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Sigenergy has released an optional accessory for SigenStack, and for most Perth installations we would not buy it.
The product is the SigenStack PACK Thermal Insulation Board. It snaps around an individual battery pack, four boards to a pack, covering all four sides. Sigenergy states that it reduces heat loss, cuts the power the pack's heating pads draw, and improves overall system efficiency. It arrives on 15 September 2026, supplied as a set of four pack kits, 16 boards, covering up to four packs.
The reason to care about heating pad consumption at all is that it is not free. A SigenStack pack keeps its cells inside their operating temperature window in cold weather, and the energy to do that comes out of the battery. On a system where every stored kilowatt-hour is already committed to the evening peak, that draw is a real loss rather than a rounding error.
Sigenergy's latitude guidance
The application guidance in the release notice is drawn in three latitude bands.
| Latitude | Guidance | Examples Sigenergy gives |
|---|---|---|
| Above 43 degrees | Strongly recommended | Nordics, United Kingdom, Germany, Poland |
| 23 to 43 degrees | Optional, based on regional conditions | Southern Europe, Japan, southern Australia |
| Below 23 degrees | Not required | Not specified |
Southern Australia sits in the middle band. Read that carefully, because it is the whole decision: the manufacturer does not recommend this accessory anywhere in Australia. It permits it and hands the call back to the site.
That matters more than it looks, because the top band is where the product was designed to earn its keep. A battery pack outside a house in Poland in January is in a different world from a battery pack in a garage in Bibra Lake in July.
Western Australia straddles two of the three bands
Perth sits at about 32 degrees south. So do Albany, Esperance and Kalgoorlie, which puts all of them in the optional band. Broome, Port Hedland and Karratha sit below 23 degrees, in the band Sigenergy says does not require the accessory at all.
There is no single Western Australian answer here, and a business specifying across the state should stop looking for one. The right call at Karratha is not the right call at Katanning.
Site conditions in the optional band
The wording of the middle band puts the weight on regional conditions. That is the more useful test, because latitude is a weak proxy for how cold a battery enclosure gets overnight in this state.
Frost is a recorded feature of the Wheatbelt, studied for what it does to wheat yield. It is not a feature of coastal Perth, where the Bureau of Meteorology puts the long-term July mean daily minimum at 8.1 degrees. A garage in Willetton and an unheated shed outside Wagin are not the same thermal environment, and the shed is the one where the heating pads work for a living.
So the profile where this accessory is worth pricing is narrow and specific:
- The pack is inland, in the Wheatbelt, the Great Southern or the Goldfields, rather than on the coastal plain.
- The installation position is exposed or unheated. An external wall on the southern side of a shed, not a sheltered garage.
- The stored energy is fully committed, so a few per cent lost to heating is a few per cent the household or the business notices.
Miss any one of those and the case thins out fast. A pack in a Perth garage, on a system with headroom, has close to no case at all.
Assessing value in Perth
We sell Sigenergy and we are a Sigenergy Gold Installer, so this is an accessory we could put on a quote without anyone blinking. On a metropolitan Perth system we would leave it off.
The reason is not that the product is poor. It is that the gain it is designed to deliver scales with how hard the heating pads are working, and in Perth they are barely working. Buying insulation for a problem the climate is not creating is money that would do more sitting in a larger pack, or in nothing at all.
If you are inland and exposed, the conversation is different and worth having properly.
Fitting insulation after installation
This is the part that separates the accessory from the other SigenStack change in the field this month. The battery controller product code transition, which takes effect on 30 September 2026, is decided when the controller is ordered, and a controller without the -BST suffix cannot later be connected to the new combiner box. We wrote that one up separately because the cost of getting it wrong is locked in months ahead.
The insulation board carries none of that. It snaps around a pack that already exists. A system installed before 15 September 2026 loses nothing, and a marginal site can be assessed after a winter of real data rather than on a guess made in August.
If your SigenStack sits somewhere cold and you want the numbers looked at properly rather than assumed, get in touch on (08) 6171 4111 or get a quote.