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petej avatar image
petej asked

Multiplus 3000 - Is This Really a 2400W Inverter

I'm looking to replace a 3000W modified sine wave inverter on a houseboat and I'd like to replace that old Xantrex unit with an equivalent pure sine wave unit. Looking at the spec sheet for the Multiplus 3000 (12 V) unit, it looks like true wattage output capabilities of this unit is only 2400W. Am I reading this incorrectly perhaps? Looking at some of the other inverters on the market, it seems like they all list 3000W continuous output in their spec sheets (no mention of VA ratings). Just wondering if this is a case where Victron is being more upfront about including the power factor multiplier in their wattage output spec or if the Victron unit is really just a 2400 W unit.

MultiPlus Quattro Inverter Charger
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Alexandra avatar image
Alexandra answered ·

@PeteJ

Usually an inverter is 3000W if the powerfactor is 1. And in practice that is never the case. We have tested a few brands that claim 3000W or whatever their rating is and found them to be not so.

Victron assumes a power factor of 0.8 closer to most home/basic user average PF. So a little more realistic 3000VA - 2400W

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petej avatar image
petej answered ·

Interesting. To meet a 3000W output specification with the correct power factor applied, I'm thinking this could be done if the inverter were over rated to account for the power factor and still meet the 3000 W requirement. To your point, I doubt anybody is claiming a power factor of 1 though.

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kevgermany avatar image kevgermany ♦♦ commented ·
Not quite the same, but I've been researching generators. Most quote VA and Watt outputs, using a power factor of 80%.

To me the inverter makers quoting Watts and not bothering to show the VA value as well are, let's say 'economical with the truth', which can be very misleading.


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petej avatar image petej kevgermany ♦♦ commented ·
Yep, good point. If you had both VA and W ratings, you could at least figure out the power factor. If I understand the power factor correctly, this really only applies to inductive loads but most applications will have inductive loads in the mix.
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kevgermany avatar image kevgermany ♦♦ petej commented ·
Yes. Even LED lights running off AC are inductive. Something like a kettle, not.
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mvas avatar image mvas kevgermany ♦♦ commented ·

In the USA, LED's are not inductive. In fact, non-dimmable LED's usually have no inductors and two capacitors. The power factor is actually negative = Capacitive. For some odd reason only the magnitude of an LED's power factor is reported and not its sign = "-" capacitive. Add a PFC circuit and the power factor could approach 0.99 (capacitive) while also reducing the % THD.

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kevgermany avatar image kevgermany ♦♦ mvas commented ·
Check it properly. By the time the AC has been dropped to LED DC voltages, you have a power factor way below 80%
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denzel avatar image
denzel answered ·

I currently use the Multi 3000W / 24v inverter and as per documentation one can say that 2400W is the safe continuous watts. I first ran a single unit install and had instances of an overload warning at around 2800W , i recently learnt that the unit temperature also contributes to the continuous watts . I then went to 3 units in parallel , i now can run at 7200W quite comfortable . it would be nice to use the remaining power as per spec but i assume the recommendation's to 2400W are for safety reasons as well.


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crms avatar image
crms answered ·

Yes, reading correctly. Here https://www.victronenergy.com/inverters-chargers/multiplus-12v-24v-48v-800va-3kva

Listed/described as VA power, not W, taking power factor into account. With a tumble dryer drawing a measured 2450W, the overload light is just starting to flash.

Yes, honesty from V!!

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nickdb avatar image nickdb ♦♦ commented ·

The output is based on internal temps of 25C and derates, like all electrical goods, above this, documented in the specification sheet.

Sizing an inverter to run at 100% continuously is bad sizing.

Airflow and environment play a big part in performance.

In warmer climates , I don’t see more than 1900W off the 3kVA.

Additional forced cooling/extraction can help.

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