inverter doesn't like my coffee maker

[birdhouse]

hello-

last weekend i was at my ranch, and finally purchsed a standard issue cheap coffee maker to get away from burning propane via a perculator. 

plugged in the coffee maker (900w on label) and the inverter tripped.  the inverter is a xantrex prosine 1800w with surge of i think 2800w on a 24v bank.  bank voltage never dropped below 24.8 while coffee maker was on. 

so, i turned off the stereo and coffee maker, reset the inverter, then turned back on just the coffee maker.  no other loads on the inverter.  it finished the pot. 

so the next morning, NO other loads on the inverter, and it tripped out about three quarters the way through the brewing. 

what gives?  later the same day, i had my pancake 2.0hp air compressor running, and without thinking, i cut a 2x6 with my 10" hitachi chop saw (1520w) and even both of them running in tandem didn't trip out my inverter, yet a 900w coffe maker will?? 

i'm very confused!

adam

[tomw]

Adam;

Maybe the long extension cord trick will work?

Some loads are funny on start up but it sounds like your issue is different since it runs awhile before it kicks out.

I would suggest all the "regular" stuff to check like good, solid connections on all the battery connections. Check the drop across the battery to inverter cables to be sure you are not losing power in the cabling. I am not familiar with how new coffee machines work but if it has some kind of switching power supply feeding the heater it could draw huge spikes.

Might check the actual load of the maker with a watts up or other method as it is running. Maybe check it on a grid or generator supply so it doesn't lose the data when the inverter resets. If possible. Could even be a faulty machine that would work fine on the grid but overloads the inverter?
The only thing that is going to help much is some logical testing. One of my 32" CRT televisions makes my Outback beep an overload error when it switches on and the degaussing coil activates. It keeps running but apparently that load is huge for a short time and it literally pegs the 150 amp ammeter on the battery to inverter cable which indicates a 3600 watt load on a 2500 watt inverter or nearly 1.5X its rating.

Good luck with it.

Tom

[birdhouse]

tom-
i didn't have any time to put meters on things while i was up there.  too busy building another deck with RE.  i'll post about that tonight. 

the inverter is connected to the bank with 3/0 copper with anti-ox and solid copper connectors (6') and has a 150 a fuse that has never blown.  the AC side of things is all #10 hard wired to the inverter and branches off to various locations.  the coffee maker was plugged into an outlet ~110' from the inverter (still #10), and on a 15' #14 extension cord. 

i'm guessing my air compressor draws ~800w min.  while running, and my chopsaw, which doesn't have a soft start feature draws WELL over 1200w when your first pull the trigger.  (induction motor)...  and my inverter did that just fine, so, i'm guessing there aren't issues with the wiring connections. 

I am not familiar with how new coffee machines work but if it has some kind of switching power supply feeding the heater it could draw huge spikes.

i think this might be the case.  either that, or my wiring is too stout, and maybe the coffee machine on a 100' #16 cord would do it??  i've read about putting capacitors across the AC hot and neutral, much like a motor start capacitor.  is it actually that simple, given the correctly sized/rated capacitor is used?   

i'd be more than willing to drop $150 on capacitors if that might solve these finnicky issues.  i just don't know how to find and or install them.  (help!)

i'm already thinking about getting an outback 3500 vented jobby, but even then, the same capacitor rig could be used with the new inverter. 


thanks for any info!

adam

[bj]

  Wondering if the Prosine has fault protection?  Maybe it's not draw but fault?  Does seem odd that
you can load it up even more with no problems.  Probably off base, good luck with it.

[birdhouse]

Wondering if the Prosine has fault protection?

there probably should be some GFCI's in place, but there aren't. not even breakers on the AC output.  just hardwired straight to the inverter. 

heck, that inverter will even run my miller-matic 135 MIG welder if the dials on the welder aren't cranked.   

adam

[ksouers]

Adam,
It almost sounds like a problem with the coffee maker. Any chance you can try a different one?


Kevin

[David HK]

Inverter related but not coffee machine.

A few weeks ago an acquaintance locked his keys in his car. After trying many other methods the decision was taken to drill out the lock on the rear door.

I produced one Hilti drill, one inverter and a 12 volt battery. It all worked as required except that the adjustable speed Hilti drill had to have the switch handle pulled on to full power before the inverter was turned on.

The inverter does not like adjustable speed equipment, but was quite happy powering the drill. The rear door eventually opened in the usual way.

David in HK

[birdhouse]

The inverter does not like adjustable speed equipment, but was quite happy powering the drill.

that makes me think.  also, the inverter has been sitting doing nothing all night, then a 900w load put on it all a sudden.  does an inverter like to be warmed up first?  seems counter intuitive to me as the cooler the inverter is,  the better it could perform??? 

i've read similar things to what you've stated.  maybe a few 100w light bulbs running first and left on while the coffee maker brews might do it??  seems stupid, but might work?? 

seems inverters don't like to be ramped up too quickly??  but if they're already working they handle it fine?? 

my inverter will start all sorts of thing in the early AM when it has sit hour hours at idle, i reallly don't get why it has a fit with the coffee maker! 

oz, or ross, where are you to explain this to me, and to explain how to use caps to lessen this issue!!!!!     just joking, but i'd love your input!

adam

[Rover]

Do you have just an all cheapo Hot Plate.. (single burner /coil).. see how that behaves.

Just a thought.

Rover

[birdhouse]

its a standard cheap $25 12 cup coffee machine made by "mr coffee"...

[97fishmt]

Huh...

I have the same set up.  24 volt 1800 watt prosine and mr. coffee maker and it works just fine.
Maybe its the long wire run?  The inverter puts out clean power so it must be after it.  Or maybe
just low on power first thing in the morning. 

I placed some solar panels facing more to the east just for getting the morning sun to charge faster
for coffee in the morning.

I put a motor start cap across the input terminals on a heart inverter once, it wasn't charging.
The tech guys there sold me one for $25.  It worked but the real issue was turning up the throttle
of the genny to get the volts and frequency more in the ball park for the inverter.

I'm sure it's not the inverter.  All the weird tricks were for modified sine wave inverters.  Unless your
dealing with noise or reception problems then some of those old techniques help.

Good luck with it.

Mike

[rossw]

oz, or ross, where are you to explain this to me, and to explain how to use caps to lessen this issue!!!!!     just joking, but i'd love your input!

A decent capacitor right across the DC INPUT lines will help provide some of the extra surge current the inverter needs to deliver high output bursts.

Most decent inverters operate at very high frequencies internally, and to them even one AC cycle is a "long time". As you say, the longer they're running the hotter they get, which is generally a bad thing. (unless it's stupid cold of course!)

Capacitors on the AC side won't do anything to help with peak loads directly - however if your peak load is a largely inductive load (like a motor), then a correctly-sized capacitor on the AC side may help correct the power-factor sufficiently that the inverter will manage the starting current. This won't be the case with your coffee pot, I'm sure.

[David HK]

The following is an extract from my inverter instructions:-


Current Draw of Equipment

Most electrical tools, appliances and audio/video equipment have a label indicating the power consumption in amps or watts. Check to ensure that the power consumption of the item you will be using at 230 Vac is below 1.43 Amps for the INV33O.

Resistive loads are easiest (or the Inverter to drive, through larger resistive loads such as heaters and cookers would require more wattage than is available from these inverters,
Inductive loads, such as TV’s and stereos (devices with a coil or a transformer in it) may require more current to operate than a resistive load of the same wattage reading.

Televisions may require several times their wattage reading to ‘start up’.

This condition may require repeated ON/OFF switching of the inverter in order to get them started.
 
Experimentation is the only means of determining whether the inverter can handle the surges required to start up a particular load.

NOTE: The inverter will not operate mug appliances designed to produce heat, such as hair dryers, irons, heaters etc. The current draw of these items is beyond the capacity of this unit.

My be of some help or interest.

David in HK

[kensue49]

Take the coffee maker back and ask for a replacement.
It maybe that unit has a poor electrical connection.
That would be worth a try.

[ChrisOlson]

Are you sure the inverter is shutting down/tripping from overload or ground fault?  Really sounds to me like something is funky in the coffee maker causing a ground fault shutdown.  If you have a generator handy quick wire up a GFCI outlet and plug that coffee maker into it and see if it trips the GFCI.  Doing it with the inverter won't work because the ProSine has built-in GFCI protection via auto-shutdown if it detects a fault.

I'll bet a crisp new dollar bill it kicks out the GFCI outlet on the generator, and the problem is in the heating coil that heats the water for brewing.

We've had a couple of those cheap coffee makers go up in smoke with a POP SIZZLE FIZZ, then the breaker kicks out, because that brewing heating element got a short in it.

Edit: I just went out to the shop to see what brand the last one was that blew up.  It's a Mr. Coffee 12 cup with computers in it.  I saved it to steal the hot plate out of it because that's still good.  My wife went to several different stores looking for a coffee maker that don't have computers in it.  They all told her that they all got computers now.  But she found a Sunbeam one at Farm & Fleet that just has a on/off switch and no computers.
--
Chris