bomadsen avatar image
bomadsen asked

MultiPlus-II 24/3000/70-32 temp alarm at 2300w load


I am in the process of load testing the Victron system in my camper, and I have a question regarding the inverters performance.

I ran a load test with a heater pulling 2.300w (reported by the inverter), and after about 30 minutes the inverter shut down with a high temperature alarm. The ambient temperature was around 15 degrees and the inverter is (currently) mounted free without anything enclosing it. The inverter is running the latest firmware.

What could the issue be here? I would expect the inverter to be able to pull the 2.300w load until the batteries was empty.

Yours sincerely,

Bo Madsen

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1 Answer
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solarhack answered ·


In my opinion your inverter is undersized for this continuous load. The reason I say this is:

  1. A Multiplus II 24/3000 is a 3000va device, not a 3000w device. Taking a normal power factor correction calculation into account (assuming 20%). The wattage you are consuming would be around 80% to 100% of the inverters continuous power at 2400w (internal temperature of 25C).
  2. The temperature rating is the internal temperature of the device not the ambient temperature. The rate at which this temperature will increase will depend on a few factors including the ambient temperature, the airflow and the load. If airflow is constrained or load is continuous this could rise quite quickly.
  3. Once the internal temperature increases to 40C, you would be running at 100% to 120% of its maximum continuous power
  4. Any decent inverter (Multiplus / Quattro / other manufacturer) isn't designed to run at maximum load for an extended period of time. The device will protect itself from over-heating or over-loading by shutting itself down. A Quattro will shutdown with an overload error if its load is 130% for more than 30 minutes and the temperature is still within safe parameters.

In my view if you want to run an inverter at a continuous load, you should really aim at the load been 50% to 70% of the inverters maximum continuous power, depending on the cooling environment. The inverter seems to be behaving as designed. It was running below the 130% load for 30 minutes but was running at between 80% and 130% and got hot and shutdown.


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