Choosing an Inverter for Use in Caravans

Inverters for caravans

This blog post aims to help auto electricians select the most suitable MEAN WELL inverter for use in a caravan’s electrical system.

MEAN WELL offers three types of inverters: 

  • Modified Sine Wave Inverters 
  • True Sine Wave Inverters 
  • True Sine Wave Inverter with Built-in Solar Charger 

We look at the applications for each one and discuss the features of benefits offered by MEAN WELL.  

All inverters take direct current (DC) from a battery, solar panel or other generating source and convert it into the 240V alternating current (AC) made available at a power point, or 2 power points on the inverter. 

It is at the AC output stage where the types of inverters differ. 

Modified Sine Wave Inverters 

MEAN WELL A300-1K7 Modified Sine Wave Inverter
MEAN WELL A300-1K7 Modified Sine Wave Inverter

 

Modified sine wave inverters are highly cost effective, but they are limited by the number of applications they can be used for. 

As you know AC alternates its direction of travel repeatedly at a fast rate. This rate is measured in frequency (Hz). In Australia, the 240VAC power supply is delivered at 50Hz (50 cycles per second). 

AC mains power alternates smoothly with a sinusoidal curve that has a rounded peak and a clean ‘zero cross’ to a rounded valley. This is known as a true sine wave or pure sine wave, as depicted in the following diagram: 

True Sine Wave
True Sine Wave

 

Where the output of a modified sine wave inverter differs is that it produces instantaneous peak voltage for a few milliseconds, drops down to zero for a few milliseconds, then returns to the valley. The result looks like this: 

Modified Sine Wave
Modified Sine Wave

 

Modified sine wave inverters do not work well with sensitive or advanced electronics. This is because some digital clocks use the incoming AC current to calculate time. 

Because modified sine waveforms ‘rest’ on zero for a few milliseconds. The microprocessor could read this ‘rest’ as multiple zero crosses resulting in the time being calculated incorrectly. Many electronic devices have built-in clocks. 

Modified sine wave inverters are a cost-effective option for powering electrical equipment that does not have any sensitive electronic circuitry. For example, a simple induction load like a motor, or a resistive load like a heating element. In other words, appliances such as fans, toasters, vacuum cleaners, etc.  

Modified Sine Wave Inverters Stocked by ADM 

We have listed the range of stocked modified sine wave inverters at the end of this blog post.

True Sine Wave Inverters 

Unlike a modified sine wave inverter, true sine wave inverters deliver the AC current in the same form as is available from a standard GPO power outlet. 

This means they can power any device that you would normally plug into a power point at home or in the office, including electronic devices.  

MEAN WELL offers two series of true sine wave inverters. The TS series and the NTS series. 

The NTS series was launched in Q4 2021, and the TS series is likely to be phased out over a period of time. At the time of writing this blog post, there was no NTS series inverter available larger than 1200 WATTS. 

MEAN WELL NTS Inverter Range 

MEAN WELL NTS-450 True Sine Wave Inverter
MEAN WELL NTS-450 True Sine Wave Inverter

 

The NTS series inverters differentiate themselves from general consumer grade inverters by adopting an industrial-grade high reliability, high safety, high quality design, which is why they are available with a longer warranty period.  We have listed the models ADM stocks at the end of this blog post.

They also feature several protections such as: 

Input side: 

  • Reverse polarity 
  • DC low alarm 
  • DC low shutdown 
  • DC overvoltage 

Output side: 

  • Short circuit 
  • Overload 
  • Protection 

There is an RS232 cable available as an optional extra, which allows you to remotely monitor the inverter from a laptop or PC.  

Some of the NTS and TS series inverters can also be controlled remotely via a remote-control unit, which is available as an optional extra. We discuss these in more detail toward the end of this blog post.  

Inverters with Built-in Solar Chargers 

MEAN WELL TN-3000 True Sine Wave Inverter with Solar Charger
MEAN WELL TN-3000 True Sine Wave Inverter with Solar Charger

 

The TN-1500 and TN-3000 inverter / solar chargers incorporate many of the features of the TS-1500 and TS-3000 inverters, with the addition of a built-in solar charger. 

They also feature an AC bypass mode. When AC power is available this will be passed directly to the AC outlet on the inverter.  

There are two operating modes that can be selected: 

  • UPS mode 
  • Energy saving mode 

The unit will be factory set in the UPS mode.  

Depending on the weather and availability of AC power, users may opt to switch to the Energy saving mode.  

In UPS mode, the inverter will remain in the AC Bypass mode if AC power is available. This is likely to be the most appropriate mode for use in caravans. 

In Energy saving mode, the inverter will select external solar panels as its priority input. In case of insufficient solar power and lack of AC power, battery power will be drawn on as the last resort. When the capacity of batteries is around 10~20%, the CPU will alert the user by continuously sounding a warning siren until the system shuts down. 

Monitoring software is available that allows you to monitor the status of the inverter / charger to adjust the following parameters: 

  • Output voltage 
  • Charging related voltage, frequency, and operation mode 

MEAN WELL Inverter Solar Charger Software

The TN-1500 and TN-3000 can also be controlled remotely via a remote-control unit, which is available as an optional extra.

We have listed the stocked models at the end of this blog post.

Remote Controls for MEAN WELL True Sine Wave Inverters 

MEAN WELL IRC1 Inverter Remote Control
MEAN WELL IRC1 Inverter Remote Control
MEAN WELL IRC2 Inverter Remote Control
MEAN WELL IRC2 Inverter Remote Control
MEAN WELL IRC3 Inverter Solar Charger Remote Control
MEAN WELL IRC3 Inverter Solar Charger Remote Control

 

There are 3 remote control units available  

The one you choose will depend on the level of functionality required and the inverter you are using.  

 

IRC 1

IRC 2

IRC 3

Remote on / off

Yes

Yes Yes

LED status indicators

Yes Yes Yes

Power saving enable / disable

Yes Yes Yes

Battery level display

No Yes Yes

Output load level display

No Yes Yes

Operating status display

No Yes Yes
Controls inverter models

NTS-450, NTS-750

TS-1500, TS-3000

NTS-450, NTS-750

TS-1500, TS-3000

TN-1500

TN-3000

Please do not hesitate to contact ADM if you have any questions about MEAN WELL inverters. 

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17 November 2021