Inverter question when boondocking

[Stan Simpson]

I tried the search function here, and didn't get a hit, so here is my dumb question for today.  :-/

We are on our third straight day of boondocking (practicing for the pre-rally at Redmond) so today when I got up...started the generator and made coffee. Becky sleeps a couple hours longer than me, so I'm wondering if I can run the inverter while the generator is also running. My purpose is to shut off the generator once the coffee is done but still have the inverter on so it will take over keeping the coffee hot. I know we could just nuke the coffee later, but I'd rather the coffee pot do its job. Or will having the inverter on without the generator allow me to make coffee? I watched the Aladdin and the coffee pot was drawing 10 amps (nothing else except a couple of laptops plugged in to 120).

Safe travels all,

Stan

[Larry Williams]

I tried the search function here, and didn't get a hit, so here is my dumb question for today.  :-/

We are on our third straight day of boondocking (practicing for the pre-rally at Redmond) so today when I got up...started the generator and made coffee. Becky sleeps a couple hours longer than me, so I'm wondering if I can run the inverter while the generator is also running. My purpose is to shut off the generator once the coffee is done but still have the inverter on so it will take over keeping the coffee hot. I know we could just nuke the coffee later, but I'd rather the coffee pot do its job. Or will having the inverter on without the generator allow me to make coffee? I watched the Aladdin and the coffee pot was drawing 10 amps (nothing else except a couple of laptops plugged in to 120).

Safe travels all,

Stan

You could have made the coffee with just the inverter. But if really boondocking you would want to use the generator since the coffee maker drains the battery. On the other hand if you are near people and you don't want to run the generator in the morning, the inverter works fine. The generator would recharge it later when you run it.

[Edward Buker]

Stan,

It would seem that you would run the generator without the inverter for a bit while the coffee is being made given that would cover the AC load using the generator and be adding charge to the batteries. When you shut the generator down then go to invert mode and let the hot plate work. Now 10 amps at 120V is 1200watts. 1200 watts at 12V is using 100amps from your house battery bank to handle that load. Heating loads are pretty heavy so whatever you see in amps on your AC panel multiply by 10 to approximate the DC load coming from your battery. A thermos carafe would probably serve you well here given this load while boon docking.

If it takes 5 - 10 minutes to make the coffee using the inverter, that is just fine but probably wise to shut off the hot plate after and save the long term load. Your wife will like the quiet...

Later Ed

[Stan Simpson]

Stan,
When you shut the generator down then go to invert mode and let the hot plate work.

Later Ed

Thank you Larry & Ed. The reason I wanted to have them both running while making the coffee is this:

If I shut down the generator and then go to invert mode, the coffee pot shuts off momentarily. Turning it back on will only cause it to attempt to brew more coffee. I thought if it never went off...the hot plate would still be functional after the brewing was done. Does that make sense?

Safe travels all,

Stan

[Joel Ashley]

Yes, I know what you mean, Stan.  You are trying to maintain power during the switchover so the pot's circuitry doesn't reset.  

But I often turn my pot on with no water added to its tank to reheat coffee if the automatic warmer gets shut off too early.  It soon figures out there's no water and goes to warm mode.  So I would either not fret about it, make the coffee with the inverter in the first place, or take Ed's advice re. a thermos, although I've never known one that kept things hot all that long unless full the entire time, and that wouldn't happen if you pour cups regularly.

To the base of the issue, I'm not really sure if having the inverter switched on with the genset running is doable or not.  I'd have to give that some extensive thought, but would guess the inverter wouldn't actually start except after it sensed the lack of other AC, so there'd be a delay regardless.  Our more electrically-inclined guys probably know for sure.

When I get up on boondock mornings I run the genset for a couple hours to get the Magnum panel to read "Float" or at least well into "Absorb" to cover the day to come.  Thereafter we may use the thermos method and/or we do the invert just briefly as needed to microwave-reheat cups thereafter.

Joel

[Edward Buker]

Stan,

To be honest I do not know how the heat cycles in a coffee maker work if you have not put water in. You would have to try it and watch the AC current monitor in the coach. You could simulate a momentary shut down of power using the plug being pulled for a second or two after it brewed and see if the current goes up when you plug back in beyond what the hot plate draws.

If you are charging I believe that you are using the circuitry that does inverting to charge and invert is not available. It will just go into standby which makes sense, one or the other but not both functions. The unit passes the AC through rather then generate it from DC when AC is available from the campsite or genset.

Thermos type carafes work well if you run hot water in them from the Aquahot or whatever you have for hot water before you put the hot coffee in.

Later Ed

[Stan Simpson]

Thanks Joel and Ed. I tested it, and it will still run the hot plate as long as the water is gone. So its a moot point. I will just make coffee with the inverter from now on.


Safe travels all,

Stan

[Gerald Farris]

Stan,
If you decide to start running your coffee pot through the inverter every morning, you should be careful not to run your house batteries below the 11.9 to 12 volt range. Discharging your house batteries to a lower state of charge than that will significantly reduce their life expectancy. Remember that a coffee pot can be a power hog.

Gerald

[Edward Buker]

Stan,

Remember whatever the AC load in amps, you have to multiply by 10 to get the DC amps that has to be supplied to the inverter to handle the AC load and that is a conservative estimate. If you make the coffee with the inverter I would shut off the hot plate right after to conserve your battery bank as Gerald is eluding to. After you shut the coffee pot off give the batteries a minute or two and see where the battery voltage settles out. If  they are getting to the voltage range Gerald is concerned about then the genset might be in order. The battery voltage state will tell you if the coffee making using the inverter is working out.

Later Ed

[Larry Williams]

Gerald/Edward,

A related question about the inverter/charger. Even though you are connected to shore power you can turn on the inverter and it says it is inverting (the light is on and blinking). But I know it has a sensor/transfer switch that does not provide inverter power to loads unless the shore power/generator is disconnected. In fact the inverter/charger is actually in the battery charge mode when AC power is connected even if the control panel says it is inverting. I assume that the panel really means it is in inverter standby mode. Am I interpreting that correctly?

Larry

[Edward Buker]

I think you are right, just stand by mode rather than invert. I have had several inverter chargers in RVs but not a newer Magnum. You could have an electrical design with the inverter available as an option with external AC available but it seems like that may be an unlikely design option. I am giving you my current experience with the inverter chargers that I have owned. Not to say one might come along with that capability, the manual should spell that out.

Later Ed

[LarryNCarolynShirk]

Consider having external AC connected and the inverter is left on.  If there is a power failure at the pole, the inverter will take over and run on batteries until they are depleted.  If you leave the inverter off while plugged in to AC, you will know when there is an AC power failure, before your batteries are dead.

Larry

[Joel Ashley]

My notion was that perhaps there is no delay involved if Stan made his coffee while inverted (no Stan, please don't stand on your head to make your morning cup of Joe!   ), so as soon as the pot goes to warm mode he could turn on his genset.  The reverse is a problem because of the built-in delay until the inverter senses a lack of AC.

And for years we've skipped the problem altogether when boondocking by using a Melitta filter similar to Bill's, but that fits a 32oz vacuum dispenser.  It's only problem is how slow it filters, and it doesn't hold the heat as well if you pour out 2 cups (half the jug) right off the bat.  A cup at a time isn't as handy as having pre-made coffee on hand, and goes through more filters, but disposes of the heat retention issue.  The trick is to bring water up to just short of its boiling point which is 212 degrees, or boil it and let it cool a couple of minutes;  coffee officiandos say the optimum water temperature through the grounds is around 200-206 degrees.

Joel