A 12V diesel pump is the difference between a usable transfer tank and a glorified jerry can. Get the pump right and you're refuelling a ute in under three minutes, off any vehicle battery, anywhere. Get it wrong and you're swearing in a paddock with a flat battery and a leaking hose. Here's the practical guide — flow rates, wiring, mounting, and the spec choices that actually matter.
Flow rate in plain English
Flow rate is measured in litres per minute (LPM). For portable diesel tanks the realistic Australian range is 40–60 LPM at 12V.
40 LPM — the workhorse rate. Fills a 100 L ute tank in about 2.5 minutes. Used on Joey's 210L and 400L tanks.
56 LPM — heavy-duty rate, paired with hose reels and larger fittings. Used on the 1000L tank.
Higher LPM isn't always better — it draws more current from your vehicle battery and needs heavier-gauge wiring. Match the pump to the tank and the typical refuelling job, not the spec-sheet hero number.
Self-priming vs gravity-fed
A self-priming pump can pull fuel up from a tank that sits below it — useful if the tank is on the ground and you're refuelling a higher vehicle tank, or if the pump is mounted on a wall or post above the tank.
A gravity-fed setup relies on the tank being higher than the outlet. Simpler, fewer moving parts, but less flexible for installation.
Joey's 400L and 1000L tanks both ship with self-priming pumps for exactly this reason — install flexibility matters when the tank lives on a trailer one week and a depot the next.
Wiring it up properly
Every 12V diesel pump ships with a power cable terminated in alligator clips (red to positive, black to negative). Joey tanks ship with a 4 m cable as standard — long enough to reach a vehicle battery from the tray or a nearby trailer.
Battery health matters. A pump pulling 30–40 A from a tired battery will struggle to maintain flow and may blow internal fuses. Run the vehicle while pumping if you're refuelling more than 100 L at a time.
Fuse sizing. Joey pumps have an internal fuse. If you're hard-wiring to a battery (rather than using the supplied alligator clips), put a 40 A blade fuse in line within 30 cm of the battery terminal. This is non-negotiable from a safety perspective.
Cable gauge. Don't extend the supplied cable with thin wire — voltage drop will starve the pump. If you need to reach further, run 8 AWG or heavier from the battery to a switched outlet near the tank.
Nozzles, hoses and the bits between the pump and the vehicle
Automatic shut-off nozzle — this is what stops overfill spills. Worth every cent. All Joey diesel and petrol tanks ship with one as standard.
Digital flow-read bowser — a small LCD on the nozzle showing exact litres transferred. Useful for cost recovery in mixed fleets and for tracking fuel theft.
Hose length and diameter — 4 m × 3/4" is the portable standard. For depot use, a 10 m hose reel (like the 1000L tank) lets one operator refuel from a fixed position.
Swivel fittings — small detail, massive workflow improvement. Stops hose kinks at the pump end and saves the connection from twisting itself loose over months of use.
Maintenance to make the pump last 10 years
12V diesel pumps fail in three predictable ways: water ingress (run an air breather and water separator on bigger tanks), running dry (don't pump an empty tank — it cooks the seals), and battery undervoltage (covered above).
Every 3–6 months, run a small amount of fuel through to keep seals supple, check the in-line filter, and look over the hose for cracking near the nozzle end.
When something does fail, the pump assembly is typically a 20-minute swap. Joey stocks pump assemblies, nozzles, hoses and seal kits for next-business-day Australia-wide dispatch.
Frequently asked questions
Tanks come pump-ready
Every Joey transfer tank ships with the right 12V pump, automatic nozzle, hose and cable already fitted. No assembly, no shopping list — plug into a battery and pump.
