Compact Inverter
Troubleshooting guide
PROBLEM: Low output voltage
Possible Cause
MP:120 inverter is overloaded.
Unsure about the appliance rating.
Suggested Remedy
Reduce load, not exceeding MP:120 maximum rating.
(Consider upgrade, RINV300 to 3000).
Check the data label on the appliance or the instructions.
If this is unsuccessful consult the manufacturer.
PROBLEM: Re-occurring low battery shutdown
Possible Cause
Inadequate power or excessive voltage drop.
Poor battery condition.
Suggested Remedy
Check connections from battery to MP:120 inverter.
Replace or charge battery.
PROBLEM: No power output
Possible Cause
MP:120 inverter in thermal shut down condition.
Low battery voltage.
MP:120 inverter blown fuse.
Vehicle blown fuse (DC socket).
Poor DC plug connection.
Suggested Remedy
Remove power and load, allow to cool (10 minutes).
Charge or replace battery.
Check / replace the 15 Amp fuse in the DC plug.
Check vehicle handbook to locate relevant fuse.
Use the DC plug switch to ensure a good connection.
PROBLEM: Liquid ingress
Possible Cause
Drinks spillage.
PROBLEM: No power output from USB socket
Possible Cause
Appliance is not rechargeable
USB not inserted correctly
Suggested Remedy
Unplug the MP:120 inverter and wipe immediately with a
dry cloth (Permanent damage can occur with liquid ingress).
Suggested Remedy
Check appliance is rechargeable and uses
rechargeable batteries.
Check connections are the correct way up with
the USB symbol facing up on the USB plug.
PowerSource Model
Part Number
Max. Continuous power (Watts)
Peak Power (Watts) 0.01 Seconds
Standby current (Amps)
Input Voltage Range
AC Socket
USB socket
Cooling Fan
Product Dimensions (mm) (D x H x W)
Pack Dimensions (mm) (D x H x W)
Coiled Cable length (mm)
*Percentage of battery power to mains voltage power.
MP:120 inverter
120w (30 mins) 100w (4 hours)
Modified Sine Wave
10v – 15v DC
3 Pin mains 230v AC
USB2 DC5v / 150mA
Yes / Continuous
30 x 105 x 75
55 x 180 x 185
650 (extended length)
Compact Inverter
12v DC to 230v AC Mains Inverter
User Manual
This inverter should only be used to power Class II (non earthed) products, identified by the symbol:
Distributed by: Ring Automotive Limited, Gelderd Road, Leeds, England LS12 6NA
+44 (0)113 213 2000
+44 (0)113 231 0266
Compact Inverter
Operating Tips
The Ring MP:120 inverter is an electronic device that converts a low voltage 12v DC current from a battery,
or other power supply and provides 230v AC current.
NOTE: The MP:120 inverter is not designed to run products that provide heat, such as hair dryers,
heaters and irons.
• Do not handle the MP:120 inverter with wet hands or if it has come into contact with liquid.
• Ensure while driving all accessories powered by the MP:120 inverter are positioned securely.
• Do not use distracting accessories such as mobile phones whilst driving.
• To ensure optimum performance from the MP:120 adjust the DC plug switch for the correct fit
in the vehicle’s DC socket.
• Ensure the USB plug is inserted correctly in the socket. With the USB symbol facing up.
• The MP:120 uses a USB2 type socket and will therefore charge USB1 & USB2 devices.
• Do not exceed the maximum input voltage (15 Volts DC).
• Improper use of the MP:120 inverter can cause damage to property and possibly harm to the user.
• The MP:120 contains no user serviceable parts – Do not open.
Special attention should be made to CAUTION statements in this user manual.
CAUTION statements identify conditions or practices that could result in damage to your MP:120 or to
the equipment you are using with it.
Power Supply
The battery or power supply must provide between 10.5 and 14.5 Volts DC (a car battery will usually provide
this) and must be able to provide sufficient current to operate the load (the item you require to power).
• Only clean the MP:120 inverter using a clean dry cloth.
• Do not use cleaning products.
• Ensure the USB socket is clear of any dust or other debris before connection.
The power supply used may be a battery or a regulated DC power supply. In order to find out if your power
supply is large enough, divide the power consumption of the load (in watts) by the voltage (12v in the case
of the MP:120 inverter) this will give you the current (in amps) that the power supply must deliver.
EXAMPLE: Load is rated at 48W / 12v = 4 Amps
Fuse Replacement
• The fuse is located in the MP:120 DC plug. Unscrew the end of the DC plug and extract the 15 Amp fuse.
Check the fuse and replace if necessary with an equivalent 15 Amp fuse.
Connecting to your power supply
Protective features
Connect the DC plug on the MP:120 inverter to the vehicle battery by plugging directly into the 12v DC
socket (cigarette lighter socket). The LED power monitor illuminates green when power is on. The MP:120
must only be used on vehicles where the centre contact of the cigarette lighter socket holder is positive.
Ensure the load requirements are within the specification (max 120w) of the MP:120 output. Plug your
appliance into either the 3 pin or USB socket of the MP:120 inverter.
Auto shutdown – The MP:120 inverter will automatically shut down if the supply voltage is less than 10v.
At this point the green LED will go out. The inverter will automatically restart when the input voltage is
above 10v.
Overload protection – The MP:120 inverter will automatically shut down if the continuous power draw
exceeds the maximum rating.
Positioning of the MP:120 inverter
Included in the pack are two pieces of hook and eye tape to allow for the most suitable positioning of the
MP:120 inverter in your vehicle. By use of the hook and eye tape the MP:120 can be removed from the
vehicle when left unattended.
When positioning the following points should be noted:
The MP:120 inverter is not waterproof.
Take care if adjacent drinks holders contain or have contained liquids.
The MP:120 should be used in a ventilated area.
Do not obstruct the vents at the front and side of the MP:120.
Do not put the MP:120 on or near sources of direct heat or expose to direct sunlight.
Do not operate the MP:120 in or around flammable environments.
Ensure cables and leads connected to the MP:120 do not interfere in the safe operation of the vehicle.
When not in use store securely in a cool, dry dust free environment.
Do not leave connected to 12v DC socket unattended.
Remove from 12v DC socket when not in use as the unit will continue to draw 0.4 Amps stand-by current.
Do not operate continuously for more than 4 hours.
Do not use the power lead to move or carry the MP:120.
The USB socket is for charging only, NOT data transfer.
Short circuit protection via automatic thermal resetting fuse.
Temperature Protection – If the temperature of the internal heat sink reaches >65˚C the MP:120 will shut
down automatically. Remove from power and allow to reset when cool before using.
Cooling Fan – The internal cooling fan runs continuously once the MP:120 is connected to a power supply,
to optimise performance.
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