Thread: 12v Inverter for Coffee Machine

Hi again RVR and if you have not yet got an inverter, make sure you look into the specs before parting with your money.

The cheap ones may save you money up front but because they are not that well designed, they tend to use FAR more input energy than a good quality inverter will and this just adds a far greater high current draw on your battery.

A few extra dollars spent now will save a lot more by protecting your battery long term.

Originally Posted by drivesafe

Hi again RVR and if you have not yet got an inverter, make sure you look into the specs before parting with your money.



The cheap ones may save you money up front but because they are not that well designed, they tend to use FAR more input energy than a good quality inverter will and this just adds a far greater high current draw on your battery.



A few extra dollars spent now will save a lot more by protecting your battery long term.

Thanks - and this gets to the heart of the matter - other than the wattage & wave type, what should I specifically be looking for in the specs?

Hi RVR, it can be hard to get full specs for things like DC/DC devices and inverters.

The one to look for is the efficiency under load ( if it is available ).

Most brands list their inverter's efficiency as being 90% or 95%, which sounds great but this is what they use with an input voltage of 14.5v.

Here is an example. This test was carried out on a Sterling 800w Modified Sine Wave inverter, using a 30 amp Promariner Battery charger, running at full output load.

At 14.5v the input current was 40.4A, at 12.5v it was 46.9A, and at 11.5v it was 50.9A

Note, your battery will discharge to a much lower voltage while under this sort of load and at 11.0v, the current draw was 53.5A.

This is to get 30 amps out of the battery charger, so you can see, efficiency numbers can be very deceptive, and these figures are for one of the best brands of inverters.

Poor quality inverters can have an input current as much as 50% higher, and that why they are cheaper.

I was wondering about running the engine while drawing that kind of current - what sort of current will a 120A alternator be able to supply at engine idle?

Originally Posted by 999

Originally Posted by SouthOz

I use one of these on the road and at home.

AeroPress

Dave

Yeh you cant beat the Aeropress. Why complicate things.

Actually we have one of these that was lent to us by a friend a few months ago so that we could try it out... I should get off my butt and give it a test run!

Originally Posted by Toxic_Avenger

I'm all for the technical way, but have you tried using one of these?



They are rugged as ****, make a decent coffee and IMO way better than the pod style. Come in sizes from 3 cup (espresso cups, that is), up to 12 cup. Just add water, coffee and heat.

I've got both at home, and reach for the stovetop model every time. I flogged my nespresso (style) machine off on buy/swap/sell for whatever I could get for it, as it was just wasting space.

One of them is all I use now. We have several coffee machines, they all gather dust as I much prefer the coffee these make. All you need is a gas hotplate if there is no power.

everyones tastes are different though

He's talking crazy money now when you could buy a eu1000 for less money than the inverter!

seeya
Shane L.

Interesting discussion - am watching to see where you head with this John but you must really love your coffee if you're talking around $2000 plus or minus a few hundred.
As a tangent, I personally think the commercial coffee produced by all the coffee shops in Sydney tastes like **** compared to the aroma that entices us to buy a cuppa, HOWEVER I tasted a brand called Coffeex down in Port Campbell, Vic and it tastes just like it smells so if you get the chance to try that one do so- very nice; apparently its a blended mix.
Badicat - what's a resistive load? sorry for the "dumb" question

Originally Posted by drivesafe

Hi RVR, it can be hard to get full specs for things like DC/DC devices and inverters.

The one to look for is the efficiency under load ( if it is available ).

Most brands list their inverter's efficiency as being 90% or 95%, which sounds great but this is what they use with an input voltage of 14.5v.

In welders and generators that I work with, the machine often advertises a 'power factor'. I've always understood this as the ability of the machine to convert input power to output or usable power. Probably a simplistic way to look at it, but that's the superficial level that I need to understand.
Is this the same thing?