Multiplus Efficiency Loss on Heat Up

DIY
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1

Hello all,

I just want to ask this question to verify what I am seeing is normal, or if maybe it is a component inefficiency as opposed to a victron inefficiency. I am using a 3000W 120v/12v multiplus and have it hooked up to a large battery bank. I am doing testing on the run time of a coleman mach AC unit hooked up to the inverter. When I started the test, the inverter was outputting roughly 1300W of power. After a few hours, the inverter heated up (as expected while under load) but is now outputting about 1700W for the same load. Is this normal due to the heat up of the inverter, or does this sound like an inefficiency due to the AC, or both?

Thank you!

2

Heat derates and inverter. Meaning its max continuous output drops not that it needs more power to run.

What is more likely is now ambient is hotter or the head pressure is higher and the aircon is using more power to work towards the target temperature.

3

I noticed the same thing on my 24V system running my Dometic A/C doing a capacity test. I assumed it was from battery voltage drop as it discharged.

4

Compressors will use more power the hotter ambient air becomes.

The OP is nowhere near a derating threshold. If the load is increasing it’s because more power is being used. Measurement accuracy improves the greater the reading.

5

That would only change the amperage being drawn out of the battery, not increase the wattage on the AC load side.