Question about inverter efficiency and if it's worth it to have 2 different wattage inverters

crayfish21

New Member
Joined
Mar 12, 2022
Messages
8
I'm trying to understand the efficiency of inverters.

I'm planning on getting the Victron Multiplus 12v 3000w inverter/charger because I'll have 600+ AH of LifePo4 batteries and because it can charge the house battery bank faster than the 2000w inverter/charger.

However, (with the exception of a microwave) the devices that I'll be using regularly will be consuming under 500w at any given moment (laptop, computer peripherals, and Starlink).

Would it be a lot more efficient to get a second inverter that's just 800w to run the laptop and Starlink? And only turn the 3000w inverter on when I'm charging house batteries or on rare occasion I need to power my microwave?

The Victron Multiplus data sheet lists the efficiency of the 800w at 92% and the 3000w at 93%. If my typical usage is 500w for 5 hours, is there any significant difference in the watts I'd be losing through inefficiency between the two inverters?

The data sheet lists Zero Load Power as 8w for the 800w and 20w for the 3000w inverter. Is that how many watts the inverter uses just to stay turned on? Does it also use this much when it's supplying power to devices?

Thanks!
 

OffGridInTheCity

Photon Sorcerer
Joined
May 23, 2021
Messages
1,236
Location
Southern Oregon
I'm trying to understand the efficiency of inverters.

I'm planning on getting the Victron Multiplus 12v 3000w inverter/charger because I'll have 600+ AH of LifePo4 batteries and because it can charge the house battery bank faster than the 2000w inverter/charger.

However, (with the exception of a microwave) the devices that I'll be using regularly will be consuming under 500w at any given moment (laptop, computer peripherals, and Starlink).

Would it be a lot more efficient to get a second inverter that's just 800w to run the laptop and Starlink? And only turn the 3000w inverter on when I'm charging house batteries or on rare occasion I need to power my microwave?

The Victron Multiplus data sheet lists the efficiency of the 800w at 92% and the 3000w at 93%. If my typical usage is 500w for 5 hours, is there any significant difference in the watts I'd be losing through inefficiency between the two inverters?

The data sheet lists Zero Load Power as 8w for the 800w and 20w for the 3000w inverter. Is that how many watts the inverter uses just to stay turned on? Does it also use this much when it's supplying power to devices?

Thanks!
Yes, the 8w (1%) and 20w (0.7%) are continuous, and my understanding is this continues even with load. The overall efficiencies of 92% and 93% are pretty close but my experience shows that my actual inverter efficiency can vary (5-10%) depending on it's % load - e.g. the closer to max load is more efficient on my AIMS inverters. For example, you might find that the 3000w / 93% inverter goes down to <90% at only 500w.

Personally, I'd advise doing some monitoring to answer your question as the paper specs looks pretty close but actual operating efficiencies are not always linear :).
 

Mousie

New Member
Joined
Dec 10, 2021
Messages
13
I just went through this and the Meanwell TS-3000 (12v-230v) has a high standby current for small devices so in went a Victron 12/250 to run all these light application. Both of these units do have ECO modes as well but I am having trouble understanding their effective use as things like microwaves and tv etc on standby are all well under the threshold to fire up the inverters continuous hence they are just flashing on and off which cannot be good. The only time I can see a benefit is when you plug device in and turn on, otherwise these modes look useless to me. Happy to get any advice on eco modes as well.
 

MichaelK

Photon Sorcerer
Joined
Mar 21, 2020
Messages
2,780
I played with the idea of a smaller inverter for standby use when I'm away from the cabin, but I finally decided against it because of the hassle of dealing with re-setting clocks, re-booting the router, and updating the TV stations. I just went with the "more panels" route and it has worked for me. My XW 6848 consumes about 0.7kWh per day, which in my case is a trivial load.
 

73powerstroke

Solar Addict
Joined
Jun 17, 2022
Messages
724
Location
Arizona
I have 2 systems. A small 12v system for basic stuff with a few panels, then a 24v system with more of everything. The advantages for me are I can power 12v stuff still and I can shut down one system and still have power
 
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