so i can use a microwave but not brew coffee?

[Sabatical]

I've read several times here that folks are able to use a microwave and other high draw items on small scale solar/battery systems. Bob has stated that with a two battery setup, he has been able to use a microwave daily for years. I don't want to use a microwave but I do want to brew coffee and the wattage of a small auto drip is similar to a microwave (mine is 600 watts), so i use it as a basis for my question.

Background...constantly searching for a better cup of coffee. We use a drip pot at home but struggle to find something good when traveling. I don't want to rehash the debate on what's a good cup of coffee in this thread but rather the possibility of using an electric pot.

We have a 12v two battery setup equaling 225ah. Solar input is 260w and charging happens with a Midnite Kid charge controller. A/C devices run through a 1000w modified sine wave inverter.

The other day I plugged the pot in to try and brew some coffee and it didn't go well. Something was tripping and resetting but i decided to let it run it's course. Maybe not smart but curiosity was running the show. The whole brew time was less than 10 minutes and after the first couple it stopped tripping, that is until system voltage dropped below the 11.5 threshold of the inverter. I checked amp draw and it is just over the pots rating of 600w.

So anybody have any ideas? Is it my modified sine wave inverter? Is it something to do with the resistive load of the coffee pot? Some other factor i'm not considering? I am not super knowledgeable on these things, but i am trying to educate myself. I have been trying to learn about the use of capacitors and whether incorporating them into the system will help handle the surge of draw of something like a coffee pot.

All input is appreciated,
Scott

 

[Sabatical]

...also at the time of the experiment, the system was in float with no direct sun on the solar panel.

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[wagoneer]

First thing I do when the sun is rising drink a glass of water get outside and stretch go to the galley get my hand crank coffee grinder and get some exercise breathing in and out. Grind up some Petes fresh coffee put some wood in the rocket stove fire it up and marvel at my accomplishments. To go the extra mile I will roast my own coffee as green coffee has a shelf life of 10 years.

 

[wagoneer]

better

 

[Trebor English]

The coffee maker is resistive so there is no start up surge like a refrigerator or microwave.  All you need is enough watts for the time it takes to run the brew cycle.  

What was tripping and resetting?  If you have a breaker between the battery and inverter it could be your guilty party.  Do you have a long wire between the battery and the inverter?  To put in a large fuse (less drop than breaker) you may need a fatter wire between the battery and the inverter.  Making that wire only 2 feet instead of 12 might make that change possible.  

If the problem is the inverter then the next size bigger would be the fix.  Theoretically a 1000 watt should work a 600 watt load.  I wouldn't rule out the possibility that it can't.  For a resistive load MSW should be fine.  If your coffee maker has no extra stuff like a clock it could work on 120 volts DC.  Sine stuff uses more power in the inverter, not what you want.  

The battery itself and the wiring to the inverter is the limit for the low voltage cut off.  Shorter fatter wire and higher rated fuse will help, then you need a bigger battery or charging between pots of coffee.

 

[Sabatical]

Thanks Adrian! We are following your lead, mostly. Using a hand crank to grind our own roasted beans.

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[slynne]

I know nothing about power but I have seen drip coffee makers that use 12v sold at Truck Stops. I wonder if one of those might work better?

 

[Trebor English]

I really like the Mr Coffee drip 4 cup.  Aeropress and cold brew don't do it for me.  The espresso pot that works on propane is ok but not what I want.  If there is a particular coffee you want you can have that.  You might need more electric stuff but it is possible.  

There is a thing where the guy at the coffee shop heats the water then uses a container with a long curved tubular spout to pour the water with great flair and flourish over the grounds.  The secret is that he pours slowly and takes the same amount of time as the Mr Coffee drip machine.  The ratio of grounds to water, water temperature, and time to brew are the variables.  The 4 cup and 12 cup use the same brew time by having fewer watts heating the 4 cup to take the same time as the 12.

 

[highdesertranger]

first off I believe Bob has four 6v batteries to run his micro. usually you only run a micro for a couple of minutes at a time, 5 minutes is a long time to nuke something.
2nd point heating anything with electricity is very inefficient. throw an inverter in the mix and more inefficient.
on the 12v side off things you need very short fat cables, your batteries need to be fully charged.
highdesertranger

 

[Weight]

I use my 4 cup Mr Coffee every morning. I have a 2000 w PSW inverter. I have lots of battery. If your inverter pulls too many amps from the battery bank, it cuts out on low voltage, then recovers. If your coffee pot pulls too many watts from the inverter, it may cut out or it may leak all it's blue smoke.

 

[jimindenver]

I was looking for a smaller auto drip but the four cups I saw used the same wattage as the 12 cup. I know they exist but I could not find one this year. I have the 12 volt autodrip, don't waste the cash.

What is the inverter? Some inverters can't hold their rated loads for long and the peak is a split second.

How long and thick is the wire to the inverter? Too long or too thin means the inverter will see less voltage than the battery is sending.

I could run my microwave off of a single large 12v 8D the size of your bank but only for a minute or two without the solar assisting. Longer requires a larger bank or a large solar system assisting.

Last thing is you can always heat the water via a stove and pour it over the grounds in the coffee maker. You could get a 12v tea kettle for heating the water too.

 

[Optimistic Paranoid]

Last thing is you can always heat the water via a stove and pour it over the grounds in the coffee maker.

That's an interesting thought.  I take it there is some kind of sensor in the Mr. Coffee that detects when the water is hot enough, which then kills the power to the electric heating element and allow the hot water to proceed?

 

[John61CT]

Whatever you experiment with, get away from using electricity to heat up or boil liquids, that's what propane is for.

If you insist otherwise, can be done but then you'll need to upsize various elements of your electric setup, basically need one that would run a fridge. If you also want to run a fridge, then upsize sone more.

Key to KISS is only "going up" when you **really** need to, learning how to "compromise" without actually losing functionality, just a little comfort.

Satisfying your wants as opposed to needs leads to a very big expensive and complicated system.

 

[Sabatical]

Inverter is a Bestek 1000w modified sine wave connected to battery bank by #6 wires approx 3' in legnth. Positive side has a breaker in line.

Voltage at batteries now is 13.62 (float). Voltage at inverter is 13.62.

Coffee pot is a 5 cup black and decker rated at 600w. It drew 5.6 amps plugged into 120 in the house so it's a bit over 600 but well under the 1000w the inverter is rated for.

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[Sabatical]

Whatever you experiment with, get away from using electricity to heat up or boil liquids, that's what propane is for.

If you insist otherwise, can be done but then you'll need to upsize various elements of your electric setup, basically need one that would run a fridge. If you also want to run a fridge, then upsize sone more.

Key to KISS is only "going up" when you **really** need to, learning how to "compromise" without actually losing functionality, just a little comfort.

Satisfying your wants as opposed to needs leads to a very big expensive and complicated system.

The goal here John was to use what we have to reduce overhead. If we have enough stored electricity then i would rather use it than propane which we have to buy and haul.

Coffee is something we enjoy and don't plan to give up. Some "wants" are just like that. We continue to try to find ways to streamline our setup while maintaining quality and enjoyment. When the gas fridge craps out, i will be going to electric and adding two more batteries. Not only because it's cost effective, but also because that power storage can supply many different things.

I could be happy with doing what Adrian does and use a rocket stove to brew fresh ground and roasted coffee in a eapresso pot, but i'm not alone in this journey. I've been at this long enough to know which areas there are compromise and which there aren't, if you get my drift.

Thanks for your input[TEACUP WITHOUT HANDLE]

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[Sabatical]

That's an interesting thought.  I take it there is some kind of sensor in the Mr. Coffee that detects when the water is hot enough, which then kills the power to the electric heating element and allow the hot water to proceed?

When the brew was done the amp draw went to zero. I was surprised by that. Apparently the warming plate is smart!

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[Trebor English]

It's just a thermostat.  The water flow keeps the warming plate less than boiling.  After the water runs out it gets hot enough to shut off the thermostat.  It cycles on and off keeping the coffee too hot making it taste terrible in short order.

 

[John61CT]

The goal here John was to use what we have to reduce overhead. If we have enough stored electricity then i would rather use it than propane which we have to buy and haul.

Yes of course I was assuming you already carry propane, my bad.

And God forbid anyone think I meant to give up coffee [HOT BEVERAGE]

But both French press and drip funnels really are superior in taste to a Mr Coffee, according to many aficionados I know, and neither requires electricity.

True, excess solar if you really do have it, is a great thing, especially if the load demand coincides with the afternoon after the bank charge amps have started dropping way down.

Heating water is a great load dump, as is making ice, if you have the room to spare.

 

[SternWake]

MSW inverters are known for causing clocks to not work properly. Same thing for a timer. Perhaps the MSW is screwing up the electric drip's timer causing it to restart. A possibility anyway

As others said it sounds like you could also be suffering a lot of voltage drop on the cabling and the low voltage alarm on inverter is kicking in.

When you present this rather large load on the batteries, I would recopmmend putting a voltmeter on the Inverters DC lugs, and also testing for heat on the inverter lugs and any terminations on the inverter's DC circuit. The thumbscrews holding 2awg cable to the inverter lugs can easily loosen up an cause even more heating and voltage drop

Your Pic shows one of those plastic covered crimps. My Friends class C rig used those terminals as the battery connections. They were an absolutley horrid electrical connection, likely when new, and much much worse after a few years in the presence of battery fumes. I cut off the offending crimps and hydraulically crimped on closed end lugs for the Win.

Most electrical issues are connection related. With thick wires it is usually the ring terminals their crimps and how they are mounted/ held in place. Big electrical loads cause wires and ring terminals to heat and expand. When they cool that connection can be compromised, allow oxidation to set in where it should not, increasing resistance, increasing heating the next time.

I use a '7 cup' bialetti Moka pot over a single burner stove for coffee using regular ground coffee, not espresso. Others either love my coffee, or hate it. Often when given a cup of coffee from an electric drip machine I am really liking it. I am no aficionado though, I just want the caffeine, and only in the morning, and the Moka pot can be packed tight with grounds, and the coffee barely changes color when I pour in the fat free milk.

Sometimes i use the Moka pot to make tea, I empty a bag of earl grey into it. A little milk and honey, and all I need are some ginger snap cookies.

 

[Sabatical]

I could easily switch the lugs to something like the copper ones from tractor supply.

Upping the wire size from 6 to 2 would be a possibilty.

I keep thinking back to when i was running a sharpening business out of a van. I had two optima d31s and i beat the snot out of them and although the batteries only lasted three years before run time dropped off too much, i could always start the load. My clipper hone had a 1" thick 16" diameter aluminum plate to spin up. It drew 40 amps ac for several seconds. So i look at this little coffee pot and wonder why it is being a pain.

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