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12V water pump selector for mobile detailing

Calculate a tank-fed mobile detailing pump duty point from required flow, pressure, lift and line loss, then screen an exact 12V pump using its curve, current and duty-cycle evidence.

Define the flow and pressure the complete water path must deliver, then compare one exact 12V pump at that duty point. Do not enter the pump's open-flow headline as its working flow.

Real system requirement

Switch display units without changing the stored calculation.
The downstream equipment and use case determine the evidence you need.
Use the exact washer or outlet instructions and a measured workflow—not another setup online.
L/min
Enter the minimum flow required where the water reaches the downstream equipment.
%
A transparent allowance above the minimum; this does not replace testing.
bar
Enter zero only when the exact application genuinely has no minimum delivery-pressure requirement.
m
Vertical rise from the operating water level to the delivery point; this adds static pressure.
m
Vertical lift to a pump above the water level; check against exact self-prime evidence.
Use a measured or supplier-calculated figure for the full hose, filter, valves and fittings—or confirm a justified zero.
bar
Do not invent this figure: restrictions depend on flow, bore, length, condition and fittings.
min
Use the longest normal period before the pump can stop and recover.
min
Count powered delivery time, not the total appointment length.
jobs
Used to expose daily active time and approximate electrical demand.
V
Use the designed or measured supply at the pump installation—not a guess from the vehicle badge.

Exact pump candidate

Use the current manufacturer data sheet or manual for the exact suffix and voltage.
Find flow and current at the calculated pressure—not only maximum flow and shut-off pressure.
Confirm port threads, hose bore, materials, liquid service, pressure and strainer arrangement.
Record the exact cable, protection, isolation, switching and supply instructions.
Self-priming is not permission to run dry; use the exact start, strainer and shutdown instructions.
Use the exact model statement; do not infer continuous duty from an automatic pressure switch.
L/min
Read or interpolate only where the exact manufacturer curve supports it; otherwise leave zero.
bar
A boundary check only; this does not prove working flow at that pressure.
m
Enter the exact published figure and conditions; leave zero if no suction lift is needed.
A
Use the current from the exact curve or data at the required working pressure.
V
Match the exact pump voltage to the designed supply.

12V pump direction

Define the real duty point first

Still needed: the exact downstream flow and pressure requirement, a measured, supplier-calculated or explicitly zero line-loss figure, the required downstream flow, the longest uninterrupted run, active pump minutes per job, planned jobs per day

A maximum-flow label is normally measured at little or no pressure. Record the downstream requirement, geometry, line loss and work pattern before comparing pumps.

Required flow—
Duty pressure—

Compare the exact manufacturer curve at this intersection—not at zero pressure.

Elevation pressure0 bar
Daily active time0 min
Candidate flow marginAdd curve value
Pressure boundary marginAdd candidate
Approx. DC demandAdd current
Approx. energy useAdd current
Amp-hours describe entered pump demand only. They do not size a battery, cable, fuse, connector, charging system or safe installation. Voltage drop, other loads, battery chemistry and manufacturer instructions remain separate checks.
  1. 01

    Record the exact downstream flow and pressure requirement, delivery rise, suction lift, line loss and work pattern.

  2. 02

    Confirm the pressure washer or outlet manufacturer permits the intended supply arrangement; a pump result cannot approve an incompatible inlet method.

  3. 03

    Use the exact pump instructions for ports, strainer, mounting, ventilation, priming and dry-run avoidance. Visually similar pumps can have different limits.

  4. 04

    Have the complete 12V path—battery or supply, isolation, cable, protection, switching, connectors and wet-environment routing—designed and checked for the actual current and installation.

  5. 05

    Confirm the exact duty statement. “Continuous” still does not remove temperature, environment, maintenance or supply-voltage limits.

  6. 06

    Test the assembled system at the most demanding normal tank level and hose route. Stop if flow becomes unstable, the pump overheats, cycles unexpectedly, leaks or runs dry.

Screen the filter and strainer path Turn pump current into battery demand Measure the complete inlet path Create an installer-ready fit-out brief Check tank and system payload

Installation boundary: this tool deliberately does not output cable or fuse sizes. Those depend on the exact pump instructions, conductor type and length, routing, protection method, terminals, environment and supply design.

Affiliate disclosure: As an Amazon Associate I earn from qualifying purchases. The price is unchanged for you. Retailer results are not pump curves, electrical instructions, duty-cycle approvals or compatibility decisions. Outside the UK, use an appropriate local retailer and the rules that apply where the equipment is installed and used.

The useful number is an intersection

Flow changes as pressure changes.

A pump labelled with a large open-flow figure can deliver much less after elevation, hose, filters, fittings and the downstream pressure requirement are added. The selector builds one duty point: required flow at required pressure.

01Define the outlet

Record the exact washer inlet or low-pressure delivery requirement.

02Add the route

Count vertical rise and a measured or supplier-calculated complete-line loss.

03Open the exact curve

Read flow and current at that pressure for the exact model and voltage.

04Test the installed system

Use the most demanding normal tank level, hose route and work cycle.

Three limits stay separate

A pressure switch does not prove the work pattern.

Working flow, maximum or shut-off pressure, and duty cycle answer different questions. A candidate only clears this screen when all three are evidenced for the exact model.

  • Use the flow/current curve at the calculated duty pressure—not a zero-pressure headline.
  • Check suction lift separately from delivery rise and line loss.
  • Keep an intermittent-duty pump inside its run and recovery limits.
  • Confirm the exact downstream equipment supports the proposed supply arrangement.

Screen the inlet path with the filter and strainer selector, turn the entered current into a battery demand, or measure final delivery with the tank-to-washer checker.

Current-source boundary

Read the exact curve and manual together.

These primary manufacturer examples show why voltage, pressure, flow, current and duty cycle must be read together. They are evidence examples, not endorsements or substitutes for the exact model being considered.

Pentair SHURFLOOfficial 12V flow, pressure and current performance tablePentair SHURFLOOfficial installation manual and intermittent-duty statementXylem FLOJETOfficial Triplex pump specification and head-flow chartXylem FLOJETOfficial Triplex installation and duty-cycle guidanceHSEWork equipment, supply suitability and electrical checks
Source review: 13 September 2026. Recheck the current exact-model curve, instructions and applicable rules before purchase, installation or use.

Questions before checkout

12V water-pump questions

How many litres per minute does a mobile detailing water pump need?

Start with the exact downstream equipment or outlet requirement, then add a stated reserve. The pump must deliver that flow at the real pressure created by the downstream requirement, vertical rise and complete hose-and-fitting loss—not only at zero pressure.

Can I choose a 12V pump by its maximum flow rate?

No. Maximum or open flow is normally a different duty point from the installed system. Use the exact manufacturer curve to find flow and current at the pressure your complete water path requires.

Is pump shut-off pressure the same as working pressure?

No. Shut-off or maximum pressure is a boundary, not proof of working flow. The exact flow-versus-pressure curve and the downstream equipment instructions are needed at the intended duty point.

Does self-priming mean a pump can run dry?

No. Self-prime capability and dry-run permission are separate manufacturer statements. Follow the exact strainer, priming, mounting and shutdown instructions for the model.

How much battery power will a 12V water pump use?

Current multiplied by active hours gives an approximate amp-hour demand for the pump only. Battery capacity, cable, over-current protection, charging, voltage drop, other loads and installation safety require separate design using the exact current and manufacturer instructions.

Can a 12V pump feed any pressure washer from a water tank?

No. Pressure-washer inlet arrangements are model-specific. Confirm the exact washer instructions and compare measured delivery through the assembled tank, filter, valves, hose and fittings at the machine inlet.

Why does a diaphragm pump pulse or cycle?

Cycling can have several model- and system-specific causes. Stop if behaviour is unstable, the pump overheats, leaks or runs dry, then use the exact troubleshooting instructions or a competent installer rather than changing settings by guesswork.