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Holt Systems

Grain bin temperature monitoring: catch a hot silo before the mill

We hang temperature cables in the silos beside your mill and text the mill manager and nutritionist when a pocket starts to heat.

  • MeasuresGrain temperature in each silo
  • AlertSMS to mill manager and nutritionist
  • Reads every15 to 60 minutes

Silo 2, cable 2, sensor 3

Dashboard view

Sensor 3
30 °C
Neighbour sensors
23 °C
Headspace
32 °C
22 26 30 Alert at 25 °C SatSun pmMon pmTue pmWed pm °C
Example readings for illustration.

18 to 23 °C

GRDC's summer target for stored grain. Under 15 °C in winter.

Source: GRDC, 2024

600 to 2,000 t

GRDC reports flat-bottom silos this size are now common, and hard to check by hand.

Source: GRDC (Qld DAF authors), 2021

Warm grain gets to the flaker before anyone knows

On a feedlot, grain is your biggest cost, and it sits in silos beside the mill for weeks. Without grain bin temperature monitoring, a heating pocket can go through the mill and into the ration.

Nobody's selling this grain, so there's no rejected load to warn you. The loss shows up as feed value: less energy in the ration and cattle that don't eat it as well.

  • Mould is reported to cut starch, fat and digestible energy, and often hurts palatability (Qld DPI feedlot grain paper).
  • Grain goes in hot after harvest.

What one warm pocket can cost a feedlot

  • Three silos holding 1,500 t of grain in total.
  • Grain valued at $400/t, so $600,000 in the silos.
  • A pocket of about 100 t loses $60/t of feed value if found at the next monthly probe.
Grain at risk in the pocket100 t
Lost feed value at $60/t$6,000
Share of the 1,500 t heldunder 7%

One caught pocket can cover a fair share of the cables on one silo. These numbers are illustrative only.

What we put on your silos

We set the cable count per silo at the site visit, with the silo maker or an engineer.

  • Multi-point temperature cables

    Hang from the roof and give a temperature profile right through the grain.

    A sensor every 1 to 3 m

  • Headspace and ambient sensors

    Read the air under the roof and one shaded spot on site, so you know when to aerate.

    Sealed, outside the grain

  • LoRaWAN roof node

    Sits outside the steel shell and sends each silo's readings by radio.

    Reads every 15 to 60 min

  • Fan current sensor

    Shows when each aeration fan ran, wired in under our electrical contractor licence 1513082.

    Fan run time logged

  • Gateway with Starlink or 4G

    Collects readings from the silo group and sends them to your phone.

    Mains power, battery backup

How grain bin temperature monitoring works at your mill

Grain bin temperature monitoring at a feedlot feed mill Three grain silos stand beside a feed mill and a flaker. Each silo has a roof-hung cable with three temperature sensors and a LoRaWAN node on the roof. Silo 2 shows a warm pocket reading 31 degrees Celsius against about 22 elsewhere. A cost bar shows 1,500 tonnes held, worth 600,000 dollars in the example, with a 100 tonne pocket and 6,000 dollars at risk. The alert path runs from the site gateway over 4G or Starlink to an SMS, which reaches the feed-mill manager and the nutritionist. Three silos, readings in °C Roof node (LoRaWAN) 212221 223123 222122 Silo 1 Silo 2 Silo 3 500 t 500 t 500 t Feed mill Flaker Cost at risk (example) Silo 2 pocket: 100 t, $6,000 at risk Held: 1,500 t, $600,000 of grain Alert path Gateway 4G or Starlink SMS alert Feed-mill manager Nutritionist
Three silos beside a feed mill and flaker. Each has a roof-hung cable with three sensors and a LoRaWAN node on the roof. Silo 2 shows a warm pocket at 31 °C against about 22 °C elsewhere, and the alert runs via the gateway to the mill manager and nutritionist.
  1. 1

    Cables hang from the roof

    Each silo gets several cables with a sensor every 1 to 3 m of grain height.

  2. 2

    A roof node sends the readings

    The node sits outside the steel shell and sends by radio every 15 to 60 minutes.

  3. 3

    A gateway passes them on

    It has line of sight across the silo group and reaches us by Starlink or 4G.

  4. 4

    The mill manager and nutritionist get the text

    It checks each sensor against its neighbours and trend, then sends an SMS.

What lands on your phone when a silo heats

We start with set alert values, then tune them to each silo and grain.

Mill silo alerts
  1. Mon 5:40 am

    Silo 2 cable 2 sensor 3 at 27 °C, 3.5 °C above its neighbours for 12 h. Probe that depth. Check the aeration.

  2. Tue 5:40 am

    Silo 2 cable 2 sensor 3 at 30 °C, up 3 °C in 24 h. Urgent: draw from another silo and run the fan.

  3. Thu 6:10 am

    Silo 2 cable 2 sensor 3 back to 23 °C after 26 h of fan run. Profile is even.

Messages go to the people you nominate, by SMS to any phone.

Messages go to the people you nominate, by SMS to any phone and by email, with the reading and the time in every alert.

A monthly probe versus a reading every hour

TopicTodayWith monitoring
How oftenAbout once a monthEvery 15 to 60 minutes
A pocket warmsFound at the next probe, if at allAn SMS within days
Aeration workingFan ran, result unknownThe profile shows if grain cooled

What grain bin temperature monitoring costs

We set a fixed price after a short scoping call or site visit. It depends on silo and cable numbers, distance to the gateway and backhaul. Ongoing support is available as a plan after handover.

Price grain bin monitoring

The fixed price covers

  • Cables, nodes and sensors for each silo
  • Gateway and Starlink or 4G backhaul
  • Installation and electrical work under licence 1513082
  • Alert set-up, commissioning and training
  • Ongoing support plan: we keep it running, fix faults and tune alerts

Grain bin temperature monitoring beside a working mill

We hang cables when a silo is empty or low, working from the roof. Nobody goes into the grain.

Your silo maker or engineer approves the suspension points. A contractor you engage does any roof or structural work. We do the electrical work under licence 1513082.

Check grain on hand with feedlot silo level monitoring. Hay sheds beside the mill suit feedlot hay temperature monitoring. Fans next? See grain aeration fan monitoring.

Row of steel grain silos with a grain auger at a country site
Illustrative photo. Photo: Pexels

What this won't do

  • A cable only reads near itself, so a pocket a metre away can be missed.
  • It doesn't measure moisture. You still need a meter or a sample.
  • It's not fire detection or a certified safety system. It doesn't replace silo entry, confined space or fumigation procedures.
  • Readings come every few minutes at best. You get alerts and trends, and it doesn't run your fans.

With you every step

The mill never stops, so we plan the work around a silo that's empty or low.

  1. 1

    Discovery

    We walk the silos, mill and flaker, check roof access with the silo maker and agree which silos matter most.

  2. 2

    Design

    You get a fixed-price proposal with cable counts, node and gateway positions, alert rules and who gets the texts.

  3. 3

    Build and test

    We build and test the nodes, enclosures and gateway in the workshop, and set the alert rules before delivery.

  4. 4

    Install and commission

    We hang the cables, mount the nodes and gateway, do the electrical work, and check each sensor against a hand probe.

  5. 5

    Ongoing support

    We train the mill manager and nutritionist, then support the system and tune alerts.

Why Holt Systems

We design, install and commission every system ourselves, then look after it with an ongoing support plan. Monitoring supplements the site's own control, protection, fire and safety systems; it does not replace them.

Alerts
SMS to any phone, no app
Based in
Brisbane, QLD
Electrical licence
QLD 1513082
After install
Ongoing support plans
Call
07 2150 3666

Feedlot grain silo monitoring questions

How many temperature cables does a feedlot silo need?

It depends on silo diameter and height. A cable reads only near itself, so bigger silos need several, spread across the silo. We set the count at the site visit with the silo maker.

Can it tell me the moisture of the grain?

No. Temperature shows something is heating, not why. Moisture needs a meter or a sample. The alert tells you which silo and which depth to probe, so you test the right spot first.

Will the cables survive filling and unloading?

Cables take real load as a silo fills, settles and empties, and a restrained cable can stretch or break. The silo's engineer checks the suspension points and roof loading. We plan for cable replacement as a running cost.

Does it work if the feedlot has weak mobile coverage?

Yes. The nodes talk to a gateway on site by LoRaWAN, and the gateway reaches us by Starlink or 4G. A steel silo weakens the signal, so nodes sit on the roof and the gateway needs line of sight across the group.

Can it run the aeration fans?

No. Readings suit alerts and trends, not control. We can monitor fan state and current, but fan control stays with your existing controller or a separate approved control system.

Price grain bin monitoring

Tell us what you need to watch and where. We confirm the sensors, gateway location and alert recipients, then give you a fixed price.

Or email hello@holtsystems.com.au

Your details are handled in accordance with our privacy policy.

  1. 1

    Tell us about the site

    A few lines on the assets, distances and what you need to know about.

  2. 2

    A call to scope it

    We confirm the sensors, gateway location and alert recipients, and whether a site visit is needed.

  3. 3

    Fixed price

    You receive a defined scope and a fixed price before any work starts.