Town and see the cold front rolling in and switch off the pool pump. The added advantage is that you halfway to your home automation project. They are cheaper than geyser timers but don't have the Amp rating of a Geyser timer.

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1 minute ago, Chris Hobson said:

Look at Sonoff switches.

Jip, Paul introduced me to them as he built an awesome system with them, all programmable. But as we chatted over time, as awesome as it gets, it does not make for simplistic, if we are not "there".

We both are looking at plug and forget, therein us both going grid tied recently.

Just need to find that right balance between array size and loads, being grid tie. That spot where you add one more panel, you went too far, WANTs took over.

As said before, I am starting with a smaller array, going bigger, not a big array that I need to find use for the power. 

Any help would be appreciated, to find that balance.

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2 minutes ago, Chris Hobson said:

Your tik supplies running low?

Hahaha! I hear in Australia they make a street drug called "P" from that. I believe Tik is mostly Meth though, right?

1 minute ago, The Terrible Triplett said:

WANTs took over.

Nothing wrong with that, within bounds of course.

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13 minutes ago, The Terrible Triplett said:

So I explain the newer fridges and their A+++ rating and price tag.

Back in 2013 I worked out around 4.5 years repayment. Then I had a few surprises...

1. It's bigger, so we saved more money on buying in bulk

2. Milk and vegetables actually lasts longer, so less wastage.

This had the strange additional effect of causing us to buy less from PnP and more from Woolworths, because once the fridge did a better job of keeping the food cold, we realised how much longer the food from the more expensive store lasts.

So overall economic benefit? I have no friggin clue, but it sure improved our quality of life, that is for sure.

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9 minutes ago, plonkster said:

Hahaha! I hear in Australia they make a street drug called "P" from that. I believe Tik is mostly Meth though, right?

Nothing wrong with that, within bounds of course.

You asking the wrong oke. The closest I have come to drugs is nearly killing a street kid high on something late at night just outside of  Laingsburg and he wandered into the road with dark clothing on. I see tik is meth based but there is something that they do brew with ephedrine or pseudo-ephedrine.

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1 minute ago, Chris Hobson said:

there is something that they do brew with ephedrine or pseudo-ephedrine.

Yeah, I know about it. Pseudo-ephedrine is a schedule 2 drug, so at least somewhat controlled (over the counter). The other one that works is called Phenylephrine.

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45 minutes ago, The Terrible Triplett said:

I want to drive trucks in the USA

I have a very strong feeling that, that will be a career that will be automated out of human hands in the US within the next 15 years.

 

We live in a scary time people, if you are in your 20's ,30's or even low 40's be afraid, be very afraid, the machines are coming :P

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32 minutes ago, PJJ said:

I have a very strong feeling that, that will be a career that will be automated out of human hands in the US within the next 15 years.

I predict even quicker, just have a look at what Tesla is doing.

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