Solar options for home in 2022.

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#3039046 19-Feb-2023 15:40

Just talked to a friend of mine who has ridiculous amounts of off-grid capacity set up and he said your best bet for UPS-like behaviour is a GoodWe EH which is essentially the same as the Fronius (integrated charge controller + inverter), supports a much larger range of external batteries, and has a 10ms (not seconds) cutover time. He demoed it to me some time ago, you can disconnect from the grid and nothing in the house even notices.

So despite my approving of the Fronius based on where it's made, it looks like the GoodWe is a better bet. Only problem at the moment is that the absolutely perfect location to install it is in the largeish storage space under the stairs which has no natural ventilation.

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#3039051 19-Feb-2023 16:41

The GoodWe inverters don't appear to have active cooling so in warmer areas that may cause issues (inverters reduce solar generation when they get too warm, may reduce lifespan), apart from that it does look nice as far as the specs go. For completely seamless switch overs that can be achieved with any inverter and a Tesla Powerwall and gateway.

neb

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#3039060 19-Feb-2023 17:06

eonsim:
The GoodWe inverters don't appear to have active cooling so in warmer areas that may cause issues (inverters reduce solar generation when they get too warm, may reduce lifespan), apart from that it does look nice as far as the specs go.

That's not a problem, the area is already full of networking and embedded systems gear and has an AC Infinity thermal management system set up, it's just that where the GoodWe would go it'd need its own solution and possibly venting outdoors which will require some careful thought because if it's not constantly running it'll allow damp air in. The current setup just pulls cool air off the basement slab and exhausts it up the stairwell, and in any case barely ever runs except on the hottest days.

neb

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#3039131 19-Feb-2023 21:14

Given that I don't have to wait for IQ8s any more, can anyone recommend a good installer in Auckland, possibly the north shore? There's a ton of places out there but in this case I'm looking more for whoever will do the best job rather than whoever's quote is lowest, since I've got a specific goal in mind that isn't "the most stuff at the lowest price".

In particular back when IQ8s were about to arrive any day now I phoned around a couple of places and they seemed optimised for shipping generic setup #6a or #3b rather than paying attention to the specific things I was after. I realise that going through all the details rather than taking the closest cookie-cutter setup they have will cost a bit more but since this is a long-term home I'd rather do it right the first time.

billgates

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#3039159 19-Feb-2023 23:00

If you are not strictly budget and space constrained then the best setup IMO is a string inverter from the likes of SMA or Fronius connected to a battery charger inverter via AC coupling from the likes of SMA, SelecTronics or Victron which then connects to your 48V battery like BYD LVS or LVL for e.g. OR you can set up a string inverter and connect that to a Tesla PW2 if you are happy with 13.5kWh usable capacity and Elon Musk. The Tesla PW2 is a legit nice piece of kit although the battery chemistry is not as good as LifePo4 because it has cobalt but saying that I have never heard or read of a PW2 catching fire anywhere unlike the Tesla car's which have the same battery chemistry as the PW2.

A string inverter without any hybrid capability to charge battery will last a long time. Hybrid inverters have limited life due to a lot of heat and some companies only provide certain battery charge cycle amount of warranty. If your battery charger inverter eventually breaks down, you will still have Solar PV generation happening during the day via the string inverter while your warranty or out of warranty replacement for battery charger inverter gets sorted out. If your hybrid inverter is out of action, you have neither Solar working during day nor battery backup at night. Hybrid inverters are not really designed for extended power outages as they will heat up.

To back up the above claim, look at weight of SMA Sunny Island 5kW (German made) battery charger inverter, Victron MultiPlus II 5kW (Netherlands) and Selectronics SP Pro 2I 5kW (Australian made) model. They weigh 65KG, 30KG and 40KG, respectively. They are primarily battery charger inverters. The GoodWe or Fronius Gen 24+ hybrid weighs around 15KG. There is a lot of copper, heat sink and good tech inside the above battery charger inverter compared to Hybrid inverter so you can imagine which will last a long time.

With battery voltage type you have 2 options, 48V low voltage or ~460V high voltage and depending on which battery voltage type you choose you will be limited to certain battery charger inverter models as well. By far and large 48V is the most common type, with more brands available in NZ incl setting up your own LifePo4 packs if you want to go down that route and cheaper than high voltage battery. The advantage high voltage battery has over low voltage is that you can place the battery packs 5m to 10M away from the battery charger inverter unlike the 48V which needs to be within 2M max of the battery charger inverter.

My installer went off GoodWe because they had too many warranty claims coming their way for their liking, and they are happy with Sungrow (Chinese brand) although this could have been a while back and perhaps GoodWe's newer models are more reliable. Another option you have is to go with a string inverter and I see that GoodWe has an AC couple only battery charger inverter with same less 10ms switch input time for UPS functionality but saying that SMA Sunny Island for ex takes 5 seconds to switch over so yes it's not a UPS but if we lose power for 5 seconds, I know that the SMA unit will hold up just fine for years to come if need be because it's used in Off grid application across the globe. The Victron model above has true UPS functionality and pairs nicely with Fronius.

Do whatever you want to do man.

neb

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#3039161 19-Feb-2023 23:35

Ah, that's good to know, thanks for the detailed comments! Since the best place to put it (plenty of room for batteries next to it and right next to the main power board for the house, with easy access to drop cables from the solar cells into the area) is the under-stairs storage area, massive heatsinks and less heat generation is helpful.

Looking at the SMA docs for the Sunny Islands, they quote a switchover time of 0ms and 20ms:

Switching times for backup operation (without switch box or MC-Box) − 0 ms (high impedance) / 20 ms (low impedance)

so possibly they've updated the electronics since then? That makes it more or less a toss-up between the Victron and SMA, I'll need to read the docs a bit more to see if one is obviously better than the other. At the moment the main feature is UPS capability to avoid potential problems with about 20 devices and controllers, but if another 27 Jan event hits us and the Wairau GXP gets taken out then it may also need to run off-grid for quite some time.

With the MPPT controller now separate, is it better to have it closer to the solar cells, so the longer cable run is to the inverter, or closer to the inverter, so the longer cable run is to the cells? Being able to site the MPPT controller in open air (but under a roof) will help with cooling if the best option is to have it close to the cells, so that leaves only the inverter generating heat (battery heat will be minimal from what I've seen with friends' setups, while the GoodWe runs quite hot).

Edited to add: SMA document everything with teutonic thoroughness, of the million manuals the best reading for this case appears to be the Planning Guidelines - SMA Energy System Home with Battery-Backup Function. For Victron there's much less paperwork, probably the ESS design and installation manual is the one to read.

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#3039415 20-Feb-2023 14:18

neb: With the MPPT controller now separate, is it better to have it closer to the solar cells, so the longer cable run is to the inverter, or closer to the inverter, so the longer cable run is to the cells? Being able to site the MPPT controller in open air (but under a roof) will help with cooling if the best option is to have it close to the cells, so that leaves only the inverter generating heat (battery heat will be minimal from what I've seen with friends' setups, while the GoodWe runs quite hot).

Answering my own question, from lots of reading of various manufacturers' data sheets and whitepapers it looks like the best option is to have a grid-tied inverter close to the solar panels, which means outdoors under a roof with good ventilation, then an AC feed-in into an SMA or Victron. Most of the consumption will be during the day so there's no concerns about dual conversion losses, the biggest source of heat in the system stays outside the house, and presumably shipping power over a longer run down to where the batteries are will be more efficient with AC than DC (there's not much discussion of 240VAC vs. 400-oddVDC runs so that last bit may not be true).

neb

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#3039440 20-Feb-2023 14:56

And for anyone else who may be looking into this, some notes from reading about a thousand pages of whitepapers:

Both SMA and Victron have whitepapers/tech docs on running as an energy storage system (ESS), i.e. UPS mode.

- Grid-tied inverter/AC coupled is better then MPPT/DC-coupled when most of the consumption is during the day as there's direct conversion from PV output to AC. OTOH it's less efficient for charging due to the dual conversion PV -> AC -> DC.

- Can reserve part of the battery for non-discharge use when the grid is up, e.g. only discharge to 80% rather than deep discharge.

- Can schedule charging off grid for certain times, e.g. during power company free-power periods in the evening, so you're drawing 100% of power used from the grid rather than battery.

- Victron has a BatteryLife feature that dynamically varies discharge amounts during periods of poor weather to try and keep the battery close to full charge, i.e. prevents it being run down during poor weather with no reserve then available.

In terms of products and their suitability for an ESS / big-UPS mode:

Fronius: Hybrid, 20s (not ms) switchover time, only BYD batteries, 15kg weight, fan cooling, 42dB.

GoodWe: Hybrid, not stated but fast switchover time, 17kg, passive cooling, needs external fans to avoid running hot.

SMA/Sunny Island: 0/20ms switchover time, 63kg, AC coupled.

Victron: < 20ms switchover time ("no break"), 30kg, AC or DC coupled.

Finally, a note on naming for the SMA gear, their grid-tied inverter is called the Sunny Boy. This is probably from the weird German habit of taking random English words and applying them inappropriately to things, e.g. "Handy" = "mobile phone". In this case the "boy" suffix is used with a noun to mean "thing", so "Phone boy" might be a mobile phone holder, "Shower boy" could be a soap holder or loofah hanger. "Sunny boy" would then mean "solar thing".

HarmLessSolutions

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#3039490 20-Feb-2023 15:55

Some good info coming up in this thread in regards to storage systems.

I've been putting together a few of our own circumstances and am now wondering if or how an EV and bidirectional charger could be used in regard to putting together a surrogate home battery system.

Our situation is that we have an older Leaf which gives us the opportunity to use it for bidirectional charging by virtue of its Chademo connectivity. This also increases the viability of upgrading the Leaf's battery which is gradually reaching the 'must do' stage.

Our current charger is a 7kW Juicepoint unit which is now a redundant and unsupported model and despite it still working fine to charge both of our EVs it has no smart functionality so is due for an upgrade.

We are in the process of increasing our PV capacity from 5kW to 8.5kW with issues to address in doing so with another inverter needed, 5kW phase cap to comply with and the addition of battery storage now looking increasingly tempting.

The solution I've considered is to use the Leaf as the storage for our excess generation, with upgraded battery pack needed in the near future I'm not overly concerned about adding to battery degradation. The investment in upgrading the Leaf and getting a bidirectional charger can be justified in not having to add a home storage battery to our system is my theory.

Essentially is there anybody out there that is already using bidirectional charging and if so how have you married it into your PV and home supply system?

https://www.harmlesssolutions.co.nz/

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#3039512 20-Feb-2023 16:43

Thanks for the summary @neb. One other inverter related capability is its functionality during a power cut if grid tied. I understand that the Fronius is that it will still produce up to 3kw (via solar) when there is a power cut. My understanding that the NZ version of the SMA Sunnyboy is that it doesn’t do this, whereas the US version does.

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#3039516 20-Feb-2023 16:47

shim99: Thanks for the summary @neb. One other inverter related capability is its functionality during a power cut if grid tied. I understand that the Fronius is that it will still produce up to 3kw (via solar) when there is a power cut. My understanding that the NZ version of the SMA Sunnyboy is that it doesn’t do this, whereas the US version does.

The SMA can do this but it functions differently, it uses an external automatic transfer switch to disconnect the house from the grid. It looks like the Victron does the switching internally. The details are probably in one of the 1,000 other SMA documents but in their ESS design docs it's just present as a black box.

eonsim

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#3039531 20-Feb-2023 17:17

neb:

...

In terms of products and their suitability for an ESS / big-UPS mode: Fronius: Hybrid, 20s (not ms) switchover time, only BYD batteries, 15kg weight, fan cooling, 42dB. GoodWe: Hybrid, not stated but fast switchover time, 17kg, passive cooling, needs external fans to avoid running hot. SMA/Sunny Island: 0/20ms switchover time, 63kg, AC coupled. Victron: < 20ms switchover time ("no break"), 30kg, AC or DC coupled.

Also note that most of these inverters can be paired with a Tesla Powerwall or similar AC battery system (Qcells Q.Home battery, sonnenBatterie, Panasonic sunvolt, Energizer Homepower etc), these can add the fast switchover time to any solar system, they're just a bit more expensive than DC battery systems as they have a second inverter to charge and discharge the battery. The upside is they're completely separate from the solar system (while coordinating with it) so if either the battery or solar system has issues the other part continues to function normally.

neb

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#3040208 21-Feb-2023 17:29

So... can anyone recommend an installer or company in Orkland? The sole one listed on NoCowboys is useful in that I'll avoid them at all costs but apart from that there's not much out there outside of Google reviews which aren't useful because they're typically from people who have been nagged into giving positive reviews. There's also some auto-generated recommender sites which don't inspire confidence, but I haven't been able to find anything like NoCowboys for solar installers. In particular I'm after someone who will listen to what I need and provide a good technical solution, not just slap in the cheapest off-the-shelf thing they have and tell me it's what I need.

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#3040282 21-Feb-2023 19:07

Contact Sean at Bay Solar. I know they have done couple of jobs in Auckland in the past so they might still be happy to service that area. I can highly recommend them.

Do whatever you want to do man.

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#3040499 22-Feb-2023 11:07

HarmLessSolutions:

1. Which model is your current EVSE? Is it a solar smart EVSE?

2. You mentioned currently that the shed (where panels and inverter is located) only has a single phase running to it from your home. I take it, two phases in your home are using grid power all the time and the third phase connected to solar pv in shed is your critical loads back home like fridge, lights, internet router etc?

1. Our EV charger is a JuicePoint 7kW unit. No smart capabilities whatsoever.

2. I've just assumed that we have 3 phase as the previous owner here had woodworking machinery downstairs and I have discussed multiple phases with our sparky in the past in regard to allotting circuits to the 2 phases on the fuseboard. I've requested clarification from my sparky (2 or 3?) but he has yet to reply on this.The link from the fuseboard to the sheds which house the EV charger and PV is from the same phase that powers the house water pump, HWC (via Paladin), kitchen bench (espresso machine & grinder, toaster, jug and food processors) fridge and both chest freezers. The total amperage of the circuits is well in excess of the 63A main breaker but as the EV charger and HWC are both mostly fed from PV the import limit is not likely to be breached and hasn't caused any issues to date.

Our routers are on the other phase as they aren't considered essential as a power outage would knock out our local rural wireless broadband so the router would be redundant in such an event.

The addition of extra PV capacity and battery storage would entail a rethink of the apportionment of our circuits in order to gain the priority required to get best use from the battery, I guess.

@HarmLessSolutions

The first thing would be for you to decide whether you want to continue using just the 1 phase where your existing Solar PV is connected in the shed or pay up and pull the other 2 phases to shed so 3 phases available in both home and shed. More phases do mean that you have a bigger export limit, you can have an EVSE connected on each phase and charge multiple EV's at the same time without worrying about maxing out on your 63amps limit on single phase. It also means that you can upgrade your PV in the future to an even bigger system. If you do decide to bring your 3 phase to the shed, you can just use the 2 phases from it and connect a single phase SMA inverters like I did on each phase.

If you decide to stick to single phase in shed then buy another 5kW SMA Sunny Boy and you should be allowed up to 10kW of inverter power on your single-phase connection. Also recommend buying the SMA Home Manager 2.0 and set the 5kW export limit on the Home Manager 2.0 which will automagically control both your 5kW Sunny Boy on same single phase export limit to not exceed 5kW combined total. I can recommend either the SMA 7kW EV Charger which will integrate nicely into Home Manager 2.0 and you can set it to charge your EV's using excess solar or use your grid power if needed etc. The other smart EVSE I can recommend is EVNEX or Tesla Gen 3 charger. Both these chargers can work and charge on 2 phases as well while the SMA is either single phase charging or 3 phase charging depending on the model you pick. For the EVNEX, you will need to pick either their single phase 7.2kW or 3 phase 22kW charger, The 3-phase charger can be connected on 2 phase with EVNEX.

@Newtown had ordered the SMA EV Charger 7.2kW recently and might have now already got it installed so he can hopefully offer his thoughts on the SMA EVSE for his single phase setup.

Do whatever you want to do man.

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