Hay heats up quietly while everyone's away
A hay bale temperature probe tells you the one thing a walk past can't: how hot the core of the stack is, and whether it's climbing.
Hay baled too damp breeds microbes that make heat. Past about 55 °C in the core, the NSW Government says it can start giving off flammable gases and catch alight with no spark.
At Nobby on the Darling Downs, both fires fell over Christmas and New Year, when the owners were away. The local fire captain called spontaneous combustion a common cause in the warmer months.
- Risk is highest in the weeks after baling, up to about eight weeks.
The same week, with and without a text
Without monitoring
- Day 1The stack starts heating. Nobody's at the shed.
- Day 3Core passes 55 °C. Nothing shows from outside.
- Day 5Hay runs away between visits. Smoke, or flames.
- Day 6You hear about it. The shed is gone.
With monitoring
- Day 1Probe reads the core every 15 minutes.
- Day 3Core hits 50 °C for an hour. Text to the manager.
- Day 3Core reaches 55 °C. Owner and neighbour get a text.
- Day 4You've checked the moisture and sorted the hot lot.
How a hay bale temperature probe reports from the stack
- 1
Probes go in the core
A stainless probe sits in a middle bale of the older stack, and a second in the freshest or wettest lot.
- 2
A node outside the stack
Cables run out of the shed to a LoRaWAN (long range wide area network) node, clear of machinery. It sends a reading every 10 to 15 minutes.
- 3
Radio to the homestead
The gateway on the homestead roof picks up the radio. Starlink or 4G carries it out to the dashboard.
- 4
A text lands on your phone
The alert goes to the people you name, and goes quiet again when the core cools.
What we put in the shed and on the homestead
-
Stainless bale probe
Sits in the core of a bale in the middle of the stack, and one in the freshest lot.
Reads every 10 to 15 min
-
LoRaWAN node
Sits outside the stack, with the cable run protected from machinery.
Cable laid in at stacking
-
Shed air sensor
Gives the air temperature under the roof, so a hot core stands out.
Reads every 15 min
-
Homestead gateway
Picks up the radio from the shed on the roof of the homestead or shed.
Tested before stacking
-
Starlink backhaul
Carries every reading out to the dashboard and your phone.
4G where signal is good
What lands on your phone when the stack heats
Hay shed probe 2, core temperature
Dashboard view
- Probe 1, older stack
- 36 °C
- Probe 2, fresh lot
- 55 °C
- Shed air
- 31 °C
Today versus with a hay bale temperature probe
| Topic | Today | With monitoring |
|---|---|---|
| Checking the core | Crowbar left in for 2 hours, then judged by hand | A reading every 10 to 15 minutes, with a trend |
| Over the holidays | Nobody there between visits | A text to you and a neighbour, wherever you are |
| Hot spot found | Smoke or steam, often too late | A text while heating is still manageable |
On a station hay shed
Stations hold hay for drought and weaning feed, often far from town. We walk the shed and stack layout with you, pick the probe lots and test the radio path to the homestead.
Steel sheds and dense bales weaken radio, so we test the path before stacking. Our electricians do the gateway power under QLD Electrical Contractor Licence 1513082.
Got silos too? See grain silo temperature monitoring. Running a feed mill? There's feedlot hay temperature monitoring for the shed beside it.
Baling for sale? See hay shed temperature probes for cropping farms. Out at the bores, add power outage alerts.
What it costs
We set a fixed price after a short scoping call or a site visit. It depends on how many probes, how far the shed is from the gateway, and how the readings get out. Ongoing support is available as a plan after handover.
Get a quote for hay shed alertsThe fixed price covers
- Probes, node and air sensor
- Gateway and Starlink or 4G backhaul
- Installation and electrical work under QLD Electrical Contractor Licence 1513082
- Alert set-up, who gets each text and in what order
- Testing the uplink and text before the hay is committed, and training
- Ongoing support plan: keeping it running, fixing faults, replacing batteries and probes, tuning alerts
What this probe won't do
- It's not a fire detection or suppression system, and it meets no certified alarm standard. It doesn't replace calling 000.
- A probe reads one point, so a hot spot somewhere else in a big stack can be missed.
- Readings are indicative, not a calibrated compliance instrument, and they don't show moisture or oxygen.