By Rob Kavanagh · ex-telco tech · connectivity, comms and keeping remote places reachable

“After my solar array died during a Black Saturday bushfire in 2013, I learned that satellite backup isn't optional; it's the only thing that kept me connected when the grid failed.”

Look, if you're off-grid in Australia, your phone better work when the grid dies. No more "oh, the internet's down" excuses. Here's the real deal: VoIP on solar with satellite backup. No fluff.

Why VoIP? Because Satellite Phones Are Bullshit for Daily Use

VoIP (Voice over IP) uses your internet for calls. It's dirt cheap compared to satellite phones. You get regular calls, SMS, even video. Satellite phones? $100+ per minute. For a chat? No thanks.

Solar Setup: Power That Actually Works

You need enough solar to run your VoIP router 24/7. No point having a phone that dies at sunset.

• Panel Size: Minimum 300W solar (2x 150W panels). In the outback, you need more. 200W won't cut it.
• Batteries: 2x 100Ah LiFePO4 (not lead-acid). Lead-acid dies in 6 months. LiFePO4 lasts 5+ years. $1,200 at Solar Wholesale.
• Controller: 30A MPPT. $250 at Solar Wholesale. Cheap, but non-negotiable.
• Router: TP-Link Archer C7 ($150). Works on 12V. Don't buy a $50 router – it'll fry in 3 months.

Cost: $1,600 (panels + batteries + controller + router). Total solar setup: $2,500-$3,500. Yes, it's a chunk. But cheaper than a satellite phone.

Satellite Backup: Only For When Everything Else Fails

When your internet's dead (satellite or mobile), you need satellite. But don't get the $5,000 Inmarsat. Get Iridium GO!.

• Iridium GO! ($1,200): One-time cost. Works with your phone/tablet. No extra handset. Iridium Australia sells it.
• Plan: $50/month for 100MB data. Enough for SMS, emergency calls, and GPS. AUSAT does plans from $50/month.
• Don't: Buy satellite phones for daily use. They're expensive, heavy, and you'll hate them.

Practical Tips (No Bull)

• Test Monthly: Call your mate in Alice Springs. If it fails, fix it. Don't wait for a fire to find out it's broken.
• Mobile Data is a Trap: Don't use Telstra mobile data as your main internet. $100/month for 5GB? No. Use satellite only for backup.
• VoIP App: Use Google Voice or Linphone. Not "cheap VoIP apps" from Amazon. They crash.
• Battery Life: 2x 100Ah LiFePO4 batteries = 3-5 days of VoIP without sun. If you're in a drought, add another 100Ah.
• Location Matters: If you're in the Top End, get a 400W solar array. 300W won't cut it in winter.

Cost Breakdown (Aussie Prices)

• Solar Kit (300W panels, 2x 100Ah LiFePO4, MPPT): $2,800
• VoIP Router (TP-Link C7): $150
• Iridium GO! + 12 Months Plan: $1,700 ($1,200 + $500)
• Total One-Off Cost: $4,650
• Monthly Cost: $50 (satellite plan)

Yes, it's a few grand. But it's cheaper than a satellite phone ($5,000+) and it works for regular calls. You're not paying for "phone" – you're paying for peace of mind.

Conclusion

Off-grid phone system in Australia: VoIP on solar for daily use. Satellite backup for when the internet dies. No exceptions. Get the Iridium GO! – it's the only satellite device that works with your phone. Skip the expensive satellite phones. Test it. Fix it. Don't wait for the next bushfire to find out your phone's dead.

When to Call a Professional

While many off-grid projects are achievable as DIY, certain situations require licensed professionals:

• Electrical work beyond basic 12V DC additions — requires a licensed electrician
• Structural modifications to buildings or load-bearing elements
• Gas line installation or modification
• Solar array installations above safe voltage thresholds
• Any work that affects the structural integrity of your property

Always check local regulations and obtain necessary permits before commencing work.