I have a cargo trailer with a 50 amp rv service. It has an 18k 220 volt mini split with a 20 amp breaker. It has a hot water heater that is 120 volt on a 20 amp breaker. It also has a 120 volt 20 amp circuit for an outlet used for a microwave. I would like to use a Victron Energy Autotransformer to run the trailer on a 30 amp rv circuit being 120 volts and boost it to 240 volts. Is this a viable solution? What would the amp draw be on the 120v side? Is there a better solution? Thanks for the anticipated help.
When you up-convert from 120V to 240V using the autotransformer, the current is halved.
So if you put in 20A at 120V, you will get roughly 10A out at 240V.
The autotransformer has a 28A continuous (32A max) current limit on the neutral, which means you are effectively limited to 14A of 240V continuously.
If only the mini-split is using 240V, and it is wired that way, find out what its running amps are at 240V. It should be in the manual. It will need to be under 14A. Is 18k the BTU rating?
You may not have enough 120V to run everything at once, that will depend how things are wired and how much current each device draws.
Yes 18k is the btu rating. I will check the amps tomorrow.
Also, most mini-splits are inverter types, so they do not have an initial surge of current when they start up, which should help greatly. Please verify your mini-split is an inverter type.
Yes it is an inverter type. Amp draw for cooling and heating is between 7-8 amps.
Ok great, so the autotransformer would use 16A of the 120V to power the mini-split.
For a standard 120V 30A RV service, that leaves 14A to run your other 120V loads.
I suspect the microwave and water heater will exceed this, but you’ll have to check either the amperage in each device, or the wattage (and divide by 120 to get amps).
The hot water heater has a 20 amp 120 volt plug on it. I’m going to install a port plug on the trailer to run the hot water heater on. Most rv parks have a 120 30 amp and 20 amp plugs. This should eliminate a huge load when having to run on 30 amps. Thanks for your help.