Hybrid inverter vs. Standard inverter + AC charger

[Ken]

Thanks for that but i am not too quick to ignore inverter efficiency as at 1/2 max output of the inverter you can be down to 85% efficient which X3 ? surely makes a very sinificant No.?

Solar Inverter Efficiency Curve

http://www.solarselections.co.uk/blog/t ... ak-vs-euro

So with a pre Pv inverter batt storage one has a transformer say 400V DC to 50V DC (charger) and then inverter 50V DC to 240V AC all of which is in one box the Hybrid Inverter. Have i got that right ? If so is this not the favoured option all things considered until we talk about DNO and FIT rules.?

The post PV inverter batt is necessary so that the PV goes throught the generation meter.

For a seperate batt system one needs to get permission from the DNO if it is possible to export to the grid from the batt through another inverter than the PV inverter.? Why would one do that unless cheating? How can you cheat if it is a DC side batt that is then going through the limited hybrid inverter.?

Am i nearer getting this right?

[Ken]

[quote=Burble61 post_id=11624 time=1651058625 user_id=120

Having gone through a few of these installs the advice is spot on - hybrid units can be an easier install (especially the "All In One" models also including the battery stack) and can make the DNO approval process slightly less complex.

[/quote]

Why does one need DNO approval if the hybrid inverter is incabable of exporting more than allowed under the PV export. I suppose you are then limited to the output of the PV inverter when powering the house - now i see the/a problem

[Burble61]

Short answer....

if its just a PV system with maximum AC output under the limit (3.68kW / 16 amps per phase) then generally all thats needed is to advise the DNO within 28 days of commissioning. (Theres a few conditions and requirements but nothing outrageous).

If you go down the route where PV inverter and battery system (with its inverter) are separate, then the what counts is the maximum output of each combined and if that exceeds 16A per phase, DNO prior approval to connect is required. There is a simplified fast track process for smaller installations (PV inverter output <=16A plus Battery inverter output <= 16A, with export limiting).

For a hybrid inverter route, as its including energy storage, it should be that same fast-track prior approval route. If the maximum output of the hybrid is no more than 16A that wouldn't require export limiting

Having said that, depending on your location, the DNO may be quite happy allowing higher (you will need to pre-apply to find out). When we first installed a Powerwall, the DNO was happy with the output of the existing PV (2.8kW), plus two 5kW output Powerwalls. All depends on location.

As @marshman said, some DNO folk can very extremely helpful!

With regard to your other question, yes if you want a straightforward system, with as few boxes as possible and no more complex requirements - yes the hybrid approach is the most straightforward as along as you are happy with the slightly compromises.

I'm with @Nowty on the efficiency front, in practice theres a limited amount that can be done about it.

Hope that answers the questions!

[richbee]

Thanks to all for the replies and knowledge - that does explain the situation quite well (I think).
Sounds like I need to work out the loads I'm expecting to run during the day, and is it enough to have maximum 3.68kW at any 1 time - in which case the hybrid solution would be fine.
If not, the separate AC charger would allow up to double if you had 3.68kW from the PV and 3.68kW from the battery(ies).
My guess is that the hybrid solution would be fine for us at the moment, I'm only planning to install a single battery for now - no EV yet.
And as this is the first PV install, FIT is not a consideration.

[richbee]

So, I have my new inverter & batteries (not fitted yet, due to various problems).

I have 1 question, again for the hybrid inverter - Growatt SPH3600.
Looking at the data sheet, it says max solar array size of 6.6kW, but max battery charge / discharge rate of 3kW.
Does this mean that anything greater than 3kW solar output has to be used by the house instantly, or it will be exported to the grid?
My array is 5.6kW across east/west roof sides.

[Fintray]

Just had a quick look at the spec. of the inverter and it says 3680W so it will only output that amount regardless of how much PV is available, any excess above what is being used to charge the battery will be used by the house first and anything above that will be exported.

[richbee]

Just had a quick look at the spec. of the inverter and it says 3680W so it will only output that amount regardless of how much PV is available, any excess above what is being used to charge the battery will be used by the house first and anything above that will be exported.

Thanks for confirming.
I guess it won't be too much of a problem most of the time, especially with East/West panels

[nowty]

That's why I don't like the hybrid ones, especially when you need to charge the EV, cook the dinner and avoid the peak rate import.

[ClockmanFRA]

For most folk who need proper power and want a simple system.

Then a stand alone Inverter.

Good ones say at 6Kw all day and half an hour at 15KW and 50KW surges, and just ticking over/ in idle use, about 35w.

Now days i suggest to normal folk, (you need to know what you are doing with my stuff), to get 2 off 5KVA Victron Phoenix. One becomes master and the over a slave, can also get 3 then you have 3 phase. Like my inverters the Phoenix can also handle AC coupling and run backwatds through the toroids and charge your batteries. They can be tweeked.

I also recomend the USA MIDNITE classic 200, as a very good battery moderator/charger etc. And it can handle 200 volts at 78amps input for 48 battery charging. Had them years and years since they came out, never had issues, nice bit of gear.

I am all for simple understanable no messing with systems.

[openspaceman]

Your first point is correct but its not a huge difference. And in summer you generally have so much excess power from Solar it makes even less difference apart from maybe less export but if your on a low export limit like me then makes no difference. And in winter if your charging the batts from the grid, it makes no difference at all.

We're on the verge of accepting a quote which specifies a 5kW hybrid inverter, the battery will be pylontech.

One of the reasons for getting solar is to divert excess to my daughter's EV, currently she is on a standard tariff (bumped to OVO who do not have an offpeak rate on offer).

If she gets an offpeak tariff will it be possible to charge the pylontech battery at the offpeak rate with a charger separate from the hybrid inverter?

Current installation lead time means installation will be late October.