question

celts88 avatar image
celts88 asked

Connect Multiplus II to power Caravan Aircon - Australia

Hi

The aircon in our caravan only works when the external 15A is plugged into the caravan, and not via the Multiplus (all other 240V items work via the inverter). It would seem the manufacturer wired the caravan so that the AC can only work when connected to external power.

We've upgraded our batteries (1080A) and Solar (2430W) to handle our power needs.

Is there a simple way to change the setup so that all 240V power, including our AC is controlled via the Multiplus?

Thanks

ESSmultipluss ii
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4 Answers
n3wby avatar image
n3wby answered ·

What size Multi?
What size A/C (Electrical kW rating)?

What did the Van manufacturer recommend? Did the van manufacturer provide any Electrical diagrams? Are any other electrical items on the 15A plug?

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celts88 avatar image celts88 commented ·

We've a Multiplus-II 12/3000/120-32, with Dometic Ibis 3 A/C 2.7kW (5.5A) Cooling / 3.1kW (5.8A) Heat.

The van is 2018 and the manufacturer has not replied (their renowned for bad communication even though fantastic quality vans). All 240V appliances are linked to the 15A external connection, but only the A/C is dedicated to it, whereas all others can use both the external 15A or the inverter.

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kevgermany avatar image
kevgermany answered ·

Basic answer is that there are two AC outlets on the bigger multiplus units. One is shore/external power only, the other is shore/external plus inverter.

As long as the multiplus is large enough to run the aircon and other loads, simply switch the aircon input wiring to the other AC outlet. Assuming DC and AC cabling sufficient!

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celts88 avatar image celts88 commented ·

We've a Multiplus-II 12/3000/120-32, and if needed also have a spare Phoenix Inverter 12/3000 we can add to the system too if required.

Just need to find an electrician who can help us link the A/C to the same 240V line as the other 240V gear in our van.

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Duivert NL avatar image
Duivert NL answered ·

your multiplus is to small to run your A/C from battery, its 2400W (3000VA) cont load @ 25 degrees

that's why the installer connected it to ac out 2 or direct to the power input


if you want to run it from solar/battery you need a bigger multiplus 5000, but with heating that is also almost maxed out

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celts88 avatar image celts88 commented ·

The Multiplus is not connected yet, it's the van manufacturer that's connected the external 15A to the A/C.

I've only just now seen that Victron have brought out a new MultiPlus-II 12/5000/220-50 230V here in Australia, this must be just recent as previously maximum 12V was 3000VA. Looks like more money to spend :(

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nickdb avatar image nickdb ♦♦ celts88 commented ·
It gets impractical to run higher power systems at 12V, hence the preference for 24/48V.
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celts88 avatar image celts88 nickdb ♦♦ commented ·
I've already got the 12V batteries (4 x 270A) therefore can't change to 24V/48V now.
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Duivert NL avatar image Duivert NL celts88 commented ·
Hi technically you can, 2s2p for 24v or all in series for 48v, but you might need more


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celts88 avatar image celts88 commented ·

I've just checked the specs for the IBIS 3, as per below, and the maximum required input power is 1700W which is covered by the Multiplus-II 12/3000/120-32 with 2400W.

Now I realise when the A/C is first starting to cool it will be drawing near max power and as such can't run any other power hungry gear, but once it settles down then the power draw is a lot less.


Power Input Cooling - 1300 W

Power Input Heating - 1210 W

Current Cooling - 5.8A

Current Heating - 5.5A

Maximum Input - 1700W

Maximum Current - 7.5A

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nickdb avatar image nickdb ♦♦ celts88 commented ·

The specs don’t indicate this is an inverter aircon. So while the draw may be low, the surge every time the compressor starts can be many times the rating of the unit. Consider a soft starter. Also remember that the 2400W is at 25C. Under constant load and higher temps the inverter will derate down to 1700W (give or take).

Something made worse by mobile installations and restricted airflow.

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celts88 avatar image
celts88 answered ·

Hi All

Appreciate all the comments and info.

FYI, to save any potential hassle I've went and bought the MultiPlus II 12/5000/220-50 therefore no need for me to worry if the AC will overload the Multiplus when starting.

Hope everyone is safe and sound.

Thanks, John

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