The first thing many buyers ask is: "I already have a delivery vehicle — can I just add a cold box on top?"
The answer is — yes, but not just any cold box. Refrigerated boxes differ from standard cargo boxes: they must match your vehicle's available space, power system, and payload capacity. A mismatch in any of these three dimensions leads to boxes that won't fit, won't work, or create safety hazards.
This guide covers size matching, power systems, payload calculation, mounting & sealing, and installation process — everything you need to know before adding a cold box to your existing vehicle.
1. Size Matching — The Box Must Actually Fit
Size matching is the most basic yet most overlooked step. Many buyers only look at the box's "external dimensions" without considering the vehicle's actual usable space.
3 Key Measurements
Interior Dimensions (L × W × H)
Measure the minimum usable space inside the truck bed or cargo area. Account for wheel arches, side panels, and mounting brackets.
External Box Size vs. Usable Cargo Space
The box must be smaller than the vehicle interior (leave 3-5cm clearance per side). Usable cargo space is typically 8-12cm less than external dimensions (insulation wall thickness).
Door Opening Size
Confirm cargo can pass through the door opening. Recommended minimum: 600mm wide × 700mm tall.
Typical Fit Solutions by Vehicle Type
| Vehicle | Cargo Space | Recommended Box | Key Notes |
|---|---|---|---|
| Electric Tricycle | Rear frame ~1.5-1.8m | Flandcold 1.5m / 1.8m complete unit | Factory-matched, no modification needed |
| Pickup Truck | Bed ~1.8-2.4m | 1.8m or 2.0m standalone cold box | Check box height vs. bed walls |
| Van / Minivan | Cargo area ~1.2-1.6m | 1.0-1.2m compact cold box | May need rear seat removal; check door height |
| Box Truck | Cargo ~2.0-4.0m | 2.0m+ large cold box | Ample space; can fit multiple units |
| Cargo Motorcycle | Rear rack ~0.8-1.2m | 0.8-1.0m mini cold box | Note payload limits; small unit only |
2. Power Systems — 12V / 24V / 60V / 220V: Which One?
The refrigeration unit needs continuous power to maintain temperature. Different vehicle types have different power conditions — choosing the right power solution is essential.
4 Common Power Supply Options
| Power Option | Best For | How It Works | Pros | Cons |
|---|---|---|---|---|
| Direct Battery (60V DC) | Flandcold e-tricycles | Unit draws directly from vehicle battery | Zero conversion loss, highest efficiency | Limited to matched EV models |
| Battery + Inverter | Fuel vehicles (12V/24V) | Vehicle battery stepped up via inverter | Universal fit for most vehicles | 10-15% conversion loss; battery drain |
| Independent Battery Pack | All vehicle types | Separate Li-ion battery dedicated to unit | Doesn't affect vehicle battery; controllable range | Extra cost & weight; charging management needed |
| Diesel Generator | Medium-large trucks | Onboard diesel genset powers unit | Unlimited range; high power output | Noisy, emissions, high cost |
For most small-to-medium delivery scenarios, independent battery pack + inverter is the most universal solution. For electric tricycles (like Flandcold's), 60V DC inverter unit with direct battery supply is the most efficient — no conversion equipment needed, power utilization near 100%.
3. Payload Calculation — Overloading Is the Biggest Safety Risk
Refrigerated boxes are significantly heavier than standard cargo boxes. Many buyers only consider "how much cargo can I fit" without checking whether the box + unit + cargo total weight is within the vehicle's safe limits.
Weight Data by Cold Box Size
| Box Size | Box Weight | Unit Weight | Rated Payload | Total Weight |
|---|---|---|---|---|
| Small (0.8-1.0m) | ~35-45 kg | ~15-20 kg | 100-150 kg | ~150-215 kg |
| Medium (1.5m, Flandcold) | ~80-100 kg | ~25-30 kg | 255 kg | ~360-385 kg |
| Large (1.8m, Flandcold) | ~100-120 kg | ~25-30 kg | 300 kg | ~425-450 kg |
| X-Large (2.0m+) | ~130-160 kg | ~30-40 kg | 300-500 kg | ~460-700 kg |
Why Overloading Is Especially Dangerous
❌ Risks of Overloading
- Significantly longer braking distance
- Reduced steering stability
- Accelerated frame & suspension wear
- Tire blowout risk
- Greatly reduced EV range
- Unfavorable accident liability
✅ Benefits of Proper Loading
- Safe, controllable braking
- Stable handling for city delivery
- Longer vehicle lifespan
- Optimal battery range
- Lower maintenance costs
- Compliance with local traffic laws
4. Mounting & Sealing — Safety and Insulation on the Road
Getting the cold box onto the vehicle is step one. Improper mounting causes box shifting or detachment; poor sealing causes continuous cold air leakage and temperature failure.
Mounting Method Comparison
| Method | Best For | Stability | Difficulty |
|---|---|---|---|
| Bolt Mounting | Permanent installation | ★★★★★ | Requires drilling |
| Steel Band | Semi-permanent / removable | ★★★★ | Moderate |
| Bracket Clips | Quick swap needed | ★★★ | Easy |
| Rope / Straps | Temporary / NOT recommended | ★★ | Easy but unsafe |
Sealing Check Points
Insulation performance depends not just on box materials but on sealing integrity. Check these 4 critical areas:
- Door gasket: Magnetic or compression seal — ensure no aging, cracking, or deformation. Worn gaskets cause 3-5°C temperature rise.
- Box joints: Panel seams should be fully sealed. FRP (fiberglass-reinforced plastic) boxes use integral foam construction with fewer joints and better sealing.
- Drain port: Drain cover must seal properly to prevent cold air leakage during operation.
- Unit mounting interface: The connection between the refrigeration unit and the box must be sealed to prevent warm air infiltration.
5. Installation Process — From Delivery to First Run
When you receive the cold box, don't rush to mount it. Follow this 5-step process to ensure proper installation and safe operation.
Unbox & Inspect
Check box exterior for damage or dents; test door operation and seal; verify refrigeration unit condition; cross-check packing list. Document any shipping damage with photos and contact the supplier immediately.
Position the Box
Place the box on the cargo area and confirm positioning: no view obstruction, door access clearance, center of gravity low and centered. Mark mounting points with chalk.
Mount & Secure
Drill holes at marked positions (if needed), install brackets or bolts. Ensure all mounting points bear load evenly. After installation, try to shake the box — it should not move.
Connect Power
Follow the wiring diagram to connect the refrigeration unit. Verify wire insulation integrity — no short circuit risk. Connect temperature sensors and monitoring module. Confirm voltage match before first power-on.
Test Run
Power on with empty box, set target temperature, and observe for 30-60 minutes: confirm temperature drops normally, no unusual noise, no refrigerant leaks, alarm functions work. Only begin actual delivery after successful testing.
6. Frequently Asked Questions
You don't need to change your vehicle — just choose the right cold box. Size, power, payload: confirm these three dimensions, and your existing vehicle becomes a professional cold chain delivery solution.
Installation Checklist
- Measure vehicle usable space (L × W × H) and door opening dimensions
- ⚡ Confirm power supply method (EV direct / fuel vehicle needs inverter or independent battery)
- ⚖️ Calculate total weight (box + unit + cargo) ≤ vehicle rated payload × 85%
- Choose appropriate mounting method (bolts for permanent, steel bands for removable)
- Follow the 5-step installation process and test run 30-60 minutes empty
- Check mounting bolts monthly, inspect gaskets quarterly
If you already have a delivery vehicle and want to evaluate cold box compatibility, contact Flandcold for a free fit assessment — just provide your vehicle model and cargo dimensions, and we'll deliver a complete selection and installation plan within 48 hours.
