By Dave Miller · off-grid sparky · 22 years wiring solar, batteries and sheds in central QLD
“After losing three months' worth of meat to a battery bank that died at 4.8 volts, I now insist on a minimum of 400Ah for any Aussie off-grid freezer.”
— Dave. Measure twice, buy once.
ArticlesCalculatorsSite PlannerShopLook, if you're off-grid in Australia and want to keep meat frozen without dying of heatstroke, you need a proper solar freezer. Not that flimsy $300 "solar fridge" from the internet. Here's how to do it right.
Look, if you're off-grid in Australia and want to keep meat frozen without dying of heatstroke, you need a proper solar freezer. Not that flimsy $300 "solar fridge" from the internet. Here's how to do it right.
100mm insulation? Pathetic. In Australia, you need 150mm minimum. Seriously. 100mm won't cut it when it's 40°C outside and your freezer's sweating. 150mm is the bare minimum for reliable freezing. If you're in the Top End, go 200mm. Your food (and sanity) will thank you.
Practical tip: Use rigid polyurethane foam (like Kingspan Kooltherm). It's expensive but worth it. Bunnings sells 100mm boards for ~$15/sqm – but you'll need to buy 150mm or 200mm from a specialist. Don't use fibreglass – it's useless in humidity and you'll end up with mouldy food.
That little dial on your freezer? It's a lie. You need a real digital thermometer. Mount it inside the freezer compartment, not on the door. Check it daily. If it's above -18°C, your food's already spoiled. No excuses.
Suppliers: Get a Bosch DS100 probe thermometer from Data Logger Australia ($180). Or grab a cheap $25 probe from Bunnings (but it's not reliable – don't risk it).
One compartment for frozen stuff, one for fridge. Simple. If you don't, your ice cream melts while your steak's still frozen. You'll waste money and food. Build it right from the start.
Practical tip: Use a solid partition wall with 150mm insulation. Add a small door for the freezer compartment only. No flimsy plastic dividers – they fail in heat. If you're building it yourself, use a 100mm PVC pipe for the door seal. Costs $10 at Bunnings.
Don't believe the $800 "solar freezer" scams. Here's what actually works:
Solaris 120L Dual Compartment Freezer – $1,495 (includes 150mm insulation, dual temp control). Best for serious off-grid. Get it from Solaris Australia.
DIY Kit (insulation + frame) – ~$450 (Kingspan 150mm boards, 2m²). Build it yourself. Saves $1k+.
Final word: If you're not using 150mm insulation, dual compartments, and a real thermometer, you're just wasting money. Your freezer won't work in Australian heat. Get it right or get a fridge. No in-between.
While many off-grid projects are achievable as DIY, certain situations require licensed professionals:
Always check local regulations and obtain necessary permits before commencing work.
Worth a watch: Off Grid Solar | How to DIY in Australia | The Off-Grid Shop · The Off-Grid Shop