9 hours ago, The Terrible Triplett said:

So when the Axpert has no panels on it, there is no problem. But the moment you connect panels, some meters trip?

Axperts don't trip pre-paid meters- they cannot either grid or solar not both - its the hybrids that do - and with Conlog specifically.

I would risk saying that Conlog contributes to the problem since it samples every 15 seconds or so any is accurate to within 40W whereas the limiter I use seems accurate to within 5W.

21 minutes ago, Chris Hobson said:

samples every 15 seconds or so any is accurate to within 40W

It samples more often than that. This is a guess, but probably not a bad one. It has a 15 second window within which it does its calculations. In my post about KW vs KVA I referred to taking readings/samples of your instantaneous voltage and current readings, multiplying them and adding them up, and that in mathematical (calculus more specifically) terms this is a mechanic way of doing integration. Prepaid meters do the same thing. They take a number of samples, and then they multiply voltage and current (dot product, this gives you the power vector, which is signed... it has direction) and then that gets multiplied by a time increment, and then all the little samples are added up. It seems this value is then low-pass filtered over something that resembles a 15 second window to implement tamper/reverse detection.

The BEC44 is even more sensitive, I think it comes down to 20W.

1 hour ago, gabriel said:

i do not know whether the axpert was advertised differently prior to this registration debacle [on the list or off etc], but it is now strictly marketed as 'off-grid' by solarmd

The context differs.

When I sell you something, I will say that it is 1) Grid tied, 2) Hybrid, or 3) Off-grid. Grid-tied generally means no battery. Hybrid means grid-tied with a battery, by-directional, grid-interactive, grid-assist, mixing of power. Off-grid means no mixing of power, either the inverter carries the whole load or the grid does, nothing in between.

When Cape Town talks about off-grid, they mean the battery carries everything PERIOD. No switching to the grid at all.

I don't think it is inaccurate to market something as off-grid by the former context, nor was any dishonesty intended.

What gets my goat more often is when the Victron's are listed under off-grid. They are hybrids.

1 hour ago, gabriel said:

according to a spokesperson from solarmd in cape town they will have compliant rebranded 'axperts' in by end august ...

But what about their existing client base? I actually spoke to one of their people before, and they did not seem concerned at the time about the effect of NRS097-2-1. And as I have indicated above more than once, if you do the foot work once (show the reasoning from "this is a good UPS" and "it has a interlocking changeover switch"), then that solves the problem for everyone, right? If anyone would want to do it, it should be them. If they cannot do it... that spells really bad trouble. Well... for you guys anyway...

(Reminds me of this joke about three friends sitting in a room, one of them is reading and looks up: It says here 1 out of 3 men is affected by ED... I'm fine, so it has to be one of you two!).

At this point I want to summon @Coulomb and ask about the changeover switch in the MPPSolar/Axpert inverter. Does it have some kind of interlocking design to ensure that both cannot be on at the same time, for example, like you might use an auxiliary contact in a star/delta starter to ensure that both contactors cannot close at the same time? :-)

3 hours ago, gabriel said:

yip, the jury still waits for the take-away order before applying their minds

The lower courts have ruled - not going to sign it off, period.

We are now onto the Con Court to reverse their decision. 

 

2 hours ago, Chris Hobson said:

Axperts don't trip pre-paid meters- they cannot either grid or solar not both - its the hybrids that do - and with Conlog specifically.

Aaah, my mistake. I had a picture in mind, combining a lot of titbits, not focusing on the finer details.

I stand corrected.

In my defense though, as it is a rather large blunder, this is not a product I will purchase, have been trying to elicit responses for the Axpert owners, with limited success. :-)

 

3 hours ago, gabriel said:

... according to a spokesperson from solarmd in cape town they will have compliant rebranded 'axperts' in by end august ...

And I bet you that is only new ones going forward, the ones out in the market need to be replaced?

If saw this, accidentally, a range of off grid inverters in their list of inverters?

http://www.voltronicpower.com/oCart2/index.php?route=product/product&product_id=123

52 minutes ago, The Terrible Triplett said:

If saw this, accidentally, a range of off grid inverters in their list of inverters?

And they are, by traditional marketing parlance. But look carefully, they have an AC input, so to Cape Town these are not off-grid.

Also have a rather wimpy MPPT max voltage...

2 hours ago, The Terrible Triplett said:

saw this, accidentally, a range of off grid inverters in their list of inverters

no accidents..., but still not coct compliant?

2 hours ago, The Terrible Triplett said:

the ones out in the market need to be replaced?

this is not ford or vw who will recall and repair, this is china!

saw a thingamajig the other day with a sticker 'not made in china'

Edited July 26, 20187 yr by gabriel
xtra data

21 minutes ago, gabriel said:

this is not ford or vw who will recall and repair, this is china!

So IF it comes down to it, Axperts are not going to get approved, and the new "approved" ones comes out, how does that make you feel? 

 

So, with Plonkster's posts on the Axpert should be seen as UPS, I thought to email a national UPS company that has been around for yonks, and are installing solar systems.

I asked them why don't they have Axperts as an option, their reply: 
We don’t import anything from Voltronics, only buy them out from the local guys when there is a specific request for one. But they are not very reliable, but do have their uses. I’m not sure if it’s because of cheap components or what the actual case is with them. We have had numerous failures with them. I guess they are not good in the South African environment where there are voltage fluctuations on the input to equipment.

Now I know the guys, they are always ready to help, understand UPS'es and they do service and repairs on all the makes they sell. And I have had to use them before see, a lot, for Pos and Neg getting confused inside UPS'es and all that. So I asked them about the SANS Regulations and the changeover switch:
Unfortunately I am not clued up on the certifications of any Voltronics machines and at what standard they are manufactured to.

Now what is interesting to me, if I asked them about say a APC, or any other product they sell, they would have given me an straight answer, or would have research it, and then let me know.

Edited July 26, 20187 yr by Guest

4 hours ago, plonkster said:

At this point I want to summon @Coulomb and ask about the changeover switch in the MPPSolar/Axpert inverter. Does it have some kind of interlocking design to ensure that both cannot be on at the same time, for example, like you might use an auxiliary contact in a star/delta starter to ensure that both contactors cannot close at the same time? :-)

If you are talking about the inverter and AC in relays, indeed they can be on at the same time. In fact, every time that AC charging is happening (charging the battery from the "AC input" terminals), these relays are on at the same time. I still don't know whether they stop the inverter MOSFETs and just use the back diodes to rectify the mains, or if they switch them and run the inverter in reverse for AC charging.

33 minutes ago, Coulomb said:

I still don't know whether they stop the inverter MOSFETs and just use the back diodes to rectify the mains, or if they switch them and run the inverter in reverse for AC charging.

Aaah, what you call synchronous rectification. The inverter runs hotter when it charges, right? That might be an indication that they are only using the back-diodes.

Not that it matters in this context. I suspect that's where it is going to break down on certification in South Africa. It does not have mechanically interlocking changeover arrangement. (Neither does the Multi, for that matter, but it is already classified as a hybrid so that ship has sailed in any case).

Not accidentally energising the grid input is essentially done in software then.

So, @The Terrible Triplett, I am now inching closer to your finding that these things might in fact be uncertifiable in their intended use case. Your only option is going to be to to take if off-grid (no AC connection) and to put a transfer switch on the output. Something like this or the Filax 2. Neither of them can be remotely controlled though.

Edit:  Just have to add, for clearness: It isn't necessarily a problem that the output of the inverter (which is also the charger) is connected to the grid purely under software control, not from an engineering viewpoint. The problem is that for that arrangement... someone qualified needs to look it over and declare it safe. You'll have to send the Axpert to a testing lab.

Edit 2: The 3kva model looks like it has a changeover arrangement. You have a better chance with that one.

Edited July 26, 20187 yr by plonkster

47 minutes ago, plonkster said:

So, @The Terrible Triplett, I am now inching closer to your finding that these things might in fact be uncertifiable in their intended use case. Your only option is going to be to to take if off-grid (no AC connection) and to put a transfer switch on the output. Something like this or the Filax 2. Neither of them can be remotely controlled though.

ok, now from me as one of the late comers to solar 101 like myself, a few questions [maybe others are also lurking here with the same questions]:

can the axpert be used to charge batteries from pv without being connected to the grid?

and having done so could it then use the batteries in its capacity as inverter to power loads say during the night?

now i know that in the latter case the same circuitry as the grid must be used, can the axpert be totally isolated from the grid during this phase and how would i be able to make sure that there is a physical disconnect, not software, which will be acceptable to the coct?

as you can see i play around with ideas, answers to which will help me fathom the axpert owners predicament.

Just now, gabriel said:

can the axpert be used to charge batteries from pv without being connected to the grid?

Yes.

Just now, gabriel said:

and having done so could it then use the batteries in its capacity as inverter to power loads say during the night?

Yes.

1 minute ago, gabriel said:

now i know that in the latter case the same circuitry as the grid must be used, can the axpert be totally isolated from the grid during this phase and how would i be able to make sure that there is a physical disconnect, not software, which will be acceptable to the coct?

I suspect, though I am not an authority on this, that the only way for it to comply will be to leave AC-in disconnected. Hopefully that is enough, it is possible that because of the danger of someone reconnecting the input once the system has been signed off, it might still be problematic. Jury is still out, but this is probably the most favourable outcome right now.

There is a possibility, a tiny one: Maybe fitting a Ziehl UFR1001E to the input will do it. Technically, it is not enough. NRS097-2-1 requires an active anti-islanding measure. The Ziehl only does passive anti-islanding. But maybe it will be accepted. It is on the list!

1 hour ago, plonkster said:

Your only option is going to be to to take if off-grid (no AC connection) and to put a transfer switch on the output.

Jip, that was my collective understanding "put it in that box and close it". Just cannot explain the tech side so well. :-)

 

8 minutes ago, gabriel said:

... can the axpert be used to charge batteries from pv without being connected to the grid?

...  can the axpert be totally isolated ...

As I have said somewhere here before, to try and make a Axpert off grid, use a interlock along the lines to what I have, but it is a long long shot, I think the engineer said.

And as Plonkster mentions, one can still go back and connect it like before. 

The break in the power, 40-60ms I think my new relays will switch at, is enough to switch everything off, when switching between Eskom and solar.

Manual changeover was also mentioned to me. 

So how to overcome the break in power, for a house, I am not sure.

 

8 minutes ago, gabriel said:

... help me fathom the axpert owners predicament.

Is that not what the Blue side have been trying to do the last week, fathom the Axpert owners predicament? 

Lets touch on the elephant in the "room". No, we are not gloating.

Twinkle in our eye maybe, but not gloating.

5 minutes ago, The Terrible Triplett said:

So how to overcome the break in power, for a house, I am not sure.

Use something like the Filax 2. It has the same <20ms changeover, and it has paperwork.

16 minutes ago, The Terrible Triplett said:

Twinkle in our eye maybe, but not gloating.

Definitely not. I would be p*ssed if it happened to me. In the ever-raging V vs A war, this is not the kind of victory you want (if it even be fair to call it that). What you want is to win by providing the better product at a reasonable price. I really feel for you guys. In fact, with the exception of @gabriel, where on earth are you? What's the plan?

49 minutes ago, plonkster said:

Use something like the Filax 2. It has the same <20ms changeover, and it has paperwork.

Price is about R4 703.50 at CA.

EDIT: Max current 16amps - Is that enough for a house, if Axperts powers the house?

Edited July 26, 20187 yr by Guest

13 minutes ago, The Terrible Triplett said:

EDIT: Max current 16amps - Is that enough for a house, if Axperts powers the house?

Yeah, that's a bit low. Well, something like it. Ideally I would like something that switches automatically but can be overridden (with a BMV for example), so above a certain SoC you can force running from the inverter. Then you have something pretty similar to what you have right now, all you lose is the AC charging capability.

17 minutes ago, plonkster said:

... what you have right now, ...

My BEEF has suggested they quote on a simpler design, seeing as what I have done is way over the top and the idea is not new anymore.

So they propose I remove the interlock and have the BMV switch a new relay. New one is 40-60ms break. So I still need a UPS.

Thanks to Victron, for giving the BMV such a long cable, for the BMV will now move further away from the batteries.

Edited July 26, 20187 yr by Guest

4 hours ago, plonkster said:

Aaah, what you call synchronous rectification. The inverter runs hotter when it charges, right? That might be an indication that they are only using the back-diodes.

Definitely runs hotter when it charges from AC. The SCC has a external heatsink but I have noticed daytime temperatures of between 36-40°C (I have the fans reversed) and if we charge in the evenings from the gennie temperatures vary between 44 and 52°C.

My thinking is if I was in Cape Town and I owned an Axpert I would go totally off-grid. I would then have an auxiliary 48V battery charger - one with a 3 pin plug. I know Victron make a 12/24V AC charger do they make a 48V charger? Come a rainy day I would charge the batteries via the grid and have a changeover switch and run from grid for a day or three. I don't think I have ever been in the W Cape and it was cloudy and overcast for one day only.

8 minutes ago, Chris Hobson said:

I would then have an auxiliary 48V battery charger - one with a 3 pin plug.

48v chargers are not that common, when you find one, they are quite expensive, compared to a Axpert.

Case sample, from Gumtree: GX482020 Amp 48V UltraSafe Industrial / Golf Cart Battery Charger: R 8,625

Here is another idea:
If it was me, I would just dig in and go the Victron MP-II route, once they appear on the list. Would want nothing to do with Voltronic.

Step 1: Get the CoC sorted, ready for the grid tied scenario.
Step 2: Get a Victron MPPT in the meantime, to spread costs, if I decide to go this route.
Step 3: Get a Pi ready to take the Venus free software, to read data.
Step 4: Then get the inverter when it appears on the list, or latest when my municipality forces me to.

Or Goodwe. Fronius - if I can get the data I am used to.

And if I have to replace a battery bank, SMA or such grid tied. Keep the Axpert if one day Eskom goes down again, then get batts for it for a select bunch of stuff.

9 minutes ago, The Terrible Triplett said:

If it was me, I would just dig in and go the Victron MP-II route, once they appear on the list. Would want nothing to do with Voltronic.

The Multiplus-II is presently still listed as the Multigrid-II on the price list. That was its initial name, because that is the stable that it hails from (it is the next-gen Multigrid). It has since been renamed to the Multiplus-II. Just in case anybody starts to look in that direction.

Now, some bad news. The first is that this device, though very similar to its predecessor, is not on the list yet (though it already complies with the codes in other countries and this is likely a mere formality). It should be certified by next year, and we know it is definitely happening, but we simply don't know when.

The second is that it isn't really cheaper than the older Multigrid yet, I think it will come down in price as volumes increase.

The third is that this unit uses a steel case. I haven't seen one in real life yet, it looks very decent in pictures, but if you are partial to the aluminium you might want to go for the older one.

The fourth is that presently there is only one MP-II available, the 3kva 48V one. Most Axpert users will likely want a larger unit (though of course it is hardly necessary when you have a true hybrid).

Finally, to be fair again, the infinis are on the list. You may want to stick with Voltronic as it does still have a price advantage, and before TTT takes me on again for playing against my own team, we want to do apples vs apples, right? Price isn't everything. Support and a decent warranty counts something too.

Also, it is entirely too early to start talking about switching. That's like making jokes about the recently deceased...

5 hours ago, plonkster said:

where on earth are you? What's the plan?

yes, WHERE ARE YOU

re the plan - like in all things get the facts, obtain knowledge, do brain-storming and interact - don't be stingy with ideas etc, sometimes the weirdest ones work, ask elon musk

the more i read here and elsewhere the better i understand the problem, not that i can put my finger on it exactly for i lack formal training in the subject, but the picture starts to emerge and as soon as that happens logic can be applied. i mean i still get my volts, amps and watts mixed up sometimes, but less so than a couple of months back

as was stated, newbies must be reached. it was not long ago when i was one and boy, this forum is a crash course in reality i wish i was exposed to prior to entering the idyllic world of alternative energy - this is NOT on par with rain water harvesting

so my plan is to continue to read, bug people, make comments [sometimes totally off topic] and otherwise lurk around. spending a lot of money is NOT my plan.

apart from the above i have to ask again, what is an 'interlock' -  a link will suffice