Bobster.

22 hours ago, frivan said:

Surge protection is mandatory according to insurance but I think this is just an excuse not to pay for some claims. They do not guarantee that transients can't pass through them. Disconnection and a steel cage is your best defence.

A general principle of insurance is that you can't insure against what you know is going to happen. This was the advice given to several big JSE listed companies in the run up to Y2k. Insurance won't pay for your losses or damages because you KNOW 1st January 2000 is coming and so you have to take precautions. The legal test that a court would apply, we were told, is whether or not you took REASONABLE precautions. You can't take infinite precautions, but you should take some. If you took precautions and the court ruled that they were "reasonable", then insurance probably would have to pay out.

So this is where we are now, I think. You KNOW there is going to be load shedding, and you KNOW that surges are likely, so what precautions have you taken? Insurance is not going to listen to you if you did nothing at all. They probably won't be too impressed with a couple of Ellie's red plug top thingies with LEDs inside. SPDs in the DB with sign off by a suitably qualified electrician and a good brand name and things start tipping back your way.

Not to take sides or anything, just to explain the overarching principles that are being applied. 

There are incentives available, though not for the likes of me. Well, a bit for the likes of me, though that tax rebate only runs for a couple more days. Businesses do better - they can write off any generation (solar or wind) pretty quickly. And they can write off 125% of the price they pay. This makes some sense: City Power would much rather deal with one shopping mall that has lots of roof space than with individual householders and 60A connections.

Currently businesses installing PV or Wind (must be able to generate, not just have backup) can write that off pretty quickly and can already sell back.

4 minutes ago, Kalahari Meerkat said:

Here's a "Make the smart switch" leaflet they included with the final/last bill,

What's the deal there? Individual households can sign up for load limiting? Or do they need everybody in whatever the area is?

4 minutes ago, Kalahari Meerkat said:

I made the switch, I'm off the grid... point is, though, their peak hours... 05:00 to 10:00 and again 17:00 to 21:00... not too many solar installations are producing power before sunrise and after sunset, I'd imagine...

That's it. Though how far can the power I put into the grid travel? If they're getting enough in the right places they can use that to pump water up hill during the day for release during the evening peak. 

I presume this what COCT are doing as they have their own pump storage scheme.

OK... my last word on this. For about 25 minutes today I had a situation where there was load shedding, not a lot of PV, battery not completely charged, and (because of the shedding) light loads. For that time span the Goodwe drew about 1.2kW from the panels whilst the load was about 450 - 520 W. So, again, the battery charged and the draw from PV only dropped off when SOC hit 100%.

I'm still on 2525J.

So now I'm as sure as I can be that this problem can be addressed by firmware.

There's more than one way to skin a cat. I'm not keen to dump the contents of my battery back into the grid. But I do nearly all my consuming of electricity during the sunlit hours. I heat water at 6:30 in the morning, it's true, but I use the battery for that. The rest of the water heating happens in the early afternoon. The pool pump runs during the day. It's off by 16:00. Our appliances run during the day. By 18:00 were running low loads and that's off the battery which lasts into the morning peak demand time. So I'm taking load out of those two peaks. So are lots of us. If resell tariffs were more attractive some might sign up, but already we make a difference and Eskom feel it. 

If load shedding gets sorted out in the next 6 months, and if attractive, time of day tariffs are set so that I can sell into that evening peak THEN I might sell back because there will be juice to keep the TV on. 

I wouldn't. I'd wait another 6 months to be sure that the Minister really has got the ship in order. 

On 2022/02/22 at 8:54 PM, kellerza said:

If you have some energy meter (measuring total consumed kWh). You can try the following (I use it in packages\prepaid.yaml). My energy from the grid is measured by the sunsynk inverter, but any meter should work

The useage your inverter sees is not necessarily the same amount by which your prepaid balance changes. I say this from personal experience.

So if you want to track the inverter's net draw from the grid then your method is a good one. If you want to track the actual balance on the meter then we're back to interfacing with the meter itself.

On 2024/02/20 at 2:06 PM, Shockin said:

Hi,

My current system runs perfectly,  it's a 5kva Axpert inverter with 3 pylontech batteries  built into a 19 inch rack. I want to add solar panels soon.

Want to get more power into the house so do i:

Add a second axpert inverter as a slave and a 4th pylontech or

Fit an 11kw Axpert inverter with 2 most and dump the 5kva axpert or

Sell the whole system and fit a Sunsynk 8kva and Volta stage 3 10kw battery then add lots of panels.

Which could be the best option?

 

Thank you 

Who is going to be doing all the work? If it's you then that's one thing, but if, like me, you'd have to rely on an installer then that's another.

I got a quote to change my inverter. Well, it nearly amounts to a new install. This is maybe not so outrageous as I would expect a guarantee on the job and some support after installing, and the installer's risk is increased if he relies on old cabling, old breakers etc.

Of course these things can be negotiated, but then you have to be careful to balance the level of support you will get with the amount you are willing to pay.

For most homes an 8kW inverter will support a lot of load, and a 10kWh battery will give you plenty of backup, especially if you minimise the loads once the sun is down.

If it's working fine, then maybe just stick some money away each month so that you have money for batteries when that time comes.

I have a little less on the inverter side than you do. I'm not sure about your current battery, but I have 10kWh, and that will easily get us through the night and can go some hours into the next morning as long as we stick to our usual routines which are really summed up as doing as much electrical stuff as possible whilst the sun is shining.
 

22 minutes ago, Shubs said:

Firstly I had to google GIMF ... the irony 

Thanks folk.  So in summary, both @Bobster. and I have a 11a MPPT threshold. We can use the newer panels but won't be able to reach optimum performance by ~20% with clipping?

That sucks long term when I'd want to replace an existing old string in 3-4 years, as 11A ones will likely be extinct. 

Have to reconsider the good deal on the GW5048D-ES, or suck it up and buy the newer GW5000-ES20 instead ... decisions 

If your system is specced correctly now, and your circumstances stay more or less the same, then you system will still be adequate.

My system is 4.5 years old now. I've thought about getting some newer panels so that I have better performance on overcast days, but it's not clear how much better the performance would be, and the reality is that we have had the lights on for 4.5 years (except for an hour odd, caused by finger problems, the fingers being mine), and day to day the system works. If anything, our electricity usage has declined a little.

I got a quote for the panel upgrade. It made my eyes water. Not just the cost of the panels, but cabling, circuit breakers, lightning protection....they didn't want to use much of what was there and I kind of understand that. Those cables are 4.5 years old and they might still do the job BUT they ain't new, and the guy has to offer and honor a guarantee,

If you're a DIY type then it may not be so bad.

Just a note: Panel rated current is measured under test conditions. A certain mounting angle, irridesence, ambient temperature etc. Mine regularly show more than the figure given on the spec sheet.

Ah. GIMF.

Inverter Shortcircuit Current
 

https://help.solar-app.org/article/210-inverter-isc-dc-input-ratings

OK... this is above my paygrade now. 

Hang on! What is this Isc PV figure? Both my inverter and that of @Shubs show that at 13.8A

1 hour ago, Shubs said:

@Bobster. can you pls help explain your sentence to a newbie like me ... Back to the original point: The spec sheets specify a current limit, not a power limit. The ES will allow 14A per MPPT, whilst the EM allows only 11A.

I'm buying a GW5048D-ES (model below) and just want to make sure it supports the latest panels which all seem >11A

I understand there are 2 versions (old supports 11 and new 14).  Is this one capped at 11 and does that mean I can't buy any of the latest panels?

 

 

 

Yours is not the same as mine. Even the layout of the label is different. 

Mine shows 13.8 per MPPT (the Goodwe website says 14, which I assume is rounding) 

7 minutes ago, Kory said:

Thanks for this. The final question is we have lived in this house for 8 years and haven’t changed the geyser or worked on it ever.

Hmmmm.... get the anode checked. That won't cost much, and if you get it changed in time then it will extend the life of your geyser.

7 minutes ago, Kory said:

I am not sure if there has been any significant improvements in geyser technology. The previous owner of the house wasn’t one for buying the very best of things, though the house was liveable we have spent quite a bit of time and money doing quality improvements. My question is over the past 8 years has there been any changes or improvement in geyser technology? Would we benefit from a more recent electric geyser in terms of energy efficiency? Yes our system will cover the geyser especially if we use a timer to ensure it heats during the day mainly. Ultimately,  I am opting for oversizing our solar system to cover the geyser rather than buying a solar geyser. So the plan is to in the near future change our two geysers to the most energy efficient ones we can get and use the system to power it. Currently I know we have a 150lt geyser for our 1 bedroom granny flat- I plan to change that to a 100lt as the maximum occupancy for the flat is 2. We have occasional had 3/4 guests but that’s under special circumstances. 

I would think that new geysers now are better insulated, so heat losses are reduced.

The most economical way to heat water electrically is with a heat pump. I have a heat pump (I had it before I got solar). They take less power and run for less time to heat the same amount of water. I can run mine as a backed up load, so if the sun doesn't shine or if I want it heated early in the morning (and I do) then I have no problems - even if there's no grid.

My heat pump is 13 years old now. I would think that the new ones are more efficient because of improvements in motor technology and the use of different gasses that are more compressible and so can move more heat (or need less power to compress). 

Get your geyser insulated. I have the outlet pipes and the pipes between the geyser and the heat pump insulated. And I have a thick ass "blanket" on the geyser. 

If your routines allow you to heat water only or mostly during the day then you are heating it for free. Win! With any sun-driven technology you have to literally learn to make hay whilst the sun shines. Not just heating water: Your pool pump, your dishwasher, other appliances.... run them whilst the sun is up. That also means you can stretch your batteries further when the sun is down.

Don't overheat the water. Some people turn the thermostat all the way up and then have to add lots of cold water - they've overheated.

 

Just to drive the point home, with inverterter still in economical mode and loadshedding ongoing

19 hours ago, Bobster. said:

7) Since then Goodwe have upgraded me a second time. Now I have to repeat my tests again. With sunny days and no day time load shedding at present I can't do meaningful tests.

So serendipitously we have load shedding this morning AND we have some PV but it's not great.

But look at this

Loadshedding starts at 10:00 and you can see the load drop as the pool pump is no longer on. But the battery is charging. Not at a great rate (it's overcast) but it is charging. This is with the inverter in economical mode.

So @LLTHB I think you need to check the firmware version on your Goodwes checked and then upgraded. I say to check first because if something goes badly wrong you will have the previous version number recorded and can ask a roll back to a known version (this is my attitude towards all firmware upgrades on any type of device)

To get upgraded you will have to have the inverters powered up and connected to the internet. Goodwe identify them using the serial number. They can push the update onto the inverter, and no restart by you is necessary.

Your challenge now is to get through to somebody at Goodwe SA who can make this happen, or get whoever sold you those inverters to intervene on your behalf.

It can be done! What I record above shows that. If Goodwe SA can't help you, then try going to Goodwe EU or Goodwe themselves.

1 hour ago, Jobravo3 said:

The Inverter I will be getting is a GroCoal Apple Mars 10KW hybrid inverter 48V but I can't find anything on the internet about it whatsoever. Do any of you gurus know about this

brand and what the quality is like?

It is an Apple Mars, not a GroCoal Apple Mars. 

One thing you should check, if the installer hasn't provided this information, is whether or not this inverter is on the COCT approved list.

Even if you don't live in CT. 

If it's on that list then it's been through and passed some sort of test routine and so the manufacturer has the will and the means to do that. If it's not on that list then either it was never submitted or it failed.

Then look for local support. Also the people who are offering you this package - what's their reputation? Ask around about them. Remembering, of course, that most folks are slow to post complements on line, quick with complaints. If you don't have a lot of technical expertise then you are going to need to rely on the installer for guidance and support. 

If you spend some time reading this forum you will find some brand names come up over and over. Sunsynk being an obvious example, Deye another, but not just those two. If you buy one of those brands then you have a lot of on-line help available to you.

If it's 10kW of backup power, that is a big banger. You will not be like me who has less than half of that and has to check the kettle, the deep frier and the dishwasher don't all get turned on at the same time. 8kW is plenty for most people, so do you have some special requirement?

And the date with destiny has been set. Wednesday 6th March.

5 hours ago, LLTHB said:

Morning Bobster, please let me know if this has solved my problem - Goodwe not charging batteries unless Eskom power is present.
Fingers X this patch will work, otherwise I sit with 2 perfectly functioning inverters I cannot use.
Thanks. LLTHB

 

Hi @LLTHB

Let's try to recap:

1) I was experiencing the same problem as you. Battery would not charge when there was solar but no grid.
2) this problem could be overcome at a pinch by switching the inverter into off-grid mode
3) I was on firmware 2121D
4) Goodwe upgraded me to 2121E.
5) Test results above after this upgrade showed that when the grid was down, solar was abundant, the battery charged - in general and in economical mode
6) So it does seem to be down to firmware version
7) Since then Goodwe have upgraded me a second time. Now I have to repeat my tests again. With sunny days and no day time load shedding at present I can't do meaningful tests.

Note that I didn't contact Goodwe. I contacted my installer who themselves contacted Goodwe. They called me to confirm the serial number because that is what Goodwe use to find and connect to your inverter.

16 hours ago, FFJG said:

It's nice when real life obeys the laws of physics and all the theoretical bits fall into place with an equipment saving "click" at the right time. Thinking back, the current 40A breaker was chosen because the rated Isc of the panels is 9.38A, so "the system won't go above 40A". Is there some rule of thumb about what sort of fudge factor to add to this? i.e. how do they arrive at the 15A fusing recommendation for this type of panel?

Right now I'm pulling more current from my panels than the spec sheet shows. 

But under the table where the current at maximum power is listed, there is a footnote: That the tests were all done presume "irradiation at 800W/m2, Ambient temperature 20C, Wind speed 1mS". 

Then they go on to give various curves for power characteristics at different irradiations. This goes up to 1000W/m2, and the power for that curve and the one beneath it (900W/m2) exceeds the rated maximum.

So what they can put out depends on the conditions, and the stated current, voltage etc are under a certain set of conditions. Exceed those conditions (especially if you exceed the irradiation) and you can exceed the rated figures.
 

10 hours ago, Josephine said:

We have installed a hybrid system on the 9th of February on the first night we still used 3.8kw hrs according to data logged by system. 

After that we did not use any eskom units according to data logged by inverter, we have a prepaid meter and on the prepaid meter we are however using between 1kwh and 0.5kwh a day. 

Now I know this is nothing but I am in data analytics and discrepancies makes me wonder about all the data.  

 

Am I right that the discrepancy is between what the app tells you and what the meter shows?

I have had prepaid electricity for years, before I had PV actually. Sigh... life was simple back then.

So once I moved to prepaid solar I started picking up discrepancies on the meter between
1) The movement of the total power that passed through the meter (this is the usual running total that any meter would show)
2) The reduction of the credit amount.

What seems to have happened is that despite my system being set for zero export, it does actually send a little power back to the grid each day. Somewhere inside the meter two parts of it's firmware, the one that handles the credit balance and the one that records how much has passed through the meter, handled this small export differently. The credit would run down faster than the total would go up. Usually the discrepancy was in the order of 1/2 a kWh a week, so I lived with it. It's a few rands in the month, and any solution I could think of was likely to cost more.

Recently that meter failed completely and was replaced. The new meter is a different brand and the discrepancy I describe above is much smaller with this meter - about 0.1 kWh a week (or I have just been lucky).

So check to see if your system is exporting electricity. Some meters see that power but they don't have a way of sensing which direction the power is flowing, and so they show it as power drawn from the grid.

On 2024/02/10 at 7:35 AM, Bobster. said:

So this morning I notice that the firmware version is changed. Now 2121E. 

The installer now has a help desk, and they told me they were going to take this issue up with Goodwe. So I am guessing that this is how the update happened. 

I now have to wait for the right combination of conditions. The City are not helping by restoring our power two hours early. 

I am now wondering if this condition hasn't been present all along, but was only exposed by the increased load shedding. 

The other user I mentioned is on 2121H

Well smack the cow and paint the barn red! This morning I am on 2525J.

Now I have to start all my checks all over again. Under current conditions with no load shedding from 5:00 to 16:00 there is no way to do any useful testing. I was just getting relaxed about 2121E. 

Necro post. City Power recently announced the inauguration of a municipal microgrid in Alexandra which will supplement the grid feed to about 150 properties. 

Two more micro-grids are in progress.

I suspect lower power toasters will be like low power geyser elements. They get the job done, but slowly.

What they do offer is a lower peak draw, which is handy when one is current limited.

Actually there's a third reason for auditing. The client phones up City Power and says that their meter is a load of because they can't possibly be using that much electricity a month.

On 2024/02/16 at 3:35 PM, KW39 said:

For the guys who were audited by CoJ when they installed pre-paidd with solar –

How does one go about proving you're not stealing electricity because you have a PV system? What sort of things do you need to submit?

OK. I know of two kinds of audit, but they really amount to the same thing.

1) Routine audit
2) Checking your meter because the usage has dropped significantly

In both cases they are going to check for tampering, for signs of bridging, and that the serial number on the meter matches what they have on their database for the property. If the meter number is correct and there's no signs of bridging then how you can you be stealing?

They might ask if you have an alternative source of power, but I presume that is they because they are tired of getting electric shocks when they think the power is off.

I've had them several times at my place since I went to prepaid. Since I got solar they have, on a couple of occasions, taken photos of the panels on the roof, but nothing happened as a result.

I'm currently registering my system with the City. There is a process. It is supported by (poorly communicated) by-laws. I figure that at some point they are going to get more aggressive with this requirement. Part of that process is a warning sign on the box where the municipal breaker and the meter live, warning that there are dual sources of power on the property.

2 minutes ago, Bobster. said:

I have a surge protector on each string of panels.

I also a pair of Dehnguard SPDs on either side of the inverter. So the order is

Grid -> SPD -> Input to inverter   Output from inverter -> SPD -> backed up circuits.

The garage door is on the backed up circuits.

I detailed this in another post. Sorry for not responding to you first. They will pay for a REPAIR if I provide photographic evidence (of what?), a quote, a report from whoever is doing the repair, and I have to supply that in advance. In the event of a replacement there must be a credible report explaining why a repair was not appropriate.

Eish. I just spotted that @psyclown was not actually asking those questions of me.