RV and off-road camper parts glossary

Plain definitions for the words that show up on our product pages, in Black Series manuals and in Victron documentation. If a term you need is missing, email Support@rvpartsgiant.com and we add it.

12V system

The low-voltage DC side of a camper: battery, fuses, lights, pump, fans, fridge. Everything that works with no shore power.

Absorption charge

The second stage of a charger: voltage held steady while current tapers off. Comes after bulk, before float.

AGM battery

Absorbed glass mat lead-acid battery. Sealed, no maintenance, heavier and shorter-lived than lithium at the same capacity.

Alternator charging

Charging the house battery from the tow vehicle while driving, through a DC-DC charger such as a Victron Orion.

Amp-hour (Ah)

A unit of battery capacity. A 100 Ah battery can supply 5 A for 20 hours in theory.

Anderson plug

A gray two-pole DC connector (SB50 is the common size) used between the tow vehicle and the camper for charging.

Anode rod

A sacrificial magnesium or aluminum rod inside a tank water heater that corrodes instead of the tank. Replace when mostly gone.

Articulating coupler

An off-road hitch that pivots on two or three axes so the camper can twist independently of the vehicle. Cruisemaster DO35 and DO45 are examples.

ATC / ATO fuse

The standard blade fuse in most 12V panels. ATO is the open version, ATC is the sealed version, same size.

Ball weight

See tongue weight.

Black tank

The holding tank for toilet waste. Emptied through the dump valve.

BMS

Battery management system. The electronics inside or beside a lithium battery that stop over-charge, over-discharge and low-temperature charging.

Breakaway kit

A small battery and switch on the trailer that applies the electric brakes if the trailer separates from the vehicle. Required by law in most states.

Bulk charge

The first stage of charging: maximum current until the battery reaches absorption voltage.

Busbar

A metal bar with several terminals that lets many cables share one connection point. Positive and negative busbars sit near the battery.

Cassette toilet

A toilet with a removable waste tank you carry to a dump point, instead of a fixed black tank.

Cerbo GX

Victron's central monitoring hub. Connects the inverter, MPPT and shunt and shows them on a screen or on the VRM portal.

City water inlet

The threaded connection on the outside wall where a hose from a campground tap pressurises the plumbing without using the pump.

Converter

Turns 120V shore power into 12V DC to run the camper and charge the battery. Not the same as an inverter.

DC-DC charger

A charger that takes the vehicle's 12V and delivers a proper multi-stage charge to the house battery. Needed with lithium and smart alternators.

Deep cycle

A battery built to be discharged a long way and recharged many times, unlike a starter battery.

Depth of discharge (DoD)

How much of a battery's capacity has been used. Lithium tolerates 80 to 100 percent; lead-acid should stay under 50 percent.

Diamond plate

Patterned aluminum sheet used on the front and lower sides of off-road campers as stone protection.

DO35 / DO45

Cruisemaster articulating couplers rated for 3.5 t and 4.5 t. The DO45 uses a larger pin and a different tow-pin kit.

Ducted AC

A rooftop air conditioner that pushes air through ceiling ducts to several outlets, instead of one grille under the unit.

Dump valve

The gate valve on the gray or black tank outlet. Pull the handle to empty the tank.

Equalisation

A controlled overcharge that some lead-acid chargers run to balance cells. Never used on lithium.

Float charge

The final charging stage: a low voltage that keeps a full battery topped up without overcharging.

Fresh water tank

The tank holding potable water for the sink, shower and toilet flush.

Gas strut

A gas-filled cylinder that holds a window, hatch or pop-top open. Sold by extended length and force; measure eye to eye.

GFCI

Ground fault circuit interrupter. The outlet with test and reset buttons that cuts power if current leaks to ground, required in wet areas.

Gray water

Waste water from the sink and shower. Goes to the gray tank, not the black tank.

GX device

Any Victron monitoring hub: Cerbo GX, Ekrano GX, Venus GX.

Hitch pin

The pin that locks a coupler onto the tow ball or pin. Off-road couplers use a specific tow pin kit.

Holding tank

Any onboard waste tank, gray or black.

HQ series

Black Series camper models HQ12, HQ15, HQ17, HQ19, HQ21 and HQ22T. The number is roughly the body length in feet; T means toy-hauler or tandem, check the model page.

Inverter

Turns 12V DC from the battery into 120V AC for household appliances. Pure sine wave is the type to buy for electronics.

Inverter/charger

One unit that inverts battery power to AC and charges the battery from shore power, switching automatically. Victron MultiPlus is the common one.

Jerry can

A 20 L (5.3 gal) steel fuel can of the NATO pattern. Wavian is the original maker. Smaller 10 L cans exist.

Jockey wheel

Australian term for the trailer jack or tongue jack that supports and steers the coupler when unhitched. ARK XO series is the OEM on Black Series.

LiFePO4

Lithium iron phosphate. The lithium chemistry used in RV house batteries: safe, long-lived, no equalisation.

Load rating

The weight a jack, step, or tire is built to carry. Static rating is parked; dynamic rating is while moving.

Low-temperature cutoff

A BMS feature that stops charging a lithium battery below about 32 F (0 C) to prevent damage.

MEGA fuse / MIDI fuse / ANL fuse

Bolt-down high-current fuse formats used on battery cables. Size the fuse to the cable, not the load.

MPPT

Maximum power point tracking. A solar charge controller that adjusts panel voltage to harvest the most power. Victron SmartSolar is MPPT.

MultiPlus

Victron's inverter/charger line. The name is followed by system voltage, VA rating and charger amps, for example 12/3000/120.

Non-ducted AC

A rooftop air conditioner that blows through a single air distribution box under the unit.

Off-grid

Camping with no shore power or water hookup, running on battery, solar and tanks.

Orion

Victron's DC-DC charger line (Orion-Tr Smart, Orion XS).

Pop-top

A roof section that lifts on gas struts to add headroom when parked.

Pure sine wave

Inverter output that matches household AC exactly. Modified sine wave is cheaper and can damage electronics.

PWM controller

Pulse width modulation solar controller. Cheaper and less efficient than MPPT; fine for small panels.

Rock guard

A deflector on the front of the camper that stops stones thrown by the tow vehicle.

Shore power

120V AC from a campground pedestal or a house, through the RV power cord (30 A or 50 A).

Shunt

A precision resistor on the battery negative that a monitor uses to measure current in and out. Victron SmartShunt and BMV-712 are shunt monitors.

Slide-out

A room section that extends outward when parked to add floor space.

Soft start

A device fitted to a rooftop AC that reduces the compressor's startup surge so it can run on a smaller inverter or generator.

Solar charge controller

The device between panels and battery that regulates charging. See MPPT and PWM.

Stabilizer legs

Corner legs wound down when parked to stop the camper rocking. They are not for lifting the camper.

State of charge (SoC)

How full the battery is, as a percentage. A shunt monitor reads it properly; voltage alone does not on lithium.

Tankless water heater

A heater that warms water on demand as it flows, instead of storing hot water in a tank. Black Series HQ campers use a 12V-ignition gas tankless unit.

Tongue weight

The downward force the coupler puts on the hitch, usually 10 to 15 percent of camper weight. Also called ball weight.

Transfer switch

Automatically selects between shore power, generator or inverter so only one feeds the AC panel.

VE.Bus / VE.Direct / VE.Can

Victron's three communication links: VE.Bus for inverter/chargers, VE.Direct for MPPTs and shunts, VE.Can for larger networks.

VRM

Victron Remote Management. The free web portal that shows your system from anywhere once a GX device is online.

Wheel bearing

The tapered roller bearings in each hub. Repack or replace on schedule; Timken is the common brand.

Winterizing

Draining and protecting the water system, and storing the battery, so freezing does not split pipes or tanks.

Y-hitch receiver

The Y-shaped hitch frame on some Black Series models that carries the coupler and the jack.