Power For An Inverter?

[C08]

What would be the current draw from the 12v system of a mains invertor providing 1000W?

 

[matthewriches]

https://www.redarc.com.au/faq-tech-tips/inverter-current-draw

 

[elton]

What would be the current draw from the 12v system of a mains invertor providing 1000W?

1000/12 Amps (which is 83 amps), minus any inefficiency in the conversion.

 

[Norman_E]

1000/12 Amps (which is 83 amps), minus any inefficiency in the conversion.

Actually any inefficiency adds to the amps drawn. If the inverter outputs 1000 watts but is 90% efficient it would need to draw over 92 amps.

 

[PaulRainbow]

Divide the watts by 10. 1000w inverter at full power will draw around 100a.

 

[skipmac]

Divide the watts by 10. 1000w inverter at full power will draw around 100a.

Exactly. Divide by 10 is a very close rule of thumb and will account for typical system inefficiencies, power losses and power factor correction between the inverter output and the final AC load.

 

[C08]

Thanks for replies. That is pretty much what I calculatedit to be but I thought that a power draw of a sustained 80/90 amps was not something that most boat systems would accomodate so I thought there must be something clever in the inverter conversion that would avoid this but it seems not.

 

[pvb]

Thanks for replies. That is pretty much what I calculatedit to be but I thought that a power draw of a sustained 80/90 amps was not something that most boat systems would accomodate so I thought there must be something clever in the inverter conversion that would avoid this but it seems not.

Remember too that, unless you have the engine running to provide extra amps, your batteries will discharge very rapidly at a 100A load, due to the Peukert's effect. A typical 200Ah domestic bank will be down to 50% charge in only around 20 minutes.

 

[Spyro]

You'll need some pretty hefty wiring too.

 

[pagoda]

You'll need some pretty hefty wiring too.

Well, Inverters are not the most efficient energy conversion devices. Quite a lot ends up as heat in the inverter. Other losses can be added to by the massive currents to transfer Kilowatts at 12VDC. So as Dpyro suggests, the DC side needs welding cable!
Forget microwaves unless you are on mains or running a genny?

 

[macd]

...so I thought there must be something clever in the inverter conversion that would avoid this but it seems not.

That would be well beyond clever. Closer to magic

 

[DuncanHall]

Well, Inverters are not the most efficient energy conversion devices. Quite a lot ends up as heat in the inverter. Other losses can be added to by the massive currents to transfer Kilowatts at 12VDC. So as Dpyro suggests, the DC side needs welding cable!
Forget microwaves unless you are on mains or running a genny?

Not so for microwaves. Microwaves are only used for a short time. I have 390AH and find it knocks off about 0.5% of capacity per minute as measured on a Victron battery monitor.

 

[skipmac]

Not so for microwaves. Microwaves are only used for a short time. I have 390AH and find it knocks off about 0.5% of capacity per minute as measured on a Victron battery monitor.

I usually only use a microwave for warming up leftovers and such which only takes a minute or so at most. Even though I'm pulling 100-180 amps out of my 12V battery bank it's such a short time that I don't use much capacity.