Electric-only coffee solution

boathealer · April 5

For those electric-only folks who want to make coffee without a lot of fuss – I found a great (so far) solution. We bought this one on Amazon: https://www.amazon.com/dp/B0DDL9YTY7

The small K-cup coffee maker that consumes an advertised 800W for 3 minutes per cup. Doing the math:

* Assuming an inverter efficiency of 85%, 800W AC requires 690W from the batteries
* 920W for 3 minutes = 46 Watt-hours (per cup)
* 46 Watt-hours at 12V = 3.83 Amp-hours

I used a “Kill-O-Watt” meter and made some actual measurements (I’m geeky that way):

* Peak power is actually 912W AC.
* Peak power is intermittent at about 70-80%-on, 20-30%-off duty cycle during heating (maybe the reason for the 800W specification)
* The “Kill-O-Watt” meter showed a total consumption for one cup of 0.02 KWh (probably inaccurate - made for larger appliances). This is 20Wh -- lets round up to 30Wh which lines up with the math above at approx. 70--80% duty cycle.

We have used it about 10 times so far and it seems reliable. It also will accept the reusable K-cups for ground coffee.

So, you can make one cup of coffee at a cost of 4Ah at 12V. For $37. Not too shabby IMHO. Provided you have a ~1000W inverter already.

AnOldUR · April 5

For our morning coffee we use a French Press and the propane stove to heat water, but I found this interesting. A small electric kettle might be an easier alternative to firing up the burners. The amp hour numbers aren't as bad as I had imagined.

boathealer · April 5

AnOldUR said:

For our morning coffee we use a French Press and the propane stove to heat water, but I found this interesting. A small electric kettle might be an easier alternative to firing up the burners. The amp hour numbers aren't as bad as I had imagined.

We also have one of these. https://www.amazon.com/dp/B09KCC7V6W. 600W - same math. Looks to be out of stock now, but there are hundreds of others - just check wattage.

Sharon_is_SAM · April 5

We heat water on the stove and use a pour over into an insulated thermos.

elbolillo · April 5

We have a small Espressione espresso machine along with a nespresso frother. Using the inverter to make coffee in the morning we will use about 1.5% of our battery bank.

We have since purchased a Nespresso Citiz machine that uses pods. The machine is much smaller, and since it won’t have to grind the bean like the Espressione, it should have even less impact on the batteries.

AnOldUR · April 5

elbolillo said:

... won’t have to grind the bean like the Espressione, it should have even less impact on the batteries.

I wouldn't want to miss my morning workout!

Image: https://us.v-cdn.net/5021717/uploads/editor/r9/2i1mea80qooq.jpg

Slackers · April 5

We don't have an inverter but appreciate the info you (all) have shared. Like @AnOldUR we used to use a French Press, but now use a cheap pour-over method. I researched 12 volt cigarette plug-in kettles but the reviews showed them to be slow and unappealing.

Yoshi_TAB · April 5

AnOldUR said:

A small electric kettle might be an easier alternative to firing up the burners .

Hi,
That is what we use with our inverter. Heats 2 cups of water up in less than a minute and hardly puts a dent in battery consumption. Happy Coffee Drinking

elbolillo · April 6

AnOldUR said:

elbolillo said:

... won’t have to grind the bean like the Espressione, it should have even less impact on the batteries.

I wouldn't want to miss my morning workout!

I get my workout lifting my coffee cup to my mouth… 😂

rfuss928 · April 6

One pound of propane contains roughly 6.2 kilowatt-hours (kWh) of energy. In common 12v battery terminology this is ~500 amp-hours.
When possible and practical, a lot more stored energy can be carried as propane than electrical energy both volumetrically and weight. IMO, for heating and cooking off grid, even a small propane tank seems like a better solution than adding and using battery capacity.

AnOldUR · April 6

rfuss928 said:

IMO, for heating and cooking off grid, even a small propane tank seems like a better solution than adding and using battery capacity.

Probably depends on your setup and overall battery use. If solar is recharging your batteries on a daily basis, electric is the most efficient use or resources.

pthomas745 · April 6

@boathealer is the owner with this 1200 amp hour battery setup. This may be...the largest amp hour capacity in any of the Tabs...ever. The propane setup in this trailer has been removed. They also worked things so the trailer can provide power to their home down in hurricane country.

4 amp hours used in this case would be (according to my calculator if I did the numbers correctly) about.003 percent of the 1200 amp hours available.

Image: https://us.v-cdn.net/5021717/uploads/editor/hc/9fx3r8a94u9x.jpg

This is the link for the mod back in February.

https://tab-rv.vanillacommunity.com/discussion/19208/home-battery-backup-mode

Slackers · April 6

Dang @boathealer !!!

swiftwave · April 6

Mornings are often cold in Northern Canada. One advantage of an electric kettle is that I don’t have to turn the ceiling fan on in order to vent the propane exhaust out of my T@B 400. The exhaust venting also effectively removes a layer of warm air from the ceiling area, thereby unpleasantly cooling the trailer before I've even enjoyed my coffee.
Battery consumption is generally overcome on travel days via alternator charging through the 7-pin connector. During Northern summertimes, daylight hours are long, so solar recharging is usually quite effective during camp days.
I’ve used an insulated stainless steel Bodum French press for decades. Simple technology that works very well.

Basil48192 · April 7

I think you guys are making this way too complicated.

Image: https://us.v-cdn.net/5021717/uploads/editor/ro/gl2yupd84vwu.jpg

valkraider · April 8

Basil48192 said:

I think you guys are making this way too complicated.

This works until the burn bans kick in mid-summer.

valkraider · April 8

Maybe a mini induction cooktop:

https://www.amazon.com/Induction-Electric-Countertop-Portable-Abangdun/dp/B0C1YHLMLD

And an induction friendly coffee maker

https://www.amazon.com/Bialetti-Stainless-Induction-Capable-Stovetop-Espresso/dp/B07ZKZXM4B

AnOldUR · April 8

Well, I took the bait and used some rewards points on Amazon to buy cheap electric kettle. It's 600W and 110V. I gave it a test run in our T@B. With just the inverter on (along with parasitic draw) there is was a 1.25 amp load reading on our shunt. With the kettle heating it went to 60.5 amps. It took almost six minutes to bring the .8 liters to a boil and the shunt showed 6Ah consumed. With the 200Ah of battery we have, I consider this a practical use. Thanks for the idea @boathealer.
.
https://www.amazon.com/dp/B0BCPZJ3CW?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1

Image: https://us.v-cdn.net/5021717/uploads/editor/eq/kjrbhmnh90sx.jpg

bubbazanetti · April 9

I bought one too! $29 cdn !

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