Congratulations Mike, a very tidy looking installation. Just a little bit neater than my good old forklift battery and still uncovered Warpverter and MPPT's.

Did they add more panels too or just hook up what you already had? How many kW?

Thanks Roger, we had 13.5kW of panels on the roof which used to feed a 10KW 3 phase Fronius. They were going to AC couple the existing Fronius, meaning even if we were able to generate 13.5kW it would have only charged the batteries at 10kW.
It made more sense to DC couple the panels to the inverter and just remove the Fronius.

I looked on Marketplace and there are at least 6+ 10kW Fronius inverters starting from $100, most refer to a recent battery upgrade. I don't think I will even bother advertising mine, might do a teardown to see what goodies are inside - might be a good source of ringcores suitable for stripping and rewinding as inverter chokes.

Considering they were worth ~ $3K just a few years ago I sense there will be an avalanche of inverters about to flood the "used" market thanks to the recent battery subsidy.

Hi,
We have a saying: "a shoesmaker without shoes" – this is in the context of your energy storage system, Mike  

My first thought was: what's so crazy about installing an LFP outdoors? But I looked at the winters in your latitude and realized there's no need to worry. In my location, winter temperatures often drop well below 0°C and stay there for many days.

Do you know what type of cell your battery storage uses? Cylindrical cells, such as the EVE C40, are common in these products.

BTW. I haven't been here in a while; my thread should be dusted off and updated  

Hi Dex, good to hear from you again. How's that inverter running - the warranty period has expired now  
Today was a warm day in South Australia it reached ~37 Deg Celsius in the afternoon - I won't need to worry about cold batteries for a while yet.

The batteries are Lithium Iron Phosphate types, I read somewhere there are supposedly 9 battery cells each 280AH.  I think they may well be EVE LF280Ks ?

However, the pamphlet eludes to "low voltage" but also lists the voltage range in the battery specs as 600 - 900V which is at odds with low voltage. The max power you can draw is 0.5C or 4kW for the 8kWh module.

Sig Battery Info Sheet:
Sig Battery Info.pdf

Another information document:

Advanced battery technology

SigenStor uses LFP (lithium-iron-phosphate) cells with a capacity of 280 Ah, offering several advantages over conventional battery solutions:

Higher reliability and safety: The 280 Ah cells have a lower voltage of 32.85 volts, significantly reducing safety risks compared to conventional solutions that use 100 Ah or smaller cells, which can raise the battery voltage above 91 volts.
Extended lifespan: The 280 Ah cells also have a longer lifespan, so the energy storage system remains reliable for many years.

So I can draw the following conclusion I think;

Perhaps the Battery voltage is 33V nominal but there is a boost converter in each battery module that provides the high voltage rail used by the top inverter.
Otherwise for its full rated 24kW output the 33V batteries each provide a total of ~ 750A at the rated output which divided between six modules means each battery is providing ~ 125A and I'm confident there are not 750A busbars passing the energy up to the top inverter. Second observation the inverter is too light to be a LV toroidal type, so I conclude it must use HF HV SPWM switching.
Edited 2025-12-18 22:54 by wiseguy

Interesting to see Sigen.  What's the warranty?  They are still rare in the US with unproven support track record.

Don't know if you have an EV but Sigen offers a V2X module that looks interesting.

  analog8484 said  

Interesting to see Sigen.  What's the warranty?  They are still rare in the US with unproven support track record.

Don't know if you have an EV but Sigen offers a V2X module that looks interesting.

No we don't own an electric vehicle yet but in a few years it is on the cards. Yes I was aware of Sig's EV support and modules.

I am posting the SIG PDF documents here that I have to hand as they will answer most queries.  I am not on a finders fee or receiving commissions etc for Sig referrals......

After doing some research online, mainly from the UK, many of the premium installers there swear by SIG products and after seeing their installs and their efficiency & perceived reliability, I decided to bite the bullet. Initially I was only going to install 16kWh of storage but when the Government started the home battery subsidy scheme the cost of each 8kWh module was only around $1K9 extra so I decided to up the reserve to 48kWh and upgrade the inverter to 24kW 3 phase so on the nights where it doesn't get below 28+ degrees, then we can run the ducted air all night.

The other advantage is that in winter where we typically only use ~ 6kWH per day we could have a week of essentially no sun and no Mains power and still be self reliant.

Last night we did just that and this morning we still had 49% battery capacity remaining & no power consumption from the grid despite running the Air most of yesterday and the batteries started at sunrise yesterday with 0% charge remaining however we only returned ~ 3.5kWh to the grid around 4.00pm yesterday instead of ~ the usual 50-60kWh for a typical day at this time of year).

Now we are starting at ~%50 storage capacity so I estimate we will export ~ 30+kWh today. That will help pay for the "supply" connection which even with no power drawn is $2.19 per day, whilst receiving a whole 0.09c per kWh returned but being charged 68.92c per kWh consumed at the peak rates (where we usually had to consume energy outside of solar generation). Thanks Engie (our provider) what a great deal.....

Sig Warranty:
Warranty-Document-Sigenergy.pdf

Sig Spec sheet:
Spec-Sheet-Sigenergy.pdf

It does not state implicitly the battery warranty but it implies 10 years which is what sales said (yeah I know) - I will ask for further clarification.
Edited 2025-12-19 08:38 by wiseguy

Thanks for the info.

Only 6kWH per day used in the winter ... you must have a pretty efficient home with gas heating?

  analog8484 said  

Thanks for the info.

Only 6kWH per day used in the winter ... you must have a pretty efficient home with gas heating?

Ok to clarify the winter 6kWh is essentially the minimum budget power we could get by on if the grid goes down to keep fridges & lights & maybe a PC or TV running and little else.

Yes you are correct we have Gas heating & Gas instant hot water. All lighting throughout the house is via LED downlights. We upgraded from the calculated energy coefficient for insulation and went a couple of grades higher for roof and walls and added sisalation (sarking? dont know if thats what you call it - reflective film under the tiled roof) It all helped make us pretty energy efficient.

Now I have excess electrical energy, our next upgrade will probably be a roof solar water pre-heater feeding into a heat pump hot water system.
Edited 2025-12-20 11:19 by wiseguy

The Sig storage/inverter system has been in & operating, essentially beginning on 18/12/25.  I think its only fair to inform now about the negatives of a Sigenergy system and some of its internal workings and secrets. I was checking on our overnight consumption and was alarmed at how high it appeared.

First a bold statement. Overnight my 48kWh system appears to self-consume over 4kWh of standby power or close to 400W continuously, nearly 10% of overall capacity.This has nothing to do with phantom static loads of the house it is just what it requires to exist. So in a typical 24 hour cycle it consumes, I estimate over 8kWH of our solar bank consumption.

The Sig graphs gave the dirty secret away if you look carefully enough you see it. Overnight there is ~ 650W minimum consumption disguised as house standing load but curiously at ~ 7AM the house minimum standing power remarkably drops to ~ 200W then in the evening around 7pm it increases again back to ~650W.  The 7/7 time points align with the beginning of solar start and solar stop for this time of year. I could not understand why the 650W dropped by around 400+ watts before the solar appeared to start in the morning, then I started to realise what was going on & the reverse at dusk. Why was the standing 650W dropping to 200W before the solar appeared to begin?  

The energy consumption is hidden in the daytime as the standing inverter self consumption appears to be robbed from the solar energy created before it actually reports on what is the resultant solar generation (ie what is left after we remove ~ 400W from the actual solar generation).

So a check with Mr Google and the first hit revealed some interesting information.

"There was a post in the Sigen app community about a week ago commenting on this. One user suggested 60W for the inverter plus 35W for each 8kWh battery module."

I knew there would be some inverter standing loss and 60W sounds slightly plausible albeit on the very light side for a 25kW inverter, the real shocker (pardon the pun) was for the 6 x 8kWH battery stack to be using over 200W continuously over-night. Some other Sig information on the Web mentions BMS and Battery monitoring and balancing power consumption as the cause.  Do we need a balancer overnight when not charging & surely monitoring and BMS should draw less than 5W.

I believe what is going on is that the 32V to 600V converters running continuously in each module is chewing up the extra 30+ watts per battery module.  This tells us that the overall trip from batteryV to mainsV ie inverter idle current is really around 400W. I am unsure if the 35W per module was calculated/derived/assumed from the total energy on the HV "bus" to the inverter, divided by the number of battery modules or if the standing current per battery module also increases proportionally for fewer battery modules ?

Sorry for the longish post but if considering a Sig system, be armed with some hidden detail of what is going on internally. Nearly 10% of your battery capacity is not available as it is eaten when the sun isn't shining, and when the sun is shining it takes ~ 4kWH of consumption before you ever see it.

Here is a picture of the Sig information graph. The green is battery energy being used, the lower purple is shown as energy for the house. Look at 6am and you will notice a decline of battery energy supplied to zero at about 7:30 as the solar is now reported to have started generation.
The decline in battery energy is caused by the true beginning of solar energy from the panels from ~ 6:am.  The 300W house consumption shown was a snapshot of the graph during a house minimum load during solar generation.

Sig information graph



Zoomed in: The house load (violet) & battery energy required (green) magically drops from 650W to ~ 200W before solar supposedly "started"!

Battery was fully charged before 11am.
Edited 2025-12-21 10:29 by wiseguy

Within 3 days bedlam on Facebook Marketplace, today there are 71 Fronius inverters available in Adelaide from $75 to $2,600 !  The total number of inverters at a quick count is 191!  All the high priced ones will get a good reality check very soon, I reckon if they get ~ $50 scrap value for one they should be thankful. Just a few years ago a Fronius price was in the thousands. Is this happening in other states?  There should be plenty of ring cores for inverter chokes to be had very cheaply in the near future.