I guess @plonkster prediction came true for me. Not because of the Sunsynk failing though but rather because I’m getting a hand-me-down from Bro.
I currently have 2x Sunsynk 5kw inverters coupled with about 42 kWh of pylontech
Have 4 strings of panels as follows with only a west facing tile roof. Other panels are mounted on the wall on brackets.
East 8x420 Canadian poly. 3360w
West top 8x390 JA 3120w
North 9x460w jinko 4140w
West down 8x360w Canadian 2880w
Total 13500w
As panels are dirt cheap now, I plan to change the 2 west strings and the east string and maybe add another 5 panels on a separate north tilted string on the tile roof. My current north string is on 2 different sections, 1 4 panels and the other 5 and have Tigo optimizers on them due to shading. At different times of the day. .
Bro currently has 3x 10kva quatro together in 3 phase with pylontech and he is changing to sigen.
He didn’t have any panels on his Victron. I will get 2 of the quatros together with the gx.
What else do I need to replace the Sunsynks? What’s the advantage / disadvantages of dc vs ac coupled. I was thinking of adding both.
For DC, the RS mppt look nice and I wouldn’t need t split my strings but they are also expensive.
For AC coupling, what’s the best option.
With the pending Eskom registrations / disconnections / fines, I’m also thinking about a full off grid system together with a generator. For most Sept 24 - May 25, I hardly used any Eskom. Winter heating is always a problem but I’m experimenting with a water to air heating system. Heat water during the day and then use that for space heating at night. If it works then freezing water in summer days and using it for cooling also becomes an option.
So firstly, what’s the best options to complete my migration to Victron and what should I look out for.
I have a similar issue with a Solis inverter that cannot quite convert the peak of the PV (but it is within the max spec), so I lose about 300W or so on the noon peak. I decided it is not worth spending heaps of money on to get that back
Outside of that, The Victron world is pretty simple really. You have 250V units, and the 450V units. And you have to decide whether you want to rewire for 250V, or pay slightly more for the 450V unit.
For AC coupling, depends on whether you can feed excess into the grid. If yes, then you can use anything that uses frequency scaling to reduce power. If you need to grid limit, then since the latest GX firmware version (v3.60), there is support for a lot more inverters. The top two remain Fronius and Fimer (formerly ABB).
A Fronius inverter will probably cost more than an RS450, so I would probably not go that way.
Solis/Ginlong apparently does support Sunspec these days, but it is unclear if they support limiting. I’d love to know. Because that would be a cost effective way to go about it.
SMA and SolarEdge are both supported for limiting now. When correctly configured and all that. But neither of them are cheap either.
Oh, and of course you need something like a Cerbo GX to control things and log the data to VRM.
If you’re already planning to go offgrid, why even bother with AC coupled PV? You’ve got the panels so I would say get some Smartsolars MPPT’s, even smaller one’s, one for each array and wire the strings accordingly.
If my maths are correct, each array can use a 150/70 Smartsolar with either 3s3p or 4s2p configration. Wiring wil depend on what you currently have installed and what the distance is from your equipment.
I’ve got 4 strings of 3 x 330W canadians pointing North running through a 150/70 Smartsolar and it’s been producing good power for more than 4 years now, peaking at 70Amps often on cool summer days.
I recently added 3 x 545W panels West and 3 x 545W East, each array using a 150/45 Smartsolar MPPT. Angle on all arrays around 35deg so quite low. The extra arrays increased my monthly winter production with approximitely 240Kwh, compared to the same timeframe last year and the year before.
I guess this will increase even more with summer months coming.
What I’m trying to say is that you don’t necessarily need to used huge expensive MPPT’s to do the job and you’ll probably be able to get away with smaller units coupled to each array.
For some reason I thought the current is a lot more than 13A. Maybe I was looking at the Isc. Imp is actually 13.6A so if the Sunsynk specs are correct, I only lose about 0.6A so roughly 25w per panel. But I remember before the firmware updates, the rated max current was 11A but my inverter would cap it at 10A. Will be replacing my panels over the coming weeks before I get the Victron kit so will be able to check it on the Sunsynk.
I currently don’t feed in as I have a smart meter and haven’t registered or changed to a bidirectional meter.
Something that just occurred to me today is that I’m probably going to need to rewire my DBs again. Does Victron have a zero export capability where it can feedback to the non essential loads like geysers which are still on the grid side? I assume this can be controlled with the ET meter and the GX
That’s my long term plan but winter and a few rainy days in summer my problem. So I need to make sure I can cover everything before I can tell Eskom to take their cable.
When I talk about AC coupled though, I’m referring to a PV inverter connected to the output of the Quattro. Dc coupling means that the dc power needs to either get stored in the battery and / or converted to AC by the Quattro. I’ve also heard that the mppts run relatively hot and the Victron inverters also derate with heat. With ac coupling, there’s less stress on the Victron inverter as the PV inverter converts directly to AC which is directly used by the loads. So ideally, the dc coupling should be used to charge batteries during the day and the AC coupled to power the ac loads directly during the day.
If the grid is off and you want excess solar power to be used for non essentials, you can only do this with an ET meter yes.
If you are going to rewire your DB, have it done in such a way that you have a changeover switch for the “essential” non essentials of which the most important one is probably the geyser.
And it goes without saying that you should have a changeover switch between grid and inverter as well.
I purchased the ET meter but have been reading a bit and see many people actually recommend an external CT instead. I can’t feed-in but do have a smart meter so don’t want it to trip. Have a landis Gyr E460s. Anyone have any experience with those?
One of my 2 Sunsynks decided to die on me and is no longer inverting from battery or charging batteries from grid. Solar charger still works though. Lasted 4 years and don’t think I want to go through Sunsynk repair center again.
Those are known to have issues with feed-in, at least some of them do. On the upside, you need to feed in significant amounts of energy before it becomes a problem, but the corresponding downside is that the meter goes into tamper mode instead of just switching off for 30 seconds like the Conlogs do.
I don’t think you can use the external CTs with the Quattros. That’s a feature that came with the Multiplus-II inverters.
If things are close enough that the CTs would have reached… then why not just put those non-essential loads on AC-out 2?
With the Sunsynk, I’ve extended the ct cable and it’s about 20 meters away but I didn’t think about using the 2nd AC out. That would mean everything runs off the Quattros.
The only things on my non-essentials currently are 2 geysers and central aircon system so I think it’s doable.
If I do this, does it mean I don’t need the energy meter either.
I should have a 48kwh pylontech battery bank so that should be enough even for winter.
If you put all your loads on one of the outputs of the Quattros, then you don’t need the energy meter. The internal energy meter on the input of the Multi is then used. This is also far faster in avoiding feedback to the grid than using the grid meter.
With an ET112, the Multi will take as much as 15 seconds to pull back fully from a sudden reduction in energy consumption (eg Kettle switching off, geyser switching off, etc). With a faster EM540 meter, that is about 3 seconds, but if you look at the energy under the graph (when you plot it), the Multi/Quattro still does it better without the external meter.
Because you have that Landis meter, about which we don’t know what it does with feed-in, I would definitely consider this option more strongly.
I vaguely remember at some point when I initially deployed my system that I would see some feedback per day (<0.1kwh per day) without any issues but I would not want to have issues with Eskom now.
15s is a long time for it to throttle especially seeing that all my non-essential loads are large consumption ones.
To be clear, the 15 seconds isn’t quite as bad as it sounds perhaps. It gets down to a negligible amount within about half that, but because there is a low pass filter in there to ensure it doesn’t oscillate, getting it down to zero takes a bit more time.
The problem is simply that it takes time to get a measurement out of the meter. An ET112 gives makes a new reading available in its internal registers every 750ms, and then it takes about another 125ms to read that over modbus-RTU, so that by the time the calculation takes place, that value is almost a second old. Then you still have to send the new setpoint to the Multi, and it needs a little time to react…
When you use the built-in current sensors, you avoid all that comms.
@plonkster Is this new to the new Q and MP? I don’t remember the MPII (5 years ago) having this functionality (I could be wrong). I needed the ET112 on the Grid feed…
The Multiplus and Quattro inverters have always had current sensors on their input side (which they use for PowerAssist, even when not using ESS), and since at least somewhere in 2017, even before support for the ET112 was added, you could use those to regulate ESS.
Edit: Just to be clear, I am not talking about the CTs that used plug in with a 3.5mm jack, or that connects with a terminal these days. I mean built into the Quattros and Multiplus, there is a CT soldered into the main board that does this… example…
So that if you have an installation where it is hard to rewire things… you don’t have to. I assume that is what you are asking?
Why this meter? Well, first only the EM24 was supported, but that was quite an expensive meter, and the way it accounts for total energy makes it less suitable for PV-inverters (no individual reverse energy counters). So support for the cheaper ET340 was added. And then for the ET112, because it is even cheaper when it’s a single-phase installation. And then the EM24 went out of production, and we had a global chip shortage, so support for the EM300 range was added, then they made their new meter, the EM500 series, so support for that was also added, but because of those same shortages, and backlogs on the EM540, support was also added for the ABB B-series meters… and finally Victron decided to just get their own energy meter, because that way you don’t have to dance to the tune of other makers.
